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Title: The Boy's Book of New Inventions
Author: Maule, Harry E.
Language: English
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Copyright Status: Not copyrighted in the United States. If you live elsewhere check the laws of your country before downloading this ebook. See comments about copyright issues at end of book.

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Transcriber's note:
    Italic text has been marked with _underscores_. Subscript numbers
    are displayed as _{2} as in the equation in Chapter VII.  Please
    see the end of this book for further notes.



  [Illustration: WILBUR WRIGHT

  Who with his younger brother, Orville Wright, invented the first
  practical aeroplane. Wilbur Wright's death of typhoid fever in
  the summer of 1912 was an irreparable loss to aviation.]



    THE BOY'S BOOK
    OF NEW INVENTIONS

    BY
    HARRY E. MAULE

  [Illustration]

    MANY ILLUSTRATIONS

    GARDEN CITY      NEW YORK
    DOUBLEDAY, PAGE & COMPANY
    1912



    _Copyright, 1912, by_
    DOUBLEDAY, PAGE & COMPANY


    _All rights reserved including that of
    translation into foreign languages,
    including the Scandinavian_



TO MY MOTHER

In Appreciation of Her Broad Interest In All the Activities of the
World



_ACKNOWLEDGMENTS_

_The thanks of the publishers and author are due a great many
individuals and publications for aid in securing photographs and data
used in the preparation of this volume._

_Although space prevents giving the names of all, opportunity is here
taken to express to each the heartiest appreciation of their generous
help and valuable suggestions._

_More than to all of these are my thanks due my wife, Edna O'Dell
Maule, for her constant aid and coöperation._



PREFACE


In the preparation of this book the author has tried to give an
interesting account of the invention and workings of a few of the
machines and mechanical processes that are making the history of our
time more wonderful and more dramatic than that of any other age
since the world began. For heroic devotion to science in the face of
danger and the scorn of their fellowmen, there is no class who have
made a better record than inventors. Most inventions, too, are far
more than scientific calculation, and it is the human story of the
various factors in this great age of invention that is here set forth
for boy readers.

New discoveries, or new applications of forces known to exist,
illustrating some broad principle of science, have been the chief
concern of the author in choosing the subjects to be taken up in the
various chapters, so that it has been necessary to limit the scope
of the book, except in one or two instances, to inventions that have
come into general use within the last ten years. In "The Boy's Book
of Inventions," "The Second Boy's Book of Inventions," and "Stories
of Invention," Mr. Baker and Mr. Doubleday have told the stories
of many of the greatest inventions up to 1904, including those of
the gasoline motor, the wireless telegraph, the dirigible balloon,
photography, the phonograph, submarine boats, etc. Consequently for
the most part the important developments in some of these machines
are treated briefly in the final chapters, while the earlier chapters
are devoted to new inventions, which, if made before 1904, did not
receive general notice until after that time.

Although the subjects treated in the earlier chapters are here spoken
of as new inventions, all of them are not recent in the strictest
sense of the word, for men had been working on the central idea of
some of them for many years before they actually were developed to a
stage where they could be patented and sent out into the world.

    H. E. M.



CONTENTS


    CHAPTER                                           PAGE

    I. THE AEROPLANE                                     3
    How a Scientist Who Liked Boys and a Boy Who
    Liked Science Followed the Fascinating Story of
    the Invention of the Aeroplane.

    II. AEROPLANE DEVELOPMENT                           49
    How the Inventors Carried On the Art of Aviation
    Until It Became the Greatest of All Sports
    and Then a Great Industry.

    III. AEROPLANES TO-DAY                              91
    Our Boy Friend and the Scientist Look Over
    Modern Aeroplanes and Find Great Improvements
    Over Those of a Few Years Ago. A
    Model Aeroplane.

    IV. ARTIFICIAL LIGHTNING MADE AND HARNESSED
    TO MAN'S USE       129
    Our Friends Investigate Nikola Tesla's Invention
    for the Wireless Transmission of Power, by
    Which He Hopes to Encircle the Earth With
    Limitless Electrical Power, Make Ocean and Air
    Travel Absolutely Safe, and Revolutionize Land
    Traffic.

    V. THE MOTION PICTURE MACHINE                      164
    Machines That Make Sixteen Tiny Pictures Per
    Second and Show Them at the Same Rate Magnified
    Several Thousand Times. Motion Pictures
    in School. Our Boy Friend Sees the
    Whole Process of Making a Motion Picture Play.

    VI. ADVENTURES WITH MOTION PICTURES                195
    Perilous and Exciting Times in Obtaining Motion
    Pictures. How the Machine Came to Be Invented
    and the Newest Developments in Cinematography.

    VII. STEEL BOILED LIKE WATER AND CUT LIKE
    PAPER                                              224
    Our Boy Friend Sees How Science Has Turned
    the Greatest Known Heats to the Everyday Use
    of Mankind.

    VIII. THE TESLA TURBINE                            263
    Dr. Nikola Tesla Tells of His New Steam Turbine
    Engine, a Model of Which, the Size of a
    Derby Hat, Develops More Than 110 Horse
    Power.

    IX. THE ROMANCE OF CONCRETE                        288
    The One Piece House of Thomas A. Edison and
    Other Uses of the Newest and Yet the Oldest
    Building Material of Civilized Peoples, Seen By
    the Boy and His Scientific Friend.

    X. THE LATEST AUTOMOBILE ENGINE                    320
    Our Boy Friend and the Scientist Look Over the
    Field of Gasoline Engines and See Some Big
    Improvements Over Those of a Few Years Ago.

    XI. THE WIRELESS TELEGRAPH UP TO THE MINUTE        332
    The Scientist Talks of Amateur Wireless Operators.
    The Great Development of Wireless That
    Has Enabled It to Save Three Thousand Lives.
    Long Distance Work of the Modern Instruments.

    XII. MORE MARVELS OF SCIENCE                       352
    Color Photography, the Tungsten Electric Lamp,
    the Pulmotor, and Other New Inventions Investigated
    by Our Boy Friend.



LIST OF ILLUSTRATIONS


    Wilbur Wright                                  _Frontispiece_

                                                      FACING PAGE

    The First Wright Aeroplane                                  4

    The First Wright Glider                                     5

    The Second Wright Glider                                    5

    A Long Glide                                                5

    Motor of the Wright Biplane                                12

    A 16-Cylinder, 100-Horsepower Antoinette Motor             12

    An 8-Cylinder, 50-Horsepower Curtiss Motor                 12

    Standard Gnome Aeroplane Motor                             13

    A 14-Cylinder, 100-Horsepower Gnome Motor                  13

    Testing a Gnome Motor on a Gun Carriage                    13

    Model Aeroplane Fliers                                     16

    A Modern College Man's Glider                              17

    Otto Lilienthal Making a Flight in His Glider              17

    The Chanute Type Glider                                    32

    The Herring Glider                                         32

    An Early Helicopter                                        32

    Prof. Samuel Pierpont Langley                              33

    Sir Hiram Maxim                                            33

    Octave Chanute                                             33

    Langley's Steam Model                                      36

    The Maxim Aeroplane                                        36

    Medals Won by the Wright Brothers                          37

    The First Santos-Dumont Aeroplane                          44

    The Cross-Channel Type Blériot Monoplane                   44

    A Voisin Biplane                                           44

    Glenn Curtiss About to Make a Flight                       45

    Henri Farman Starting Aloft with Two Passengers            45

    Louis Blériot                                              45

    Glenn Curtiss Making a Flight in the _June Bug_            52

    Orville Wright Making a Flight at Fort Myer                52

    The First Letter Ever Written Aboard an Aeroplane
      in Flight                                                53

    The Goddess of Liberty                                     60

    First Actual War Expedition of an Aeroplane                61

    War Manoeuvres                                             61

    Harry N. Atwood Arriving at Chicago                        64

    Finish of Atwood's St. Louis to New York Flight            64

    Starting with the Aeroplane Mail                           65

    Chavez on His Fatal Flight Across the Alps                 80

    The Late Calbraith P. Rodgers, Trans-Continental
      Flier                                                    81

    The World's Longest Glide                                  96

    The End of a Glide                                         96

    Landing on a Warship                                       97

    Boarding a Battleship                                      97

    The Curtiss Flying Boat                                   112

    The Flying Boat Starting                                  112

    Glenn Curtiss Allowing His Hydro-Aeroplane to
      Float on the Water After Alighting                      112

    Hydro-Aeroplanes at Monte Carlo                           113

    The Wright Biplane                                        116

    Standard Curtiss Biplane                                  117

    Curtiss Steering Gear                                     117

    Standard Farman Biplane                                   120

    Farman with Enclosed Nose                                 120

    A Modern Blériot                                          121

    A Standard Blériot                                        121

    Passenger-Carrying Blériot                                121

    The Antoinette Monoplane                                  124

    The Nieuport Monoplane                                    125

    Like a Bolt of Lightning                                  136

    Dr. Nikola Tesla                                          137

    Doctor Tesla's First Power Plant                          137

    Electricity Enough to Kill an Army                        164

    A Battle Scene in the Studio                              165

    The Men Who Gave the World Motion Pictures                172

    The Motion-Picture Projector                              173

    A Section of Motion-Picture Film                          176

    Making a Motion-Picture Play in the Studio                177

    A Motion-Picture Studio                                   192

    A Realistic Film of Washington Crossing the Delaware      193

    The Corsican Brothers--A Famous Trick Film                200

    The Guillotine                                            201

    A Romance of the Ice Fields                               216

    The Spanish Cavalier                                      216

    All Ready for a Thermit Weld                              217

    Thermit in Eruption                                       224

    Dr. Hans Goldschmidt                                      225

    Thermit Weld on Sternframe of a Steamship                 240

    A Large Shaft Welded by the Thermit Process               240

    Cutting Up the Old Battleship _Maine_                     241

    Cutting Away the Decks                                    241

    An Oxy-Acetylene Gas Torch Weld                           260

    Tiny 200-Horsepower Turbine                               261

    The Tesla Turbine Pump                                    261

    The Marvellous Tesla Turbine                              280

    Thomas A. Edison and His Concrete Furniture               281

    Model of Edison Poured Concrete House                     281

    What One Set of Boys Did with Concrete                    288

    Massive Concrete Work                                     289

    A Level Stretch of Catskill Aqueduct                      289

    Huge Concrete Moulds at Panama                            304

    Concrete Locks on the Panama Canal                        305

    The World-Wide Use of Concrete                            308

    The Catskill Aqueduct                                     309

    The Aqueduct Deep Under Ground                            309

    The Silent Knight Motor                                   316

    A Portable Army Wireless Outfit                           317

    The Wireless in the Navy                                  317

    The Navy Wireless School                                  344

    An Amateur Wireless Outfit                                345



LIST OF DIAGRAMS

    A Simple Model Aeroplane               120

    Diagram of the Earth                   147

    A Motion-picture Camera                177

    A Motion-picture Printing Machine      184

    Diagram of the Tesla Turbine           275

    The Curtiss Turbine                    285

    Marconi Transmitter Layout             342

    Marconi Detector Layout                344

    The Pulmotor                           372



THE BOY'S BOOK OF NEW INVENTIONS



CHAPTER I

THE AEROPLANE

   HOW A SCIENTIST WHO LIKED BOYS AND A BOY WHO LIKED SCIENCE
   FOLLOWED THE FASCINATING STORY OF THE INVENTION OF THE AEROPLANE.


When, with engine throbbing, propellers whirling, and every wire
vibrating, the first successful aeroplane shot forward into the teeth
of a biting December gale and sailed steadily over the bleak North
Carolina sand dunes for twelve seconds, the third great epoch in the
age of invention finally was ushered in. First, man conquered the
land with locomotive, electricity, steam plow, telegraph, telephone,
wireless and a thousand other inventions. Almost at the same time he
conquered the ocean with steamship, cable, and wireless. Now, through
the invention of the aeroplane, he is making a universal highway of
the air.

Such was the way the real beginning of aviation was summarized one
day to a bright young man who spent all his spare time out of school
at the laboratory of his good friend the scientist. Always in good
humour, and with a world of knowledge of things that delight a
boy's heart, the man was never too deep in experiments to answer any
questions about the great inventions that have made this world of
ours such a very interesting place.

The laboratory was filled with models of machines, queer devices
for scientific experiment, a litter of delicate tools, shelves of
test tubes, bottles filled with strange smelling fluids, and rows
upon rows of books that looked dull enough, but which the scientist
explained to the boy contained some of the most fascinating stories
ever told by man.

Coming back to aeroplanes the boy said, "But my father says that
aviation is so new it is still very imperfect."

"That is true," answered the scientist, taking a crucible out of the
flame of his Bunsen burner and hanging it in the rack to cool, "but
it has seen a marvellous development in the last few years.

"It was less than ten years ago--the end of 1903, to be exact--that
Orville and Wilbur Wright first sailed their power-driven aeroplane,"
he continued, "but so rapid has been the progress of aviation that
nowadays we are not surprised when a flight from the Atlantic to the
Pacific is accomplished. It seems a tragic thing that Wilbur Wright
should have been called by death, as he was in May, 1912, by typhoid
fever, for he was at the very zenith of his success and probably
would have carried on his work to a far, far greater development."

  [Illustration: THE FIRST WRIGHT AEROPLANE

  This was the machine that made the first successful flight in the
  history of the world, of a power-driven, man-carrying aeroplane.]

  [Illustration: THE FIRST WRIGHT GLIDER

  This device was first flown as a kite without a pilot, and the
  levers worked by ropes from the ground, to test the principles.]

  [Illustration: THE SECOND WRIGHT GLIDER

  The machine was launched into the air from the top of a sand dune
  against a high wind, and proved a great success.]

  [Illustration: A LONG GLIDE

  Wright glider in full flight over Kill Devil Hill, N. C.]

After a little pause the scientist continued, saying that, at
the time the Wright brothers made their first flight they were
experimenting with what we now know as a biplane, or Chanute type
glider, at Kill Devil Hill, near Kitty Hawk, N. C. It is a desolate
wind-swept spot on the coast where only a little rank marsh grass
grows on the sheltered sides of the great sand dunes. The brothers
chose this barren place for their experiments because here the winds
were the most favourable for their purpose.

They were not ready for their first attempt to fly in a
motor-propelled machine until December 17th, and though they sent out
a general invitation to the few people living in that section, only
five braved the cold wind. Three of these were life savers from the
Kill Devil Hill station near by. Doubtless the other people had heard
of the numerous failures of flying machines and expected the promised
exhibition of the silent young men who had spent the autumn in their
neighbourhood, to be just another such. They were sadly mistaken,
for they missed a spectacle that never before had been seen in all
the history of the world. Nowadays we are familiar with the sight of
an aeroplane skimming over the ground and then soaring into the sky,
but to the five people who, besides the inventors, were present it
undoubtedly was almost beyond belief.

The brothers had installed a specially constructed gasoline engine
in their glider, and after thoroughly testing it they carried the
machine out on to a level stretch of sand, turned it so that it
would face the wind, and while the life savers held it in place the
brothers went over every wire and stay. They felt perfectly confident
that the machine would fly, but they made no predictions, and in fact
spoke but few words between themselves or to the five men gathered
about the aeroplane. The machine was not the smoothly finished one
we know to-day as the Wright biplane. The operator lay flat on his
face on the lower plane, the elevating rudder composed of two smaller
planes stuck out in front, instead of behind, and there were several
other important differences in design, but in principle it was the
same machine that has carried the fame of the American inventors
around the world.

Finally the operator took his place, the engine was started, the
signal was given, the men holding the machine dropped back and it
started out along the rail from which it was launched. It ran along
the track to the end, directly against the wind, and rose into the
air.

It meant that the air had been turned into a highway, but the Wright
brothers were very modest in setting down an account of their
achievement.

"The first flight," they wrote, "lasted only twelve seconds,"
a flight very modest compared with that of birds, but it was,
nevertheless, the first in the history of the world in which a
machine carrying a man had raised itself by its own power into the
air in free flight, had sailed forward on a level course without
reduction of speed, and had finally landed without being wrecked. The
second and third flights (the same day) were a little longer, and the
fourth lasted fifty-nine seconds, covering a distance of 853 feet
over the ground against a twenty-mile wind.

"After the last flight the machine was carried back to camp and set
down in what was thought to be a safe place. But a few minutes later,
when engaged in conversation about the flights, a sudden gust of wind
struck the machine and started to turn it over. All made a rush to
stop it, but we were too late. Mr. Daniels, a giant in stature and
strength, was lifted off his feet, and, falling inside between the
surfaces, was shaken about like a rattle in a box as the machine
rolled over and over. He finally fell out upon the sand with nothing
worse than painful bruises, but the damage to the machine caused a
discontinuance of experiments."

"Thus," said the scientist, "we see the record aeroplane flight for
1903 was 853 feet while in 1911 a Wright biplane flew more than 3,000
miles from the Atlantic to the Pacific. In ten years more we may
look back to our monoplanes and biplanes of to-day in the same way
we do now on the first cumbersome 'horseless carriages' that were
replaced by the high-powered automobiles we know now. Some experts
in aeronautics say that we may even see the complete passing of the
monoplane and biplane types in favour of some now unknown kind of
aeroplane."

Who knows but that the man to invent the perfect aeroplane will be
one of the boy readers of this! Everywhere the making and flying of
model aeroplanes by boys is looked upon, not only as play, but as a
valuable and instructive sport for boys and young men of any age. One
of the indications of this may be seen in the public interest taken
in the tournaments of boys' model aeroplane clubs. Not only do crowds
of grown people with no technical knowledge of aeroplanes attend the
tournaments, but also older students of aviation who realize that
among the young model fliers there may be another Orville or Wilbur
Wright, a Blériot, or a Farman.

So important is this knowledge of aviation considered that the
principles and the practical construction of model aeroplanes are
taught in many of the public schools. Instead of spending all their
school hours in the study of books, the boys now spend a part of
their time in the carpenter shop making the model aeroplanes which
they enter in the tournaments. Of course, dozens of types of models
are turned out, some good and some bad, but in the latter part of
Chapter III is given a brief outline for the construction of one of
the simplest and most practicable model aeroplanes.

Not only the schools but the colleges also have taken up aviation,
and nearly every college has its glider club, and the students work
many hours making the gliders with which they contest for distance
records with other clubs. As a consequence aviation has become a
regular department of college athletics, and intercollegiate glider
meets are a common thing.

The epochs of invention go hand in hand with the history of
civilization, for it has been largely through invention that man has
been able to progress to better methods of living. In the olden days,
when there were few towns and every one lived in a castle, or on the
land owned by the lord of the castle, war was the chief occupation,
and the little communities made practically everything they used by
hand. When they went abroad they either walked or rode horses, or
went in clumsy ships. Pretty soon men began to invent better ways of
doing things; one a better way of making shoes, another a better way
of making armour, and the people for miles around would take to going
to these men for their shoes and armour. Towns sprang up around these
expert workmen, and more inventions came, bringing more industries to
the towns. Inventions made industry bigger, and war more disastrous
because of the improvement invention made in weapons. Then came
inventions that changed the manner of living for all men--the
machines for making cloth, which did away with the spinning-wheels of
our great-grandmothers, and created the great industry of the cotton
and woollen mills; the inventions for making steel that brought about
the great steel mills, and enabled the armies of the world to use the
great guns we know to-day, and the battleships to carry such heavy
armour plate; the steam locomotive that enabled man to travel swiftly
from one city to another; the steamship that brought all the nations
close together; the telegraph, cable, telephone, and wireless, that
made communication over any distance easy; the submarine that made
war still more dangerous; and finally the aeroplane that makes a
highway of the air in which our earth revolves.

But even from the time of the ancient Greeks and Romans man had
tried to fly. Every nation had its list of martyrs who gave their
lives to the cause of aviation. In modern times, too, many attempts
had been made to discover the secret of flight. Otto Lilienthal, a
German, called the "Flying Man," had made important discoveries about
air currents while gliding through the air from hills and walls by
means of contrivances like wings fitted to his person. Others had
made fairly successful gliders, and Prof. Samuel Pierepont Langley
of the Smithsonian Institution in Washington actually had made a
model aeroplane that flew for a short distance. Also, Clement Ader,
a Frenchman, had sailed a short way in a power flier, and Sir Hiram
Maxim, the English inventor, had built a gigantic steam-driven
aeroplane that gave some evidences of being able to fly. But these
men were laughed at as cranks, while the Wrights kept their secret
until they were sure of the success of their biplane. However,
the question as to who first rode in a power-driven flier under
the control of the operator still is the subject of a world-wide
controversy.

It was as boys that the Wright brothers first began experiments
with flying, and though they have received the highest praises from
the whole world, Orville still is, and until his death Wilbur was,
the same quiet, modest man who made bicycles in Dayton, and the
surviving brother of the pair is working harder than ever. In telling
the story of their own early play, that later proved to be one of
the most important things they ever did, the Wright brothers wrote
for the _Century Magazine_: "We devoted so much of our attention
to kite-flying that we were regarded as experts. But as we became
older we had to give up the sport as unbecoming to boys of our age."
As every boy knows, kite-flying was one of the early methods of
experimenting with air currents and greatly aided the scientists
in their exploration of the ocean of air that surrounds the world,
eddying and swirling up and down, running smoothly and swiftly here,
coming to a dead stop there--but always different from the minute
before.

But before the Wright brothers gave up flying kites they had
played with miniature flying machines. They were known then as
"helicopteres," but the Wright brothers called them "bats," as the
toys came nearer resembling bats than anything else the boys had seen
about their home in Dayton, Ohio. Most boys probably have played with
something of the kind themselves, and maybe have made some. They were
made of a light framework of bamboo formed into two screws driven in
opposite directions by twisted rubber bands something like the motors
on boys' model aeroplanes of to-day. When the rubber bands unwound
the "bats" flew upward.

"A toy so delicate lasted only a short time in our hands," continues
the story of the Wright brothers, "but its memory was abiding. We
began building them ourselves, making each one larger than that
preceding. But the larger the 'bat' the less it flew. We did not know
that a machine having only twice the size of another would require
eight times the power. We finally became discouraged."

This was away back in 1878, and it was not until 1896 that the
Wright brothers actually began the experiments that led to their
world-famous success.

Strangely enough it all started when Orville, the younger of the two,
was sick with typhoid fever, the same disease that caused Wilbur
Wright's death. According to all accounts, the elder brother, having
remained away from their bicycle factory in order to nurse Orville,
was reading aloud. Among other things he read to Orville the
account of the tragic death of Otto Lilienthal, the German "Flying
Man" who was killed while making a glide.

  [Illustration: MOTOR OF THE WRIGHT BIPLANE]

  [Illustration: A 16-CYLINDER 100-HORSEPOWER ANTOINETTE MOTOR

  A frequent prize winner.]

  [Illustration: AN 8-CYLINDER 5O-HORSEPOWER CURTISS MOTOR]

THE GNOME MOTOR

  [Illustration: Standard Gnome aeroplane motor, showing interior.]

  [Illustration:

    Photo by Philip W. Wilcox.

  Fourteen-cylinder 100-horsepower Gnome motor. Used on many racing
  aeroplanes.]

  [Illustration:

    Courtesy of the _Scientific American_

  Testing a Gnome motor on a gun carriage. So great is the power of
  the engine that the tongue of the heavy carriage is buried in the
  ground to hold it in place.]

"Why can't we make a glider that would be a success?" the brothers
asked each other. They were sure they could, and they got so excited
in talking it over that it nearly brought back Orville's fever.
When he got well they studied aeronautics with the greatest care,
approaching the subject with all the thoroughness that later made
their name a byword in aviation for care and deliberation.

Neither of these two young men was over demonstrative, and neither
was lacking in the ability for years and years of the hardest kind
of work, but together they made an ideal team for taking up the
invention of something that all the scientists of the world hitherto
had failed to develop. Wilbur was called by those who knew him one
of the most silent men that ever lived, as he never uttered a word
unless he had something to say, and then he said it in the most
direct and the briefest possible manner. He had an unlimited capacity
for hard work, nerves of steel and the kind of daring that makes the
aviator face death with pleasure every minute of the time he is in
the air.

No less daring is Orville, the younger of the two, who is a little
bit more talkative and more full of enthusiasm than was Wilbur. He
was the man the reporters always went to when they knew the elder
brother would never say a word, and his geniality never failed them.
He also is a true scientist and tireless in the work of developing
the art of aviation.

First, the brothers read all the learned and scientific books of
Professor Langley, and Octave Chanute, the two first great American
pioneers in aviation, and the reports of Lilienthal, Maxim, and the
brilliant French scientists.

They saw, as did Professor Langley, that it was out of the question
to try to make a machine that would fly by moving its wings like a
bird. Then they began with great kites, and next made gliders--that
is, aeroplanes without engines--for the brothers knew that there
was no use in trying to make a machine-driven, heavier-than-air
flier before they had tested out practically all the theories of the
earlier scientists.

They fashioned their gliders of two parallel main planes like those
of Octave Chanute. The width, length, distance between planes,
rudders, auxiliary planes and their placing were all problems for the
most careful study. It was very discouraging work, for no big thing
comes easily. As their experiments proceeded they said they found one
rule after another incorrect, and they finally discarded most of the
books the scientists had written. Then with characteristic patience
they started in to work out the problem from first principles. "We
had taken aeronautics merely as a sport," they wrote later. "We
reluctantly entered upon the scientific side of it. But we soon found
the work so fascinating that we were drawn into it deeper and deeper."

The Wrights knew that an oblong plane--that is, a long narrow
one--driven through the air broadside first is more evenly supported
by the air than would be a plane of the same area but square in
shape. The reason for this is that the air gives the greatest amount
of support to a plane at the entering edge, as it is called in
aviation--that is, the edge where it is advancing into the air. A
little way from the edge the air begins to slip off at the back and
sides and the support decreases. Thus, it will be seen that if the
rear surface, which gives little support because the air slips away
from under it, is put at the sides, giving the plane a greater spread
from tip to tip and not so much depth from front to rear, the plane
is more efficient--that is, more stable, less subject to drifting,
and better able to meet the varying wind currents. Scientists
call this proportion of the spread to the depth the aspect ratio
of planes. For instance, if a plane has a spread of 30 feet and a
depth of 6 feet it is said to have an aspect ratio of _5_. This is
a very important consideration in the designing of an aeroplane,
because aspect ratio is a factor in the speed. In general, high
speed machines have a smaller aspect ratio than slower ones. The
aspect ratio also has an important bearing on the general efficiency
of an aeroplane, but the lifting power of a plane is figured as
proportionate to its total area. In order to hold the air, and keep
its supporting influence, aviators have tried methods of enclosing
their planes like box kites, and putting edges on the under sides.
This latter was found a mistake because the edge tended to decrease
the speed of the flier and did more harm than the good obtained
through keeping the air.

In aviation, as we know it to-day, aeroplane builders believe in
giving their planes a slight arch upward and backward from the
entering edge, letting it reach its highest point about one third
of the way back and then letting it slope down to the level of the
rear edge gradually. This curve, which is called the camber, is
mathematically figured out with the most painstaking care, and was
one of the things the Wright brothers worked out very carefully
in their early models. Also, planes are driven through the air at
an angle--that is, with the entering edge higher than the rear
edge--because the upward tilt gives the air current a chance to
get under the plane and support it. This angle is called by the
scientists the angle of incidence and is very important because of
its relation to the lifting powers of the planes.

  [Illustration: MODEL AEROPLANE FLIERS

  Every fair Saturday the model makers and fliers spend in the
  parks either practising for or holding flight tournaments.]

  [Illustration: A MODERN COLLEGE MAN'S GLIDER]

  [Illustration: OTTO LILIENTHAL MAKING A FLIGHT IN HIS GLIDER]

Another one of the difficult problems the inventors had to struggle
with was the balance of their fliers. Before the Wright brothers
flew, it was thought that one of the best ways was to incline the
planes upward from the centre--that is--make them in the shape of
a gigantic and very broad V. This is known in science as a dihedral
angle. The idea was that the centre of gravity, or the point of the
machine which is heaviest and which seeks to fall to earth first
through the attraction of gravitation, should be placed immediately
under the apex of the V. The scientists thought that the V then would
keep the machine balanced as the hull of a ship is balanced in the
water by the heavy keel at the bottom. The Wrights decided that this
might be true from a scientific point of view, but that the dihedral
angle kept the machine wobbling, first to one side and then righting
itself, and then to the other side and righting itself. This was a
practical fault and they built their flier without any attempt to
have it right itself, but rather arched the planes from tip to tip as
well as from front to rear.

The winglike gliders of Lilienthal and Chanute had been balanced
by the shifting of the operator's body, but the Wrights wanted a
much bigger and safer machine than either of these pioneers had
flown. In their own words, the Wrights "wished to employ some system
whereby the operator could vary at will the inclination of different
parts of the wings, and thus obtain from the wind forces to restore
the balance which the wind itself had disturbed." This they later
accomplished by a device for warping or bending their planes, but in
their first glider there was no warping device and the horizontal
front rudder was the only controlling device used. This latter device
on the first glider was made of a smaller plane, oblong-shaped and
set parallel to, and in front of, the main planes. It was adjustable
through the system of levers fixed for the operator, who in those
days lay flat on the front plane.

Thus the two main planes and the adjustable plane in front with
stays, struts, etc., made up the first Wright glider.

The Wright brothers took their machine to Kitty Hawk, N. C., in
October, 1900, presumably for their vacation. They went there because
the Government Weather Bureau told them that the winds blew stronger
and steadier there than at any other point in the United States. Also
it was lonely enough to suit the Wrights' desire for privacy. It was
their plan to fly the contrivance like a boy does a huge box kite,
and it looked something like one. A man, however, was to be aboard
and operate the levers. According to the Wright brothers' story the
winds were not high enough to lift the heavy kite with a man aboard,
but it was flown without the operator and the levers worked from the
ground by ropes.

A new machine the next year showed little difference of design, but
the surface of the planes was greater. Still the flier failed to
lift an operator. At this time the Wright brothers were working with
Octave Chanute, the Chicago inventor, engineer and scientist whom
they had invited to Kitty Hawk to advise them. After many discussions
with Chanute they decided that they would learn the laws of aviation
by their own experience and lay aside for a time the scientific data
on the subject.

They began coasting down the air from the tops of sand dunes, and
after the first few glides were able to slide three hundred feet
through the air against a wind blowing twenty-seven miles an hour.
The reason their glider flights were made against the wind was
because the wind passing swiftly under the planes had the same effect
as if the machine was moving forward at a good clip, for the faster
the machine moves, or the faster the air passes under it, the easier
it remains aloft. In other words, no one part of the air was called
upon to support the planes for any length of time, but each part
supported the planes for a very short time. For instance, if you are
skating on thin ice you run much less danger of breaking through if
you skate very fast, because no one part of the ice is called upon to
support you for long.

In 1902 the Wright brothers were approaching their goal. Slowly and
with rare patience they were accumulating and tabulating all the
different things different kinds of planes would do under different
circumstances. In the fall of that year they made about one thousand
gliding flights, several of which carried them six hundred feet or
more. Others were made in high winds and showed the inventors that
their control devices were all right.

The next year, 1903, which always will be remembered as the banner
one in the history of aviation, the brothers, confident that they
were about to succeed in their long search for the secret of the
birds, continued their soaring or gliding. Several times they
remained aloft more than a minute, above one spot, supported by a
high, steady wind passing under their planes.

"Little wonder," wrote the Wright brothers a few years, later, "that
our unscientific assistant should think the only thing needed to keep
it indefinitely in the air would be a coat of feathers to make it
light."

What the inventors did to keep their biplane glider in the air
indefinitely, however, was to add several hundred pounds to the
weight in the shape of a sixteen-horsepower gasoline motor. The total
weight of the machine when ready to fly was 750 pounds. Every phase
of the problem had been worked out in detail--all the calculations
gone over and proved both by figures and by actual test. The
planes, rudders, and propellers had been designed by mathematical
calculations and practical tests.

The main planes of this first machine had a spread from tip to tip of
40 feet, and measured 6 feet 6 inches from the entering edge to the
rear edge, a total area of 540 square feet. This will show how great
is the spread of the main planes as compared to their length from
front to rear. The two surfaces were set six feet apart, one directly
above the other, while the elevating rudder was placed about ten
feet in front of the machine on a flexible framework. This elevating
rudder was composed of two parallel horizontal planes which together
had an area of eighty square feet. The elevating planes could be
moved up or down by the operator just as he desired to fly upward or
downward. The machine was steered from right to left or left to right
by two vertical vanes set at the rear of the machine about a foot
apart. They were a little more than six feet long, extending from the
upper supporting plane to a few inches below the lower supporting
plane. These also were turned in unison by the operator, according to
the direction toward which he wished to fly.

The most intricate device of their machine, however, was not
perfected on their first biplane. This is the one for maintaining a
side to side balance, or lateral equilibrium, as the scientists say.
In watching the flights of gulls, hawks, eagles, and other soaring
birds, the brothers had observed that the creatures, while keeping
the main part of their wings rigid, frequently would bend the extreme
tips of their wings ever so slightly, which would seem to straighten
their bodies in the air. The inventor decided that they needed some
such device as nature had given to these birds.

The system was called by the scientists the torsional wing system,
which means that the tip ends of the wings were flexible and could
be warped or bent or curled up or down at will by the operator. Only
the rear part of the tips of the wings on the Wright machines could
be bent, but this was enough to keep the machine on an even keel when
properly manipulated. How the Wright modern machines are operated is
fully described on page (99). The whole machine was mounted on a pair
of strong light wooden skids like skiis or sled-runners.

To start the early Wright biplanes, the machines were placed on a
monorail, along which they were towed by a cable. The force for
towing them at sufficient speed was obtained by dropping from the top
of a derrick built at the rear of the rail a ton of iron which was
connected with the cable. The later Wright biplanes were equipped
with rubber-tired wheels mounted on the framework, which still
retained the skids. Heavy rubber springs were provided to absorb the
shock. With the wheels the machine could run over the ground of its
own power and thus the cumbersome derrick and monorail were done away
with.

The operator was supposed to lie on his face in the middle of the
lower plane, but in the later machines a seat was provided for him
alongside the engine, and in still later ones seats for one or two
passengers.

The engine which was designed by the Wright brothers themselves
for this purpose, was a water-cooled four-cylinder motor which
developed sixteen horsepower from 1,020 revolutions per minute.
The engine was connected with the propellers at the rear of the
biplane by chains. The propellers were about eight feet in diameter
and the blades were six to eight inches wide. The materials used
in the biplane were mostly durable wood like spruce pine and ash,
the metal in the engine and the canvas on the planes. There was not
one superfluous wire. Everything had a use, and even the canvas
was stretched diagonally that it might fit more tightly over the
framework of the planes and offer less wind resistance, and also
stretch more easily for the wing warping.

Finally on December 17, 1903, everything was in readiness for the
first attempt of these two patient men--then unknown to the world--to
fly in a power-driven machine. That first flight, made practically
in secret amid the desolate sand dunes of the North Carolina coast,
lasted only twelve seconds. However, it was the first time, but one,
in the history of the world that a machine carrying a man had lifted
itself from the ground and flown entirely by its own power.

The two succeeding flights were longer, and the fourth covered 853
feet, lasting fifty-nine seconds.

The inventors were not heralded as the greatest men of their time.
There were no medals or speeches. The five men--fishermen and life
savers--who saw the flights agreed that it was wonderful, but they
kept the Wrights' secret and the brothers calmly continued their
studies and experiments.

The spring of 1904 found them at work on Huffman Prairie about eight
miles east of Dayton. The first trials there were not very successful
and the brothers, who had worked seven long years in secret, had the
unpleasant experience of failing to show satisfactory results to the
few friends and reporters invited to see an aeroplane flight. Their
new machine was larger, heavier, and stronger, but the engine failed
to work properly.

Of course this was no great disappointment to those two silent,
determined young men. "We are not circus performers," they said. "Our
aim is to advance the science of aviation."

And advance it they did.

Their experiments continued, and in 1904 they made a record of three
miles in 5 minutes 27 seconds. The next year, 1905, they made a
record flight of 24.20 miles and remained in the air 38 minutes 13
seconds at heights of from 75 to 100 feet.

All this time the brothers were solving problems and correcting
faults, but in 1904 and 1905 their chief endeavour was to keep their
machines from tipping sidewise when they turned. Only the most
technical study and the final development of their wing-warping
device solved the problem.

Perhaps the strangest part was the lack of interest shown in their
work by the world and even by their own townsmen, for, though there
had been several newspaper accounts of their test flights, no great
enthusiasm was aroused.

They were not wealthy and they had spent more on their experiments
than they could afford, so all this time they had proceeded without
attracting any more attention than necessary. They desired to perfect
their patents before letting the world know the secret of their
inventions, and spent the next two years in business negotiations.
Meanwhile, the French inventors were making much progress and soon
brought out several successful aeroplanes.

Why was this?

Why was it that the art of air navigation sought by man since the
earliest times should have been discovered and mastered so quickly?

The answer lies in the putting together of two things by the Wright
brothers--that is, their discovery of the kind of a plane that would
stay aloft with the air passing under it at a swift enough clip to
give it support, and their adaptation of the gasoline engine to the
use of driving the plane forward with enough speed.

When they began work, the gasoline engine was just coming to its
real development. It was light, developed a high power, and its fuel
could be concentrated into a small space. These things were essential
to the success of the aeroplane--light weight, high power, and
concentrated fuel. And these were things that the early inventors
lacked. Sir Hiram Maxim equipped his machine with a steam engine,
while Langley used steam engines in most of his models. These were
very heavy, cumbersome, gave slight power in comparison to their
weight, and could carry only a little fuel with them.

Undoubtedly the adaptation of the gasoline engine to the use of the
aeroplane marked the difference between mechanical flight and no
flight, but it also is not to be doubted that those aviators, who are
more mechanical than scientific, have overrated the importance of the
engine in aeroplane construction. Before engines ever were used, the
Chanute type of biplane had to be worked into a state of reliability,
if not perfection. Now the scientific leaders in aviation are giving
every bit as much attention to the perfection of their planes, their
gliding possibilities, and the scientific rules governing their
action as they are to their engines.

Most boys understand, at least generally, how an automobile or
motor-boat engine works. Scientists call gasoline engines "internal
combustion motors," and that means that the force is gathered from
the explosion of the gasoline vapour in the cylinder. Enough gasoline
to supply fuel to run an aeroplane motor for as much as eight or nine
hours can be carried in the tank. From the tank a small pipe carries
the gasoline to a device called the carbureter. The carbureter
turns the gasoline into gas by spraying it and mixing it with air,
for gasoline turns into a very inflammable and explosive gas when
mixed with the oxygen in the air. So this gas, if lighted in a closed
space, will explode. The explosion takes place in the motor-cylinder
by the application of an electric spark, and the force pushes the
piston, which turns the crank and drives the aeroplane propeller,
automobile wheels, or motor-boat screw.

Thus we have the piston driven out and creating the first downward
thrust, but the thrusts must be continuous. The piston must be
drawn back to the starting place, the vapours of the exploded gas
expelled, and the new gas admitted to the cylinder ready for the next
explosion. On the ordinary four-cycle motor two complete revolutions
of the flywheel are necessary to do all the work. First, we must have
the explosion that causes the initial thrust; second, the return of
the piston rod in the cylinder by the momentum of the flywheel as it
revolves from the initial thrust, thus forcing out the burned gas of
the first explosion; third, the next downward motion to suck in a
fresh supply of gas; and, fourth, the next upward thrust to compress
it for the second explosion. It sounds simple enough, but it isn't,
as every one knows who has tried to run a gasoline motor for himself.

The carbureter must do its work automatically and convert the air
and gasoline into gas in just the right proportions. A slight fault
with the feed of gasoline or air would cause trouble. Also the
electric-spark system that ignites the gas and causes the explosions
must be in perfect running order. The explosions cause great heat, so
some system of cooling the cylinders either by air or water must be
used.

Only one cylinder has been explained here, but most engines have
several, each working at a different stage, so that the power is
exerted on the shaft continuously. For instance, take a four-cylinder
engine; on the instant that the first cylinder is exploding and
driving the shaft, the second cylinder is compressing gas for the
next explosion, the third is getting a fresh supply of gas, and the
fourth is cleaning out the waste gas of the explosion of a second
before. Thus it will be seen why the explosions are almost constant.

Now think of the aeroplane motor that has fourteen cylinders and
develops 140 horsepower! This is probably the most powerful aeroplane
engine in the world, although there are many motor boats that have
engines developing 1,000 horsepower.

In the early days when scientists were groping for the secret of air
navigation the best that the clumsy steam engines they had at their
disposal would do was to generate one horsepower of energy for every
ten pounds of weight. These days the light powerful aeroplane engines
we hear roaring over our heads are generating one horsepower of
energy for every three or three and a half pounds of dead weight,
and engines have been constructed weighing only one pound to every
horsepower, though they are impractical for general use.

The first engines that were used in aeroplanes were simply automobile
engines adapted to air navigation. The main question in those days
was lightness and power. This was achieved by skimming down the best
available automobile engines so that they were as light as safety
would allow.

Although lightness is still an important factor in aeroplane engine
construction, many authorities declare that it is growing less so as
the science advances and aeroplanes are able to carry heavier loads.

There were many intricate and difficult problems, however, that
attended taking a motor aloft to drive an aeroplane. The motor had
to run at top speed every second, for it could not rest on a low
gear as an automobile engine could. First one part and then another
would give out and the motors were constantly overheating. Experience
taught the makers how to make their machines light enough and yet
strong enough to do the required work.

It was in cooling that the greatest difficulties were met, and it
was this that brought about the great innovations in motor building.
The system of cooling the engine with water required much heavy
material, such as pipes, pumps, water, water jackets, and radiator.

On account of the general efficiency of a water-cooled engine many
builders of aeroplanes stuck to it and developed it to a very high
standard. At present many of the prize-winning engines are water
cooled, as, for instance, the Wright and Curtiss.

All of these water-cooled engines and several standard air-cooled
makes are of the reciprocating type that have stationary cylinders
and crankcase while the crankshaft rotates like that of the motor
boat.

The famous Curtiss, Anzani, Renault, and others are all engines of
this type. They all differ, but all have a high capacity, as we know
from the records they have broken. The Anzani and R. E. P. makers,
whose motors are air cooled, have used to great advantage the plan of
making their motors star-shaped--that is, with the cylinders arranged
in a circle around the crankshaft.

This is the shape taken by the famous air-cooled rotary engines of
which the much-discussed Gnome is the best known make. In this rotary
motor the cylinders and crankcase revolve about the crankshaft which
is stationary. Authorities are divided over the Gnome, which has many
severe critics as well as many enthusiastic supporters. Its lightness
is certainly an advantage. The ordinary Gnome has seven cylinders
and develops fifty horsepower while the newest models have fourteen
cylinders and develop 100 and 140 horsepower.

A brief description of the motor here will suffice to show the
general principle of the rotary engine. The stationary crankshaft
is hollow, and through it the gasoline vapour passes from the
carbureter at the rear to the cylinders. Of course the inlet valves
in the pistons are made to work automatically. The magneto is also
placed behind the motor and the segments revolve on the crankcase.
Wires extend from the segments to the spark plugs in the cylinders,
and revolve with them. The cylinders are turned out of solid steel
and the whole engine is conceded by experts to be one of the most
wonderfully ingenious ever built. The cylinders and crankcase
themselves serve as flywheel, thereby eliminating the dead weight
of the usual heavy flywheel in the other types of motors, and the
rotation serves to cool the engine perfectly. Again, the rotary
motor is light and small, while it develops a tremendously high
power. Aviators also claim for it other advantages too technical for
consideration here.

Many authorities, in fact, declare that the rotary engine is the
aeroplane motor of the future. It is very popular among the French
aviators and at present holds a great many speed records. It was with
one of these high-power Gnomes that Claude Grahame-White, the English
flier, won the Gordon Bennett race at Belmont Park in the fall of
1910, and Weyman again in England in 1911.

While this high state of development in the aeroplane motor has been
attained comparatively within a few years, the art of flying has
occupied the mind of man since it was described in Greek mythology.
The Chinese for thousands of years have used kites and balloons.
The ancient Greeks watched the wonderful flights of the birds and
invented myths about men who were able to fly. Then Achytes, his mind
fired by these stories, invented a device in the form of a wooden
dove which was propelled by heated air. Other inventors made devices
that were intended to fly, and during the reign of Nero, "Simon the
Magician" held the world's first aviation meet in Rome. According to
the account, he "rose into the air through the assistance of demons."
It further states that St. Peter stopped the action of the demons
by a prayer, and that Simon was killed in the resultant fall. Simon
made another record that way by being the first man to be killed in
an aeronautical accident. Other records show that Baldud, one of the
early tribal kings in what later was named England, tried to fly over
a city, but fell and was killed. A little later, in the eleventh
century, a Benedictine monk made himself a pair of wings, jumped from
a high tower and broke his legs. These wings really were rude gliders
and the principle remained in the minds of men, even in those days
when their chief occupation was war. According to the legends, a
man named Oliver of Malmesburg, who lived during the Middle Ages,
built himself a glider and soared for 375 feet.

  [Illustration:

    Courtesy of the Smithsonian Institution

  THE CHANUTE TYPE GLIDER

  Upon this machine was based the invention of the biplane.]

  [Illustration:

    Courtesy of the Smithsonian Institution

  THE HERRING GLIDER

  Based on the idea of the Lilienthal gliders.]

  [Illustration: AN EARLY HELICOPTER

  An idea that was abandoned before the aeroplane became a reality.]

THE THREE GREAT PIONEERS IN AVIATION

  [Illustration:

    Courtesy of the Smithsonian Institution

  Prof. Samuel Pierpont Langley]

  [Illustration:

    Courtesy of the _Scientific American_

  Sir Hiram Maxim]

  [Illustration:

    Courtesy of E. L. Jones, N. Y.

  Octave Chanute]

It was in the fifteenth century that men first began to make flying a
scientific study by making records and, in part at least, tabulating
the results of their experiments.

Among these early students of the science were Leonardo da Vinci,
who is best known to the world as a painter and sculptor, but who
was a great engineer and architect of his time, and Jean Baptiste
Dante, a brother of the great poet. Although Da Vinci was the more
scientific in his experiments, Dante made greater progress, and it is
on record that he made many wonderful flights with a glider of his
own construction over Lake Trasimene. He launched his glider from a
cliff into the teeth of the wind, showing thereby his knowledge of
the fact that a glider works best when flown against a high wind,
because in that way the air is passing under it at greater speed. In
one flight he made about 800 feet, which would be a fine record for
any glider manipulated by an expert to-day. Finally Dante attempted
an exhibition at Perugia, at the marriage festival of a celebrated
general, fell on the roof of the Notre Dame Church and broke one of
his legs.

Da Vinci had three different schemes for human flight. One was the
old idea of bird flight, first dreamed of by the Greeks when Ovid
wrote the poem of "Dædalus and Icarus." Scientists called the
machine that Da Vinci proposed an orthopter and the operator was
supposed by the movement of both arms and legs to fly by flapping
the wings. Needless to say it did not work, and we know to-day that
bird flight by wing flapping is probably impossible for man. Another
of Da Vinci's ideas is still being worked upon by some inventors.
This was a machine known as the helicopter, which was supposed to
fly upward by the twisting of a great horizontal screw ninety-six
feet in diameter. The idea was just the same as that of the toy that
started the Wright brothers to thinking. The trouble with Da Vinci's
machine was that he had no power to run it. Boys in playing with toy
helicopters to-day can run them with rubber bands, but Da Vinci had
to turn his screw by human power. Little was accomplished with this
machine, although Da Vinci showed its practicability with models.
The third scheme of this Italian scientist is one that many years
later was perfected and demonstrated at every county fair--that is,
the parachute. The first parachute was very crude, but it soon was
developed to a fairly high stage of effectiveness and men came down
from the tops of towers in them without much injury.

Again, in 1742, the Marquis de Bacqueville, then sixty-two years
old, made a contrivance with which he flew about nine hundred feet
before he fell into a boat in the Seine River and broke his leg. The
Marquis had announced in advance that he would fly from his great
house in Paris, across the Seine River and land in the famous Garden
of the Tuileries. A crowd assembled and marvelled when the nobleman
sailed into the teeth of the wind supported by what apparently were
great wings. Something went wrong after a flight that would be
considered remarkable by a scientific glider to-day, and his fall
resulted in a broken leg for the experimenter. According to the
authorities, all these experiments were not very valuable to science,
because while the flights were accurately described the construction
of the fliers (except in the case of Leonardo da Vinci) was not
given, or only indicated in the most uncertain and unscientific
language.

In 1781 a French scientist named Blanchard attempted to make a flying
machine of which the man driving it was to be the power. He was still
working with it when ballooning became known, and he took up that
sport with avidity.

At that point came the true division between heavier-than-air and
lighter-than-air machines. Before 1783 many scientists had hinted at
the practicability of a hot air or gas balloon, but all successful
flying experiments had been made with what we suppose to have been
some form of gliders. However, in 1783 Tiberius Cavallo, an Italian
scientist living in London, made a small hydrogen balloon, and was
followed by the manufacture of fairly successful balloons by the
Montgolfier brothers, two French inventors.

From that time ballooning, with which this chapter has no concern,
made rapid strides, until to-day the balloon has reached the stage
where great motor-driven balloons are used by the European armies,
and also to carry passengers.

The next step in the heavier-than-air machine, known these days as
the aeroplane, was taken in 1810, by Sir George Cayley, an Englishman
and a true scientist, who constructed a glider and tabulated much
valuable information. It was this scientist who made the first
conclusive demonstrations looking toward the proof that man can never
fly like a bird, but must proceed upon the principle of sustained
planes. Sir George set down many laws of equilibrium governing the
control of flying machines, estimated the power necessary to carry a
man, and even hinted at the possibility of a gas engine more powerful
and lighter than the then crude steam engine. He declared that a
plane driven through the air, and inclined upward at a slight angle,
would tend to rise and support a weight, and also that a tail with
horizontal and vertical vanes would tend to steady the machine and
enable the pilot to steer it up or down.

  [Illustration:

    Courtesy of the Smithsonian Institution

  LANGLEY'S STEAM MODEL

  This tandem monoplane made several successful trial flights.]

  [Illustration: THE MAXIM AEROPLANE

  Maxim's great machine was claimed as the first successful
  aeroplane. In trials it rose a few inches off the ground.]

  [Illustration: MEDALS WON BY THE WRIGHT BROTHERS

  Top, Langley medal bestowed by the Smithsonian Institution;
  bottom, medal authorized by Act of Congress.]

This, it will be seen, was a very close approach to the idea of the
aeroplane as we know it to-day. It remained for another British
inventor, by the name of Henson, to carry these ideas to a further
development, and with his colleague, F. Stringfellow, he worked out a
model that embodied most of the principles of the present-day flier
of the monoplane type. They decided the proper proportion for the
width and length of the plane and steadied their machine with both
horizontal and perpendicular rudders. In 1844 Henson and Stringfellow
built a model of their aeroplane and equipped it with a small steam
engine. A subsequently constructed steam-propelled model made a free
flight of forty yards. This is claimed to be the first flight of a
power-driven machine, although it was only a model. In 1866 F. H.
Wenham, another Englishman, took out a patent on an aeroplane made
up of two or more planes, or, as the scientists call it, two or
more superposed surfaces. Immediately following this, Stringfellow
constructed a steam-propelled model of triplane type, but it was no
more successful than his monoplane. This latest model may be seen in
the Smithsonian Institution at Washington to-day along with other
models marking the progress of aeroplanes.

In the years following other inventors contributed much valuable
information to the data concerning aviation. Among these was Warren
Hargrave, the Australian, who had discovered the box kite, and who
had seen in it the principle for the aeroplane. Hargrave even built
a small monoplane weighing about three pounds and propelled by
compressed air, which flew 128 feet in eight seconds.

Though the Wright brothers were the first to make a practical
man-carrying, power-propelled aeroplane, they were not the first
men to be carried off the ground by such a machine. The first
man admitted by most authorities to have flown in a power-driven
aeroplane was Clement Ader, a Frenchman, who had spent his life in
the study of air navigation. His first machine was of monoplane type
driven by a forty-horsepower steam engine. It was called the _Eole_
and it had its first test before a few of the inventor's friends near
the town of Gretz on October 9, 1890, making, according to witnesses,
a free flight of 150 feet. Ader built two more machines in subsequent
years and succeeded in interesting the French military authorities.
In October of 1897 he made several secret official tests of his last
machine, the _Avion_. It had a spread of 270 square feet, weighed
1,100 pounds, and was driven by a forty-horsepower steam engine. The
day for the trial was squally but he persevered. The flier ran at
high speed over the ground, several times lifted its wheels clear
off its track and finally turned over, smashing the machine. The
officials did not consider the exhibition successful, and the support
of the army was withdrawn. Ader in disgust gave the _Avion_ to a
French museum and abandoned aviation, with success almost within his
grasp.

Shortly before this time Prof. Samuel Pierpont Langley of the
Smithsonian Institution and Octave Chanute, the great American
pioneers in aviation, were making their early experiments. Professor
Langley experimented with numerous kinds of model fliers, and
finally, on May 6, 1896, launched a steam-propelled model over the
Potomac River. According to the scientist Dr. Alexander Graham Bell,
who was present, it flew between 80 and 100 feet and then "settled
down so softly and gently that it touched the water without the least
shock, and was in fact immediately ready for another trial." The
second test was equally successful. The speed was between twenty and
twenty-five miles an hour and the distance flown about 3,000 feet.
Professor Langley's first aerodrome, as he called it (the word is
now used to mean aviation field), was made in the form of a tandem
monoplane about sixteen feet long from end to end and with wings
measuring about thirteen feet from tip to tip. The steam engine and
propellers were placed between the forward and aft planes. The whole
machine weighed about thirty pounds and of course was too small to
carry a pilot.

Langley next made a model which took the form of a tandem biplane,
and which had some success in flights. When the Government
appropriated $50,000 for him to build an aerodrome that would carry a
man, Langley began to experiment with a gasoline engine. He used his
tandem biplane and a motor that developed two and a half to three
horsepower. The whole machine weighed fifty-eight pounds, and the
planes, which were set at a dihedral angle, had sixty-six square feet
of surface. A successful test without a pilot was made on the Potomac
River below Washington on August 8, 1903, and while the spectators
and reporters were lauding him the inventor merely remarked: "This is
the first time in history, so far as I know, that a successful flight
of a mechanically sustained flying machine has been seen in public."

The man-carrying machine was ready for its tests a few months later.
Ever since having been financed by the Government, Langley had been
at work, and the result was a tandem monoplane much like his early
models. It was driven by a gasoline motor placed amidships which
acted on twin screw propellers, which also were between the tandem
planes. The whole machine with the pilot weighed 830 pounds, and
had 1,040 square feet of wing surface. It was fifty-two feet long
from front to rear and the wings measured forty-eight feet from tip
to tip. The wings were arched, like those of modern aeroplanes,
and the double rudder at the rear had both horizontal and vertical
surfaces to steer the machine up or down, or from right to left. The
aerodrome did not have any device for keeping it on an even keel,
such as the ailerons we know to-day, or the wing-warping system of
the Wright machine. This was a serious drawback, according to the
present-day scientists, but Professor Langley had set his wings in
a dihedral angle--that is, like a broad V, to give what is called
automatic stability. This dihedral angle, it will be remembered, is
one of the principles discarded by the Wright brothers early in their
experiments as one that tended to keep the machine oscillating from
side to side. Professor Langley realized this, it is said, and to
offset it had already advanced several ideas along the line of wing
warping, for keeping his machine on an even keel when buffeted by the
wind.

The aerodrome also lacked the wheels now used on aeroplanes for
starting and alighting, and even the skids that were used on the
first Wright machines. His motor was remarkably well adapted to the
work. It developed 50 horsepower with a minimum of vibration, and
with its radiator, water, pump, tanks, carbureter, batteries, and
coil weighed twenty pounds, or about five pounds per horsepower. The
arrangement of the five cylinders around the shaft like the points of
a star was one that has become very popular in modern aviation motors.

The first trial took place at Widewater, Va., on September 7, 1903.
The machine was placed on a barge on the Potomac River; the pilot,
Charles M. Manley, Professor Langley's able young assistant, took his
seat in the little boat amidships, and a catapult arrangement, like
the early Wright starting device, sent it into the air. To the bitter
disappointment of Langley and his friends the machine dived into
the water. It came up immediately, the daring Manley undaunted and
uninjured. Investigation showed that in launching it the post that
held the guys which steadied the front wings had been so bent that
the forward planes were useless.

At the next trial, December 8, the rear guy post was injured in a
similar accident and the machine fell over backward. This ended the
experiments, as the Government appropriation had been spent, and the
machine was repaired and stored in the Smithsonian Institution, where
it is yet.

Professor Langley died a few years after this, feeling that his great
work had never been appreciated or understood by the world. Many have
declared that he died of a broken heart as a result of the frequent
ridicule of the public and press. Although he never saw the triumph
of aerial navigation, he died firm in the belief that it was only a
matter of time and the working out of theories then laid down until
man could fly. His last hours were cheered by the receipt of a copy
of resolutions of appreciation passed by the Aero Club of America.

In the meantime, the Frenchman Ader had actually flown in a
power-driven machine of his own construction, at private tests, while
Captain Le Bris and L. P. Mouillard, Frenchmen, and Otto Lilienthal,
a German, had been carrying on important glider flights. Also Sir
Hiram Maxim, the American-born inventor who was knighted in England,
made a great aeroplane that was tested with some success. The
machine was built in 1889 and was mounted on a track. It was called
a multiplane--that is, it had several planes, one above the other,
and was driven by a powerful steam engine. The whole machine weighed
three and a half tons and had a total surface of 5,500 square feet.
During its tests on the track it lifted a few inches off the ground.
Thus Maxim claimed that his was the first machine that had ever
lifted a man off the ground by its own power.

It was Otto Lilienthal, however, the "flying man," who established a
systematic study of one phase of aviation which became general enough
to be called the Lilienthal School. This was the system of practising
on gliders before attempting to go into the air with power-driven
machines. As will be remembered, this was exactly the system the
Wright brothers followed out.

Lilienthal's first experiments were made in 1891 with a pair of
semicircular wings steadied by a horizontal rudder at the rear. The
whole apparatus weighed forty pounds and had a total plane surface of
107 square feet. He would run along the ground and jump from the top
of a hill. He made many good flights, and in 1893 with a new glider
averaged 200 to 300 yards and steered up or down or to either side
at will. Lilienthal found that the air flowing along the earth's
surface had a slightly upward current, as science tells us it does,
and that it would carry him upward if the wind was blowing strong
enough. Hence he could go forward either up or down in about the same
way that a yacht tacks against the wind. But Lilienthal had the same
trouble in balancing that the Wright brothers had at first, so he
kept an even keel as best he could by swinging his legs and body from
side to side as he hung underneath the glider.

The "flying man" made about 2,000 flights and then constructed a
still more successful biplane glider for which he built an engine.
He was killed while making a glide on August 9, 1896, however, and
the motor was never used. Several authorities who were in touch
with Lilienthal declared that the machine had become wobbly and
unreliable. This, they said, was the cause of its collapsing in
midair under the heavy strain.

Lilienthal's death, though mourned by scientists all over the world,
did not interfere with the great work he had started, for his system
had many disciples both in Europe and America. Among these, besides
the Wrights, were the Americans Octave Chanute and A. M. Herring, and
Percy S. Pilcher of the University of Glasgow. Pilcher was killed
three years after Lilienthal, September 30, 1899, while trying to
make a glide in stormy weather.

  [Illustration: THE FIRST SANTOS-DUMONT AEROPLANE

  This was the first successful aeroplane to be flown in Europe,
  and was quickly followed by others.]

  [Illustration: THE CROSS-CHANNEL TYPE BLÉRIOT MONOPLANE

  The Blériot monoplane was the first of the monoplane type to make
  a success in Europe.]

  [Illustration: A VOISIN BIPLANE

  The Voisin brothers perfected the first permanent aeroplane used
  in Europe. Henri Farman made his first wonderful flights in a
  Voisin.]

  [Illustration: GLENN CURTISS ABOUT TO MAKE A FLIGHT]

  [Illustration: HENRI FARMAN STARTING ALOFT WITH TWO PASSENGERS]

  [Illustration: LOUIS BLÉRIOT SHORTLY AFTER COMPLETING HIS
  TRANS-CHANNEL FLIGHT]

Great credit must be given to Chanute because it was in great part
through his advice that the Wright brothers achieved final
success, and all biplanes to-day are known to the technical side of
the aviation world as Chanute type machines. Chanute and Herring
started experiments with gliders among the sand dunes on the southern
shore of Lake Michigan, and, after some indifferent success with the
Lilienthal monoplane type of glider, made a flier of five surfaces
one above the other. The rudder was in the rear and the pilot hung
below the machine. One by one experiments pared down the number of
planes to three and then to two. The planes were arched, as they are
in modern aeroplanes. The rudder extended behind the contrivance and
had both horizontal and vertical blades. The whole machine weighed 23
pounds and had 135 square feet of plane surface.

The biplane was eminently satisfactory and Herring decided to make
an engine for it and sail in a power-driven flier--or a dynamic
aeroplane, as the scientists call it. His motor was a compressed air
machine and he proposed to go into the air as if for a glide and then
start the engine. According to newspaper accounts, he accomplished
this and his compressed air engine drove him forward seventy-three
feet in eight or ten seconds against a strong breeze. The flight was
not given very much consideration, however, for lack of authoritative
witnesses.

This brings us around again to the activities of the Wright
brothers, who started their work with the glider built along the
lines laid down by Octave Chanute. They had the active support
and aid of this inventor throughout their three or four years
of experiments, although many other scientists were inclined to
discredit their work.

While the brothers were going ahead with their practical flier the
European scientists were developing with rapid strides and Prof. John
J. Montgomery of Santa Clara College, Santa Clara, Cal., who was
killed in a glider accident in 1911, was astonishing the far West
with gliding experiments of great importance.

Montgomery's best glider was a tandem monoplane with a device by
which the pilot could change at will the amount of curvature of any
of the wings. This gave him the tremendous advantage of being able
to vary the lifting power of the wings independently of each other
and hence a means of maintaining side to side balance. Professor
Montgomery made his own flights until injuring his leg in alighting,
and then he hired trained aeronauts to glide from great heights. As
it turned out it would have been better had he never resumed flying
himself. He used balloons to carry up the gliders and when they
reached the required altitude the operator cut the cable. Daniel
Maloney, a daring parachute jumper, and two other aeronauts, named
Wilkie and Defolco, carried on these hair-raising experiments.

Flights were made at Santa Clara, Santa Cruz, San José, Oakland, and
Sacramento, in 1905. The balloon would take up the aeroplane, and
aviator, who sat on a saddle like a bicycle seat between the tandem
planes and manipulated the wing control and rear rudder with hand
levers and a pair of stirrups for his feet. In April of that year a
forty-five-pound glider, such as the one described, with Maloney in
the seat, was taken up four thousand feet. When the aviator cut loose
he glided to earth, making evolutions never before made by man in the
air, and finally landed as lightly as a feather on a designated spot.

Shortly afterward Maloney while making a sensational glide was
killed. As the balloon was rising with the aeroplane, a guy rope
switched around the right wing and broke the post that braced the two
rear wings and which also gave control over the tail. Those below
shouted to Maloney that the machine was broken, but he probably did
not hear, and when he cut loose the machine turned turtle.

One of the saddest of all the many aeroplane fatalities was the
accident early in the fall of 1911, in which Professor Montgomery was
killed while experimenting with his glider.

Thus we see that the pioneers whose work has counted for the most in
the early history of aviation were Americans--that the science can
almost be claimed as a development of American genius. True, Ader was
the first man to fly in a power-propelled machine, and Lilienthal
led the way in the science of gliding, but it remained for Chanute,
Langley, Montgomery, and the Wright brothers to gather all this
scientific data together and put it to practical use so that the
motor could be installed and power flight, or dynamic flight, as the
scientists call it, begun.



CHAPTER II

AEROPLANE DEVELOPMENT

   HOW THE INVENTORS CARRIED ON THE ART OF AVIATION UNTIL IT BECAME
   THE GREATEST OF ALL SPORTS AND THEN A GREAT INDUSTRY


So interested in aviation had our young friend become that he forgot
all other inventions in his enthusiasm for flying. He never missed
a chance to go to the aviation field, and sometimes his scientist
friend would go with him. These days were rare treats indeed, for
the boy always learned some new and important points from their
conversations.

With them we have seen how the science of aeronautics has been
divided into two great departments: balloons, or lighter-than-air
fliers, and all other machines that are not maintained in the air
by hot air or gas. We have seen also the three great divisions of
heavier-than-air aviation--that is, orthopters or wing-flapping
machines; helicopters or machines that fly upward through the
operation of horizontal screws; and aeroplanes. Lastly we see the
three divisions of aeroplanes: gliders; dynamic aeroplanes, or the
machines we know to-day; and true bird soaring, the art of flying
without artificial power and without the flapping of wings.

But on every side the boy heard people talking of great feats of
flying that he knew nothing about.

"Who was Santos-Dumont? What was that first trans-Channel flight?
Why do they always talk about the first Rheims meet?" he asked one
afternoon as he was returning home from the field with the scientist.

The man could not answer the questions all in one breath, but we will
follow his explanation, which extended over many pleasant hours, and
see how aviation developed into a mighty sport and industry.

For several years following 1905 the world of aviation was led by
Europeans--mostly Frenchmen who readily grasped the principles of the
science and made the best and lightest motors that the world has ever
seen. The United States, however, was the first nation to experiment
with aeroplanes for military purposes, although at present the
country is far behind France, England, and Germany in the development
of aeroplanes for use in war.

Alberto Santos-Dumont, a daring young Brazilian who a few years
earlier had astounded the world with his achievements with dirigible
balloons, was the first of the aviators working in Europe to
construct a practical man-carrying power flier. Scores of brilliant
foreigners were working on the principles for gliders laid down
by Lilienthal, but Santos-Dumont, working along the ideas of the
scientists who had built power-propelled models, made himself a
clumsy biplane equipped with a 50-horsepower motor and actually
inaugurated public flights, considering that all done by the Wrights
up to that time was experimental and practically in secret.

On August 22, 1906, he made his first flight near Paris. It was
brief, but authorities agree that it was the first time in Europe
that a power-propelled flier had risen in free flight with a man at
the steering wheel since Ader's secret flight in 1892. Two months
later he made a public flight of 221 metres in 21 seconds, winning
the world's first regularly offered aviation prize. This was the
Archdeacon Cup of 2,000 francs authorized by the Aero Club of France
for a flight of 100 metres.

Scientists gave these flights more attention than they did the
flights of the Wright brothers the year before because they were
viewed by many thousands of people and also by men who had studied
the science of aviation for years. Besides this, Santos-Dumont
made no secret of the construction or workings of his machine as
the Wright brothers did. He was already a popular idol through his
work with dirigible balloons, and being very rich--the son of a
millionaire plantation owner in Brazil--he did not have the same
financial incentive for keeping his plans secret.

His flights gave the aviators of France tremendous encouragement and
it was but a short time until half a dozen aeroplanes, the makes of
which are all well known now, were making successful flights and
breaking records.

Santos-Dumont called his biplane an aeromobile. The two main planes
had perpendicular surfaces enclosing them so that the wings of each
side looked like two box kites hitched together side by side, as
shown in the picture. The rudder extended to the front and it also
looked like a box kite. The pilot sat just in front of the wings and
could manipulate his rudder from side to side or up and down. Thus
he could steer his machine from right to left, upward or downward.
The Brazilian had not solved the problem of keeping his aeromobile
from tipping sideways, so he arranged its wings in a dihedral angle,
which balanced it fairly well. The starting and alighting device was
a set of wheels which we know so well to-day. The biplane contained
65 square feet of plane surface and the total weight was 645 pounds.

Perhaps the most important factor in this machine was an
eight-cylinder 50-horsepower Antoinette gasoline motor. This was the
first time that this now famous motor was used in an aeroplane and it
gave promise at that time of the prize-winning capabilities it later
developed. The propeller, which was made of aluminum, was about six
feet in diameter, or about two feet less than the diameter of the
twin screws in the early Wright biplanes.

  [Illustration:

    Copyright H. M. Benner, Hammondsport, N. Y.

  THE JUNE BUG

  Glenn Curtiss making a flight in one of his first aeroplanes.]

  [Illustration: ORVILLE WRIGHT MAKING A FLIGHT AT FORT MYER

  The aeroplane first became well known in this country when the
  Wright brothers carried on their Fort Myer tests.]

  [Illustration:

    Courtesy of the _Scientific American_

  THE FIRST LETTER EVER WRITTEN ABOARD AN AEROPLANE IN FLIGHT

  This was written at the time Ovington was carrying aeroplane mail
  from Garden City to Mineola, by aeroplane.]

Several years before this the Voisin brothers had been taken by the
general fever for aviation and in 1907 they finished a practical
biplane in which Henri Farman, a former auto racer, and Leon
Delagrange, an artist, astonished the world. This early machine
is described by one authority as something like a cross between a
box kite and a Chanute glider. Extending out behind the two main
planes was a rudder like a huge box kite, which was used to steer
the machine from right to left. This also helped to keep the biplane
from tipping forward or backward. A single horizontal rudder in front
steered it upward or downward. These rudders were manipulated by
the operator, who sat between the two main planes in front of his
engine, by either pushing his pilot wheel forward or backward or by
turning it like the steering wheel of an automobile. There was no
device for balancing the aeroplane, but the construction kept it on
a fairly even keel--or, as the scientist said, it had inherent or
automatic stability--i. e., stability automatically gained from the
construction of the machine. Also the operator was supposed to swing
his body from side to side to aid this. The aeroplane started from
and alighted on four wheels set under the main plane and the tail.
It had 559 square feet of surface and with the engine weighed 1,100
pounds. The motor was a 50-horsepower Antoinette, which drove a
single aluminum propeller.

After preliminary "bird hops" at Issy-les-Mollineaux, Farman on
October 26 beat Santos-Dumont's record by flying 771 metres. On
January 13, 1908, he won the Deutsch-Archdeacon Cup of 50,000 francs
for the first person to make a circular flight of 500 metres. Two
months later Delagrange challenged Farman for his world championship,
but lost, Farman twice circling the two pylons, or marking poles,
that had been set up 500 metres apart, in 3 minutes 31 seconds. The
distance covered with turns was 2004.8 metres. Delagrange flew the
500 metres in 2.5 minutes.

Then for the first time in the world's history two men rode in an
aeroplane, Delagrange taking his rival behind him and sailing over a
part of the course. A month later Delagrange took the distance record
from Farman with a flight of 5,575 metres in 9-1/4 minutes.

While these pioneers were winning prizes and breaking records Louis
Blériot was bringing his aeroplane to a successful stage. He had
been working on the problem of aviation since 1900, but had failed
with wing flappers and machines like box kites. Finally he had some
success with a tandem monoplane like Professor Langley's. The first
of his machines of this kind was smashed in a fall, but the second,
Blériot's seventh flier, flew steadily and was the fastest aeroplane
ever developed.

Thus Blériot at the opening of 1908 had developed his monoplane
idea far past the stage Professor Langley ever had developed it. He
had increased the size of the forward plane and decreased the size
of the rear plane until the great forward wings did all the work
of sustaining the machine in the air, while the chief uses of the
tail were steering and steadying the machine. Moreover, Blériot's
was the first machine among the practical European fliers to have a
system of wing warping such as the Wright brothers had developed in
their wonderful biplane, and such as Glenn Curtiss, another American
inventor, was at the same time developing for his machines.

This gave Blériot what is called three-rudder control--that is, the
vertical rudder at the rear to steer it from right to left, the
horizontal rudder, also on the tail, to steer it up or down, and
the flexible wing tips to keep it from tipping sidewise. The aspect
ratio of the early Blériots was low, which gave them greater speed.
In other words, the main plane did not have so great a spread as
most aeroplanes do, while it was much deeper, and, having less of
an entering edge, it could go faster. There were three wheels--two
under the main plane and the third under the tail for starting and
alighting. The engine was just under and at the front of the main
plane, driving a single propeller. This propeller--which is the type
most used on monoplanes--is called a tractor propeller because,
instead of pushing the aeroplane forward from the rear, it pulls
it from the front. The operator sat just to the rear and above the
engine so he could look out and over the top of the main plane.

The last day of October, 1908, Blériot jumped into international
fame with this machine by making a cross-country flight from Toury
to Artenay, a total distance of about 17 miles. This was the second
cross-country flight ever attempted. The day previous Farman had
flown his biplane from Châlons to Rheims, nearly 17 miles.

Meanwhile the Wright brothers had been making great progress, as will
be seen shortly, and Wilbur Wright had brought a biplane to France to
make demonstrations for a French syndicate. He took up quarters at Le
Mans in August, 1908. His notable flights broke the world's records
for distance and duration. Early in the month he flew 52 miles and
was in the air 1 hour and 31 minutes. A few days later he broke the
French records for altitude by going up 380 feet, and on the last day
of the year won the Michelin prize of 20,000 francs for the longest
flight of the year.

In January Wilbur Wright went to Pau, where he opened a school and
was joined by his brother Orville, who had just recovered from a
historical accident in the United States which will be described
shortly. At Pau they made a great many flights and exhibited their
aeroplane to thousands and thousands of people from all over the
world, including great scientists, military men, statesmen, and many
members of the European nobility. Among these was young King Alfonso
of Spain, who took such a delight in the machine that he would have
made an ascension were it not for the objections of his ministers.
King Edward of England also visited the famous brothers, talked with
them about their achievements, and witnessed several fine flights.
Then Wilbur took his machine to Italy, where King Emanuel attended
his exhibitions in Rome. Later in London the two brothers were
entertained by the Aeronautical Society of Great Britain and received
its gold medal. During this time they won the respect of the whole
world of aviation.

"Now to return to the progress made by the intrepid American
inventors in our own country, led by the Wright brothers, Glenn
Curtiss, A. M. Herring, Dr. Alexander Graham Bell, and his
associates, F. W. Baldwin and J. A. D. McCurdy," continued the boy's
friend.

"You remember that toward the close of 1905 the Wright brothers
suspended their flights near Dayton because it had become necessary
for them to spend all their time in business negotiations. In the
spring of 1908, after increasing the motor power of their flier,
they began tests again because the brothers had agreed to furnish a
machine to the United States Signal Corps and another to a French
syndicate."

The machine that was to be furnished to the Signal Corps, he
explained, had to be able to carry two men and to be able to fly for
one hour without stopping, at an average speed of 40 miles an hour.
Furthermore, this flight had to be made across country dotted with
hills, valleys, and forests. Another of the requirements was that the
machine should be able to fly 125 miles without stopping. The Wright
brothers agreed to furnish such an aeroplane for $25,000, and Orville
Wright went to Fort Myer, Va., near Washington, for the tests.

His preliminary flights were very successful and thousands of
Americans flocked to the drill ground to see what was practically the
first public exhibition in the United States. About the time that the
French aviators were making flights of 1 hour or so Orville Wright
flew his machine for one hour and 3 minutes. Repeatedly he took
Lieut. Frank P. Lahm or Lieutenant Selfridge for short flights.

On the 17th of September the tragic accident that put a stop to the
flights occurred. Orville Wright was flying about 75 feet high with
Lieutenant Selfridge as a passenger when one of the propellers hit a
stay wire which coiled about the blade, breaking it and making the
machine unmanageable. The aeroplane plunged to the ground, throwing
the occupants forward. Lieutenant Selfridge suffered injuries from
which he died within three hours, while Wright suffered several
broken bones. This occurred while Wilbur Wright was at Le Mans,
France.

The year before Dr. Alexander Graham Bell, the American inventor, had
invited Glenn Curtiss, a bicycle and motor manufacturer, to aid him
in equipping with power the fliers that he was constructing with the
help of Lieutenant Selfridge, F. W. Baldwin, and J. A. D. McCurdy.
They formed the Aerial Experiment Association, which later became
famous, and early in March, 1908, began the test of their first
aeroplane, which they called the _Red Wing_. The machine was tried
over the ice of Lake Keuka, near Hammondsport, N. Y., and before its
makers were ready to fly it went into the air and sailed 300 feet.
The _Red Wing_ was of biplane type and mounted on skids, with the
propeller and vertical direction rudder at the rear. The horizontal
elevating rudder was at the front. The notable feature was the curve
of the planes. The upper plane curved from the centre downward,
while the lower plane curved from the centre upward, so that the two
planes, if they had been a little bit longer, would have met. This
curvature was expected to give automatic stability, but the machine
was never a great success.

The next machine made by these experimenters was called the _White
Wing_, and made some fair flights. The next was the famous _June Bug_
which was designed by Curtiss and entered by him to contest for the
_Scientific American_ Cup for a flight of one kilometre. The test,
which was held on the 4th of July, 1908, near Hammondsport, was the
first official flight for a prize in America, and was successful in
every way, winning the cup with a flight of 200 yards. This biplane
had the three-rudder control--that is, a tail at the rear shaped like
a box kite to steer it from right to left, two small parallel planes
in front to steer it up or down, and a system of flexible wing tips
which enabled the operator to maintain a side to side balance.

In 1909 Curtiss made some important improvements over his machine of
previous years by replacing the flexible wing tips with ailerons.
This was the first time these devices were used in this country, but
they had already been introduced in Europe on several machines. There
are many kinds of ailerons, but on Curtiss's biplane they were two
small horizontal planes fixed between the outer tips of the upper
and lower planes. They could be turned so as to keep the aeroplane
balanced when making a sharp turn or when struck by a gust of wind.

Curtiss and his partner, A. M. Herring, took the machine to the
plains near Mineola, L. I., that summer, and began preliminary
flights. They won several rich prizes, including that year's
_Scientific American_ Cup for the longest flight of the season. In
this Curtiss made an official distance of 24-1/2 miles.

  [Illustration:

    Photograph by the American Press

  THE GODDESS OF LIBERTY

  Photographed from an aeroplane]

  [Illustration: FIRST ACTUAL WAR EXPEDITION OF AN AEROPLANE

  This picture shows Rene Simon returning from his scouting trip
  over the camp of the Mexican insurrectos, February 11, 1911.]

  [Illustration: WAR MANOEUVRES

  American army aeroplane manoeuvring over the troops mobilized at
  San Antonio, Texas, during the 1911 Mexican revolution.]

We will leave Mr. Curtiss and his associates for the time being and
take up again the work of the Wright brothers, who in the spring of
1909 returned to the United States after their European triumphs.
Their laurels were further added to by a medal from the Aero Club of
America, presented by President Taft at the White House, and medals
from the Federal Government, the state of Ohio, and their home town
of Dayton. All this time they were busy making the aeroplane with
which they were to resume the final tests for the Government that
had been interrupted the previous fall by the death of Lieutenant
Selfridge. They arrived at Fort Myer in June, but spent most of that
month and a large part of July in preparations and short practice
flights. The great crowds, among which were scores of statesmen and
politicians, gathered in Washington, became impatient at the delays,
but the brothers had waited for a good many years to perfect their
biplane and would not risk failure by attempting the official tests
in bad weather, with their plane out of tune, or their engine in bad
working order.

Finally ten thousand cheering spectators were rewarded by seeing
Orville Wright ascend with Lieutenant Lahm as a passenger, and sail
for 1 hour and 40 seconds, fulfilling the endurance requirements.
The next few days the weather prevented the distance test, but one
calm evening just before sunset Orville carried Lieut. B. D. Foulois
across hills and valleys to Alexandria and return at an average speed
of 42.6 miles per hour. This won the brothers a bonus of $5,000 on
the price of the machine because they were to receive $2,500 extra
for each mile per hour more than the 40 miles per hour called for in
the contract. It was the greatest feat of aviation ever seen in the
United States at the time and the ovation tendered the brothers was
equal to the occasion. Not once, however, did they lose their heads
in the slightest or show any undue enthusiasm over their achievement.
Statesmen, army officers, and newspaper men crowded around with
congratulations and praises, but the great victory was only what the
brothers had expected and they soon were planning improvements on
their biplane.

The real meaning of this feat by the Wright biplane, however, was
that the United States was the first nation officially to adopt an
aeroplane for military purposes. To Americans it seems peculiarly
fitting that it was the Wright machine that was adopted because it
was the Wright aeroplane, strictly an American product, that was the
first practical flier.

Later on Wilbur returned to Fort Myer to finish off his contract by
teaching two Signal Corps officers to handle the machine. During
this time the aviator changed his biplane by transferring one of the
forward elevating planes to the rear, where it was used as a fixed
tail to give greater stability from front to rear. This was such a
success that it was used in subsequent models, and the present-day
Wright biplanes have no forward lifting plane at all--the horizontal
plane at the rear serving as the elevator and also as the fore and
aft balancer.

In the fall of 1909, after the Fort Myer tests, the brothers
again separated, Orville going to Europe, where he achieved more
distinction, and Wilbur remaining at home to astonish his countrymen
with his exhibitions at the Hudson-Fulton Celebration. He made the
first trip around the Statue of Liberty on September 9, starting from
and returning to Governor's Island in New York Bay.

In the meantime the European aviators were making even greater
strides, and 1909 saw many new aeroplanes take the air to break
records of different kinds. Throughout the season there was hardly a
day that some record was not broken, or that some previously unknown
man did not achieve undying fame for his daring feats.

Aeroplane schools were established and aviation passed from the stage
of experimenting into the stage of record making and breaking.

The European governments, particularly France and Germany, were
carefully watching progress, and dozens of the pupils in the aviation
schools were young officers detailed to learn the art of flying and
report on its usefulness in warfare. Also the building of aeroplanes
became a great industry and in France thousands of scientists,
designers, mechanics, motor experts, and wood-working experts were
engaged in turning out machines as fast as they could.

It would be impossible in this brief space to describe all of the
important flights of the last few busy years in aviation, which were
talked of by the boy and his scientist friend, but a very brief
outline of the feats accomplished will show the wonderful progress
that has been made. The first great international meet, which was
held at Rheims, France, in 1909, did more than anything else up to
that time to show the world how far the science had gone and how many
good machines there were. So great was the public interest in this
meet that before the end of the year meets were arranged and held
at Blackpool and Donchester, England; Berlin, Juvisy, France, and
Brescia, Italy. The most notable achievements of the year in Europe
were the flight across the English Channel by Blériot in his graceful
monoplane, by which he won the prize of 1,000 pounds offered by the
London _Daily Mail_, the winning of the James Gordon Bennett Cup by
Curtiss, the only American to contest for the great honour, and the
winning of the Grand Prix by Farman in his biplane. Blériot, while
practising, before his famous flight across the English Channel,
broke many records with his monoplanes, No. XI and No. XII. He was
the first man to take two passengers in such a craft, those in the
machine besides himself being Santos-Dumont and A. Fournier. The
total weight of machine and three men was 1,232 pounds. He also
made several cross-country records and received medals from the Aero
Club of Great Britain and the Aero Club of France.

  [Illustration: HARRY N. ATWOOD

  Arriving at Chicago on his flight from St. Louis to New York.]

  [Illustration: THE FINISH OF ATWOOD'S ST. LOUIS TO NEW YORK FLIGHT

  The aviator is here seen arriving at Governor's Island in New
  York Bay.]

  [Illustration: POSTMASTER-GENERAL HITCHCOCK AND CAPTAIN BECK
  STARTING WITH THE AERO-MAIL

  This is the first time regular United States mail ever was
  carried by aeroplane. Throughout the meet at Garden City in 1911,
  Earle L. Ovington and Beck carried mail over a regular route.]

Blériot's flight over the English Channel was one of the most
dramatic that ever has been made by an aviator, as he encountered
perils that no birdman ever before had faced. He had as a contestant
one of the daring young aviators who has made the history of aviation
read like a novel. This was Hubert Latham, who used the Antoinette
monoplane, one of the most beautiful machines ever designed, and
which is described fully later on. Young Latham had become a popular
hero because of his daring feats. The aviators said that he was
carrying on an endless battle with the wind, for he seemed to prefer
flying high in the air when the wind was so gusty that other aviators
were afraid to leave their hangars. He had made several monoplane
records for endurance and altitude, and after a notable cross-country
flight announced his intention of sailing across the English Channel
to collect the 1,000 pounds from the _Daily Mail_. So he took his
graceful monoplane to Calais, and after impatiently waiting for
fair weather, soared from the towering cliffs and out over the
stormy waters of the English Channel. Thousands cheered his daring
and wished him success, but before he had gone more than six miles
his motor failed him and he glided to the water. In a few minutes
the boat that was sailing below him came up and found him calmly
sitting on the upper framework of his machine, which was buoyed up
by the great wings. He was looking as unconcerned as if he had been
sitting in a motor boat on a lake, and declared he would try again
the next day. His machine was wrecked in getting it ashore, however,
and Blériot made his famous flight before the young man could get it
repaired.

The older man had been injured in an accident and was still walking
on crutches, with a badly burned foot, when a favourable opportunity
for the trans-channel flight came. He was awakened before dawn on the
morning of July 25th, and, throwing away his crutches as he got into
his machine for a practise spin, he said: "I will show the world that
I can fly even if I cannot walk."

At 4:35, just as the sun was rising, he sailed out over the
precipice, and Latham, watching him, wept with disappointment at
not being able to enter the contest. A torpedo boat destroyer was
following him, but soon she dropped behind and he was over the
trackless channel without any landmark to guide him. Finally the
coast of France dropped out of sight and the intrepid aviator was
alone, with nothing but his carefully planned monoplane between him
and death in the tossing waters hundreds of feet below.

After ten minutes of this the cliffs of the English coast loomed up
ahead, bathed in the early morning sunlight. He saw several boats far
below him and followed their course, which brought him to the town
of Deal, near which he landed. The first man to greet him was his
good friend M. Montaine, but soon after a crowd of Englishmen were
crowding about congratulating him on his wonderful achievement. Not
to be outdone, young Latham cabled his congratulations.

August saw the beginning of the first great international meet at
Rheims. Most of the leading aviators of the world gathered there
to contest for the prizes and for fame. Curtiss, Blériot, Farman,
Latham, Lefabre, Count de Lambert, Paul Tissandier, Louis Paulhan,
Le Blanc, Roger Sommer, and Rougier all distinguished themselves and
made their names as familiar in this country as they were in France.

Latham, with his apparently fearless disregard of danger, and
his great, soaring Antoinette monoplane that looked more like a
dragon-fly when up in the air than anything else, was one of the
popular idols. Not only did he fly in rough winds but also in heavy
rainfall, as did his rival, Blériot. Of course there were several bad
accidents, but none to compare with the later fatalities.

The winning of the $10,000 Grand Prix de la Champagne for the longest
flight was not so spectacular as the next day's great race. Latham
had made a record of 96 miles that it was thought would stand. On
the day of the finals, Friday, August 27th, Latham again took the
air, making a spectacular flight several hundred feet high. At the
same time several others were performing evolutions in the air, some
high and some low. Farman was flying close to the ground and making
but poor time in his slower craft. Finally, after all the others had
come to earth, the longest flight having been made by Latham, with
68 miles to his credit, the crowd realized that Farman was making a
record. Time after time he passed the grand stand, marking off the
miles. It became dark, but the crowd still lingered, and was rewarded
finally by seeing him bring his machine softly to the ground in front
of the judges' stand, winner of the $10,000, with a record of 190
kilometres. His friends, wild with joy, pulled the exhausted aviator
from his seat and carried him off the field on their shoulders.

The next day Curtiss, the only American taking part in the meet
(although several Wright biplanes were flown by Frenchmen), brought
out his 60-horsepower biplane to try for the speed prize of $5,000
offered by James Gordon Bennett. He made two rounds of the field at
a speed of 47.04 miles an hour. Blériot then brought out his great
80-horsepower monoplane, but the test flights were discouraging.
Finally, after working over his machine all afternoon and trying
several propellers, he started at five o'clock and made his first
round in much better time than Curtiss had done. He slackened up on
the second round, however, and came to earth to find that he had lost
to the gallant American. By winning the prize Curtiss was allowed to
take the next year's contest to his own country.

There were many other records broken at the other meets held in
1909, but none of them stood long after the 1910 season had got well
under way. Altitude, endurance, distance and speed records all were
shattered by the ever-increasing army of aviators and the constantly
improving machines.

Undoubtedly the most spectacular and daring feat of 1910 was the
flight across the Alps by George Chavez, who was born in Paris of
Peruvian parents only twenty-three years before his tragic death. In
September of that year he set out to win the prize of 70,000 francs
offered by the Italian Aviation Society to the first aviator who
would fly the 75 miles from Brig to Milan, across the towering peaks
and yawning chasms of the Alps. Of the five who entered the contest
Chavez was the only one to make a real start. After waiting for
several days, during which wind, rain and fog kept him chained to the
ground, he finally rose in the air.

In a few minutes he was 7,000 feet above sea level, crossing the
famous Simplon Pass, braving the fierce eddies of wind that swirled
around the cruel, jagged crags and precipices. Finally he crossed
the mountains and glided down the Italian slope to Domodossola.
Thousands had gathered to greet his arrival, but as he was sinking
gradually to the earth, only thirty feet above the ground, a gust of
wind caught the machine, the wings collapsed and the brave young man
fell to earth underneath the machinery. He received injuries from
which he died four days later. The committee granted him one third of
the prize on the basis that he had completed the difficult part of
the journey.

No less dangerous was Glenn Curtiss's trip from Albany to New York
in his biplane, by which he won the $10,000 prize offered by the New
York _World_. Most of his route lay over wooded hills, the waters of
the Hudson River, or the cliffs along its banks, which territory,
as any one who has travelled from New York to Albany knows, offers
few landing places. Starting with a letter from the Mayor of Albany
to the Mayor of New York and followed by a special train on the New
York Central he made Camelot, 41 miles from Albany, in about an hour.
The next jump was clear to Spuyten Duyvil, the northern boundary of
Manhattan, which completed the required 128 miles in a total elapsed
time of 2 hours and 32 minutes. His average speed was 50-1/2 miles an
hour.

This stage of the journey nearly brought serious disaster to the
aviator, for, while passing the famous old mountain Storm King, he
was caught by a terrific gust of wind and his machine was twisted
sideways so that it dropped suddenly toward the river. By skilful
manipulation he righted his biplane and continued.

After a brief pause at Spuyten Duyvil he sailed down the Hudson River
and the upper New York Bay to Governor's Island. Every whistle in
the harbour, a few million people and the reporters representing
the newspaper readers of the whole civilized world, proclaimed his
victory over the wind gusts eddying around the palisades and the New
York skyscrapers.

In the United States there were many aviators besides Curtiss who
were making an effort to win long distance prizes. The New York
_Times_ and the Philadelphia _Ledger_ had offered a large purse,
supposed to be $10,000, for the first flight from New York to
Philadelphia, and on June 13th, a few days after Glenn Curtiss's
flight from Albany to New York, Charles K. Hamilton, another young
man new to aviation, sailed in his Curtiss biplane the 86 miles from
Governor's Island to Philadelphia in 1 hour and 43 minutes, and
returned the same day. His average speed was 50-1/2 miles an hour,
the same maintained by Curtiss in his Albany-New York trip. These two
flights added tremendously to the fame of the Curtiss machines.

The great International Aviation Tournament of 1910, held at Belmont
Park in October, was the climax of the season in this country. Of
course interest centred around the race for the James Gordon Bennett
Cup and prize of $5,000, which had been won the year before at Rheims
by Curtiss. The total prizes amounted to $60,000 and practically
every standard make of aeroplane was represented. The American
aviators came into prominence at this meet, as will be remembered
by the feats of Walter Brookins, Arch. Hoxsey, Ralph Johnstone, J.
A. Drexel and a dozen others. The English contingent was led by
Claude Grahame-White, who had been making himself famous at the
Harvard-Boston meet. Of the Frenchmen, Alfred LeBlanc, Hubert Latham,
Emiel Aubrun and Count de Lesseps were among the leaders.

Nearly every one nowadays is familiar with the story of how
Grahame-White brought out his 100-horsepower Blériot monoplane for
its first trial and made 100 kilometres at an average speed of
61 miles an hour. Soon after that LeBlanc came out with another
100-horsepower Blériot, acknowledged to be one of the swiftest
machines ever made at that time, and started on a race around the
course at a speed such as the world had never seen before. In the
last lap his gasoline gave out, the aeroplane shot downward and
was smashed against a telephone pole. LeBlanc was more angry than
injured, because he had lost the race, although his speed had been 67
miles an hour, or six miles better than Grahame-White's. Brookins,
with the Wright biplane racing machine, started out with high speed,
but the engine soon began to miss fire and he too came to earth.
Consequently Grahame-White carried off the prize.

The next day the aviators were out to contest for the $10,000 offered
by Thomas F. Ryan for the quickest flight from the aviation field
to the Statue of Liberty in New York Harbour, 16 miles away, and
return. Never before was there such a dramatic race. Together Count
de Lesseps and Claude Grahame-White, both in Blériot machines,
started for the Statue. John Moisant, the American aviator, who only
that summer had made the first flight from Paris to London, suddenly
determined to win the prize. It took him about five minutes to buy
LeBlanc's 50-horsepower Blériot monoplane for $10,000, and just
as Grahame-White and de Lesseps were returning from their flight
Moisant started out. Instead of taking the safer roundabout course,
where there were many landing places, this dauntless birdman sailed
directly over the church steeples of Brooklyn, cutting through the
treacherous air currents at terrific speed, circling the Statue at
great altitude and returning by the same route. His time was 43
seconds better than that of Grahame-White, who flew a machine of
double the power. The Americans were wild with delight, thinking
Moisant had won the prize, but the committee finally gave the award
to Count de Lesseps, who made the slowest time, because Grahame-White
had fouled the starting post, or pylon, as it is called by aviators,
and because Moisant in his desperation to get started had failed to
qualify.

But there were other records broken. Ralph Johnstone, flying the
small Wright biplane racer, which was equipped with particularly
large propellers, broke the altitude record of 9,104 feet which had
been set in France by climbing to an altitude of 9,714 feet. The
round trip to and from the clouds took him 1 hour and 43 minutes.
In connection with the altitude trials, the daring of Johnstone and
Hoxsey was particularly notable. Both of these aviators took up their
Wright biplanes when the wind was blowing so fiercely that they could
hardly turn the pylons. When they got to a great altitude, one time
the gale was so terrific that they were carried backward at a speed
of nearly 40 miles an hour, and both of them had to land in open
country; Johnstone at Holtsville, L. I., 55 miles away, and Hoxsey at
Brentwood, half that distance. During these flights both of them had
reached altitudes of more than a mile in the air. But these records
were not destined to stand long, as will be shown by the table on
page 75.

But world's distance and altitude records were being broken in
Europe, too, and during the summer of 1910 the record keepers were
busy putting new names at the heads of their lists, as will be shown
by the table on page 76. The long distance speed race, called the
"Circuit de l'Est," which took in a course 488 miles long, of six
towns around Paris, aroused as much enthusiasm as any. The prize
which was offered by the newspaper _Le Matin_ of Paris was for
100,000 francs. The race started on August 7, with eight contestants,
and ended on August 17 with Alfred LeBlanc, in his Blériot monoplane,
the winner. He had made the distance in six stages at an average
speed of 40 miles an hour, flying through rain, fog and wind. Next
came Aubrun in a Blériot and Weyman in a Farman. Not only was this
race one of the severest tests that the aeroplane had ever had, but
also it was a trial to the aviators that did a great deal to prove
the practicability of the aeroplanes for more serious work than
pleasant day sport.

ALTITUDE FLIGHTS IN 1910[A]

    ================================================
      AVIATOR    | ALTITUDE  |     AEROPLANE       |
    -------------+-----------+---------------------+
    Paulhan      | 4,164 feet| Farman biplane      |
    Olieslaegers | 4,490  "  | Blériot monoplane   |
    Brookins     | 4,503  "  | Wright biplane      |
    Latham       | 4,658  "  | Antoinette monoplane|
    Chavez       | 5,850  "  | Blériot monoplane   |
    Morane       | 6,691  "  | Blériot monoplane   |
    Morane       | 8,469  "  | Blériot monoplane   |
    Chavez       | 8,790  "  | Blériot monoplane   |
    Drexel, A.   | 9,450  "  | Blériot monoplane   |
    Johnstone    | 9,714  "  | Wright biplane      |
    Legagneux    |10,746  "  | Blériot monoplane   |
    Hoxsey, A.   |11,476  "  | Wright biplane      |
    -------------+-----------+---------------------+

    ===========================================
      AVIATOR    |    PLACE     |     DATE
    -------------+--------------+--------------
    Paulhan      | Los Angeles  |Jan.  12, 1910
    Olieslaegers | Brussels     |July  30,  "
    Brookins     | Indianapolis |July  16,  "
    Latham       | Rheims       |July   7,  "
    Chavez       | Blackpool    |Aug.   3,  "
    Morane       | Havre        |Aug.  29,  "
    Morane       | Havre        |Sept.  2,  "
    Chavez       | Issy, Paris  |Sept.  8,  "
    Drexel, A.   | Philadelphia |Oct.  31,  "
    Johnstone    | Belmont Park |Nov.  23,  "
    Legagneux    | Pau          |Dec.   9,  "
    Hoxsey, A.   | Los Angeles  |Dec.  26,  "
    -------------+--------------+--------------

  [A] These records were broken in 1911 and 1912. The 1912 record
  being 16,240 feet, made by Garro, France.

DISTANCE AND ENDURANCE FLIGHTS

    ========================================================
                    |                |  DISTANCE  |  TIME
       AVIATOR      |   AEROPLANE    |   MILES    |HR.  MIN.
    ----------------+----------------+------------+---------
    L. Paulhan      | H. Farman bi-p | 108 in all | 2    3
                    |                |            |
                    |                |            |
    Grahame-White   | H. Farman bi-p |  83        | 2    5
                    |                |            |
    L. Paulhan      | H. Farman bi-p | 193        | 4   12
                    |                |            |
    G. H. Curtiss   | Curtiss bi-p.  | 150        | 2   50
                    |                |            |
    C. K. Hamilton  | Curtiss bi-p.  |  86        | 1   43
                    |                |            |
    R. Labouchere   | Antoinette     | 211.27     | 4   37
                    |         mono-p |
    J. Olieslaegers | Blériot mono-p | 244.43     | 5    3
                    |                |            |
    A. Leblanc      | Blériot mono-p | 485        | 251 55
                    |                |            | elapsed
                    |                |            |   time
                    |                |            |
    E. Aubrun       | Blériot mono-p | 485        | 252 15
                    |                |            | elapsed
                    |                |            |   time
                    |                |            |
    M. Cattaneo     | Blériot mono-p | 141 miles  | 3   18
                    |                | 188 yds    |
                    |                |  in all    |
    R. Johnstone    | Wright bi-p    | 101 miles  | 3    5
                    |                |  389 feet  |
    Walter Brookins | Wright bi-p    | 192.5 in   | 5   49
                    |                |  all.      |
    Arch Hoxsey     | Wright bi-p    | 109        | 3   33
                    |                |            |
    M. Tabuteau     | H. Farman bi-p | 289.39     | 6    1
                    |                |            |
    G. H. Curtiss   | Curtiss bi-p   | 120        |
                    |                |            |
    J. A. D McCurdy | Curtiss bi-p   | 90         | 2
                    |                |            |
    Capt. Bellenger |                | 330        | 8   22
                    |                |            |
    Lieut. Bague    |                | 124        | 4   32
                    |                |            |
                    |                |            |
    Hirth           |                | 330        | 5   41
                    |                |            |
    Vedrines        |                | 267        | 3   50
                    |                |            |
    H. N. Atwood    | Burgess-Wright | 462        | 17  12
                    |   bi-p.        |            |Net fly-
                    |                |            | ing time
    H. N. Atwood    | Burgess-Wright | 1,266      | 28  53
                    |   bi-p.        |            |Net fly-
                    |                |            | ing time
    Olieslaegers    | Blériot        | 388        | 7   18
                    |                |            |
    Loridan         |                | 434        | 10  43
                    |                |            |
    Vassilieff      |                |       400  |
                    |                |            |
    Renaux          | M. Farman      |   428      | 12  12
                    |                |            |
    Vedrines        | Morane         |   504      |  8  54
                    |                |            |
    C. P.           | Wright bi-p.   | 4,029      | 82   4
     Rodgers        |                |            |Total
                    |                |            | flying
                    |                |            | time
    Helen           | Nieuportmono-p |   704      | 12  40
                    |                |            |
    Helen           | Nieuportmono-p |   778      | 14   7
                    |                |            |
    Lieuts.         | Curtiss bi-p   |   140      |  2  27
     Ellyson,       |                |            |
     Towers         |                |            |
    ----------------+----------------+------------+---------

    ========================================================
                    |                           |
       AVIATOR      |           PLACE           |  DATE
    ----------------+---------------------------+-----------
    L. Paulhan      | Chevilly-Arcis-sur-Aube   | Apr. 18,
                    |   to Châlons              |   1910
                    |   two stages.             |
    Grahame-White   | London to Rugby.          | Apr. 23,
                    |                           |   1910
    L. Paulhan      | London to Manchester,     | Apr. 28,
                    |   two stages.             |   1910
    G. H. Curtiss   | Albany to New York        | May 29,
                    |                           |  1910
    C. K. Hamilton  | New York to Philadelphia. | June 13,
                    |                           |   1910
    R. Labouchere   | Over course Rheims,       | July 9,
                    |   France, world's record  |   1910
    J. Olieslaegers | Rheims, France,           | July 10
                    |   world's record.         |   1910
    A. Leblanc      | Circular course, Paris,   | Aug. 7-17,
                    |   Troyes, Nancy, Mexziers,|   1910
                    |   Douai, Amiens           |
                    |   and back.               |
    E. Aubrun       | Same as above. Won        | Aug. 7-17,
                    |   second prize. Arrived   |   1910
                    |   only 20 minutes         |
                    |   later than Leblanc.     |
    M. Cattaneo     | Lanark, Scotland.         | Aug. 13,
                    |                           |   1910
                    |                           |
    R. Johnstone    | Boston                    | Sept. 3,
                    |                           |   1910
    Walter Brookins | Chicago to Springfield,   | Sept. 29,
                    |   Ill., two stops.        |   1910
    Arch Hoxsey     | Springfield, Ill., to St. | Oct. 8,
                    |   Louis, Mo., one stop,   |   1910
    M. Tabuteau     | Buc, France.              | Oct. 28,
                    |                           |   1910
    G. H. Curtiss   | Across Lake Erie and      | Aug. 31,
                    |   return.                 |   1910
    J. A. D McCurdy | Key West to near Havana   | Jan. 30,
                    |   (fell into ocean).      |   1911
    Capt. Bellenger | Paris to Bordeaux,        | Feb. 1,
                    |   France.                 |   1911
    Lieut. Bague    | Antibes, Italy, across    | March 5,
                    |   Mediterranean to        |   1911
                    |   Gorgona Island.         |
    Hirth           | Munich to Berlin,         | June 29,
                    |   Germany.                |   1911
    Vedrines        | London to Paris           | Aug. 2,
                    |                           |   1911
    H. N. Atwood    | Boston to Washington      | June 30,
                    |                           | July 11,
                    |                           |   1911
    H. N. Atwood    | St. Louis to New York     | Aug.
                    |                           |   14-25,
                    |                           |   1911
    Olieslaegers    | Kiewit, Belgium (over     | July 17,
                    |   course).                |   1911
    Loridan         | Mourmelon, France         | July 21,
                    |   (over course).          |   1911
    Vassilieff      | St. Petersburg to         | July 24,
                    |  Moscow.                  |  1911
    Renaux          | Chartres, France          | Aug. 7,
                    |  (over course).           |  1911
    Vedrines        | Issy, France              | Aug. 9,
                    |  (over course).           |  1911
    C. P.           | N. Y. to Long Beach,      | Aug. 14,-
     Rodgers        |  Cal., World's            |  Dec. 6,
                    |  record.                  |  1911
                    |                           |
    Helen           | Bethany, France (over     | Aug. 26,
                    |  course), 3 stops.        |  1911
    Helen           | Etampes, France (over     | Sept. 8,
                    |  course), 3 stops.        |  1911
    Lieuts.         | Annapolis to near         | Oct. 25,
     Ellyson,       |  Fortress Monroe          |  1911
     Towers         |  (over water).            |
    ----------------+---------------------------+---------

Then, too, there was the great London to Manchester race for the
$50,000 offered by Lord Northcliffe, owner of the London _Daily
Mail_. This was one of the most exciting contests of the year, not
only because of the difficulties of the trip, but also because of the
nip and tuck finish between the two contestants.

Claude Grahame-White had just purchased a Farman biplane, and hearing
that Paulhan was hurrying across the Atlantic from the United States
to try for the prize himself, the Englishman announced that he would
start as soon as his machine could be set up. He had had but little
experience with the biplane, as always before that time he had used a
Blériot, but nevertheless, in spite of the advice of his friends to
wait, Grahame-White started on the 183-mile flight on the morning of
April 23d in the teeth of a high wind. According to Grahame-White's
own account of the flight he was buffeted about so unmercifully by
the wind that several times he thought he would have to descend. At
the same time the cold was so intense that he suffered agonies. He
reached his first stop at Rugby in safety, though so cold he had to
be lifted from his seat, but soon after taking the air again the gale
rose to such a pitch that he was forced to land. He went to a hotel
to rest and wait for the wind to abate, but while there the gale
tipped over his biplane, smashing it so badly that the aviator had to
give up and take his machine back to London practically to be rebuilt.

Meanwhile Paulhan had reached England and was rushing his workmen
night and day to get his aeroplane set up before Grahame-White could
complete his repairs and make a fresh start.

Finally, with the wind still blowing a gale, Paulhan started for
Manchester. Grahame-White heard of this at 6:30 in the evening, but
manfully started after his competitor and flew 60 miles, when he
was finally forced to land in the dark. Determined to remain in the
race, he started again about three o'clock in the morning with the
intention of trying to catch up with the daring Frenchman. Besides
the bitter cold, it was so dark that the Englishman could not see
whether he was flying high or low or even toward Manchester. The
danger of this kind of flying he knew was very great, because if his
engine failed him he would have had to come to earth anywhere he
happened to light, as likely on a church steeple or in a lake as on
a level spot. Of this famous flight Grahame-White wrote in his book,
"The Story of the Aeroplane":

   "My start was really something in the nature of a confused
   jumble. Faint lights swept away on either side as my machine
   moved across the ground. I could not judge my ascent at all, on
   account of the darkness. But I elevated as quickly as possible,
   and got away from the ground smartly.

   "Directly I was at a respectable height, I could see the lights
   of the railway station very distinctly. I headed toward them.
   Looking directly down, I found that I could distinguish nothing
   on the ground below me. It was all a black smudge. I flew right
   over the lights of the railway station--and as I was doing so my
   engine began to miss fire. It was certainly a very uncomfortable
   moment--one of the most uncomfortable I have ever experienced.

   "But, very fortunately for me, after a momentary spluttering,
   the engine picked up again, and fired properly. I had begun to
   sink toward the ground, upon which I knew I could have picked
   out no landing place in the darkness. As soon as my engine began
   to do its work again, however, I rose and continued my flight
   smoothly."

With the dawn came a terrific wind which forced the aviator to land
near Polesworth. While waiting for the wind to abate the Englishman
and his friends heard Paulhan had reached Manchester and won the
prize.

Of Paulhan's famous flight, one of the men who was aboard the special
train following Paulhan, according to Mr. Grahame-White, said:

"I do not think I have ever seen a machine roll about in the air as
his did. He was, we could see, incessantly at work. One wind gust
after another struck the machine and it literally reeled under the
shock.

"Up and down it went, and from side to side. Paulhan's pluck and
determination were remarkable. I do not think that any other man
could have kept on with such determination as he displayed. It was a
strange thing to see how the wind got worse and worse as the airman
flew on."

But these feats that startled the world in 1910 would not cause a
ripple of enthusiasm now, since the North American Continent has been
crossed by aeroplane; since the trip from Boston to Washington and
from St. Louis to New York has been made; since a machine has stayed
in the air a whole day, or more than eight and a half hours, since a
dozen passengers have been carried half a dozen miles and since the
development of the hydro-aeroplane.

  [Illustration:

    Copyright, by Brown Brothers, N. Y.

  CHAVEZ ON HIS FATAL FLIGHT ACROSS THE ALPS]

  [Illustration: THE LATE CALBRAITH P. RODGERS, TRANS-CONTINENTAL
  FLIER

  This picture was taken just after Rodgers had picked himself up
  after one of the many smash-ups of his aeroplane during his ocean
  to ocean flight.]

Of course it hasn't all been the winning of prizes and the cheering
of crowds, for, as we all know, there has been a tragic side to
aviation. Up to the summer of 1912 more than 150 persons had met
death in aeroplane accidents. To analyze all these accidents would
require a whole book, but experts agree that in a great many cases
they were the result of carelessness on the part of the pilot. Of
course there were other causes, such as the collapse of the wings,
the breaking of stays, the overturning by wind gusts, "holes in
the air," the explosion of the motor, the failure of the motor at
a critical time, or the collapse of the aviator, but authorities
declare that many of these can be prevented by the use of proper care
by the designers, manufacturers, and pilots of the air vehicles.

Two of the most tragic of the recent air fatalities were the deaths
of Arch. Hoxsey and Rodgers at Los Angeles, the former in December,
1910, and the latter in April, 1912. Hoxsey had just set a world's
record for altitude in his Wright biplane, while Rodgers only a few
months before his death had completed a transcontinental flight and
made a world's record.

Several women aviators also were killed in 1912, including Miss
Harriet Quimby, one of the first American women to take up flying.
Miss Quimby's machine fell with her in Boston while she was making an
exhibition flight.

The 1911 death roll of American aviators included: Lieutenant Kelly,
U. S. A.; A. Hartle, Los Angeles; Kreamer, Badger and Johnstone,
Chicago; Frisbie, Norton, Kan.; Castellana, Mansfield, Pa.; Miller,
Troy, Ohio; Clarke, Garden City, N. Y.; Dixon, Spokane, Wash.; Ely,
Macon, Ga.; and Professor Montgomery, Santa Clara, Cal., whose early
experiments are held in such high esteem by scientists.

Just as 1910 was the year for record-breaking aeroplane contests,
1911 was the year that proved the aeroplane a machine with a greater
and more important use than that of a very exciting and a very
expensive sport. Probably the most astounding developments in the
world of aviation in 1911 were the experiments of the Wright brothers
at Kitty Hawk, which showed that man has come very near to solving
the problem of true soaring flight. We will look more closely at the
experiments in a later chapter.

Of much greater practical use was the development of the
hydro-aeroplane by Glenn Curtiss. His lead in this was quickly
followed by the Wrights and most of the European makers.

The year 1911 saw the aeroplane employed for the first time in the
world's history in actual warfare. When the revolution was raging in
Mexico in February, 1911, the Diaz Army sent Rene Simon in a Blériot
monoplane to make a scouting trip over the camp of the insurrectos.
A little later on Lieutenant Foulois of the American Signal Service,
whose name will be remembered in connection with the Fort Myer
experiments, sailed over and about the camp of the mobilized American
Army at San Antonio, Texas, while the Mexican revolution was in
progress just across the American boundary line.

Next came the use of the aeroplane for scouting by the Italian Army
in its invasion of Tripoli. All of these expeditions showed that the
aeroplane can be used more successfully in war for scouting than
as a means for dropping explosives. Of course there have been many
experiments conducted by aviators in dropping paper bombs, but army
officers both in the United States and abroad are not agreed as to
the success of such projects.

Another of the important military experiments has been the equipping
of aeroplanes with wireless apparatus so that a wireless operator in
the machine with the aviator could send and receive brief messages
such as would describe the position and strength of an enemy in war
time. Also many aviators have taken up with them photographers who
have taken accurate photographs of both the still and motion variety
of the country over which they were passing. Of course the armies of
the world are building guns which will carry to a great altitude as a
defence from aerial attack.

Although the first country to adopt aeroplanes for use by its
army, the United States is now far behind other nations in its
aviation squads. The United States Signal Corps owns only a few
Wright and Curtiss biplanes, with only a small number of officers
who know how to fly them. France has an extensive fleet of several
hundred aeroplanes and a small army of aviators, while Germany has
established a school for aviation where sixty or seventy officers are
always being instructed in flying the various types of machines.
The German Army has now more than one hundred aeroplanes, besides
many dirigible balloons. The British Government has not gone so
far, but has conducted some interesting experiments in which Claude
Grahame-White was one of the leaders.

The latest things in the aeroplane, however, are always expected to
be brought out at the French Army tests, and several machines that
were first exhibited in this way will be described a little later on.

But not only in war is the aeroplane being developed, but also in
the greater work of peace, because the aeroplane enthusiasts expect
that in the near future the art will be developed to such a degree of
safety that regular systems of passenger traffic can be installed.
Besides this, the aeroplane is the fastest mode of travelling now
known, and it may be used for the carrying of mail. It was only in
the summer of 1911 that the first aeroplane mail route of the United
States was established between the aviation field in Garden City, L.
I., and the United States post-office at Mineola, several miles away.
Daily throughout the meet at Garden City Captain Beck and Earle L.
Ovington carried a sack of officially stamped and sealed mail from
the post-office on the field to the postal station at Mineola. The
first sack was handed to Beck by Postmaster-General Hitchcock. Before
this, mail had been carried by aeroplane in England, but not on a
regularly established route.

Also the aeroplane has been pressed into service by deputy sheriffs
seeking criminals and by searching parties hunting for lost persons.
The former was done in Los Angeles when a gang of desperadoes escaped
into the California desert and an aeroplane soared over the sagebrush
in an effort to locate them, while the latter was done near New
York after duck hunters had got lost in a storm on great South Bay,
and near New Orleans when an aviation student skimmed over Lake
Pontchartrain and located the body of a man drowned there.

These are some of the useful developments of the aeroplane. Of course
there have been many spectacular achievements such as the trip of
Calbraith P. Rodgers, a comparatively inexperienced aviator, from
Sheepshead Bay, N. Y., to Long Beach, Cal., across the whole American
continent; the trips of Harry N. Atwood from Boston to Washington and
from St. Louis to New York via Chicago, Buffalo and Albany; the trip
of Vedrines from Paris to Madrid, across the Pyrenees Mountains, and
the terrific speed of about 155 miles an hour, or more than two and a
half miles a minute, maintained by Vedrines for eighty miles. Just to
think of such a speed would take the ordinary person's breath away,
but the aviators speak of it calmly and say it won't be long before
it will be a common thing for aeroplanes to make a speed of 200
miles an hour, about twice as fast as the fastest automobile has ever
burned up the road. Then, too, there was the winning of the James
Gordon Bennett Cup and prize in England by C. F. Weyman, an American
who flew a Nieuport monoplane equipped with a 100-horsepower Gnome
motor. It would be impossible in our space to give a list of the
contests, races, circuit races and endurance tests of the year. Not
only were aeroplanes seen in the United States, but they were flown
in South America, Africa, Australia, Japan, India and China. The
Sphinx in the Great Sahara Desert, the Panama Canal, Niagara Falls,
the Chinese Wall, the Far Eastern temples to Buddha, and the Islands
of the Antipodes all have been circled by the dauntless birdmen, as
well as the Goddess of Liberty in New York and the Eiffel Tower in
Paris.

Young Atwood started from Boston without much ado on June 30, 1911,
sailed 93 miles to New London, Conn., and the day following reeled
off the 112 miles to New York as easily as he would walk across the
street. The Fourth of July he went to Atlantic City; July 10th he
sailed from there to Baltimore, a distance of 122 miles, which was
made in four hours and a half; and the day after that finished up by
sailing into Washington, D. C.

This young aviator still was not satisfied and shipped his aeroplane
to St. Louis, from where on August 14th he started for New York. His
longest single flight was made from St. Louis to Chicago, 283 miles
in 6 hours and 32 minutes. Flying an average distance of 105-1/2
miles a day for the remaining eleven days, he completed the 1,266
miles on August 25th. His total flying time was 28 hours and 53
minutes, and his average speed 43.9 miles per hour.

Far more exciting was the record-breaking flight of the ill-fated
Rodgers from the Atlantic to the Pacific. He had a number of severe
falls, but his determination carried him through in spite of
everything. His machine was a specially constructed Wright biplane
model Ex, something of a mixture between the regular racing and
passenger carrying types. Starting from Sheepshead Bay, N. Y., on
September 17th, the young giant, who had only learned to fly that
summer, was off on the longest trip ever attempted by a birdman.
After being on the go for forty-nine days, he sailed over the coast
towns to Long Beach on the Pacific Ocean. He was actually in the air
the equivalent of 3 days, 10 hours, 4 minutes; made an average speed
of 51 miles an hour, and his longest single flight was from Sanderson
to Sierra Blanca, Texas, on October 28th, a distance of 231 miles. He
crossed three ranges of mountains, two deserts and the continental
plain; he wrecked and rebuilt his machine four times and replaced
some parts of it eight times; he rode through darkness and wind and
rain and lightning, at the heart of a thunder cloud. Once his engine
blew up while he was 4,000 feet high and he had to glide to earth.
A special train with duplicate parts, a complete repair-shop, and
mechanics followed as he winged his way up the Hudson across New York
State, across the plains of the Middle West, down through Kansas,
Oklahoma and Texas, across the Arizona and California deserts, over
the Pacific range, and finally to the western ocean. His worst
accident came at Compton, Cal., on the last stage of his journey,
when he was so badly injured that he was laid up twenty-eight days.
This occurred on November 12th, but, persevering to the end, Rodgers
arose as soon as he was able and sailed to the ocean on December 10th.

Rodgers remained in California the rest of the winter, giving many
exhibitions of his daring and skill, only to meet his death while
holding the world's record. On April 3, 1912, while 7,000 persons at
Long Beach, near Los Angeles, watched his evolutions, his machine
tipped forward. The crowd cheered, thinking it a daring dive, but
became silent when they saw the aviator had lost control. From a
height of 200 feet the biplane plunged into the surf where the
water was only two feet deep. When the people reached the broken
machine Rodgers was dead--his neck broken. There was nothing to
show the cause of the biplane's dive. The spot where Rodgers was
killed is only a few yards from the one where he completed his
transcontinental flight, and where the citizens of Los Angeles
planned to erect a monument to his achievement.

Most boys are perfectly familiar with the important events of 1912
in aviation, which the scientist and his young friend talked over so
eagerly, for, of course, the papers are full of them, and aviation
meets are a common thing now in nearly every city of the country.

The development of the hydro-aeroplane was probably the chief work of
the inventors for the year, but with it came many devices designed
to prevent the appalling loss of life while the art of flying is
being perfected. One of them is a parachute fixed to the top of the
plane, which the aviator is supposed to open in case his machine gets
beyond control. In tests aviators have descended to earth in these
parachutes without injury. Also a number of automatic balancing and
stabilizing devices have been brought out.

Frank Coffyn's feats in and about New York Bay during the winter of
1912 with his Wright hydro-aeroplane gave that city the best idea of
the success of the aeroplane in and over water it had ever had. He
flew from and alighted on the water and great ice floes in the bay as
easily as aviators would fly from a clear landing ground on a calm
day. It was from Coffyn's machine that the picture of the Statue of
Liberty was taken.

The world saw the first hydro-aeroplane meet in March of 1911 off the
coast of the little European principality of Monaco. Seven aviators
competed for the rich prizes, and, although the Maurice Farman
machine won the greatest number of points, the Curtiss hydros showed
the greatest speed, and alighted with perfect ease in breakers four
feet high.

Far more important than the winning of prize contests is the latest
achievement of Glen Curtiss in perfecting his "flying boat," pictures
of which are shown opposite page 23. Curtiss describes this aeroplane
as a combination between a speed motor boat, a yacht and a flying
machine. Speaking of the new plane, he said recently: "With this
craft the dangers common to land aeroplanes are eliminated and safe
flying is here. It will develop a new and popular sport which will be
known as aerial yachting." The most important factor in this machine
is its safety, but it also is speedy, for in its official tests at
Hammondsport it developed 50 miles an hour as a motor boat and 60
miles an hour as an aeroplane. The boat is 26 feet long and 3 feet
wide. The planes are 30 feet wide and 5-1/2 feet deep. The rudders
are attached to the rear; the propeller, driven by an 80-horsepower
motor, is at the front.

Before we go on to other inventions let us look closely at a few of
the aeroplanes so well known to-day, so that when we see them at the
meets we can distinguish the different makes.



CHAPTER III

AEROPLANES TO-DAY

   OUR BOY FRIEND AND THE SCIENTIST LOOK OVER MODERN AEROPLANES AND
   FIND GREAT IMPROVEMENTS OVER THOSE OF A FEW YEARS AGO--A MODEL
   AEROPLANE.


Every effort of the aeroplane inventors these days is bent toward
making the power flier useful--a faithful servant to man in his
day-to-day life--and to this end greater carrying capacity is one
of the chief objects," said the scientist one day in answer to a
question from his young friend as to what the future of aviation
would be.

"No one can tell what the future will bring forth," he continued.
"You or one of your friends might invent the ideal aeroplane. There
is one way of telling how the wind blows, though, and that is by
watching the new developments of aeroplanes very carefully. Let's
look at some of them."

Of course it was impossible for the boy to study every improvement or
every make of aeroplane, but the scientist pointed out a few examples
that served to show how science is trying to improve on aviation as
we know it to-day.

The boy's friend said that probably the most wonderful accomplishment
in the art of air navigation since power fliers became an
accomplished fact was the work of Orville Wright in the fall of 1911
with his new glider, which he tested at the Wright brothers' old
experiment station at Kitty Hawk, N. C.

"Never before in the history of aviation, so far as is known," said
the scientist, "has man come so near to the true soaring flight which
we have seen is the third stage of aeroplaning."

Not only did this wonderful glider sail into the wind and reach an
altitude of 200 feet, but, under the control of the pilot, it stayed
in the air 10 minutes and 1 second, most of the time hovering over
one spot, without the use of any propelling device.

On the day of the great test the glider was taken to the top of Kill
Devil Hill, which is 110 feet high, and while the wind was roaring
through the canvas at 42 miles an hour the machine was launched. To
those unaccustomed to the actions of gliders it would have seemed
that the engineless biplane would be blown backward over the edge of
the hill. Instead, it shot forward and upward into the teeth of the
hurricane. The force of the wind on the planes, which were presented
diagonally to it, caused the flier to rise and go ahead by just about
the same principle that a ship can sail almost into the teeth of the
wind by having her sails set at the proper angle.

When it had reached the altitude of 200 feet it stopped motionless
and to those below who saw Orville Wright sitting calmly in the
pilot's seat it seemed that some unseen hand was holding him aloft.
Suddenly the pilot pressed a lever and the glider darted 250 feet to
the left, returned to her original position, sank to within a few
feet of the hillside and hovered there for two minutes.

The Wrights had been working on the principles involved for a long
time and at the testing grounds were Orville Wright, his brother
Loren, who up to that time had not been known to the world of
aviation, and Alexander Ogilvy, an English aviator.

After the remarkable test Orville Wright was asked, "Have you solved
real bird flight?"

"No," he replied, "but we have learned something about it."

The aviator went on to explain that had he been up 3,000 feet or so,
where the wind currents are always strong, he probably could have
stayed up there all night, or as long as he cared to.

This greatest of all feats of soaring was accomplished in a glider
that looked to the ordinary person very much like the modern Wright
biplane without the engine. There were skids but they were very low.
In general outline the machine was composed of two main planes, a
vertical vane set out in front, two vertical planes at the rear
of the tail, and behind these the horizontal plane. The details of
the construction of the glider were not made public and only a few
persons saw it, but from all accounts the curve of the main planes
was much greater than is usual, thus gaining the glider a greater
degree of support from the air, and the planes were capable of being
warped much more than in the ordinary Wright biplane. The vertical
vane in front, which does not appear on any of the Wright power
fliers, was a foot wide and five feet tall. It acted as a keel and
gave the machine greater side-to-side stability because the wind
passing at a high speed to each side of it tended to keep it vertical.

In working out a biplane that could rise from or alight on the water,
Glenn Curtiss practically doubled the usefulness of aeroplanes.
The experiments, conducted under the auspices of the United States
Navy so impressed the officers that several have been added to its
equipment. Curtiss has been experimenting with hydro-aeroplanes
for several years, but before actually completing one he conducted
a number of experiments with ordinary biplanes in the vicinity of
Hampton Roads, Va., in 1911, to prove them available for use on
battleships. Finally, Lieutenant Ely flew from the deck of the
cruiser _Birmingham_ over the water and to a convenient landing spot
on land.

Later on Curtiss went to California to perfect his hydro-aeroplane,
and while conducting the work Lieutenant Ely made a flight from shore
to the deck of the battleship _Pennsylvania_ which was lying in San
Francisco Harbour. These two incidents were more in the nature of
"stunts" than developments, but they showed what an aeroplane could
do if attached to a battleship fleet as a scout.

Even more convincing was the proof when Curtiss finally worked out a
form of wooden float which was put between the mounting wheels. The
float was flat-bottomed with an upward inclination at the prow so
that when skimming over the water the tendency was to rise from the
surface rather than to cut through it. Small floats at the outer tips
of the lower main plane helped to keep the machine on an even balance
while floating at rest upon the water. The wheels served their
regular purpose if the machine started from or alighted upon land.

The experiments were conducted on San Diego Bay, and it was only
after long and patient labour that the work of Mr. Curtiss and his
military associates was rewarded with success. In the course of the
experiments he tried a triplane, which had great lifting power, but
this later was abandoned in favour of the regular biplane fitted
with a float. After the machine had been perfected, Curtiss flew his
hydro-aeroplane out into the bay to the cruiser _Pennsylvania_, upon
which Ely had landed a month before, and after landing on the water
at the cruiser's side was pulled up to her deck and later was put
back into the water from where he sailed to camp. The machine was
named the _Triad_ because it had conquered air, land, and water.

Of the machine Curtiss says: "I believe the hydro-aeroplane
represents one of the longest and most important strides in aviation.
It robs the aeroplane of many of its dangers, and as an engine of
warfare widens its scope of utility beyond the bounds of the most
vivid imagination. The hydro-aeroplane can fly 60 miles an hour, skim
the water at 50 miles and run over the earth at 35 miles."

It was not long after the Curtiss hydro-aeroplane had been
successfully demonstrated, before all the other leading makers
brought out air craft that could sail from and alight on water as
well as on land. The Wright hydro-aeroplane, which is equipped with
two long air-tight metal floats instead of one, has achieved great
success in the United States. In Europe all the leading biplane types
are now made with hydro-aeroplane equipment, and flying over water
became as popular last year as flying over land did in 1910.

The first American monoplane to be equipped with the floats of a
hydro-plane was shown by the "Queen" company at the New York Aero
show in May, 1912. It was called an aero boat as the front part of
the fuselage was enclosed like a boat and the operator sat in it,
under the wings. The propeller was at the rear and there was a small
pontoon at each end of the wings to keep it on an even keel when
stationary in the water. A short time after this the Curtiss company
turned out the flying boat which was described on page 90.

  [Illustration: THE WORLD'S LONGEST GLIDE

  This photograph shows the new Wright glider, driven by Orville
  Wright, being held above Kill Devil Hill, N. C., in the face of a
  high wind, for 10 minutes 1 second.]

  [Illustration: THE END OF A GLIDE

  After remaining aloft the new glider was allowed gently to settle
  to earth.]

  [Illustration: LANDING ON A WARSHIP

  Lieutenant Ely is here shown landing in a Curtiss biplane on the
  platform built on the deck of the cruiser _Birmingham_, at anchor
  in Hampton Roads.]

  [Illustration:

    Courtesy of the _Scientific American_

  BOARDING A BATTLESHIP

  Glenn Curtiss being hoisted aboard the battleship _Pennsylvania_
  in San Diego Harbour after alighting alongside in his
  hydro-aeroplane.]

In general outline the aeroplanes in use to-day differ greatly from
those seen several years ago, but the difference is in form rather
than in principle. There have been many improvements, of course, in
construction, control of the fliers, and in the powerful engines that
drive them. In fact the tendency of aeroplane builders has been to
adopt the successful devices on other machines rather than to work
out original ones.

The most noticeable change in the present-day aeroplanes is the way
in which builders nowadays are enclosing the bodies and landing
framework in canvas or even light metal, so that they shall offer as
little resistance to the air as possible. It gives the machines the
appearance of being armoured, as will be noticed from the pictures
of the new planes, so the term has come to be used in that sense,
although, of course, the covering would not protect them against
bullets. This armour has become particularly popular with the
designers who are making aeroplanes for the French Army, and at the
recent military tests in France most of the machines were covered to
some degree, and many of them looked for all the world like great
long-bodied gulls or mammoth flying fishes.

Several aeroplanes have been equipped with twin motors and double
steering systems so that either or both could be used. This, of
course, is a great advantage in case one fails. Also designers are
figuring on wing surfaces that can be reefed or telescoped for
better stability as well as wings that can be folded for easier
transportation.

Experts do not agree on the respective merits of the two great
general types of aeroplanes--that is, monoplanes and biplanes. Some
claim that the monoplane is the best and others that the biplane
is the most successful flier. Records show that so far monoplanes
are the faster of the two types, but biplanes can be fitted with
hydro-aeroplane floats, whereas it is impractical with most
monoplanes. Many declare the biplane to have the greater lifting
power, but the Blériot "Aero-Bus" has carried a jolly family party of
eight without difficulty. Each type has its champions as to safety,
reliability and endurance, but time will have to decide the question.


WRIGHT BIPLANE

First let us look at one of the latest Wright biplanes as it is
brought out on the aviation field and is being tuned up by its
keen-eyed young American pilot. The description of the 1909 Wright
will be remembered. Also it will be remembered how the Wright
brothers in 1910 discarded the forward horizontal elevating rudder
entirely, and substituted in its place a single elevating rudder
at the rear end of the tail, which also served to give fore and aft
stability. Also in 1910 the Wright brothers added wheels to the skids
that hitherto had been used for starting and alighting. Thus the
old system of having the machine skidded along a rail by a falling
weight, as previously described, was done away with in favour of its
running over the ground on its wheels.

After noting these improvements, we will look at the general outlines
of such a Wright racing machine as contested for the James Gordon
Bennett Cup in 1910. The two main planes are the smallest yet used
on a biplane, being only 21-1/2 feet wide from tip to tip, and only
3-1/2 feet from front to rear. Thus, the aspect ratio, it will be
seen is 7. They are the same general shape as the planes on the
other Wright machines, and their total area is 145 square feet. The
machine is steered up or down by the horizontal elevator rudder in
the rear, which is oblong-shaped, 8 by 2 feet. The rudder that steers
the machine from right to left is set vertically at the tail and is
worked in combination with the levers that work the warping of the
tips of the planes. On this little machine the twin-screw propellers,
8-1/2 feet in diameter, sweep practically the whole width of the
machine. They are connected by chains to the 60-horsepower 8-cylinder
Wright engine (in ordinary biplanes of this type the engine is
30 horsepower) and make 525 revolutions per minute (in ordinary
machines of this type they make 450 revolutions per minute). The
machine weighs a total of 760 pounds and is capable of more than 60
miles an hour.

The elevation rudder is controlled by a lever set either at the right
or left hand of the operator. The direction rudder is controlled by
a lever that also controls the warping of the planes, as in turning
it is necessary to cant the machine over to the inner side of the
curve being made, in order to prevent slipping sidewise through the
air. However the handle of the direction and warping lever is so
arranged by a clutch system that by moving the lever simply from
side to side the direction lever can be worked independently of the
warping. The direction and balancing system then, we see, is worked
in this manner. Say, while flying, a gust of wind causes the biplane
to dip at the right end. The operator quickly moves his warping lever
forward. This pulls down the tips of the right planes, and at the
same time elevates the tips of the left planes. The change of the
angle makes the right side lift to its normal position while it makes
the left side drop. Consequently the machine is restored to an even
keel and the operator lets the planes spring back to their normal
shape.

The large 1911 Wright biplanes, model B, are designed the same as the
small racing models except that the wings have a spread of 39 feet,
and a depth of 6-1/4 feet--a total area of 440 square feet. The
perpendicular triangular surfaces in front like two little jib sails,
are a distinguishing feature, although the latest Wright models
substitute narrow vertical fins about six feet tall and six inches
wide. They are placed immediately in front of the main planes. The
hydro-aeroplane substitutes two aluminum floats for the wheels.


CURTISS BIPLANE

The Curtiss biplane, which we have seen has had a great deal to
do with the development of aviation, is one of the simplest and
most successful machines known to-day. The main planes of the
regular-sized machines have a spread of 26-1/2 feet, are set 5 feet
apart, and have a depth from front to rear of 4-1/2 feet. The total
wing area is 220 feet. The direction rudder is a single vertical
vane at the rear, which is turned by the steering wheel connected
by cables. The elevation rudder consisting of one horizontal plane
24 square feet in area is at the front and is turned up or down
by the pilot as he desires to sail up or down, by means of a long
bamboo pole connecting the elevation rudder with his pilot wheel. He
pushes the wheel forward or back to rise or descend, while he twists
it from right to left to turn in either of those directions. The
side-to-side balance was maintained in the early Curtiss machines by
flexible wing tips, but these later were replaced by ailerons placed
between and at the outer tips of the main planes. Each aileron had an
area of 12 square feet and they were operated by a brace fitted to
the operator's body. Thus, if the machine tipped to the right, the
operator would swing to the left, turn the ailerons, and right the
machine. In some later Curtiss biplanes these ailerons were replaced
by others, like flaps attached to the rear outer edges of the main
planes. By raising the flaps on one side and lowering them on the
other the balance was well preserved.

As before stated, these machines are driven by Curtiss engines. In
most of them the engines are 4-cylinder, 25-horsepower motors. The
cylinders in this type, of course, are stationary, but the engine
shaft is directly connected with the 6-foot propeller at the rear,
which makes 1,200 revolutions per minute. The pilot sits between the
two main planes of his engine. On large Curtiss machines seats for as
many as three passengers have been arranged at the sides of the pilot.

The most important work Curtiss has done in the last few years is the
development of the hydro-aeroplane, which has been explained.


VOISIN BIPLANE

The next biplane with which we are familiar is the Voisin, which
Henri Farman demonstrated as the first really successful aeroplane
seen in Europe. This machine was a standard of what was called the
cellular type because it was composed of cells, like a box kite. The
two main planes, which were the same size, 37 feet by 6-1/2 feet,
were connected at the outer edges so as to make the plane a closed
cell--i. e., a box with the ends knocked out. Two other vertical
surfaces between the main plane gave the machine the appearance of
three box kites side by side. The tail out behind was composed of a
square cell. In the centre of it was a vertical vane for steering it
from right to left, while out in front was a single horizontal rudder
for raising or lowering the plane. The control was much the same as
in the Curtiss machine. The steering wheel turned the plane from
right to left, and was connected by a rod with the elevator, so that
by pushing it forward or back, the machine was raised or lowered.
There was no device for maintaining a side-to-side balance as the
cell formation was supposed to keep the machine on an even keel. The
motor drove a propeller at the rear.

The later Bordeaux type of Voisin which was built for military
purposes does away with the side curtains and box tail. On the outer
rear edge of the upper main plane are ailerons for maintaining the
balance, which are operated by foot pedals. The elevator is a single
horizontal plane at the rear of the tail, while the direction rudder
is a vertical plane beneath it. This machine carries two persons, and
is frequently driven by a Gnome engine.

Still another and later type of the Voisin Bordeaux is the front
control. In this the ailerons are used as previously described, but
also there are side curtains enclosing the outer edges of the main
planes. Out in front at the end of a long framework or fuselage are
the horizontal elevating planes, and the vertical direction planes.
Both these machines have double control systems.


FARMAN BIPLANE

Dissatisfied with the work of his first Voisin biplane in the early
days of flying Henri Farman designed and built a machine that bore
his own name, of which the military type is now looked upon with
great favour by many of the European experts.

The two main supporting planes in the regular Farman models were 33
feet by 6-1/2 feet, set 7 feet apart, and with a total area of 430
square feet. These dimensions have been varied slightly in other
machines. The elevating rudder, which was set well out in front of
the body of the machine, was a horizontal plane controlled by a wire
and lever. In the rear was a tail of two parallel surfaces, slightly
curved like the main planes of the biplanes. These two surfaces
steadied the machine from front to rear. At their two sides were two
vertical surfaces, giving the tail the appearance of a box kite,
so familiar in the Voisin. These two vertical surfaces, however,
comprised the direction rudder, and were turned from side to side by
the operator with a foot lever. In some of the later Farman biplanes
the two vertical surfaces were done away with in favour of a single
one, extending between the centres of the two horizontal surfaces of
the tail. The side-to-side balance was maintained by ailerons in the
form of wing tips set at the outer rear edges of the main planes.
The tips were hinged and connected with wires which led to the lever
that worked the elevating rudder. Thus by pulling this lever toward
him the operator tilted the rudder up, and the machine rose, and by
moving it from side to side the biplane was kept on an even keel. For
instance, if the machine were to tip to the right he would move the
lever to the left, pulling _down_ the hinged ailerons on the right.
The ones on the left would still remain standing straight out at the
same angle as the main planes. The increase in the lifting power on
the right side would cause that end to rise, righting the machine.

Most Farman biplanes these days are driven by the well known
7-cylinder Gnome rotary air-cooled engines, set at the rear of the
main plane. They are directly connected with the single propeller,
which is 8-1/2 feet in diameter. The seat for the aviator is in front
of the engine at the front edge of the lower plane, and there also
frequently are placed seats for two other passengers. The machine is
mounted on wheels and skids.

The "Farman Militaire" type is one of the largest and heaviest
machines made to date, having a total area of supporting plane of 540
square feet. The chief difference is that instead of two direction
rudders there are three, and that the lower main plane is set at
a dihedral angle. It was on such a machine ("Type Michelin") that
Farman flew steadily for eight and a half hours. It also has made
remarkable distance, endurance, and weight-carrying records, although
it is a slow machine, making but 34 to 35 miles an hour. The "Type
Michelin" is distinguished by the fact that the upper main plane has
a spread of 49 feet, 3 inches, while the lower plane had a spread of
only 36 feet.


MAURICE FARMAN BIPLANE

Soon after Henri Farman had become famous as an aviator and
constructor of aeroplanes, his brother Maurice began to build
air craft. The Maurice Farman biplane was the result. After
conducting their business separately for several years the brothers
consolidated, and each type is known by the name of the brother
designing it. The Maurice Farman biplane has some remarkable records,
among them the winning of the Michelin prize in 1910 by Tabuteau, who
flew 362-1/2 miles in seven and a half hours without stopping.

The main planes have a spread of 36 feet and a depth of 7-1/2 feet.
They have not as great a curve or camber as most biplanes, which
increases their speed. The tail is of the well-known Farman cell
formation--that is, it has four sides. The two vertical surfaces
swing on pivots and are controlled by wires connecting with the
direction steering wheel. The horizontal surfaces of the tail, except
for the tips, are stationary, and steady the machine from front to
rear. The rear tips of these two surfaces, however, work on pivots in
connection with the main elevating plane which is set out in front.
The elevator is a single plane controlled by a rod connected with the
steering wheel, while the tips of the horizontal tail surfaces are
controlled in unison with the main elevator by wires, also connected
with the steering wheel. Ailerons are set into the rear outer tips
of the main planes, for the control of the side-to-side balance, and
these are worked by foot pedals. In order to give greater safety in
case of the breakage of a wire, all the controlling parts in the
Maurice Farman machine are duplicate, which is a big step toward the
much-desired double controlling system in aeroplanes. The biplane
is mounted on both skids and wheels. The operator sits well forward
on the lower plane in a comfortable little pit enclosed in canvas.
Thus, the Maurice Farman machine was the first to adopt this device
for shielding the pilot from the wind. The engine used usually is an
8-cylinder air-cooled Renault, which drives a propeller nearly 10
feet in diameter.


BREGUET BIPLANE

Only slightly known in the United States but well and favourably
known in Europe, particularly in France, is the Breguet biplane,
which made wonderful records in the French Army tests in 1911. A
brief description will show the difference between this machine and
others of the biplane type. It has won many prizes for its stability
and lifting powers, and also has shown great speed. The framework is
mostly metal and is so elastic that it gives under the pulsations
for the wind, so that the machine is not so badly strained by gusts
as the more rigid kinds. Also it is thought the elasticity increases
its lifting capacity. Of the two main planes the upper one spreads
43-1/2 feet, while the lower one spreads 32-1/2 feet. They are 5-1/2
feet deep, and set 7 feet apart. The body and tail of the machine are
made on delicate graceful lines, terminating in the elevation and
direction rudders at the rear. There are no rudders, vanes, or other
rigging out in front. The lateral balance is maintained by warping
the planes. The propeller is at the front of the machine, and is of
the tractor type, pulling it through the air instead of pushing it.
In the latest machines a metallic three-bladed Breguet propeller, the
pitch of which is self-adjusting, is used, but in others a two-bladed
wooden propeller, such as is familiar in this country. The long body,
or fuselage, as the framework of the tail is called, is enclosed
on the latest types of Breguets in use by the French Army, greatly
adding to its gracefulness, and decreasing the wind pressure.

There are several other makes of biplanes that could be described
to advantage but space prevents it, and the descriptions here given
serve to illustrate the principle of the biplane type of aeroplane.


BLÉRIOT MONOPLANE

The first and probably best known monoplane, the Blériot, still holds
many records for both speed and endurance. The Blériot machines have
so many variations that it would be impossible to describe all the
types of monoplanes this versatile Frenchman has turned out. We are
familiar in a general way with the Blériot, the single widespreading
main plane, set at a slight dihedral angle, with its long, graceful
body out behind terminating in the horizontal elevating and vertical
direction rudders, giving it the appearance of a great soaring bird
as it sails through the air as steadily as an automobile on a smooth
road--much more steadily in fact, for as soon as the wheels of an
aeroplane leave the ground all jolting disappears, and not even the
vibration of the engine is noticeable, although the roar of its
explosions can be heard a great distance. There is nothing but the
breeze and the earth streaming along behind you, as if it were moving
and you were hovering motionless high up in the sky.

In the famous Blériot XI, in which the designer made the first trip
across the English Channel, the main plane had a spread of a little
more than 28 feet and a depth of 6-1/2 feet, a total area of 151
square feet and a low aspect ratio of about 4.6. At the end of the
stout wooden framework, that made up the body and tail, was the
vertical direction rudder 4-1/2 square feet in area which was turned
from right to left by a foot lever. The elevation rudder was divided
into two halves, one part being put at each side of the direction
rudder. The total area of the elevator was 16 square feet, while the
horizontal stabilizing plane to which the elevator was attached was
about the same. The balance was maintained by warping the main plane,
but instead of warping the tips of the plane, as is done in the
Wright biplanes, the two sides of the main plane were warped from the
base, so that the operator could change the angle of incidence--that
is, the angle at which the planes travel through the air. Thus, if
the machine should tip down on the right side, the operator would
warp the planes so as to increase the angle of incidence on the right
side and lessen it on the left side. In other words, the rear part
of the right wing would be bent downward, while on the left side the
rear edge would be raised. The forward edge remains stationary. The
increase of the angle on the right side would cause an increase of
the lifting power on that side and also the decrease of the angle
on the left side would lessen the lifting power of the left wing
so the right side, which was tipping down, would be lifted, and the
machine restored to an even keel. This warping was done by moving
from side to side the same lever on which was mounted the steering
wheel. The whole machine was mounted on a strong chassis with wheels
for starting and alighting. The pilot sat in the framework above
the main plane. The monoplane was propelled by a single propeller
of the tractor type 6 to 7 feet in diameter, placed at the front of
the machine. It was driven in the early Blériots by a 23-horsepower
Anzani motor, but more lately the Blériot machines have carried Gnome
motors.

One of the important improvements which appeared on the No. XI _bis_
was the changing of the main plane so that the upper side was curved
but the under side was nearly flat. This gave the machine much more
speed and the designers found that the flattening out of the curve on
the under side did not greatly lessen the lifting power. This same
type of machine also was made later to carry three passengers. The
machine known as the "Type Militaire" was just about like the others
except that the tail instead of being rectangular was fan-shaped. It
carried seats for two and was equipped with all the latest aviation
accoutrements, such as tachometers, barographs to record altitude,
instrument to record inclination, various other gauges, map cases and
thermos bottles.

The most distinctive feature of the Blériot No. XII, which was the
first aeroplane to carry three passengers, was the long vertical
keel, shaped like the fin of a fish at the top of the framework. The
direction rudder was at the rear of this keel, while the elevation
rudder was at the rear and a little below it. Immediately below the
direction rudder was a small horizontal plane about the size of the
elevation rudder which helped to maintain a fore and aft stability.

Then there was the famous Blériot aerobus which would carry 8 to
10 people. The machine was very large, the wings having a spread
of 39 feet and a total area of 430 square feet. It was driven by
a 100-horsepower Gnome motor and a propeller 10 feet in diameter,
which was placed at the rear of the main plane. Thus the propeller
drove the machine through the air from the rear instead of pulling it
from the front as do the tractor propellers on most of the Blériot
monoplanes. The passengers were seated underneath the main plane on
the framework which extended out to the rear. The tail terminated
in the vertical direction rudder and a large stationary horizontal
surface which gave the necessary front-to-rear stability. The
elevating plane of this type was placed out in front.

  [Illustration: THE FLYING BOAT STARTING

  The latest aeroplane is here seen cutting through the water
  preparatory to ascending into the air.]

  [Illustration: THE CURTISS FLYING BOAT

  This is the very latest development in the hydro-aeroplane, and
  moreover it is claimed by its inventor, Glenn Curtiss, to be the
  first absolutely safe aeroplane.]

  [Illustration: GLENN CURTISS ALLOWING HIS HYDRO-AEROPLANE TO
  FLOAT ON THE WATER AFTER ALIGHTING]

  [Illustration: HYDRO-AEROPLANE AT MONTE CARLO

  At the hydro-aeroplane meet at Monaco practically every
  well-known type of biplane was equipped with pontoons and entered
  the contest.]

The Blériot Canard or "duck" is one of the latest developments of
the pioneer constructor, and the chief difference between it and
the other Blériot machines is that the body extends out in front
of the main plane instead of behind, something like Santos-Dumont's
first machine. The main plane has a spread of 29 feet, and has a
total supporting surface of 129 square feet. At the forward end of
the body is placed the horizontal elevating rudder, while two small
vertical rudders, placed on the top of the outer ends of the main
plane and working in unison, serve to steer it from side to side. The
balance in this machine is preserved by large hinged ailerons at the
outer rear edges of the main plane. The pilot sits in front of the
engine underneath the plane, which is a military advantage, giving
him ample chance for looking down and observing everything over which
he is passing.


ANTOINETTE MONOPLANE

No machine that ever was flown has excited more admiration from those
on the ground than the graceful Antoinette monoplane, designed by the
famous French motor-boat builder, Levavasseur. Its great tapering
wings and long fan-shaped tail give it the appearance of a huge
swallow or dragon-fly as it sails through the air, and whenever this
type has appeared at the American meets it has received tremendous
applause.

The two best known models of the Antoinette are the type used by
Latham in this country, and the "armoured" type, entered in the
French military tests. The bow of the first-mentioned machine
is shaped very much like the prow of a boat with the 50 to 100
horsepower 8-or 16-cylinder water-cooled Antoinette engine occupying
the extreme forward part. The propeller is set in front of this,
and is of the tractor type, drawing the machine through the air
behind it. In the recent models of the Antoinette, the main plane,
set at a slight dihedral angle, spread a little more than 49 feet
(compare this with the spread of 28 feet of the Blériot). The two
sides of the main plane taper from the body of the machine, but have
an average depth from front to rear of 8 feet, which gives a fairly
high aspect ratio of about 6. The total area is 405 square feet. The
main plane also tapers in thickness, being nearly a foot through
close to the body and tapering down to a few inches at the outer
tips. The graceful tail at the rear has both vertical and horizontal
surfaces gently tapering to the height and width of the elevating
and direction rudders. The elevating rudder is a single horizontal
triangular surface at the rear controlled by cables running to a
pilot wheel at the operator's right hand. It has an area of 20 square
feet. The direction rudder is composed of two triangular surfaces
with an area of 10 square feet each. One is above the elevator and
the other below, but both are worked in unison by wires connecting
with a foot lever. The machine is balanced by a warping system
much like that on the Wright biplanes we know so well. This is
accomplished by wires connecting with a steering wheel at the pilot's
left hand, so that he uses his right hand to steer his machine up
or down, his feet to steer from right to left, and his left hand to
maintain the balance. Of course, in making a sharp turn he uses his
warping wheel as well as his direction wheel, because, as previously
explained, it is necessary to incline the machine over toward the
inside of the curve desired to be made. The pilot sits in the
framework, above and a little back of the supporting plane.

The "armoured" Antoinette, which was designed for military purposes,
is entirely enclosed, even increasing the already great resemblance
to a bird, while the direction rudder is made of a single surface,
and the elevating rudder of two rhomboid-shaped rudders. The pilot
sits in a cockpit with only his head and shoulders protruding above
and has a view below through a glass floor. Its most important
feature is the total elimination of cross wires, struts and the like.
The resistance is greatly decreased, but the weight increased. In
addition, a peculiar wing section is used, flat on the under side
and curved on the upper side. The wings are immensely thick, being
entirely braced from the inside. At the body the wings are over
two feet thick. Their thickness decreases toward the tips, which
are about eight inches thick. The shape of each wing is called
trapesoidal, and they are set at a large dihedral angle. The motor
is a regular 100-horsepower Antoinette.

The oddest feature of this type is the landing gear, which is
entirely enclosed to within a few inches of the ground; the landing
wheels at the front are six in number, three on each side of the
centre, enclosed in what is called a "skirt." At the rear are two
smaller wheels.

The dimensions are roughly as follows: Spread, 52-1/2 feet, wings,
602 square feet; length over all, 36 feet; depth of wings (from front
to rear) at tips, over 9 feet, increasing to almost 13 feet at the
centre. The total weight is nearly 2,400 pounds.


NIEUPORT MONOPLANE

The Nieuport monoplane is one of the newer machines that has
attracted a great deal of attention for its speed with low-powered
engines. Among the achievements of this monoplane was Weyman's
winning of the James Gordon Bennett Cup and prize in England in 1911,
and the demonstration of its remarkable passenger carrying abilities.
The Nieuport also is a wonderful glider, for Claude Grahame-White
took his new one up 3,000 feet at Nassau Boulevard, Garden City,
during the 1911 meet there and glided down the whole distance without
power, the downward sail taking him nearly as long as the upward
climb.

  [Illustration: THE WRIGHT BIPLANE

  Baby Wright model. Orville Wright is in front of seat, while
  Wilbur Wright is holding back on the fuselage.]

  [Illustration: STANDARD CURTISS BIPLANE

  For reliability and stability the Curtiss biplane is one of the
  best known models.]

  [Illustration: CURTISS STEERING GEAR

  Sitting in front of the engine the aviator controls the ailerons
  by straps over his shoulders, and the direction and elevation
  rudders by the steering wheel.]

The passenger machine has a spread of 36 feet with a length of
about 24 feet from front to rear. This machine is generally equipped
with a 50 or 70 horsepower Gnome motor, although the plane with
which Weyman won the Gordon Bennett contest was equipped with a
100-horsepower Gnome motor. The smaller machine has a spread of 27
feet, 6 inches and a length of 23 feet. An engine of the 3-cylinder
Anzani type is usually mounted on this monoplane.

The body of the flier gracefully tapers to a point at the rear where
are placed the elevating and steering rudders.

The chief characteristics of the Nieuport are strength, simplicity in
design, and great efficiency of operation. The smaller machine, which
is equipped with an engine of from 18 to 20 horsepower, has acquired
a speed of 52-1/2 miles an hour. The Nieuport is constructed along
original lines throughout. The wings are very thick at the front
edge, while the rear edges are flexible so that in gusts of wind they
give a little.

The fuselage, or body of the machine, which is extraordinarily large,
and shaped like the body of a bird, is entirely covered with canvas.

The weakest part of the Nieuport monoplane is the alighting and
running gear, which is so designed as to eliminate head resistance,
but unfortunately this simplicity is carried to an extreme which
makes the machine the most difficult one to run along the ground,
and to this construction may be traced most of the accidents which
have occurred to the Nieuport machines.

The Nieuport control differs from that of the majority of other
machines inasmuch as the wing warping is controlled by the feet,
while hand levers operate the vertical and elevating rudders.


MODEL AEROPLANES

After having taken in such a lot of information about aeroplanes the
scientist's young friend considered himself fairly well equipped to
build a flier.

"Why couldn't I build a little model aeroplane?" he said one day.

"No reason why young couldn't," answered his friend in the
laboratory. "You have a little workshop at home and your own simple
tools will be plenty. You will have to buy some of your materials,
but they are all cheap.

"There is no sport like model aeroplane flying, but to the average
American boy the flying is not half so much fun as meeting and
overcoming the obstacles and problems entailed in making the little
plane. These days nearly any boy would scorn to enter a model
aeroplane tournament with any machine that he did not make himself,
and a great many of the amateur aviators even prefer to make their
own designs and plans.

"When we begin to take up the construction of a glider or an
aeroplane, we must, like the Wright brothers, reluctantly enter upon
the scientific side of it, because in model building we cannot simply
make exact reproductions of the great man-carrying fliers, but must
meet and overcome new problems. The laws that govern the standard
aeroplanes apply a little differently to models, so it is necessary
for the model builder to figure things out for himself.

"For instance," explained the scientist, "most amateurs have decided
that monoplane models fly much better than biplanes. The reason
for this is probably that with the miniature makes the air is so
disturbed by the propeller that its action on the lower plane
tends to make it unsteady rather than to give it a greater lifting
capacity. This could be avoided by placing the two planes farther
apart, but they would have to be so far separated that the machine
would be ungainly and out of all proportion. Moreover, the second
plane, with the necessary stays and trusses, adds to the weight of
the machine, and this is always bad in models.

"There are as many different types of model aeroplanes as there are
of the big man carriers, but you had better make a small flier first,
experiment with it, and then work out your own variations just as you
think best."

"Will you help me build one?" asked the boy.

"No, for you don't need my help and you will have more fun doing it
alone. I will tell you how to go about it, and with what you know of
the principles of aviation from our conversations it will be easy to
make a successful model."

Then taking a piece of paper and a pencil the scientist began to draw
rough plans for the building of a little model monoplane something
like the Blériot, except that it was driven tail first, with the
propeller at the rear. As he worked he explained how the plan shown
below should be followed, saying that the beginner would find that a
length of about one foot would be the most convenient for this first
model. Later on he can make the big ones with a spread of wings of
three feet, and a length of forty or more inches.

  [Illustration: A SIMPLE MODEL AEROPLANE]

First, the three main parts of the model should be made. Those are
the two main planes and backbone. The simplest way of making the
planes for a model of this kind is to use thin boards of poplar or
spruce, which will not split easily and which can be worked with a
jackknife. The large plane should be rectangular, with a spread
of eight inches and a depth of two inches, while the smaller plane
should be the same shape, four by one inch. They should be one eighth
of an inch or less in thickness. Plane and sandpaper them down as
thin and as smooth as possible without splitting them, and round off
the corners just enough to do away with sharp edges. Now draw a line
parallel with the side that is eight inches long, three quarters of
an inch from the edge. Measure off two inches toward the centre from
the outer edges, along this line, and draw lines parallel with the
edges that are two inches deep. At the corners which are to be the
rear we find the lines make two rectangles three quarters of an inch
by two inches, and these corners are to be cut away in a graceful
curve from the corners of the rectangles. When it is done the main
plane will be shaped like a big D with the curved edge to the rear.
The front edge of the small plane also should be curved, but not
nearly so much as the larger plane. This done, the planes can be
steamed or moistened with varnish, and given a slight curve or camber
by laying them on a flat board with a little stick underneath and
weights at the front and back to hold down the edges while they dry
and set. The sticks should be about one third of the way back from
the front edges, from there tapering down to the level of the rear
edge. Of course, in this process great care must be used not to split
the delicate planes.

  [Illustration: STANDARD FARMAN BIPLANE

  Note the box tail and the single elevating plane.]

  [Illustration: FARMAN PLANE WITH ENCLOSED NOSE

  This type is sometimes used in Europe, and it led to the Farman
  "canard" with the box tail in front.]

  [Illustration: A MODERN BLÉRIOT

  This machine has the enclosed fuselage and other recent
  improvements. Note the four-bladed propeller.]

  [Illustration: A STANDARD BLÉRIOT

  This is the regular type of Blériot made famous by long
  over-water flights.]

  [Illustration: PASSENGER-CARRYING BLÉRIOT

  This type has tremendous capacity for carrying great weights.]

There are many other ways of making planes. If one does not care to
round off the edges, he can make very light wooden rectangular frames
of the size indicated, and cover them with cloth, or silk, afterward
varnishing them to make them smooth and air-tight. It is difficult
to give such planes a camber, but if the framework is made of strong
light wire, such as umbrella ribs, and then covered, the camber can
be obtained by putting light wire or light wooden ribs in the planes,
much like on the big standard makes. Plane building can be developed
to a high art, and after a boy makes one or two models he will see
any number of ways that he can make them lighter, stronger and more
professional looking.

With the planes finished, the next work is to make the backbone of
the machine by planing and sandpapering a light strong stick one
foot long and not more than a quarter of an inch square. Cut out a
neat block of the same wood, the same thickness as the backbone, and
one inch square. Glue it to the end of the backbone and reinforce it
by wrapping it with silken thread moistened with glue or varnish.
Be sure to have the grain of this block, which is the motor base,
run the same as the backbone. Three quarters of an inch from the
backbone, and parallel with it, bore a little hole for the propeller
shaft or axle. Unless you are sure of your drill, heat a thin steel
wire and burn the hole, rather than risk splitting the block.

The propeller is the next thing to make, while the glue on the
backbone is drying, and the camber of the plane is setting. Some
models have metal propellers, but most boys prefer to make wooden
ones, either from blocks of their own cutting or from blanks that
can be purchased. The blank should be four inches in diameter an
inch wide, and half an inch thick. It can be cut away very thin
with a sharp knife, and a fairly good whittler can make a propeller
that looks as businesslike as the great gleaming blades on the big
machines. A wire then should be run through the dead centre of
the propeller and bent over so that when the wire shaft turns the
propeller also turns. As a bearing or washer the simplest device
is a glass bead strung on the shaft and well oiled to lessen the
friction, between the propeller and the propeller base. The shaft is
then run through the hole in the motor base and bent into a hook for
the rubber strands that drive the propeller. Great care should be
taken in mounting the propeller and making the hook that the shaft is
kept in an absolutely straight line, and at an accurate right angle
with the propeller, so that the screw can turn free and true with
as little friction as possible, and no wobbling or unbusinesslike
vibration. Next a wire hook should be placed at the other end of the
backbone upon which to hook the other end of the rubber strands. This
hook can either be imbedded in another block the same size as the
motor base or can be set out by some other ingenious device, so that
the strands will turn free of the backbone, and will make an even
line parallel with it. Both hooks should be covered by little pieces
of rubber tubing to protect the rubber strands. Any friction whatever
in a model is bad, but it is worst of all upon the rubber strands of
the motor.

With the parts in hand the next step is attaching the planes to the
backbone. In this machine the motor should be above the planes, so
that the planes should be affixed to the upper side of the central
stick, with the rubber strands above them. The propeller is at the
rear, so the small front plane should be placed at the front, with
the slightly curved edge to the rear. It should be about an inch from
the tip of the stick and the front edge should be elevated slightly
to give the necessary lifting power. The main plane should be placed
about an inch from the rear tip of the backbone, with the curved edge
to the rear and the front slightly elevated. The planes should be
affixed with rubber bands so that it is possible to move them forward
or back, because the little monoplane might be lacking in fore and
aft stability and the rearrangement of the planes might correct it.
It might even be found more satisfactory in some models to change
the order and let the propeller, base, and strands of the motor come
below the planes instead of above them. Your own experience will tell
best.

  [Illustration: THE ANTOINETTE MONOPLANE

  New armoured Antoinette shown in the large picture, while the
  small insert shows the old-style machine.]

  [Illustration:

    Photo by Philip W. Wilcox

  THE NIEUPORT MONOPLANE

  Comparatively a new make, the Nieuport monoplane has sprung into
  great favour for its speed and passenger-carrying capacities.]

Of course, the planes must be placed on the backbone exactly evenly
or the airship will be lopsided, a fatal fault. By experimenting, the
boy can tell just how high the front edges should be elevated, or,
in other words, what angle of incidence he should give his plane.
A rudder, to keep the machine in a straight course, can be added
underneath the centre of the main plane. It should be about two
inches square, but shaved off to a curving razor edge. Also light
skids of cane or rattan may be added. They should be glued to the
under side of the backbone and curved backward like sled runners. The
front one should be two and a half to three inches high, while the
rear one should be about an inch to an inch and a half less.

After trying out the model as a glider by throwing it across
a room and making sure it is well balanced both laterally and
longitudinally, or from side to side, and fore and aft, the rubber
strands can be put on, and the motor wound up. About four strands
of rubber one eighth of an inch square, such as is sold for this
purpose, would suffice for good flights of more than one hundred
feet, if the machine were of the same weight and proportions as the
model from which this description was written. In models, however,
there are many little details that can change the conditions, and a
boy can only experiment, locate his mistakes, and try it over again.

This is one of the simplest and easiest model aeroplanes that can
be made. A trip to one of the model aeroplane tournaments will
reveal dozens of more elaborate ones, which will give any ingenious
boy ideas for development of the principles he can learn from the
simpler type. Probably the next step of the average boy would be to
build a machine with two motors, which can be done by elaborating
the single stick backbone or by making a backbone of two or three
sticks well braced with cross pieces at each end and in the middle.
Then there are interesting experiments with the size of planes,
number of planes, their aspect ratio--that is the proportion of their
width to their depth--ailerons for automatic stability, and rudders
for keeping the machine on a straight course. There are always new
things to be done with the motors, because, though the rubber motors
have driven models close to half a mile, there are now on the market
miniature gasoline motors to drive models, and experiments are being
tried with clockwork and compressed air. Indeed the model aeroplane
field is as broad in itself as that of the man-carrying machines.

Aviation has been reduced to an exact science, but it is yet in its
early growth, both in the field of models and in the field of the
various kinds of man-carrying machines. Not only are the designers
making great headway with aeroplanes, but also with dirigible
balloons so any one interested in aeronautics has a very wide field
for his work. As we said in an earlier chapter, the boy model
designer of to-day may be the inventor of to-morrow who gains undying
fame by some now undreamed-of development of the aeroplane.

The designers of the man carriers are trying to make their machines
stronger, safer, more reliable, capable of carrying more passengers,
and they hope at last to bring them to a more practical use in the
world than as a sport. The most thoughtful aviators do not favour
exhibition flying so strongly as they do long cross-country flights,
endurance tests, passenger-carrying tests, and other experiments that
will develop aeroplanes beyond their present limitations.

The next great feat of the aeroplane is the crossing of the Atlantic
Ocean, and that may not be far distant, for at the time of writing
half a dozen aviators are planning the attempt, but even more
important than that, even more important than the development of the
aeroplane for war scouting, is the development of the aeroplane as a
faithful servant of the people who are quietly going about their own
everyday business. The time will come when the readers of this may
send their mail by aeroplane, take pleasure rides in the aeroplane
instead of the automobile, and even make regular trips on regularly
established aeroplane routes, buying their tickets at the great
central aeroplane stations as they would buy railroad tickets in the
Grand Central or the Pennsylvania stations to-day, taking their seats
in comfortably arranged aero cars, and being whisked in a few hours
from one part of the country to the other, and even from one side of
the ocean to the other.



CHAPTER IV

ARTIFICIAL LIGHTNING MADE AND HARNESSED TO MAN'S USE

   OUR FRIENDS INVESTIGATE NIKOLA TESLA'S INVENTION FOR THE
   WIRELESS TRANSMISSION OF POWER, BY WHICH HE HOPES TO ENCIRCLE
   THE EARTH WITH LIMITLESS ELECTRICAL POWER, MAKE OCEAN AND AIR
   TRAVEL ABSOLUTELY SAFE, AND REVOLUTIONIZE LAND TRAFFIC.


"How would you like to send a signal clear through the earth with
your wireless outfit and get it back again on your receiving
instrument as clear and strong as at first, just about the same way
you hear the echo of your voice when it rebounds from a mountainside
or a big building?" asked the scientist one day while his young
friend was telling him about his amateur wireless experiments.

"I don't see how I could," answered the boy.

"No, of course you don't," said the boy's friend, "for it took Nikola
Tesla, 'the wizard of electricity' almost a lifetime to work out
the invention by which he could do that, but if you like we will
go and see Doctor Tesla and ask him to tell us about his wonderful
experiments.

"You see this is a series of inventions by Tesla, and wireless
telegraphy is only a small part of it. You remember the other day
you told me of having read about aeroplanes equipped with wireless.
Just think, Tesla's invention will make it possible for airships to
be propelled and operated all by electricity sent without wires. The
whole broad plan is called the wireless transmission of power, and
that simply means that electricity can be transmitted without wires
for all the uses we now have for it, as well as for a number of
entirely new and hitherto unknown devices."

The boy was delighted with the prospect of seeing the great scientist
Tesla, about whom he had read so much, and began to ask his older
friend a thousand questions about the man, his work and life.

It was a good many days before the whole thing had been talked over,
and the boy understood the series of inventions, but we will follow
through a part of our scientist's explanation and the visit to
Tesla's laboratory and plant.

Although Tesla's plan is one of the most astounding ever proposed
by science, it has been proved possible by experiments of such
hair-raising nature that the inventor has been called a "daredevil"
a "demon in electricity" and a "dreamer of dynamic dreams." In his
experiments he has produced electrical currents of a voltage higher
even than the bolts of lightning we see cleaving the sky during the
worst thunderstorms. These currents he has harnessed to his own use
and made them tell him the inmost secrets of the earth--in fact of
the palpitation at the very core of the globe--the heartbeats of our
sphere. He has given exhibitions in which he has caused currents
of inconceivably high power to play about his head as if they
were gentle summer breezes, and while working in the mountains of
Colorado, he has brought forth electrical discharges which caused
disturbances in the wireless telegraph apparatus in all parts of the
globe.

In short, Nikola Tesla plans to make artificial lightning, and so
harness it to the use of man, that it can be sent anywhere on or
above the earth, without wires.

To scientists and electrical engineers, Tesla's plan offers a field
for limitless study and discussion, but to the boy who is interested
in electricity it offers one of the most fascinating subjects for
reading and thinking in all the realm of science. Just reflect that
with the wireless transmission of power, and the development of an
art that Tesla calls "telautomatics," the navigators of wireless
power-driven airships and ocean liners will know their exact speed,
position, altitude, direction, the time of night or day, and
whether there is anything in their path, all through the wireless
"telautomatic" devices for registering such impressions.

Tesla declares that the terrible _Titanic_ disaster never would have
occurred had his system been in effect last April, for he declares
that the _Titanic's_ captain would have known of the iceberg he was
approaching long enough in advance to slacken speed and get out of
its way. Moreover, he declares that with the wireless transmission of
power, the wireless telegraph becomes a very simple matter, and that
immediately after the accident, had the ship struck an obstacle in
spite of warnings, the captain could have been in wireless telephone
communication with his offices in London and New York, and with all
the ships that were on the seas in the vicinity of the ill-fated
liner.

But making air and sea navigation safe, sure, and speedy, are only
the first steps Tesla intends to take in the wireless transmission of
power. After that he hopes to light the earth--to carry a beautiful
soft bright light to ranchmen far out on the deserts, to miners
in their cabins or deep in the earth, to farmers, and to sailors,
as well as to people in their homes in the cities all over the
world--Australia as well as the United States.

Wireless electrical power, according to Tesla, will be one of the
greatest agencies in war, if there is any, but it first will be an
argument for universal peace. "Fights," says the inventor, "whether
between individuals or between nations arise from misunderstandings,
and with the complete dissemination of intelligence, constant
communication, and familiarity with the ideals of other nations,
that international combativeness so dangerous to world peace, will
disappear."

If Tesla's plan were carried out in full it would completely
revolutionize the industries of the world, for all the power of
Niagara or any other waterfall in the world could be sent without
wires to turn the wheels of the industries in China or Australia,
while the power of the Zambesi Falls in Africa could be transmitted
to run trains, subways, elevateds, and all other forms of industry in
the United States. There is practically no limit to the possibilities
of the scheme, because through Tesla's invention, distance means
nothing, and the power instead of losing force with distance as is
the case when power is transmitted through wires, retains practically
the same voltage as at the outset.

We will visit Doctor Tesla at his office and laboratory in the
Metropolitan Tower in New York with the scientist and his young
friend to see what kind of a man it is who has invented machines for
creating and handling such tremendous voltages.

Tesla sits at a wide flat-topped desk in the centre of his sunny
office surrounded by books, a few models of inventions, and a few
pictures of some of his most remarkable electrical experiments. He is
very tall and slight, with a mass of black hair thrown back from his
intellectual forehead. His piercing gray eyes sparkle as he smiles
in greeting, and his thin pointed face lights up with an expression
of pleasure and kindness that cannot help but make the great
electrician's visitors feel that he is a good friend. Although he
was naturalized more than twenty years ago, and has been an American
citizen ever since, his English still shows some slight traces of
his foreign birth. He looks no more than forty-odd and he is as
interested in everything that is going on in the world as a young
boy, but he has passed his fiftieth year.

"For all that I am something of a boy still myself," says the
inventor. "You see I could work for the present generation to make
money. Of course that's all right, but I don't care what the present
generation thinks of me. It is the growing generation--the boys of
to-day that I want to work for, because they will live in an age
when the world has advanced far enough in science to understand some
of the deeper mysteries of electricity. The boys of to-day are the
great scientists of to-morrow, and it is to them that I dedicate my
greatest efforts."

All his life Tesla has been working with an eye to the future as well
as to the present, and some of his inventions probably will be far
better appreciated in twenty years than they are now, although to
Tesla we owe our thanks for some of the most important electrical
machinery in use at the present time.

As an inventor Tesla is best known as a pioneer in high tension
currents. It was he who introduced to the world the great principle
of the alternating current, as up to the time he carried out his
experiments only the direct current was used. Indeed, more than four
million horsepower of waterfalls are harnessed by Tesla's alternating
current system. That is the same as forty millions of untiring men
working without pay, consuming no food, shelter or raiment while
labouring to provide for our wants. In these days of conservation,
it is interesting to note that this electrical energy derived from
water power saves a hundred million tons of coal every year. Our
trolley roads, our subways, many of our electrified railroads, the
incandescent lamps in our homes and offices, all use a system of
power transmission of this man's invention.

As said before Tesla is a naturalized American citizen. He was
born in Smiljan, Lika, on the Austro-Hungarian border, in 1857. He
came by his scientific and inventive turn of mind naturally, for
his father was an intellectual Greek clergyman, and his mother,
Georgia Mandic, was an inventor herself as was her father before
her. The boy attended the public schools of Lika and Croatia, where
he was a leader among his playmates in sports where imagination and
mechanical skill were required. There are marvellous tales of the
ingenuity of Tesla while a schoolboy, but with all his play he was
a serious-minded student, and went through the Polytechnic in Gratz
and the University of Prague in Bohemia with honours. While in the
Polytechnic, Tesla saw the defects of some of the machinery that was
used in the laboratory, and made suggestions for its improvement.

After finishing college Tesla began his practical career in Budapest
as an electrical engineer in 1881. His first invention followed soon
after in the form of a telephone repeater. He continued in electrical
engineering in Paris until 1884, when he came to the United States.
His first employment in America was with The Edison Company at
Orange, N. J., but in 1887 he went into business for himself as an
electrical engineer. From that time on he has been an important
figure in the scientific world. He has made many addresses before
various gatherings of experts and has written numerous papers on
scientific subjects for the magazines. Of course the bulk of his time
has been given to his inventions and the necessary research therefor.

  [Illustration: LIKE A BOLT OF LIGHTNING

  The electrical discharge of this Tesla oscillator created flames
  70 feet across, under the pressure of 12,000,000 volts and a
  current alternating 130,000 times per second.]

  [Illustration: DR. NIKOLA TESLA

  Wizard of electricity, and inventor of the wireless transmission
  of power.]

  [Illustration: DOCTOR TESLA'S FIRST POWER PLANT

  From this oscillator Doctor Tesla sends out the electrical waves
  with which he hopes to revolutionize industry.]

Throughout his life Tesla has been more interested in the adventurous
and scientific side of electricity than the commercial side, and all
of his inventions smack of the marvellous. To name all his inventions
would be almost like giving a list of the machines and devices that
mark man's progress in the use of electricity. His invention
for the alternating current dynamo, for instance, brought forth
an entirely new principle, while his rotating magnetic field made
possible the transmission of alternating currents from large power
plants over great distances and is very extensively used to-day.
High power dynamos, transformers, induction coils, oscillators, and
various kinds of electric lamps all came in for his attention.

He became one of the foremost authorities on high tension currents
and in 1889 invented a system of electrical conversion and
distribution by oscillatory discharges which was a step toward his
great goal, the wireless transmission of power. He was very near the
prize when in 1893 he announced a system of wireless transmission
of intelligence. His studies continued and finally, in 1897, he
announced his famous high potential transmitter by which he claimed
to be able to send power through the earth without wires. The art
of telautomatics announced in 1899 was really a part of Tesla's
invention for the wireless transmission of power, for the plan was
to control such objects, for instance, as airships or boats, from a
distance by electricity transmitted without wires.

Through that marvellous invention the boat or aeroplane dispatcher,
sitting before a complex little wireless dispatching board could send
his craft, at any speed, at any height, in perfect safety, and with
exact precision to the place or port he desired it to go. It would
not be necessary for the dispatcher ever to see the craft he was
directing, for his instruments would show him everything in regard to
its speed, direction, and location; nor yet would it be necessary for
a craft to have a crew aboard, for all the operations in connection
with sending it from one place to another would be controlled
perfectly by telautomatics.

Such are the almost inconceivable inventions of Nikola Tesla.
"Sometimes they call me a dreamer," says Tesla, "because I do not
capitalize these inventions, start in manufacturing and make a big
fortune. That is not what I care to do. I want to go further in this
great mystery of wireless power, and if I am busy making money I
cannot devote my best abilities to inventions that will be in use
when the next generation is grown."

But let us try to fathom the mysteries of Tesla's scheme for the
transmission of electric energy without wires. In the first place we
must not try to think of it as being on the same basis as the radio,
or Hertzian wireless telegraph, for, although the modern developments
of the wireless telegraph take into consideration the central theory
of Tesla's invention, they are not at all the same in their practical
working.

Tesla's theory is based entirely on his discovery of what he calls
stationary electrical earth waves which he sets in motion with his
high potential magnifying transmitter, an electrical apparatus of
tremendous power.

First, let us remember the three essential departments of Tesla's
idea for world telegraphy, world telephony, and world transmission of
power for commercial purposes.

Assuming that the power is created by Niagara or some other great
waterfall--"white coal" as it is picturesquely called by many
engineers--the first necessities are a transformer and a transmitter
that will send the electrical energy, thus gathered, into the earth
and air. The next necessity is a receiving instrument that will
record the impulse, whether it be a voice, a telegraph click, or
several million volts for driving factory wheels or lighting houses.
Lastly, it is necessary to tune the currents so that millions of
different impulses can be sent without causing confusion between
them. In other words, there must be departments for sending,
receiving and "individualizing."

To ask Doctor Tesla to tell us the whole story of this invention
would be to ask him to tell us in detail the whole history of his
life work--and that would take several volumes, for he is one of
those men who have worked incessantly, day and night, sacrificing
himself and overcoming his natural desire for leisure and amusement.
It all started, Tesla explains, when he was a very small boy. He was
troubled at that time with a strange habit. Whenever any one would
mention a thing to him, a vision of the object immediately would
come before his eyes. He declares that this was very troublesome,
and that as he grew older he tried to overcome it, thinking it some
strange malady. With an effort he learned how to banish the images
by putting them from his mind. On inquiring into the cause of the
visions, the young scientist's penetrating brain brought him to the
conclusion that every time he saw a vision, some time previous he had
seen something to remind him of the object. The tracing back of the
cause of his vision so frequently caused it to become a mental habit,
and he declares that for many years he has done it automatically, and
that he has been able to trace the cause of nearly every impression,
even including his dreams. Reflecting on these things, as a mature
scientist, Tesla came to the conclusion that he was an automaton,
responding automatically to impressions registered on his senses from
the outside.

"Why couldn't I make a mechanical automaton that would represent me
in every way, except thought?" he asked himself. The answer to the
question which came only after years of study and experiment was the
art of "telautomatics," which Tesla declares can be developed just as
soon as the wireless transmission of power is an accomplished fact.

In the course of his research into the realm of high tension currents
Tesla reached the stage where it was no longer safe nor convenient
to experiment in the centres of population. Moreover, he desired to
make a study of the action of lightning. Colorado, with its vast
stretches of uninhabited plains and mountains, offered an ideal place
for his laboratory, particularly because the high, dry climate of
that state brings forth some of the worst electrical storms seen
in the United States. Consequently, in the spring of 1899, Tesla
built an experiment station on the plateau that extends from the
front range of the Rocky Mountains to Colorado Springs, and began
the experiments through which the secret with which he hopes to
revolutionize the communication and transportation systems of the
world, was revealed to him.

Besides his high power alternating current dynamo, Tesla set up an
electrical oscillator with which he hoped to send out electrical
waves, through the earth and air, that would prove to him the
possibility of an extensive system of wireless communication,
and telautomatic, or wireless control of airships, projectiles,
steamships, etc. In his early experiments he used the oscillator at
low tension, but as his success became more marked he increased the
tension, until the oscillator was giving twelve million volts, and
the current was alternating a hundred thousand times a second.

In regard to these high tension experiments in Colorado and
elsewhere, Doctor Tesla said, "I have produced electrical
oscillations which were of such intensity that when circulating
through my arms and chest they have melted wires which have joined
my hands, and still I have felt no inconvenience. I have energized,
with such oscillations, a loop of heavy copper wire so powerfully
that masses of metal placed within the loop were heated to a high
temperature and melted, often with the violence of an explosion. And
yet, into this space in which this terribly destructive turmoil was
going on I have repeatedly thrust my head without feeling anything or
experiencing injurious after effects."

Among the earlier experiments, which in themselves were wonderful
enough, were the transmission of an electrical current through one
wire without return, to light several incandescent lamps. Advancing
further along the trail of wireless transmission of power, Tesla
lighted the lamps without any wire connection between them and his
transmitter.

The oscillator, though simple in its construction, is one of the
most wonderful of all electrical devices. "You see," said Doctor
Tesla, "all that is necessary is a high power alternating dynamo
which generates a tremendous alternating current. For our oscillator
proper, we make a few turns of a stout cable around a cylindrical
or drum-shaped form, and connect its two ends with the source of
electrical energy. Then, inside the big cable, or primary coil, we
wind a lighter wire in spiral form. One end of the secondary coil
is sunk into the ground and connected with a plate, and the other is
erected in the air. When the current is turned on, our oscillator
sends these electrical impulses into the earth and air--or, as the
scientists say, into the natural media. These oscillations create
electrical waves and affect any device that is tuned to them--but
(and this is very important) no device that is not tuned to them."

Continuing the explanation of his high tension experiments, Tesla
tells us that the awe-inspiring electrical display, of which there
is a picture on page 136, was made by his oscillator which created
an alternate movement of electricity from the earth into a hollow
metal reservoir and back at a speed of 100,000 alternations a second.
The reservoir is already filled to overflowing with electricity and
as the current is sent back to it at each alternation the terrific
force makes it burst forth with a deafening roar, as great as the
heaviest lightning detonation. The electric flames shoot out in every
direction searching for something on which they may alight, just as
lightning sent from the clouds searches for a conductor upon which
it may alight and escape into the earth. The induction coils in the
picture are tuned to these tremendous electrical explosions, and the
flames shoot direct to them, a distance of 22 feet.

The flames shooting from the coil of the oscillator pictured on page
164 were nearly 70 feet across, represented twelve million volts
of electricity, and a current alternating 130,000 times a second.
These hair-raising experiments created such electrical disturbances
that it was possible to draw great sparks more than an inch long,
from water plugs over 300 feet from the laboratory. One of the
most marvellous things about these experiments is that any human
being could remain in the vicinity. The absolute safety of these
discharges when properly harnessed is well illustrated in the picture
shown there as the man seen amidst the flames felt no ill effects
from his experience, simply because this power was so thoroughly
harnessed by the wizard Tesla, that it could go only to the device
tuned to receive it. Every boy is familiar with stories of lightning
striking one person, but yet leaving another person right next to him
unharmed. Such is the action of Tesla's high tension currents, only
he directs them by induction just as he wants them to go.

"But this is just like lightning!" exclaimed the boy.

"So it is," calmly answered Doctor Tesla with a smile. "I have often
produced electrical oscillations even greater than the energy of
lightning discharges."

These experiments were marvellous enough, but they were surpassed in
a short time by his famous discovery of July 3, 1899, which showed
him that he could send his wireless waves to the opposite side of the
earth just as well as a hundred feet away.

This revelation, as the scientist calls it, came about through
his study of lightning. The scientist had set up in his Colorado
laboratory many delicate electrical instruments to register various
different electrical effects. Tesla noticed, however, that strangely
enough his instruments were just as violently affected by distant
electrical storms as by nearby disturbances.

"One night when meditating over these facts," said Tesla, "I was
suddenly staggered by a thought. The same thing had presented itself
to me years ago; but I had then dismissed it as impossible. And that
night when it recurred to me I banished it again. Nevertheless, my
instinct was aroused, and somehow I felt that I was nearing a great
revelation.

"As you know, it was on the third of July that I obtained the first
definite evidence of a truth of overwhelming importance for the
advancement of humanity. A dense mass of strongly charged clouds
gathered in the west, and toward evening a violent storm broke loose
which, after spending much of its fury in the mountains, was driven
away with great velocity over the plains. Heavy and long persisting
arcs formed almost at regular intervals of time. My observations were
now greatly facilitated and rendered more accurate by the records
already made. I was able to handle my instruments quickly, and was
prepared. The recording apparatus being properly adjusted, its
indications became fainter and fainter with the increasing distance
of the storm, until they ceased altogether. I was watching in eager
expectation. Sure enough, in a little while the indications again
began, grew stronger, gradually decreased, and ceased once more.
Many times, in regularly recurring intervals, the same actions were
repeated, until the storm, as evident from simple computations,
with nearly constant speed had retreated to a distance of about two
hundred miles. Nor did these strange actions stop then, but continued
to manifest themselves with undiminished force.

"When I made this discovery I was utterly astounded. I could
not believe what I had seen was really true. It was too great a
revelation of Nature to accept immediately and unhesitatingly."

What Tesla had discovered, and soon announced to the scientific
world, was the existence of stationary terrestrial waves of
electricity, and its meaning was that an impulse sent into the
earth was carried on these waves to the other side of the earth and
rebounded without any loss of power. He had, in fact, discovered and
turned to man's use the very heartbeats of our earth.

"Whatever electricity may be," he continued, "it is a fact that
it acts like a fluid, and in this connection, we may consider the
earth as a great hollow ball filled with electricity." He goes on to
explain that when an impulse is sent into this ball of electricity it
proceeds to the opposite wall of the earth in waves and, finding no
outlet it returns to the place it started, but in a series of waves
exactly the opposite of the outgoing ones, so that the two cross and
diverge at regular intervals as indicated in the diagram.

  [Illustration:

  A--Oscillator

  B--Opposite side of earth

  C--Waves in nodal and ventral intervals.]

As Tesla put it, "The outgoing and returning currents clash and form
nodes and loops similar to those observable on a vibrating cord."
Tesla figured from these experiments that the waves varied from 25 to
70 kilometres from node to node, that they could be sent to any part
of the globe, and that they could be sent in varying lengths up to
the extreme diameter of the earth.

In order to prove his discovery Tesla sent an impulse into the
earth, and received it back, on his delicate instrument, in a few
seconds. "It is like an echo," he explained. "When you shout and
in a few seconds hear your voice coming back, you do not think it
is another voice but know immediately that it is simply your own
vocal vibrations reflected by the house, mountainside, or what not.
It is just the same with an electrical vibration. The stationary
terrestrial wave goes through the earth, reaches the other side and,
finding no outlet, is reflected without any loss of power. Indeed, in
some cases it is returned with greater power than at first."

"Then in your system the wireless electrical current passes through
the earth, and not through the air," interrupted the scientist.

"No," he answered, "it passes through both. It is difficult to
understand the big things about electricity, but just think of the
earth as a great ball filled with electricity, as I said before.
Think of the tower of the oscillator as a tube, and of the great
mushroom-shaped top of the plant as another ball. Now from our
great alternating current dynamo we first fill the ball at the top
of the oscillator with electricity, and then we make a motion that
corresponds to squeezing it. What happens? Just what happens when
you have two rubber balls connected with a tube. You squeeze one of
them, and push the air, or water, into the other ball. In that way
we push the electricity into the earth, but it comes back to us on
the stationary waves, from the opposite side, and when it does we are
ready to give it another mighty push with another tremendous squeeze
from our dynamo. When this is going on the top of the oscillator is
gathering electricity from the air all the time and sending it out to
be used wherever there is a receiver properly tuned to receive these
rates of vibration."

"But," again asked our friend, "isn't there a great deal of valuable
electrical power wasted in that way?"

"No, there is very little waste," answered the electrician, "for
this reason: If, for instance, our oscillator can generate a hundred
thousand or a million, or any other number of volts, and we only wish
to use it for some small purpose on the other side of the earth,
the receiver at the antipodes takes as much power as is needed, and
the rest remains unused and our oscillator can be run at reduced
capacity."

Thus, according to Tesla's plan, the electrical energy will be sent
into the earth and air by the high potential magnifying transmitter
or oscillator, the stationary electrical waves carry it through the
earth and the receiving instrument on the other side of the world
collects the energy to put it to a thousand and one purposes of
mankind. And do not forget that the oscillator and the receiving
instrument are so tuned to each other that there is no danger,
according to Tesla's scheme, of different oscillators and receivers
getting mixed up.

Before Tesla had discovered the stationary electrical waves he had
gone deep into the mystery of the "individualization" of electrical
impulses, and as a result advanced plans for sending a number of
messages over one wire without their interfering with each other.
This study was continued with even greater energy, after he had taken
the first steps toward the realization of his world telegraphy and
world telephony without wires. In wireless telegraphy as we know its
practice to-day, one of the serious drawbacks is the interference
of other operators, both amateur and professional, with important
messages. Tesla holds that the simple tuning of instruments to one
another as is done nowadays would not be sufficient, when there
were millions of currents passing through and around the earth.
For instance, he says that an instrument tuned to a single rate
of vibrations would be very apt to come into contact with another
instrument sending at the same rate. Of course the confusion so
familiar in modern radio-telegraphy would result. Moreover, it makes
it difficult to send messages that cannot be intercepted and read by
every wireless operator in hearing. "This can be avoided," continues
the inventor, "by combining different tones or rates of vibration.
In actual practice it is found that by combining only two tones, a
degree of privacy sufficient for most purposes is attained. When
three vibrations are combined it is extremely difficult even for a
skilled expert to read or disturb signals not intended for him. It is
vain to undertake to 'cut in on' a series of wireless impulses made
up of four different rates of vibration. The probability of getting
the secret of the combination is as slight as of your solving the
number combination on the door of a safe. From experiments I have
concluded that this individualization will allow the transmission of
several million different messages. It is interesting when you think
that one world telegraphy plant would have a greater capacity than
all the ocean cables combined."

In regard to the amount of power to be transmitted, Tesla points out
that an impulse of low voltage, or low horsepower, will carry to the
other side of the earth without any loss of power, just as easily
as a high voltage current. "A wire," says Tesla, "offers certain
resistance to an electrical current causing some loss, but not so
when it is sent through the natural media. The earth is a conducting
body of such enormous dimensions that there is virtually no loss,
so that distance means nothing. To the average intelligence this
will appear incomprehensible. We are continuously confronted with
limitations, and those truths which are contradicted by our senses
are the hardest to grasp. For example, one of the most difficult
tasks was to satisfy the human mind that the earth rotated round the
sun; for to the eye it seemed just the opposite."

Tesla further pointed out that five-hundred miles is about the
farthest that high power can be transmitted by wires with complete
success, but that without wires, by his system, power can be
transmitted, as we have seen, to any part of the globe or the
atmosphere about it.

The plan for a world-wide system of wireless telegraphs and
telephones differs considerably from the original idea laid down by
scientists for radio or Hertzian wireless telegraphy. Originally
Guglielmo Marconi, who first successfully telegraphed without wires,
and whose system is well known all over the world, planned to send
his electrical impulses through the ether, in the form of Hertzian
rays, but later the method was amended. The theory advanced was that
since everything is afloat in the colourless, intangible something
called ether (not the drug used as an anæsthetic), and that since
waves of light, heat, and electricity travel through ether, it
would be possible to send electrical impulses through the ether in
the earth and air, just as well as through the ether in a copper
wire. In his early experiments Marconi used the light rays or waves
named after their discoverer, Hertz, but these were found to be
very limited, so electrical vibrations of a higher intensity were
substituted, as we shall see in a later chapter.

"From the very first," declared Tesla, "my system has been based on
a different principle, as you can see from what I have told you.
For instance, my invention takes no consideration of light rays
in any visible or invisible form (and Hertzian rays are invisible
light), which can only travel in a straight line. Hence, you can
see that they could not be used except as far as could be seen. In
other words, they only could be used as far as the horizon, for
just as soon as the curve of the earth's surface took the receiving
instrument below the level of the Hertzian waves they became
ineffective. You see the difference is that my system is based on the
stationary earth waves, along which the electrical currents can pass
to any distance irrespective of horizon, or matter."

A simple explanation will serve to show the principle of Tesla's
theory of wireless telegraphy and telephony. We can easily think of
a reservoir with two openings in the cover filled with some fluid.
In each of these openings is a piston and above each piston is a
tuning fork. The two tuning forks must be of exactly the same tone
or the experiment will not work. We strike one of the pistons with
the tuning fork, and continue to strike it until the fork sets up
vibrations. The vibrations pass through the air, and also communicate
vibrations to the piston, which in turn passes the vibrations on
to the fluid in the reservoir. These vibrations naturally continue
through the reservoir, as waves, just the same as when we throw a
pebble into a calm pond and watch the waves radiate out in every
direction. The water does not advance, but merely moves up and down.
The waves, however, advance. So with the waves set up by the tuning
fork, and they set up an oscillation of the piston at the other side,
agitating the tuning fork in unison with the sound vibrations coming
through the air.

It is just the same, declares Tesla, with two of his oscillators set
up on the earth's surface and tapping the great sea of electricity,
which he says is in the earth. The oscillators correspond to the
tuning forks, the reservoir to the earth, and the fluid in the
reservoir to the electrical currents with which he says the interior
of the earth is alive. Exactly attuned, Tesla says, the vibrations
set up by the sender will be communicated to the receiver through the
earth and through the air.

"Now, with the development of the world system," continued Tesla, "we
shall be able to telephone without wires just as well as telegraph,
and to any part of the world just as easily as we now talk to a
friend in an adjoining house over the modern wire circuits."

Before going with Doctor Tesla to his great plant out on Long Island
to see how he is carrying on these tremendous theories of his, the
boy asked him a few more questions about them, for it is a big and
intricate question.

"What application will you first make of the wireless transmission of
power?"

"My first concern," replied the magician of electricity, "will be to
make air and water navigation safe. We have plenty of demonstrations
of the value of the wireless telegraph in saving human lives when
ships are in danger, in the _Republic_ and _Titanic_ disasters. But
also we know that the wireless can be greatly improved upon. With
a perfect system of communication, both by wireless telegraph and
telephone, consider what it would mean to the navigators of air and
ocean craft.

"By the art of telautomatics, which is a part of the broad scheme
for the wireless transmission of power, many of the worst dangers
of air and water navigation will be avoided, which is right in line
with the modern tendency of preventing trouble rather than waiting
for it to happen before remedying it." He then went on to enumerate
the various telautomatic devices that will be carried by ocean liners
and airships of the future, as mentioned in the early part of this
chapter.

"Just for instance, how could telautomatics have saved the
_Titanic_?" the inventor was asked.

"You understand, of course," answered Tesla, "that the devices I
propose would be of almost inconceivable sensitiveness. They would
be the centre of electrical waves, and, as soon as the iceberg got
into the path of these waves from the wireless transmission plant to
the ship, it would cause the electricity to register an impression
of danger ahead. Of course mariners would become so expert in the
reading of these danger signals that they could tell the meaning of
each one, and alter their course or reverse their engines according
to the needs of the case."

"How much have you accomplished in telautomatics at this time?"

"I have made a little submarine boat that will answer to every
necessary impulse. The boat contained its own motive power in a
storage battery and gear for propulsion, steering sidewise, or upward
or downward, and all other accessories necessary for its operation.
All of these were worked from a distance by wireless impulses, sent
by an oscillator to the circuit in the boat through which magnets and
other devices operated the interior mechanism.

"This proved to me the possibility of a high development of
telautomatics. When my system is complete, a crewless ship may be
sent from any port in the world to any other port propelled by
wireless energy from a power plant anywhere on the face of the earth,
and controlled absolutely by telautomatics."

Tesla's plan for aerial navigation is even more startling than that
for crewless ocean liners. He thinks that the airships of the future
will be propelled by wireless power and that they will have, neither
planes nor other supporting surfaces, such as we are so familiar with
nowadays. Neither will they be supported by gas bags like balloons
and dirigibles. The inventor thinks they will be compact and just
as airworthy as ocean liners are seaworthy. They will be tightly
enclosed, so that the terrific rush of air through the high altitudes
will not strangle the passengers and crew. He sees no reason why the
airships of the future should not travel at a rate of several hundred
miles an hour, so that you could leave San Francisco in the morning
and be in New York in time for a six o'clock dinner, and the theatre,
or cross the Atlantic in a night.

"How will these airships be propelled?" the boy asked.

"By engines driven with power supplied by our great oscillator
wherever we care to erect it. These engines will work with such
incredible force that they will make of the air above them a
veritable rope to sustain them at any desired altitude, while they
will make of the air in front of them a rope to pull them forward at
a high rate of speed." Tesla continues to say that these ships can be
made just as large as it is practicable to make their landing stages,
or small enough for one or two passengers.

In the waterfalls of the United States alone, he pointed out, there
are twenty-five hundred million horsepower of electrical energy.
Niagara Falls could supply more than one fifth of all the power now
used in this country, he says. Moreover, none of the great sites,
such as those in the far Northwest, are developed to their highest
state, because of the difficulty in transmitting the power over long
distances to where it is used.

"It must be borne in mind," said Tesla, "that electrical energy
obtained by harnessing a waterfall is probably fifty times more
effective than fuel energy. Since this is the most perfect way of
rendering the sun's energy available the direction of the future
material development of man is clearly indicated. He will live on
'white coal.'"

"Doctor Tesla, can you tell us, please, just how far you have
developed this invention for the wireless transmission of power?"

"Well," answered the electrical inventor, "the best way to tell
you is to show you what has been done so far." In order to see
Tesla's great plant we must follow the scientist and his boy friend
out to Bay Shore, L. I., where, overlooking Long Island Sound,
we see a great mushroom-shaped steel network tower surmounting a
low building--the first of Tesla's many proposed high potential
magnifying transmitters.

"So far," said Tesla of his power plant where the first attempts
at wireless transmission are being made, "only about three million
horsepower has been harnessed by my system of alternating current
transmission. This is little, but it corresponds nevertheless
to adding to the world's population sixty million indefatigable
laborers, working virtually without food or pay."

As the boy approached the power plant he was impressed by the great
size of the tower and its circular top, as shown in the photograph.
It is this circular top, with its conductive apparatus, that gathers
the electricity from the air and from the dynamo, and sends it forth
in great waves both through the air and through the earth. The tower
is 185 feet high, from the ground to the top, and from the ground to
the edge of the cupola it is 153 feet. The diameter of the cupola
floor is 65 feet. The cupola can be reached by both a staircase and
an elevator, but it would hardly be healthy for any one to be within
the network of electrical conductors when the plant was working.
Inside the building are the high power alternating dynamos and
underneath it extends the ground wire from the cupola, through which
the electricity is pumped into the ground in great spurts at the rate
of more than a hundred thousand spurts a second. At this plant Tesla
plans to gather and concentrate millions of horsepower of electrical
energy and then, in the ways we have seen, send it out to be used in
a thousand different ways.

"This is merely an experiment," declared Tesla. "We can telegraph
and carry on other such operations as require only a small amount of
power from here, but it is nothing compared to the great power plants
we will erect in the future."

"Is it necessary," asked the boy, "to have your power plant erected
near the waterfall, or other means of producing the electricity?"

"No, it is not. This plant, for instance, can be made a great
receiving station for electric power from all the great
hydro-electric sites, and from it we hope to be able to send out
electrical waves that will run our ships, airships, trains and street
cars, carry our voices, light our houses, and turn the wheels of our
factories. It is better, however, to have the plants located close to
the seats of power, and to have a greater number of plants."

"How much horsepower did you say this plant would send out?"

"Only a mere trifle of three million horsepower, but of course this
is only an experiment. To be done properly the thing must be done on
a large scale, and the time will come--not necessarily remote--when
we will be carrying on the whole programe embraced by the wireless
transmission of power. The cost of wireless power I estimate would be
about one sixteenth of that of the present system."

"When you are sending such tremendous voltages won't it be very
dangerous to be anywhere in the vicinity of a plant, much less
anywhere that the electricity might be brought from the earth?"

"No, for the power is so well harnessed that we can send it just
where we want it and nowhere else. Of course, on the other hand, if
we wanted to make trouble with this well-harnessed lightning we could
make a terrible disturbance in the earth and on the surface of the
earth."

"What about lightning?"

"That is one of the things we had to guard against right from the
very first, and I can tell you that lightning will not bother us a
bit, although I cannot give you the details of our method of avoiding
it.

"When we are using the plant at night, however, there will be a
display far more beautiful than lightning, all about the cupola in
the form of a great halo of electric light visible for miles around."

Before we leave this fascinating subject of the wireless transmission
of power let us ask Doctor Tesla about the effect of his invention on
war.

"The wireless transmission of power will first be a big factor in
promoting world peace, as I said before, because through the great
improvement in communication it will lead to a better understanding
between nations and break down many of the old prejudices that have
lived for so many thousands of years. It will facilitate travel and
commerce so that a citizen of the United States will find it as
simple and cheap to travel abroad as he now finds it to travel in
the neighbouring state. His commercial interests also will spread to
foreign countries, and the nations will be so linked with one another
socially and commercially that war will be out of the question.

"However, in case war should break out between the nations it will
be a conflict of such gigantic proportions, and carried on with such
tremendous death-dealing machines, that it will surpass our wildest
dreams.

"For one thing, the new art of controlling electrically the movements
and operations of individualized automata at a distance without wires
will soon enable any country to render its coast impregnable against
all naval attacks.

"I have invented a number of improvements of this plan, making it
possible to direct a telautomaton torpedo, submersible at will, from
a distance much greater than the range of the largest gun, with
unerring precision, upon the object to be destroyed. What is still
more surprising, the operator will not need to see the infernal
engine or even know its location, and the enemy will be unable to
interfere, in the slightest, with its movements by any electrical
means. One of these devil-telautomata will soon be constructed, and
I shall bring it to the attention of governments. The development
of this art must unavoidably arrest the construction of expensive
battleships as well as land fortifications, and revolutionize the
means and methods of warfare. The distance at which it can strike,
and the destructive power of such a quasi-intelligent machine being
for all practical purposes unlimited, the gun, the armour of the
battleship, and the wall of the fortress, lose their import and
significance. One can prophesy with a Daniel's confidence that
skilled electricians will settle the battles of the near future, if
battles we must have.

"The future of wireless power development," explained the inventor,
"may render it folly for any nation to have afloat a vessel of war.
The secret of another nation's scheme of selectivity or combination
of vibrations might be disclosed to the enemy, when the guns of
their own vessels might be turned against sister ships and a whole
fleet destroyed by shells from their own guns, or their magazines
might be exploded by the enemy at will. However, should there be
battleships in the wireless future, they will be crewless. They will
be manoeuvred, their guns will be loaded, aimed, and fired, and their
torpedoes discharged with unerring accuracy, by the director of naval
warfare seated before a telautomatic switch-board on land.

"The time will come, as a result of my discovery," says Tesla,
"when one nation may destroy another in time of war through this
wireless force: great tongues of electric flame made to burst from
the earth of the enemy's country might destroy not only the people
and the cities, but the land itself. I realize that this is indeed
a dangerous thing to advocate. At first thought it might mean
the annihilation of the nations of the world by evilly disposed
individuals. The public might at first look upon the perfection of
such an invention as a calamity. We say that all inventions assist
the criminal in his work. To-day the safe burglar despises the use of
dynamite, turning to electrical contrivances to cut the lock from a
safe. It is fortunate for the world, therefore, that 90 per cent. of
its people are good, and that only 10 per cent. are evilly disposed:
otherwise all invention might be turned more greatly to evil than to
good."



CHAPTER V

THE MOTION-PICTURE MACHINE

   MACHINES THAT MAKE SIXTEEN TINY PICTURES PER SECOND AND SHOW
   THEM AT THE SAME RATE MAGNIFIED SEVERAL THOUSAND TIMES--MOTION
   PICTURES IN SCHOOL--OUR BOY FRIEND SEES THE WHOLE PROCESS OF
   MAKING A MOTION-PICTURE PLAY.


"I have just been to the moving-picture show," said the young man
whose inquiring turn of mind has brought him into touch with so many
recent inventions. His friend in the laboratory had just finished a
very successful chemical experiment and seemed glad to see the boy.

"Did the pictures move very much?" he asked with a smile.

"Of course they did. They moved all the time."

"No, they only seemed to move, for as a matter of fact there are no
such things as 'moving pictures.' We call them 'motion pictures' now,
for that comes nearer to expressing the idea.

"Cinematography, which is the technical name for the whole art of
motion pictures, is based on one of nature's defects, whereas most
inventions are based on some of nature's perfect processes. The
defect is called by the scientists the persistence of vision, which
means that after you look at an object, and it is quickly taken from
before your eyes, the image remains there for the fraction of a
second.

  [Illustration: ELECTRICITY ENOUGH TO KILL AN ARMY PERFECTLY
  HARNESSED

  The Oscillator shown on the left sending an alternating current
  from the earth into a large reservoir and back at the rate of
  100,000 oscillations per second causes the tremendous electrical
  explosions as the reservoir is filled each time. The flames in
  this experiment were 22 feet long.]

  [Illustration:

    Courtesy of Thomas A. Edison Inc.

  A BATTLE SCENE IN THE STUDIO

  In this picture the stage director can be seen shouting
  directions to both actors and photographer at once.]

"With this in mind you will see how the cinematograph is simply
still photography worked out so as to show a series of snapshots at
such speed that the eye cannot notice the change from one picture to
another, but will see only the changing positions of the figures.
Each picture shows the figures in a little different position, in the
same order that they move, so that the whole series thrown on the
screen at high speed shows the figures moving just as they do in real
life."

"But where does visual persistence come in?" asked the youth.

"It would be plain if you could see the pictures thrown on the screen
twenty times as slowly as they are, for each snapshot of each stage
of motion must be displayed separately. It must remain perfectly
still for an instant and then must be moved away while the shutter
of the projecting machine is closed. When the shutter is opened
again the next picture is thrown on the screen. Now, through the
persistence of vision, the image of the first picture remains in your
brain, photographed on the retina of your eye, while the shutter is
closed, and you are not conscious that there is nothing on the white
screen before your eyes.

"The scientific explanation of this is simple enough: After an image
has been recorded by your eye it will remain in the brain for an
instant even after the object has been removed. Then it fades slowly
away and gives place to the next image sent along the optic nerve
from the eye. Thus the eye acts as a sort of dissolving lantern for
the motion-picture man, and lets one image fade into another without
showing any perceptible change in pictures. Thus the 'moving picture'
is only a scientifically worked out _illusion_ of motion."

The scientist went on to say that with marvellously constructed
machines this scientific fact has been turned to such account that
boys and girls in some of the schools now study geography partly from
motion pictures, and some of the most wonderful sights of nature
are seen every day by millions of people as they sit comfortably in
their seats in the motion-picture theatre. A few years ago, before
the invention of cinematography, the magic lantern was largely used,
as many boys will remember; but it could only show scenes in which
there was no movement--or in other words, scenes that were confined
to still-life photography. Nowadays every boy is familiar with
motion pictures depicting great historical occurrences, parades,
inaugurations, coronations, volcanoes in eruption, earthquakes,
buildings burning and crumbling, railroad wrecks, shipwrecks, scenes
in every country in the world and plays of every imaginable kind.

The motion-picture photographer takes pictures in the frozen North,
and in the densest tropical jungles. He goes close to the craters of
volcanoes in eruption to make a film of the terrifying flow of molten
lava, and he sails the seas in the worst storms, that boys and girls
who have never seen the ocean may understand its mighty upheavals.
One motion-picture outfit was taken to the Arctic regions off the
coast of Alaska where the volcanic activity in Behring Sea frequently
causes new islands to spring from the ocean, or old ones to sink out
of sight, in an effort to record on the motion-picture film the birth
of a new island or the death of an old one.

"Ever connected with scientific research, cinematography," said the
boy's friend, "is now one of the important branches of recording the
phenomena of nature through which great scientific discoveries are
made. Of late years we have heard much about germs, and the science
of germs called bacteriology. A great deal has been learned about
this most important factor in the preservation of our health, through
the study of disease germs, by watching their activities through the
medium of the cinematograph. The little parasites are photographed
under a very high power microscope and the film is cast upon a screen
in the usual way.

"Also exploring parties and parties that go into remote places to
search for additions to our store of scientific knowledge invariably
carry motion-picture outfits. One of the most notable examples of
this was the expedition of Lieut. Robert F. Scott in his search for
the South Pole. Lieutenant Scott carried many hundreds of feet of
standard film, a good camera, and a portable developing outfit, with
which he made pictures of the Antarctic Continent, in order to show
the world the things that he and his men risked their lives to see.

"As I said before, the cinematograph is rapidly growing as an
educational force, and Thomas A. Edison, the pioneer inventor and
the leader in the development of the cinematograph, declares that it
will in a short time completely do away with books in the study of
geography. It is already in use in several special school and college
courses, and with the improvements in the non-inflammable film, which
will be explained later, it can be taken up far more extensively."

The man went on to say that in this connection Mr. Edison, who had
been watching the schoolwork of his own twelve-year-old son Theodore,
recently said in the magazine _The World To-day_ (now _Hearst's
Magazine_):

"I have one of the best moving-picture photographers in the world in
Africa. I told him to land at Cape Town, and to take everything in
sight between there and the mouth of the Nile. His pictures will
show children what Kaffirs are and how they live. He will show them
at work, at play, and in their homes. They will be life-size Kaffirs
that will run and skip or work right before the children's eyes.
But the Kaffirs will be but the smallest part of what the African
pictures will show. The biggest beasts of the jungle--the elephants,
lions, rhinos, and giraffes--will be shown, not in cages, but in
their native haunts. The city of Cape Town will be shown with its
characteristic streets and its shipping. The broad veldts over which
Kruger's armies marched will be shown just as they are, with here
and there a burgher's cottage. Every step in the process of mining
gold and diamonds will be put upon the film. The Nile will be shown,
not as a small black line upon a map, but as a body of beautiful
blue water, alternately plunging over cataracts and creeping through
meadows to the sea. Then will come the Pyramids, with natives and
tourists climbing them, and, lastly, the great cities of Alexandria
and Cairo. Would any child stay at home if he knew such a treat as
this was in store for him at school? Would he ever be likely to
forget what he had learned about Africa?"

"Of course," continued the man in the laboratory, "this is but an
example of the use of motion pictures in schools. Many of you boys
have probably seen them in special lectures on other subjects, for
they can be used to show how people live and work in every part of
the world and how the various commercial products that so largely
govern our lives are made."

But the motion-picture man, he explained, is not at all dependent
upon what really happens for his films, because if he cannot train
the eye of his camera on some occurrence that he desires to transfer
to a film, he reproduces it in a studio, spending thousands and
thousands of dollars, if necessary for actors, scenery and stage
fittings. Nothing is too difficult for the motion-picture man, and
he has never proposed a feat so daring but what he could find plenty
of actors willing to take the necessary parts. Battles, scenes from
history, sessions of Congress, railroad wrecks, earthquakes and
hundreds of other spectacles have been planned, staged and acted out
by the makers of cinematograph films, while, of course, all the plays
that we see on the screen are planned and carefully rehearsed before
they are photographed.

This all means that cinematography has become a gigantic industry,
giving employment to hundreds of actors, photographers, and the army
of men and women engaged in making and showing the films, to say
nothing of the thousands of picture theatres that have sprung up in
every city and town in the country.

While the boy's friend was telling him these things about the
adventurous life of the motion-picture man, the listener sat
spellbound.

"I'd love to see some motion pictures made," he said. "The machines
must be wonderful."

"Well," answered the scientist, "we can do that, and if you'd like we
can go up to one of the motion-picture studios some day soon and see
the whole process from beginning to end."

He was as good as his word, and several days later they were
initiated into all the tricks of cinematography at one of the biggest
laboratories in the country. We will follow them there and see what
they found out about the machines by which motion pictures are made
and shown.

With the fact clear in mind that cinematography is simply a series
of snapshots of figures in motion, taken at high speed and thrown
on a screen at a similar rate so that the human eye is tricked into
sending to the brain an impression of moving figures rather than
a series of still photographs, the various machines necessary in
cinematography will not be difficult to understand.

Before there can be a cinematograph play there must be a negative
film upon which the pictures are taken, a camera to take the
pictures, an apparatus for developing them, a positive film which
corresponds to the printing paper in still photography, upon which
the pictures are printed from the negative film, a printing machine
to print the positives from the negatives, and lastly a projecting
machine to throw the picture upon the screen in the schoolroom,
college lecture room, or theatre.

Every boy who is an amateur photographer is familiar with the
photographic film. Up to the time the method for making practical
cinematograph films was discovered in this country, scientists
vainly tried to portray motion by the use of photographic plates, but
had little success. In a very short time after Eastman had announced
the discovery of a celluloid substance that was transparent, strong
and flexible, light, and compressible into a small space, Edison
announced a machine for showing motion pictures.

The film base, or, in other words, the material which takes the
place of the glass used in glass plates, was discovered by George
Eastman in 1889, after years of painstaking experiment with dangerous
chemicals. The base is a kind of guncotton called by chemists
pyroxylin, which is mixed in wood alcohol. The guncotton is made by
treating flax or cotton waste with sulphuric and nitric acids. After
the guncotton and the wood alcohol have been thoroughly stirred up,
the mixture looks like a thick syrup, but it is about as dangerous a
syrup as ever was brewed, for its ingredients are those of the most
powerful explosives. Its technical name is cellulose-nitrate. It is
poured out on a polished surface, dried, rolled, trimmed, and after
being coated with the sensitive material that makes it valuable for
photography, is ready for delivery to the motion-picture maker in
lengths up to 400 feet.

  [Illustration: THE MEN WHO GAVE THE WORLD MOTION PICTURES

  Eadweard Muybridge, called the "Father of Motion Pictures."

  Thomas A. Edison, inventor of the motion-picture machine.]

  [Illustration: THE MOTION-PICTURE PROJECTOR

  This is the standard Edison projector from two points of view,
  showing its complicated mechanism as clearly as possible.]

One of the interesting points to remember about these films is that
although they are made in lengths up to 400 feet they are all one and
three eighths of an inch wide, and the three eighths of an inch
is given over to a margin at each side of the picture. That leaves a
width for each picture on the film of just one inch. The height of
each picture is three quarters of an inch. Fancy a photograph one
inch by three quarters of an inch! No matter how clear it is you
could not see with the naked eye all its details, and so it is in the
cinematograph picture. It is so clear and sharp that when put under
a good magnifying glass details that cannot be seen by the human eye
are noticed. Now fancy multiplying the area of each little picture
2,700 times, and think of the chance for magnifying imperfections!
And yet that is the amount that each picture is magnified in throwing
it on a screen of the average size.

The films are coated with the sensitive emulsion in two degrees. The
negative films must be as sensitive as possible to light, as they
are intended to receive the shortest possible exposure, while the
positive films, or the ones which correspond to the print paper in
still photography, are made less sensitive to light, inasmuch as they
are exposed for a longer time in the printing machine.

Fireproof films are probably one of the most important developments
in the whole great motion-picture industry, for through these,
schools, colleges, churches, lecture halls, and other public places
not fitted with the fireproof box in which the motion-picture
operator works, can have the advantage of cinematography.

It was a difficult matter to find a non-inflammable film, for
science has not yet discovered a base that can be made without
cellulose, but the base we know to-day was treated so as to be
non-explosive and practically non-inflammable. This film base is
called cellulose-acetate, and when it is exposed to an excessive
heat, as, for instance, the beam of the motion-picture lamp when the
film is not moving, or when it touches a flame, it melts but does not
blaze up. In the melting it gives off a heavy smoke, but there is no
serious danger from this, as there is from the spurting flames from
an exploding cellulose-nitrate base.

The films are packed in metal airtight and lightproof boxes and sent
to the motion-picture firms, where they begin a complicated and an
interesting career. The first stage is the perforating machine,
through which all films, whether negative or positive, must go. The
holes are made along the two edges of the celluloid strips, just as
shown in the picture opposite page 176. There are sixty-four holes to
the foot, on each side of the film, and each hole is oblong-shaped,
as can be seen, with a width of about one eighth of an inch and
a depth of about one sixteenth of an inch. This is known as the
Edison Standard Gauge, and it is observed by practically all the
motion-picture firms in the world.

The perforations along the edges of the films furnish the means for
drawing them through the camera, printing machine, and projector; and
as the correct movement of the films is one of the important factors
in making good pictures, they must be absolutely mathematically
exact. A fault in perforation of even as much as one thousandth
part of an inch is apt to cause the film to buckle in the camera or
projector and ruin the whole thing.

There are several different perforating machines in use now, and
all of them are claimed by their makers to be perfect. It will not
be necessary for us to take one of these machines to pieces further
than to see that the holes along the edges of the films are punched
by hardened steel punches. The films unwind from one bobbin, pass
through the perforating device, and wind upon another bobbin. Of
course the work must be done in absolute darkness, except for a small
ruby lamp, as the films are so sensitive to light that any rays other
than faint red would spoil them.

After perforation the negatives and positives are ready for use. The
negative goes to the photographer in its light-tight metal box to
be run off in making a film of a historical scene, a comedy, some
wonderful phenomenon of science, or any one of a million different
subjects. Just for the sake of seeing everything in its proper order
we will assume that the negative is about to be used in portraying a
comedy about the troubles of a book agent, and that it is all done
in the studio where the scientist and his boy friend watched this
very film made.

Now for a look into a motion-picture camera--something few people
get, because the competition among the various cinematographers is
keen, and those who hold patents on cameras fear infringement.

The camera, which is enclosed in a strong mahogany box, stands upon
a tripod. It is about eighteen inches long, eighteen inches high,
and four inches wide. (This size varies with the make, and kind of
work required.) The left side opens on a hinge, while on the right
side are the ground glass finder, the distance gauge, and a dial
to register the number of feet of film used. In the rear of the
camera is a small hole which connects with a tube running straight
through the box so that the operator looking through can sight it
like a telescope, before the film is exposed. When the sighting and
focusing are completed the opening is closed with a light-tight cap,
and the film can be threaded through the camera. Having no bellows
for focusing like an ordinary camera, the lens of the motion-picture
camera is moved back and forward a short distance in the little tube
in which it is set, to aid in the focusing. Of course the lenses of
these wonderful snapshot machines are the best that money can buy and
the factories can turn out.

  [Illustration: A SECTION OF MOTION-PICTURE FILM

  This is the exact size of the little pictures we see on the
  screen almost life size. Note how slowly the changes appear. It
  takes only one second to take sixteen of these.]

  [Illustration:

    Courtesy of Thomas A. Edison, Inc.

  MAKING A MOTION-PICTURE PLAY IN THE STUDIO

  Note the photographer, the stage manager beside him, and the
  battery of arc lights making the scene in the studio as light as
  day.]

In the rear half of the camera are two boxes. The top one holds the
unexposed roll of negative, while the exposed film is rolled in
the bottom one. Roughly speaking, the film unwinds from the top
spool, passes out of the containing box through a slit, over a set of
sprockets into the "film gate," down past the lens and shutter, where
it is exposed over a lower set of sprockets, and through a slit into
the lower containing box, where it is wound on a spool.

  [Illustration: A MOTION-PICTURE CAMERA

    A--Box for coil of unexposed film.
    A´--Box for coil of exposed film.
    B--Film passing over rollers.
    B´--Exposed film passing over rollers.
    C--Cogwheel which draws out film.
    D--Teeth which jerk film past lens.
    E--Lens and film-gate.
    H--Cogwheel which draws in exposed film.]

"It looks simple enough, doesn't it?" asked the photographer,
who was explaining the making of a moving-picture play to his
visitors. "Well, it is a simple idea, but it takes a very
complicated and a wonderfully accurate machine to accomplish the
desired result.

"In the first place our cinematography is just still photography
at high speed. We have to take approximately sixteen snapshots a
second, so you can see that it takes a perfect machine to move
the film along fast enough so that we can get sixteen good,
clear, sharp pictures only slightly bigger than a postage stamp,
on our film between the ticks of your watch.

"Now if you look through the little hole at the back of the
camera you will see that the scene in front of us is in the
proper focus, and if you look at the little ground glass finder
at the side here you will see it just the same way, except that
it will be upside down. Now I will close the telescope focus at
the rear so that when the film is brought down before the lens it
will not be light struck."

The "threading" of the camera then began. "This little flap
sticking out of this slit in the top box," continued the
cinematographer, "is the end of the film, which is tightly wound
up in its holder. You notice that I draw it out and thread
it between these rollers, making sure that the teeth of the
sprockets enter the perforations along the sides of the film. I
also make sure that the sensitized side of the film is turned
out, so that the light coming through the lens will strike it
first. After the negative has been led over the sprockets you
notice that it is allowed to make a loop of a couple of inches of
slack. Then it is led into the important device we call the 'film
gate.'

"You see the gate is hinged and that these little claws or
fingers running in grooves take hold of the perforations. The
next thing is to close the hinged gate so that the film is
tightly held against the aperture, through which the light
strikes it and makes the picture. Below the gate we let the
negative make another loop and then thread it over another system
of rollers and sprockets and so to the slit in the lower box,
where the exposed negative is rolled.

"The camera is now loaded and threaded and when I give the crank
by which the wheels are turned a few trial turns you can see the
way the mechanism works. In the first place you must understand
that the film has to be jerked down with an intermittent motion.
Don't forget to look for the intermittent motion, because, after
the persistence of vision, that jump and stop, jump and stop, is
the most important thing in cinematography--intermittent motion!

"You can see as the crank turns that the sprockets pull the film
out and guide it along its course, and the little fingers jerk it
down the space of one picture, or three quarters of an inch, at
each jump. When the fingers are jerking the negative down, the
shutter must be closed, and when the fingers are making their
back trip to take a new hold on another length of film the strip
must be as still as the Washington Monument, for the shutter to
open, let in the light and transfer the image before the lens to
the negative."

The photographer turned his crank and all the wheels in the
camera began to move. The sprockets working in the perforations
pulled out the film and made the loop larger. The little fingers
entered the perforations and jerked the film down, taking up some
of the slack of the loop. The reason that the loop is formed is
to prevent the film being torn by a hard jerk by the fingers when
it is taut.

"Now if your eye were quick enough--which it is not"--said the
photographer, "and you could see behind the gate, you would see a
movement like the following repeated sixteen times to the second:
Crank turns, top sprocket adds three quarters of an inch to the
top loop, bottom sprocket takes up three quarters of an inch of
bottom slack loop, fingers spring from groove and carry film
down three quarters of an inch, inconceivably short pause while
shutter opens and picture is taken; during this pause, while
film is stationary, fingers jump back into groove, slide back
to starting point without touching film and shutter closes. The
shutter is a revolving disk between the lens and film, and the
holes in the disk passing the negative admit the light."

After a roll of negative film has been exposed it is sent to the
studio dark room for development. Every precaution is taken, of
course, that no ray of light other than that which comes from
the ruby lamp shall enter this room where films representing
hundreds, and perhaps thousands, of dollars are being developed.
The actual process for developing is no different from that used
in developing other films, but the difficulties in handling a
delicate snakelike, strip some 300 or 400 feet long and 1-3/8
inches wide are tremendous. All amateur photographers appreciate
the difficulties of developing in one string a roll of twelve
films of a reasonable size, but think of handling a roll of film
several hundred feet long no wider than a ribbon, and holding
sixteen pictures to each foot of surface!

The difficulties of scratching, tangling, etc., were overcome
by systematizing the process. In some cinematograph dark rooms
the films are wound on racks about four by five feet, and then
plunged into the various baths, which are in vertical tanks of
convenient size. In yet other dark rooms the films are wound upon
drums about four feet in diameter and revolved in horizontal
tanks, only the lower part being immersed. The only difference is
that the racks can be manipulated easier than the drums.

While in the motion-picture dark room the boy visitor asked
the photographer in charge whether an amateur could step in
and develop a few hundred feet of film granted that he had the
necessary materials.

"Of course he could," came a cheerful voice from the darkness.
"It's just the same as developing a roll of ordinary films,
only we do more in a bunch than the amateur. If you'll step
over here and watch this reel that we are now putting into
the developing bath you'll see that it does just the same as
the single film developed in the amateur's dark room." After
watching this trained photographer and his assistant for a
few minutes, however, the newcomer decided that it was not an
amateur's job, but rather one of the most delicate operations in
all cinematography, for the developer can remedy many faults of
exposure by bringing out an under-exposed film or toning down an
over-exposed one.

Leaving the dark room the next stage of the negative is the
drying room, where the film still on the rack is hung up to dry.
This drying is a very difficult process because there is great
danger of the film either becoming too brittle and cracking or
of its being not hard enough. The air in the drying room has to
be kept at a certain even temperature and it must be filtered so
that no dust or impurity can injure the film.

After it has been properly dried the film again is wound upon a
metal spool, put in an airtight box and sent to the assembling
room, where the various scenes that go to make up the picture
play, taken at different times and on different rolls of
negative, are joined together in their proper order to make a
complete play in a single roll about one thousand feet long.

After the negative film is developed, dried and wound upon a
metal spool it is sent to the printing room, where positive
prints are made from the original impression. Right here it may
be well to say that on a negative film or plate in any kind of
photography white appears black and black appears white--hence
the name negative. The paper or film upon which the print is to
be made turns black wherever the light strikes it, so that when
the negative is laid over the positive and exposed to a strong
light the rays quickly penetrate the white spots on the negative
and turn the corresponding spots on the positive black. The light
does not penetrate the places on the negative which are black,
and consequently leaves those places on the positive white. The
result is that the positive shows the image just as it appears to
the eye.

The principle of printing positive films, then, is the same as
the principle of making photographic prints or positives from
ordinary still photography plates or films, but of course it is
far more complicated because of the mechanical difficulties of
bringing the two long, unwieldy strips of film together in the
proper position. The whole process is carried out by a machine
which takes the place of the printing frame into which the
amateur so easily puts the still-life photographic plate and
printing paper.

There are several motion-picture printing machines in use in this
country, but in their central idea they are similar, as they
all pass the negative and positive films before a very bright
light so that the impressions on the negative are transferred to
the positive. The invention of this machine was a necessity for
the commercial success of motion pictures, for obviously it was
impossible to lay a strip of film several hundred feet long and
about an inch wide in a printing frame over a positive film of
the same length and width.

  [Illustration: A MOTION-PICTURE PRINTING MACHINE

   A-A´--Rollers for negative film.

   B-B´--Rollers for positive film.

   C--Film gate where positive is held over negative for printing.

   D-D´--Negative film.

   E--Unexposed positive film.

   E´--Exposed, or printed positive film.

   F--Light which, shining through film gate, imprints image of
   negative on positive.]

The explanation of one printing machine will suffice to indicate the
general principle. Some of the machines are worked by hand power, but
in the larger reproduction studios electric power is used practically
altogether for running the battery of printing machines.

The spool of negative film is slipped on to a spindle so that it can
unwind easily, and immediately underneath it the roll of unexposed
positive film, properly perforated along the edges in exactly the
same way that the negative film is perforated, is suspended on a
similar spindle. Of course the only light in the printing room is
the photographer's ruby lamp.

The two films unwind and pass downward, with the sensitive surfaces
to the inside, and the positive on the outside of the negative.
They are drawn together, and with the positive stretched flatly
over the negative they pass over a pair of smooth rollers and
toothed sprockets which enter the perforations of the two films with
mathematical accuracy. They then make a small loop and enter a side
hinged gate which holds them tightly against the printing aperture.
This aperture is a hole just the size and shape of each picture on
the film, and through it shines a very bright light which casts its
direct rays upon the negative and imprints the image of the negative
film upon the sensitized surface of the positive film. After passing
the printing aperture, the two films make another small loop, run
down to another toothed sprocket wheel and roller, and then separate,
the printed positive being rolled upon one spool and the negative
upon its spool below.

The action of this machine is very similar to that of the
motion-picture camera, for like the device for taking the
photographs, the movement must be intermittent in order to obtain
good results.

If the operator desires to see whether the two films are in exactly
the right position and everything is going smoothly, he can, by the
use of a lever in the printing gate, drop a little red screen between
the light and the films, and by looking through the hole see through
the unprinted positive, and the developed negative, to the light
inside.

After a roll of positive has been printed, it is developed by just
about the same process as is used in bringing out the images on the
negative film. Then, after it is dried, the various scenes are joined
together, titles and sub-titles put in, any final editing that is
necesary is done, and the positive film is ready to be put on the
projection machine for the first trial.

The preparation of the titles, sub-titles, and other explanatory
writings that are thrown on the screen in the course of a
cinematograph play is a comparatively simple matter. The words are
written or printed out in large letters on cards and photographed
by a camera with a slower movement than the ones used for recording
moving figures. The positives are made from the negatives so taken,
in the same way that positives of other films are made, and after
development and drying are ready to be joined to the film in the
proper places.

Every firm engaged in the fascinating business of making and
reproducing cinematographic plays gives the most careful and
painstaking attention to the first "performance" of a film. Of course
it is held in private before only the officials and a few critics
invited for the exercise of their judgment. The event amounts to the
same thing as the dress rehearsal of a play to be reproduced upon
the stage, and any changes that are necessary in the judgment of the
critics cause just about as much trouble. Any one of a hundred things
may be wrong. Some little incongruous detail in the scenery may be
noticed, some jarring gesture by an actor or a scene in which the
action does not proceed fast enough.

If the officials of the firm decide that a film is below their
standard, parts must be cut out, and new parts photographed over
again until the whole thing suits requirements. Sometimes one scene
must be done over many times before it suits exactly, and several
hundred feet of film wasted. At a cost of about three cents a foot,
it is plain that the waste in film alone is great, but when a big
scene with a hundred or so actors in it has to be done over again,
the cost of assembling the company, paying their salaries and other
expenses is enormous.

Finally, when the officials themselves are satisfied with a
film it is thrown on the screen for the board of censors in the
various cities, and if it measures up to standard, and contains no
objectionable features, it is ready for public reproduction.

When all this is done, the printing machine again comes into play,
and as many prints of the negative as are needed are struck off, for
in cinematography, as in still photography, it is a simple matter
to run off as many prints as are desired, once a good negative is
made. These prints then are sent out to as many theatres, in as many
different cities, as desire them, and released for public view on the
same day in every theatre in the country.

Having looked at the motion-picture camera, and at the complicated
process for developing and printing the films, we are now ready to
climb into the little fireproof box from which comes the beam of
light that throws the pictures on the screen. This is the projector
and it is probably the most complicated of all the machines used in
cinematography. As it was a development through the application of
well-known mechanical principles we will not go into this subject
more deeply than merely to understand its central principle, which is
intermittent motion.

The result toward which the inventors worked was a magic lantern such
as was familiar to every boy ten years ago, that would throw upon the
screen the tiny consecutive pictures on the film, with such speed,
and at the same time so clearly and steadily, that the effect would
be that of figures in motion. Most boys will remember the flickering,
flashing and jumping that used to be noticeable in motion pictures,
and many are probably aware that it was the improvement of the
projecting machine that did away with these objectionable features.

The essential parts of the projecting machine are the lantern with
its light and lens, and the device for running the positive film
before the light with the proper intermittent motion. It might
be said generally that the projecting machine looks like a magic
lantern, but on close examination it will be seen to be an extremely
complicated affair.

The powerful electric light, usually an arc light, which is placed in
a metal box a few inches behind the rest of the projector, directs
its rays through the glass condensers, thence through the film,
and thence through the lens, which throws the image upon the white
screen or curtain. The condensers are made of two carefully ground
glass parts. The first is dish shaped, with the concave side turned
in toward the light and the convex side turned outward. Immediately
against it is another condenser the same diameter and convex on
both sides so that the collected rays from the dished part are shot
forward to a point where they will all converge. This point is the
centre of the lens. From the lens the rays of light are projected in
a widening beam to the white screen on which the pictures appear.

The film is passed before the beam of light at a point between the
condensers and the lens, so that the image is projected through the
lens. The film is run before the light with the figures upside down,
like in the ordinary stereopticon, and the lens turns the image right
side up again.

The most interesting part of the solution of the problem is the
advantage taken of the persistence of vision. Photographed at the
rapid rate of sixteen a second, and thrown upon the screen at the
same rate of sixteen a second, it is plain that the stage of motion
shown in the pictures every sixteenth of a second is reproduced.
With the inability of the eye to tell that the screen is merely
exhibiting separate photographs, the appearance is of motion. In most
persons this visual persistence is only about one twenty-fourth of a
second, but that is long enough to allow animated photography to be a
pleasing illusion to them, for it gives the shutter of the projector
time to hide one picture while the mechanism moves the film down to
the next picture, bring the film to a dead stop, and let the shutter
open again to reveal the next stage of animation.

The manner in which modern mechanical skill took advantage of
this physiological defect, proved many years ago by the leading
scientists, is nearly as interesting as this slight defect in
nature's own camera--the eye.

Above the film gate is a metal fireproof box (many of them are lined
with asbestos) in which is the roll of unprojected positive film.
Below it is another similar box in which the film that has been shown
is wound. The motion, which is directed either by a crank turned by
hand or by electrical power, is the same speed, and practically the
same in detail, as that of the film in the cinematograph camera. From
the film box the film runs to a roller, where a sprocket enters the
all-important perforations and draws out the strip to make a small
loop above the film gate.

The shutter is placed in front of the lens. It is made up of a
black metal circular disk, with either two or three open spaces,
and a similar number of solid or opaque spaces. In general it looks
like a very wide flat aeroplane propeller. Like the movement of the
camera, the film is stationary while the shutter is open, and when
the shutter is closed the film is jerked down three fourths of an
inch, or the length of one picture, and brought to a dead stop by
the time the shutter revolves and is open again. This is repeated
sixteen times every second, so the film is cast upon the screen for
one thirty-second part of a second, and the screen is blank one
thirty-second part of a second while the shutter is closed and, as we
might say, the scenes are being changed for the next act. Although
the movement is just the same as in the camera, it may be well for
the sake of making the thing perfectly clear to go through the motion
very slowly.

For the sake of keeping out of fractions entirely too small for our
consideration we have assumed that in both camera and projecting
machine the shutter is open one thirty-second part of a second and
then closed one thirty-second part of a second, the whole operation
taking one sixteenth of a second. As a matter of fact the effort
of the experts in animated photography is to have the shutter of
the camera open for just as brief a space of time as possible, and
on the other hand it is their effort to have the shutter of the
projecting machine open just as long a space of time as possible, and
closed as short a time as possible. In other words, they desire to
shorten the time when there is nothing on the screen, and lengthen
the time for the eye to photograph each image on the brain. By using
a little different mechanism in the film gate of the projector this
is accomplished to some extent, as well as obtaining a clearer,
steadier picture than formerly was shown.

You will remember that in the camera and printing machine the film
was jerked down by little teeth or fingers.

The simpler of the two methods in general use on projectors now is
called the "dog" movement. It is composed of an eccentric wheel
placed below the film gate, with a little roller projecting from it.
The wheel revolves and once every sixteenth part of a second the
roller is brought around so that it strikes the film and jerks it
down the three fourths of an inch that makes the space of one picture.

  [Illustration: A MOTION-PICTURE STUDIO

  This is where a great many of the Edison Photoplays are made.
  Besides all the other departments there is room on the stage for
  several different plays to be photographed at one time.]

  [Illustration:

    Courtesy of Thomas A. Edison, Inc.

  A REALISTIC FILM OF WASHINGTON CROSSING THE DELAWARE

  This picture was taken in zero weather on a real stream with real
  ice menacing the actors in the boats.]

The other method is known as the "Maltese Cross" movement. The name
is taken from the fact that the chief sprocket wheel is shaped
somewhat like a Maltese Cross. This wheel, with four notches in it,
is attached to the sprocket below the film gate, and it is driven
intermittently by a wheel with a pin that enters one of the notches
on the Maltese Cross wheel at each revolution, and pushes it
around the space of one quarter of a turn. This of course turns the
lower toothed sprocket and jerks the film down the space of one
picture. On the next revolution of the driving wheel the pin enters
the next notch, turns the Maltese Cross wheel another quarter of a
turn, and, by the motion imparted to the sprocket, jerks the film
down another three quarters of an inch, thereby pulling another
picture into place as the shutter opens.

Recent improvements on this movement have largely done away with the
jar resulting from the pin catching the notches in the cross. The
wheel that looks like a Maltese Cross has, instead of four notches,
three grooves, dividing the wheel into three equal parts just as if
a pie were cut into three equal parts but the knife stopped short,
leaving a solid hub in the centre. The space between each groove
represents the length of one picture on the film. Without going into
a long, tiresome, technical explanation of this very important little
feature of the projecting machine, it will suffice to say that the
three-groove wheel is connected with the sprocket underneath the film
gate. Near it is a revolving arm, and upon this arm is a horizontal
bar. When the arm makes a revolution, and reaches a point where it
touches the three-divided wheel, the mechanical adjustment is so
fine that the horizontal bar enters the groove, and the revolution
of the arm carries the three-divided wheel around one third of
a revolution--or the space from one groove to another--turns the
sprocket and pulls the film down the space of one picture, with a
quick steady pull. After getting this far, the arm on its upward
course leaves the three-divided wheel, which stands still while the
shutter is open until the arm gets around again, and as the shutter
closes pulls the sprocket around another space.

The strong light concentrated upon the film, in just the same way
that you concentrate the sun's rays upon your hand with a burning
glass, is very apt to set the film afire, particularly if through
any slip in the machinery it stops in its rapid progress of about a
foot a second. As machinery is not infallible, the manufacturers have
invented various safety devices for protecting the film in case the
machinery stops. Of course this is not necessary when non-inflammable
film is used.



CHAPTER VI.

ADVENTURES WITH MOTION PICTURES

   PERILOUS AND EXCITING TIMES IN OBTAINING MOTION PICTURES.--HOW
   THE MACHINE CAME TO BE INVENTED, AND THE NEWEST DEVELOPMENTS IN
   CINEMATOGRAPHY


With a clear understanding of the mechanism of the various
motion-picture machines in mind, we are free to go on with the
scientist and our young friend to the exciting times experienced by
actors and photographers in making the pictures that delight people
all over the world. First, however, let us briefly look back over
the history of the art, for there is nothing more interesting than
to follow up the experiments upon which Thomas A. Edison based his
invention of the original cinematograph or kinetoscope.

Long ago, even before Edison was born, scientists tinkered with
devices that would picture apparent motion, but they were rude
attempts and little progress was made for many years. The first man
to take a decisive step toward practical cinematography was Edward
(or Eadweard) Muybridge, a photographer who lived in Oakland, Cal.;
so he is rightly called the father of motion pictures.

Muybridge had been experimenting with snapshot cameras, as in those
days instantaneous photography with wet plates was comparatively
new, and, being something of an artist as well as a photographer, he
decided that snapshot photographs of animals and men while running,
jumping, and walking would greatly aid artists in transferring to
their canvases the exact positions of the figures they wished to
paint. In 1872 the people of California were considerably excited
over the feat of Governor Leland Stanford's trotting horse Occident,
which was the first racer west of the Rocky Mountains to make a mile
in two minutes and twenty seconds, and the Governor was having him
photographed on every occasion.

Governor Stanford also wagered that at one time during the trotter's
stride all four feet were off the ground. Muybridge suggested his
plan for photographing the animal's every movement, while running,
trotting or walking, as a means of settling the bet, and the
Governor, very much pleased, gave him free access to the stables and
race course.

The photographer built a studio at the course and systematically
went to work. First, he built a high fence along the track and had
it painted white. Then he securely mounted twenty-four cameras side
by side along the opposite side of the course and stretched thin
silk threads from the shutter of each camera across the track
about the height of the horse's knees. Occident was then led out
and ridden along the course so that he would pass between the white
background and twenty-four cameras. As he came to each silk thread
his legs broke it and opened the shutter of the camera to which it
was attached. Thus the animal photographed himself twenty-four times
as he passed over the track and showed that Governor Stanford's
contention regarding his movements was correct.

Laid in consecutive order in which the photographs were taken, each
picture showed a different stage of the horse's movements, and if the
series of photographs was held together and riffled over the thumb,
so that each one would be visible for just the fraction of a second,
the impression received, thanks to the persistence of vision, was
that of a horse in motion. When Muybridge went to Paris the year
after taking the photographs of Governor Stanford's horse he received
a warm welcome from some of the greatest French painters of the day.
He gave several exhibits of his photographs, but carried the work no
farther.

Almost one hundred years before this, several brilliant Frenchmen
were groping in the darkness for some way of showing motion by
means of pictures, and brought forth a device known as the "Wheel
of Life," or the Zoetrope. It was simply an enclosed cylinder, and
upon the inner lower face, which was free to rotate, were placed
a series of pictures showing the stages of some simple animation,
in sequence, such as two children seesawing, or a child swinging.
The upper surface was pierced with long, narrow slits, and when one
looked through the slits, and the lower surface with the pictures on
it was rotated, one actually saw only one picture at a time, but as
they passed before the eyes the appearance was of motion. Various
improvements on this idea were made, and silhouette paintings even
were thrown on a screen so as to give an illusion of motion.

The development of photography was necessary, however, before motion
pictures ever could be a success. About the time Muybridge took his
pictures the old wet plate was superseded by the dry plate we know
to-day, and scientists began the search for some material from which
they could make film base.

Before the invention of films, motion pictures, as they were known
at that time, were used chiefly by scientists in trying to analyze
motion which cannot be traced by the human eye. Among the leaders in
this work was the French scientist Dr. E. J. Marey, who studied the
flight of birds and the movements of animals and men so carefully
that he wrote a book entitled "Movement," which is still used by
authorities in scientific research.

Doctor Marey set up another camera at the Physiological Station
in Paris with which he and his associates made pictures of great
scientific value. Those were the days of the early experiment with
flying machines, as will be remembered from Chapter II, and the
French inventors made careful studies of Marey's pictures of bird
flight.

Doctor Marey's stationary camera was a simple bellows type which
took an exceptionally wide plate. The shutter, which was operated
by a crank, was a disk with slits in it, so that as it turned
it intermittently admitted and shut off the light. Thus, as a
white-clothed figure passed a dead-black background, in front of the
camera, the various stages of its movements in the course of its trip
from one side of the camera's focus to the other were faithfully
recorded on the plate, each slit making an exposure of the image on
a different section of the plate, showing the figure in a different
position.

Many machines that were merely developments of the old zoetrope
were brought out both in the United States and Europe, but the
greatest obstacle to their success was that they were peep-hole
machines of the kind that flourished in penny arcades a few years
ago, rather than devices for throwing pictures on a screen so that
a large number of persons could see at the same time. In general,
these old-fashioned "moving-picture" machines were simply cabinets
in which were mounted a series of transparencies made from pictures
representing the stages of some simple animation. An electric light
illuminated the transparencies and they were rotated so that one
picture at a time was seen. In some of the more improved "wheels of
life," such as were shown in this country, the transparencies in
consecutive order were mounted on a hub like the spokes of a wheel
and were rotated so that one was seen at a time, very much like the
way Muybridge riffled his horse pictures over his thumb.

All this time two American inventors had been at work on the two
most perplexing problems in animated photography at that time,
and it was through their achievements that the first practical
motion-picture machine was given to the world, just as it was through
the achievements of the Wright brothers that the first practical
aeroplane was given to the world.

These two men were Thomas A. Edison and George Eastman.

Mr. Edison had been working for several years on a motion-picture
machine, but was handicapped by the lack of a practical film.

Mr. Eastman, after years of experiment, produced the film that made
cinematography possible, in 1889.

With a strong transparent film, flexible, and compressible, to take
the place of the clumsy glass plate, Edison was ready to go ahead
with his work, started years before, and in 1893 the crowds at the
World's Fair in Chicago saw the first motion-picture machine. It was
called a Kinetoscope.

  [Illustration:

    Courtesy of Thomas A. Edison, Inc.

  THE CORSICAN BROTHERS--A FAMOUS TRICK FILM

  The parts of the twin brothers in this film were acted by the
  same man, the illusion being accomplished by the double exposure
  trick.]

  [Illustration:

    Courtesy of the Vitagraph Company of America

  THE GUILLOTINE

  Famous scene from the photoplay based on Dickens's great novel,
  "A Tale of Two Cities."]

Simple as it was, thousands and thousands dropped nickels into a slot
and peeped into the hole at the "moving pictures." Some of the boys
who read this may remember machines like it. The mechanism was in a
cabinet in which the pictures were shown on a positive film. This was
about forty feet long and was strung backward and forward inside the
cabinet on a series of spools in a continuous chain. The film passed
before the peep-hole and the pictures were magnified by a lens. They
were illuminated by an electric lamp behind them. A rotating shutter
cut off the light intermittently, so that each picture was seen for
the fraction of a second, and then a period of darkness ensued.
The shutter was the only attempt at intermittent revealing of the
pictures, for the film travelled continuously.

The camera that Edison invented for taking the pictures shown in his
kinetoscope was in principle about the same as the one described
earlier in this chapter, except that it has been wonderfully improved
in mechanical accuracy and photographic clearness. The hardest
problem facing him was the machine which would show the pictures to
a large number of spectators at the same time and do away with the
old peep-hole machine. The idea of the magic lantern immediately
presented itself, but the inventor quickly saw the necessity of an
intermittent motion, for if the ribbon of pictures was drawn before
the beam of light fast enough to give the illusion of motion, each
picture was thrown on the screen for such a short time that it was
too faint to be seen easily. From this it was to Edison but a step
to a practicable projector, and nothing remained but to improve its
mechanical working.

Getting motion pictures is the adventurous part of the business, for
this work requires operators and actors who are athletes and who do
not know the meaning of fear. As pictures of scenery and events are
taken in every corner of the world--in the jungles, in the arctic
ice, on mountains and in deserts, the photographers all can tell
absorbing stories of the strange places and things they have filmed.

In the rough the films are divided into four great general classes,
with several special classes besides. They are scenic, industrial
(showing the working of some great industry like steel making),
topical, and dramatic. Scenic and industrial films are simply taken
at an opportune time, as it is usually not necessary to make any
advance arrangements, though the photographing may incur great risks.

Topical films, such as the pictures of the recent Durbar in India
or some other great current event, are very valuable when quickly
sent broadcast. Of course the photographer must have the same news
instinct that the reporter has to get good topical films, for he
must get there first and deliver his picture "story" to his studio
"editors" as quickly as possible. The photographers often have
hair-raising adventures in taking such films, as the single instance
of the man who went up Mount Vesuvius during an eruption and took a
cinematograph film of it will show.

The greatest variety of experiences, however, is to be found in the
making of dramatic films--that is, motion-picture plays. As every
boy knows, these stories have just as wide a range as the books in a
library. There are plays based on biblical stories, and plays dealing
with Wild West adventures; there are farces, comedies, and tragedies;
in fact, there is no limit to the variety. These plays, however, can
be divided roughly into two classes--that is, those that are produced
on the motion-picture studio stage and those produced out of doors
with the natural surroundings as the stage. The interesting things
about either kind would fill a book the size of this.

In the early days of cinematography only simple shows were attempted,
but now nothing is too big or too complicated or too expensive for
the big concerns making pictures in the United States and Europe.
The first motion-picture studio here was simply a portable, glass
roofed, black walled shed set on a pivot in Edison's yard in Orange,
N. J. It was called the Black Maria and makes an interesting contrast
to the great glass studio at Bronx Park, N. Y., costing $100,000,
in which many of the Edison films are now made. All well-equipped
motion-picture studios these days are fitted out with space for
several stages; a great tank for water scenes, carpenter shops,
scene-painting studios, furniture and other stage properties to
furnish scenes, costumes, stage fittings, and a great corps of
photographers, mechanics, electricians, etc., besides the company of
well-paid actors who take part in the shows.

If a play is to be reproduced in the studio, the architect draws the
plans for the scenery, which are sent to the stage carpenters, who
make the framework and stretch the canvas. The blank scenery is then
sent to the racks, where the scene painters get to work on it.

In the meantime the property man at the studio, just like the
property man at a theatre, has received a list of the things he will
need to furnish the scene and give the actors the paraphernalia
necessary for the carrying out of the play. He ransacks his storeroom
and brings out tables, chairs, pictures, etc. The studio costumer
also checks off her list and sees that she has in her great wardrobe
costumes to dress the characters for their parts.

Meantime the stock company of actors is called together, the
scenario, or plan of the play, is read, and rehearsals begin. All
this part of it and the rehearsing are very much like the work
preliminary to the staging of a regular play, except that the scenes
are arranged, not according to the size of the stage, but according
to the focus of the camera. Each scene is timed to the second so that
the pantomime will tell the story but not tire the spectators with
useless repetition. In rehearsing, the actors sometimes speak their
lines--that is, the words the character would say--just as if they
were to be heard, because it often helps them to give the proper
effect.

Finally, when the stage director has one scene of a play down fine,
after perhaps days or weeks of rehearsing, the photographer is
called. He consults with the stage manager, measures off the distance
for his focus, so that he will get all that is necessary into the
picture, and nothing that is not wanted; and after seeing that every
detail is attended to, the great battery of arc lights overhead is
turned on, and the stage manager says, "GO!"

The photographer begins to turn his crank, keeping one eye on the
stage and the other on his stop watch, and the stage director counts
off the seconds, meanwhile shouting instruction to the actors on
the stage. To an outsider the noises sound like a riot or a street
fair rather than a theatrical performance timed to the fraction
of a second in which the movement of an eye counts in the final
effect. While the camera clicks off sixteen instantaneous snapshots
to the second the stage director calls out the seconds, "One, two,
three. One, two, three. Look out there, don't get out of focus! Keep
toward the centre of the stage. Now, Jim, run in and grab the book
agent--hurry, look angry! One, two, three. That's fine! Hey, there!
shake your fist." And so it goes, until the director rings a bell
or shouts, "That's all!" and the scene is ended. Just as the last
pictures are being run off, a stage hand rushes into the scene and
holds up a large placard with a big number on it. This number is
the number of the scene in the play, and is watched by the men and
women in the assembling room when they gather the various scenes of
a picture play together and join them up in the proper order for one
continuous roll. Of course in the joining the number is cut out of
the picture for projection.

It very often happens that a stage director in his effort to get a
graphic story reproduced on the film takes a great many more pictures
than can be crowded within the limits set for the play. Then with
the scenario in front of him, and a good magnifying glass to bring
out the detail of the pictures, he takes his scissors, just as the
editor takes his blue pencil, and begins cutting from the story the
unnecessary pictures, just as the newspaper or magazine editor cuts
useless paragraphs from the story or article. He must not cut out any
picture that helps to tell the story, and yet he must sometimes cut
out as much as 400 feet of film. He "kills" an unnecessary picture
here, and an unnecessary picture there, and adds up their length
until the story has been reduced to the proper size.

Although spectacles such as the one in the picture representing a
battle on a bridge, and others even larger, are staged in the various
big motion-picture studios, the most exciting work in the filming of
motion-picture plays is out of doors where the natural surroundings
make the stage. A great many of the shows seen to-day are taken this
way, with real trees, real water, real mountains, or real streets
affording the settings. Hence with studios in which battle scenes,
riot scenes, water scenes, and practically any indoor scene can
be reproduced; and also the great outdoors at the disposal of the
cinematographer, there is practically no limit to the subjects that
can be turned into dramatic films for the education and amusement of
the public.

A few instances of the plays made out of doors will serve to show the
limits to which the producers are willing to go to get new shows. The
Edison company, with its big studio in New York and its manufacturing
plant at West Orange, N. J., in the heart of the country where the
Revolutionary War was fought, is reproducing a whole series of
films of American history. These, so far as possible, are made on
the exact spots where the dramatic events occurred. The first of
the series entitled, "The Minute Men," was taken near Boston, where
those historic defenders of liberty fought for their country. In this
film is the famous scene representing the Battle of Concord, which
was taken on practically the identical ground where the battle was
fought. The producers spent a great deal of time in planning this
series of pictures and so far as possible had every historical fact
correct, so that the value of the series from the educational point
of view is apparent. The other titles in the series will show how the
scenes of the Revolutionary War were brought home to the American
people. They included "The Capture of Fort Ticonderoga," "The Battle
of Bunker Hill," "The Declaration of Independence," "The Death of
Nathan Hale," "How Washington Crossed the Delaware," "Church and
Country; an Episode of the Winter at Valley Forge," and so on. The
film dealing with Washington's trip across the Delaware in the ice
was made under conditions as nearly like those of the actual events
as possible to get them. The pictures were taken during the coldest
part of last winter (1912), and the photograph opposite page 193 was
taken while the big scene was being acted out. This was taken in an
arm of Pelham Bay, near New York, and the "scene shifters" had to
work for hours in the bitter cold breaking up the ice and shifting
around the great cakes in order to get the desired effect. Their
success is attested by the picture reproduced here.

The Selig Company, with studios in Chicago and Los Angeles, and big
stock companies of actors in both places also take some wonderful
outdoor films. One of these was a play representing life in the
African jungle, for which a special trainload of actors, and a whole
menagerie of elephants, camels, lions, rhinos, leopards, pumas,
zebras, and other animals, were shipped to Florida, where scenes much
like those in Africa were found. This same company also sent a stock
company and a corps of photographers to the Far North, where a film
play was made amid the Arctic ice.

The Chicago studio of this concern is one of the wonders of
cinematography, for not only has it a great building in which indoor
plays are filmed, but a great land reserve for outdoor productions.
In one place are artificial hills built in the natural forest, and
upon them artificial feudal castles. In another are log cabins for
frontier scenes, and in yet another a barren stretch for other kinds
of scenes. The Los Angeles company is close to the mountains, the
ocean, and the Great American Desert, so that it can furnish material
for an endless amount of exciting Wild West shows.

One of the big films made in Europe was "The Fall of Troy," produced
by the Itala Film Company, which reproduced the great wooden horse,
the walls of Troy, and all other historical details. The great
French, German, and English companies also have made big films.

In the production of plays built on well-known novels the
motion-picture industry has found one of its most successful fields.
Dickens's great novel, "A Tale of Two Cities," afforded the
Vitagraph Company of America, one of its best films, while James
Fennimore Cooper, Alexander Dumas, and even Shakespeare, and grand
opera have been transferred to the cinematograph. From the great
Biblical stories also have been taken films that have been shown by
missionaries, and others interested in religious work, all over the
world. The "Passion Play" was one of the first long films ever shown
and it made a tremendous success.

Big spectacles are always popular and to fulfill the demand two
locomotives have been run together at high speed, the motion-picture
concern buying the machines outright for the purpose and leasing the
railroad for a day; an automobile has been driven over the Palisades
of the Hudson River, ships have been towed out into the ocean and
blown up and whole towns of flimsy stage construction have been built
only to be burned, while the motion-picture photographer recorded
the whole thing on a film. One concern even got permission from the
Los Angeles Fire department during a big fire, and dressing an actor
as a fireman cinematographed him as he heroically rushed up a ladder
amidst the flames and rescued a screaming woman from an upper window.
The woman was an actress who had risked her life to go into the
burning building and be rescued.

Of course the great motion-picture industry has not been without its
fatal accidents. Several times actors playing the parts of men in
difficulty in the water have actually been seized with cramps and
have drowned before the eyes of the spectators. One time a picture
was being taken of a band of train wreckers who were supposed to tie
the switchman to the track. The train was supposed to stop just short
of the man, but it actually ran over and killed him. The pictures
were used at the inquest. During the filming of war pictures there
have been explosions of gunpowder that were not intended, and in the
taking of pictures of wild animals in their native haunts and in
menageries, several photographers have been badly injured.

There is another big and important department in the filming of
motion picture plays in trick photography. Every one who reads
this has seen at the picture-theatre films of things that he knows
perfectly well never could have happened--men walking on the ceiling,
fairies the size of a match acting on a table beside a man, a saw
going through a board, a piece of furniture assembling itself, a man
run over by an automobile, his legs cut off, and then stuck on again
all within a few minutes, marvellous railroad wrecks, and a thousand
other things which could not happen or which the motion-picture
photographer probably never could catch in his lens. All of these
things are done through trick photography.

Double exposure, double printing, and the stop motion are the most
common methods of obtaining these marvellous results. Opposite page
200 is a picture obtained during the reproduction by the Edison
Company of Alexander Dumas's novel, "The Corsican Brothers." This
film was obtained completely by the double exposure. In the story,
the two brothers are twins so much alike that they cannot be told
apart. They act exactly alike, and one even feels what, the other
feels. In making the film the producers decided that it would be
impossible to get two actors that looked enough alike to take the
parts of the two brothers, so the same man acted both parts. In the
picture referred to the brothers sitting at table with their mother
are one and the same actor.

The picture was made by blocking off the whole left half side of the
film with black paper and running it through the camera while the
actor played the part of the brother on the right side of the table.
He was timed to the fraction of a second, and when the exposed half
of the film was blocked off with paper and the unexposed half run
through, he acted out his part on the left side of the table, to
this time schedule. So exact was his work that when the brother on
one side of the table spilled a drop of hot coffee on his hand and
started in pain, the brother on the other side, feeling the same pain
as his counterpart, jumped at exactly the same second.

Another popular trick with the double exposure is a scene showing
mermaids or divers swimming or walking at the bottom of the sea.
First a large brilliantly lighted glass tank is set up in the studio,
stocked with fish and sea life, and photographed. In this kind of a
film the images of the real water are a little under exposed. Next a
space the size of the tank is measured off on the floor with a gray
scene laid flat. On the scene are painted faint lines to indicate
water, and faint outlines of fish, seaweed, etc. Then the actress
dressed for the part of a mermaid lies flat on the setting and goes
through the graceful motions of swimming while the film upon which
the real water pictures were taken, is run through the camera, which
is placed above her with the lens pointing directly downward.

Another example of double exposure is seen in most films where
Lilliputians or small fairies enter into the picture. The parts
of both full-grown human beings and diminutive fairies are played
alike by adult actors, but the difference in their size is obtained
by taking each on the same film at different times. For instance,
suppose a tiny fairy is supposed to appear to a grown man in the
picture play. First the man goes through his act with the camera
photographing him from a distance of about fifteen feet. Next the
fairy goes through her act, bowing, etc., to the place where the man
stood and is photographed on the film from a distance of say one
hundred and fifty feet. The two impressions when printed give a
lifelike effect of a full-grown man and a tiny sprite.

There are numberless films made by the stop-motion system, which
simply means that the stage hands rush in and arrange things while
the shutter is closed. All pictures in which you see a man or a woman
falling off a roof or out of a window and subsequently getting up
and running away are made by this system. The Edison film showing an
automobile going over the Palisades and the driver being hurled to
the rocks below was done with the stop motion. It is very simple. The
cinematographer photographed the approach of the automobile and the
human driver in the seat approaching the cliff at terrific speed. He
stopped his camera, the automobile came to a stop, the automobilist
got out and a dummy was placed in his seat. Then by starting the
automobile a little back of where it was slowed down and stopped, and
photographing, it the public could not tell that it had been stopped,
and that the man in the seat who was hurled to the rocks below with
the machine was a dummy.

A development of this is the picture-a-turn motion, which simply
means that with each turn of the crank of the camera one exposure
is made. By this trick many of the strangest films seen are made
possible. The magic carpenter shop where saws and hammers move
without human aid is an example. It is simply done by stage hands who
rush on to the stage between each turn of the camera and advance
the tools to one more stage of progress. The saw is at the top of
the board, and the hammer is suspended in air (by invisible wires),
etc. In the next picture, the saw is in different position, and the
hammer has descended to the head of a nail. In this way all the
magical effects of inanimate objects taking on life in the film are
accomplished. One of the interesting details is the appearance of
such objects as boards rising from the floor and placing themselves
upon the bench ready for the saw. To do this the operator, keeping
his shutter closed, advances his film a couple of feet and takes a
picture of the board falling to the floor from the bench (pulled off
by an invisible wire). As the film is moving backward, the picture
when exhibited in sequence shows the board not falling but rising
from the floor, and placing itself on the bench in a most mysterious
manner.

Moving the film backward will give many strange results. For
instance, in the plays where a little child is snatched from death
under the wheels of an onrushing train just as the cow-catcher is
upon her, it is no longer necessary to risk human lives before
trains. First, the onrushing train is photographed with the film
moving forward right up to the point where the child is to be
standing when rescued. Then the train is allowed to run on past the
point. It is then backed up at high speed, and the film run backward.
When the locomotive rushes past the spot where the child is to be
rescued her heroic rescuer simply dashes on to the tracks amid the
dust of the receding train and places the child between the rails.
When this section of film, which is taken backward, is fitted into
the rest of the ribbon, and is run through the projector forward, it
looks as if the rescuer rushed on to the track and grabbed the child
out of the way as the train passed by.

Another popular trick by which fairies or ghosts are made to appear
gradually in motion-picture scenes is the one by which the lens
is narrowed down or opened up gradually. If a ghost is to appear,
the hole through which the light strikes the lens is narrowed down
so that only the brightest objects are photographed. The hole is
gradually enlarged so that the light increases and brings out the
figures plainer and plainer, until the ghost is in full view.

A great many good films, such as railroad wrecks, automobile
journeys through the clouds, etc., are made with models, propelled
by invisible strings over skilfully built scenery. The scene of
figures walking on the ceiling is very simple inasmuch as it is only
necessary to set the floor of the stage to represent a ceiling and
take the pictures with the camera upside down. Men and animals can be
made to run up the sides of buildings, simply by laying the scenery
on the studio floor, and photographing the whole thing from above.

  [Illustration: A ROMANCE OF THE ICE FIELDS

  This film was taken in the dead of winter, and the man is in a
  dangerous position on a real ice cake.]

  [Illustration: THE SPANISH CAVALIER

  A whole motion-picture outfit was taken to Bermuda to get this
  photoplay.]

  [Illustration: ALL READY FOR A THERMIT WELD

  After the little hole at the bottom of the weld, through which
  the redhot shaft inside shows, is plugged up, the thermit is
  ignited.]

Of the recent developments in cinematography the ones we hear
most about are colour pictures and talking pictures. So far, these
two points which would give the last touch of realism to the scenes
thrown on the screen are in a very imperfect state of development,
but it is safe to say that it will not be very many years before we
will have them duplicating what we see and hear in actual life just
as faithfully as the black and white pictures now duplicate motion.

Science so far has not given us a method of actually taking a
motion-picture negative in the natural colours, such as now can be
taken in still photography, so at first the pictures were coloured
by hand, and later by stencils. This is a difficult and a tedious
undertaking, however, and newer methods have been introduced.

Although there are several systems being worked out the one best
known is the Kinemacolour, which achieved its greatest fame by
showing the pictures of the coronation of King George in England, and
the Durbar in India in colours. The Kinemacolour system is simply one
of photographing and projecting through screens of red and green.
The shutter of the camera is made up of four parts, as follows: a
transparent red screen, an opaque space, a transparent green screen,
and another opaque space. Thus, by the law of colours laid down by
science, when one picture is photographed through a red screen, all
the different tones but red are arrested by the screen, and only the
objects having shades of red are photographed. Next, when the green
screen exposes the next space of three quarters of an inch, only the
objects having green tints are photographed, as all other tints are
arrested by the green screen.

The film itself shows no colour other than black and white, but when
it is projected through a shutter that works exactly the same as
the camera shutter the pictures show the objects in their natural
colours. That is, the alternating pictures taken through the red
screen and shown through a screen of the same colour show all the
tones of red, while the alternating pictures taken through the green
screen and likewise projected through a green screen show all the
tones in which appear green. Thus, with the aid of the persistence of
vision and a somewhat faster system of photographing and projecting,
the tones blend and we see on the screen at the same instant
red-coated soldiers marching past beautiful green trees, and so on.
In order to make this possible it is necessary to give the films a
treatment in a solution that makes them more sensitive to all light
than they would be for ordinary cinematography.

The drawback to the system, as you will have noticed if you have
seen these pictures, is that red and green do not make up all
the _primary_ colours of light. In the direct rays of light (not
reflected light as from a painted wall) the primary colours, from
which all the other tones are obtained, are red, green, and violet,
but it has been found a little too difficult a mechanical process to
use the three screens instead of only two.

The hardest job of the inventors of talking pictures was to work
out a mechanical device that would make a good phonograph and a
motion-picture projector keep step, so that, for instance, the
actor would not be heard singing after the pictures had shown him
close his mouth and leave the stage. Ever since his invention of
the Kinetoscope, Edison has had this very thing in mind, and has
prophesied that in the near future grand opera with motion pictures
and phonographs will be within the means of every patron of the
motion-picture theatre. Edison's idea for obtaining this is to make
the phonographic and the cinematographic records at the same time in
order to insure perfect accuracy of sound and appearance, and his
experiments are meeting with success.

A fairly successful device for giving the phonograph and the
projector synchronism, or, in other words, keeping them in step, has
been worked out by the Gaumont firm of Paris. The phonograph and the
projector are run by two motors of exactly the same size and power,
from the same wires. The armatures of the motors are divided into an
equal number of sections, and each section of one is connected with
the corresponding section in the armature of the other, so that one
cannot rotate for the fraction of a second unless the other rotates
with it. A little switch working on another motor, which works on
a set of gears, will speed up or slacken down the talking machine
so that if the armatures get "out of step" one can be speeded up or
slowed down so that the figures in the pictures will appear to be
talking, laughing, or singing, just as they do in real life.

Another of the recent developments in cinematography is the di-optic
system which aims to show every stage of the motion of figures,
instead of the stage of motion every sixteenth of a second, as is in
the case with the usual apparatus. The di-optic camera is simply two
machines set side by side in one. It takes two loads of film, has
two film gates, and two lenses, but works by turning one crank. The
single shutter revolves in front of the twin lens, so that when one
side is exposing a length of film the other is closed and the film is
advancing. The two rolls of negative exposed in this way record the
complete motions of the figures before the camera. The projector also
is a di-optic machine working in the same manner as the double-eyed
camera, so that when the pictures are thrown on the screen they are
seen practically constantly, instead of every sixteenth of a second,
for while one is hidden by the shutter, another is thrown on the
screen. Also inventors are working on a scheme for taking motion
pictures on glass plates instead of on films.

As was mentioned previously the use of the motion-picture machine
has been very valuable to science, and by adapting the cinematograph
to a powerful microscope a great many motion pictures of the life
of bacteria have been obtained. Also motion pictures are sometimes
made of surgical operations. Carrying this work even farther still,
animated photography and X-ray photography have been joined so that
science now can make motion pictures of the processes that go on
inside small animals.

Owing to difficulties not yet overcome moving X-ray pictures
cannot be taken of the human body at this time. Röntgen rays
cannot be refracted, or collected in a lens. Hence the film for an
X-ray picture must be equal in size to the picture desired. It is
impossible to increase the size of cinematograph films with much
success because of the danger of breaking or tearing them when under
the strain of the rapid course they must pursue through camera
and projector. These facts made it necessary for the scientists
experimenting with X-ray motion pictures to photograph only animals,
but they were greatly encouraged because they obtained some excellent
views of the digestive processes of mice, guinea-pigs, fowls,
and other small animals. The bones of the human hand also were
photographed while the hand was opened and closed.

M. J. Garvallo, who carried on a great many interesting experiments
in France with this type of motion pictures, used a somewhat larger
and more sensitive film than the standard, combined with an apparatus
too complex for attention here. This phase of cinematography,
however, is still in its infancy and we can look for great
improvements at an early date.

Another Frenchman, Prof. Lucien Bull, who was one of Doctor Marey's
assistants in the early stages of cinematography, has made pictures
of the movement of the wings of various insects such as flies,
bees, wasps, etc. To do this he has had to make the fastest known
cinematograph. It was an especially constructed apparatus entirely
unlike the ones described here, but through the agency of an
electrical spark which illuminated the vicinity in which the insect
flew, 2,000 pictures per second were taken, instead of the usual
sixteen.

The very antithesis of the scientific are the uses of the
motion-picture film as an illustrated magazine or newspaper. There
are only a few successful "animated newspapers" in the world, but
the idea will probably spread. The staff of such a publication is
made up of photographers, who are scattered about in every nation on
the globe. There are regular offices in all the big cities which are
ready at a moment's notice to send photographers to any part of their
territory. These photographers get films of all the important news
occurrences of the day, parades, street demonstrations, wrecks, fires
and whatever else fills the newspapers you read every day. The films
are hurried to the main office where they are developed, cut down to
short "items," or allowed to run as long, "stories" just like in a
regular newspaper, pasted together with suitable headlines, printed
in one continuous roll of about 1,000 feet and rushed out to the
subscribers, who are usually theatres with audiences eager for the
"paper."

Such are a few of the many motion-picture activities which have
sprung up in the last few years, and made it possible for us to
see whatever is interesting in any part of the world, on the
cinematograph screen. Beside the professional cinematographers,
there are of course any number of smart boys and young men who are
having fine times with the amateur projecting outfits sold by the big
makers of apparatus. These machines run from mere toys made up for a
little roll of film, already prepared, to projectors with which very
creditable parlour shows can be given.



CHAPTER VII

STEEL BOILED LIKE WATER AND CUT LIKE PAPER

   OUR BOY FRIEND SEES HOW SCIENCE HAS TURNED THE GREATEST KNOWN
   HEATS TO THE EVERYDAY USE OF MANKIND


"HOW hot is it in that furnace?" asked the scientist's young friend
as he poked about the laboratory one day.

"That is not very hot now, but we could increase the temperature to
about 4,000 degrees Fahrenheit if we tried hard enough," answered
the man who, outside of his work, enjoyed best of all the visits of
the boy. "But the heat of the laboratory furnace most of the time is
nothing compared to the heat that we can put to practical use through
a couple of new inventions I have been trying here."

"What are they for?" asked the boy, immediately all interest, for
he was a member of the metalworking class in his school, and was
constantly on the lookout for better ways of working in iron, steel,
copper, and brass.

  [Illustration: THERMIT IN ERUPTION

  With a blinding, dazzling glare and a gentle hissing the thermit
  in a white-hot molten mass fills the mould and runs down the
  sides like volcanic lava.]

  [Illustration: DR. HANS GOLDSCHMIDT

  The inventor of Thermit.]

"Well, they both are used in welding metals and in one--the
thermit process--the hardest steel can be reduced to a molten mass of
white hot metal boiling like a tea kettle on a stove, in about a half
a minute. You see that requires a great deal of heat," continued the
chemist, "and in fact the temperature is 5,400 degrees, Fahrenheit.

"The other process that I have been trying is known as autogenous
welding, and in this even a greater temperature is generated than
by the thermit process. In the tiny flame no bigger than the point
of this pencil that comes from the autogenous welding torch the
temperature is about 6,000 degrees Fahrenheit."

"My!" said the boy, "how could any one ever measure such a heat as
that?"

"Science teaches us how to do that just as science taught us how to
produce these great heats. Why, you know, in the electrical furnaces
at Niagara Falls they produce a heat that they think reaches the
10,000 degrees of the sun. Outside of that, however, the thermit
process and the autogenous welding process attain the greatest known
heats."

"Those must be fine," said the boy, "because before our schools began
to teach metal working, I used to play blacksmith and heat pieces of
iron in the fire, but I could never do anything with it, and now that
we are learning welding in the blacksmith shop at school I see what a
hard job it is. I wish we could use these processes at school."

"Well, you will be able to use them some day," said the scientist,
"but it took science a long time to find out how to produce and use
very high temperatures.

"In the stone age, thousands and thousands of years ago, when men
lived in caves and ate raw the animals that they caught with their
hands, fire was first discovered by an accident. There are many
legends of how the hairy savages that populated the earth fell down
and worshipped the aboriginal scientist who taught them how to warm
their caves.

"Soon, however, fire became a necessity of life to mankind, for it
was discovered that meat tasted better when exposed to a flame--that,
is, when it was cooked--than when it was raw. That was a big step
toward civilization, but it was a bigger one when some wild mountain
tribe found that they could make much more deadly weapons than the
rude ones they chipped from flint, by melting down a certain kind of
rock and fashioning it into spear heads, arrow heads, and hatchets.
From that time on the development of the art of metal working took
only a few thousand years, until to-day man's great knowledge of
metalurgy has enabled him to make such tremendous fighting machines
that war is becoming entirely too destructive, and too expensive a
thing to rush into lightly. Thus, heat and metal working are helping
to force the world forward to another step in civilization--universal
peace.

"After learning how to make these hardest of metals, man has now
solved the problem of making them boil like water with the thermit
process and of cutting them like paper with the oxy-acetylene gas
torch, all in less than a minute.

"You see this bag of coarse black powder that looks like iron
filings? Well, it is the thermit. Put it into a crucible, set off a
pinch of ignition powder on the top, and the whole thing will ignite
in half a minute, throwing off a blinding white light and thousands
of sparks like beautiful fire works. That is the thermit reaction.

"You know more about the oxy-acetylene gas torch, for in your metal
working at school you used the gas blowpipe to make a very hot flame.
The oxy-acetylene gas torch is just a high development of this, for
instead of ordinary gas, acetylene is used and instead of air we use
pure oxygen."

The caller sat down and asked his friend to tell something more about
these two marvelous inventions. The story was several days in the
telling, for there were visits to foundries and experiments in the
laboratory, besides many long talks.

"First we will see about thermit," said the man, and began to talk as
he worked over a crucible.


THERMIT HEAT PROCESS

As a result of his discovery that by starting a terrific battle for
oxygen between two metals he could reduce one of them to almost
absolute purity, Dr. Hans Goldschmidt has converted to the use of man
a process of welding so simple and yet so forceful that it is making
world-wide changes in the working of metals. This battle itself is
the most interesting feature of the Goldschmidt process because of
the terrific heat it generates.

Imagine sticking your finger into boiling water. By so doing you
would be exposing your flesh to a temperature of 212 degrees
Fahrenheit. Imagine sticking your finger into a pot of molten lead if
even for the fraction of a second. You know very well what the effect
would be. The temperature is 618 degrees Fahrenheit. Still again,
think of a redhot iron. This is about 1,652 degrees Fahrenheit. Steel
boils at 3,500 degrees.

They are all hot enough, but compare them with the temperature of
5,400 degrees Fahrenheit or about 3,000 degrees Centigrade, which
is attained by the thermit reaction. The range of temperature in
which we can live extends from a little over 100 degrees to 70 or 80
degrees below zero, and yet man can so direct the heat of the thermit
reaction that it will work for him.

The commonest use of the process is in welding steel or iron, such
as broken parts of machinery and welding steel rails, and steel or
iron pipes. Besides this, the thermit process will reduce many metals
to a high degree of purity. After spending a few minutes in seeing
how the inventor of this process came to discover it, we will take a
little trip in our mind's eye to some of the places where the thermit
process is in use, and see what happens.

As you know, metals rarely come from the mines in a state of purity.
They usually are very much mixed up with rock, slag, and other
minerals, so that it takes a complicated process called smelting to
separate them. Even then they are not pure, and more complicated
processes have to be gone through with. Oxides, or metals that have
been oxidized, are common because oxidization merely means that the
metal has been burned so that each atom of metal has taken up an
atom of oxygen to make what is called a molecule of oxide. Iron ore
is usually found in the form of iron oxide, because when this great
earth was nothing but a swirling ball of burning gases, probably as
hot as the sun, gradually cooling and forming a great cauldron of
molten matter, boiling and bubbling more fiercely than the hottest
cauldron of molten metal in any steel mill, much of the matter
that later became iron ore was burned or oxidized. Other chemical
actions too technical for our attention just now were responsible for
other forms of ore, such as sulphides, etc. When the earth cooled
sufficiently to become solid, these things were completed, and they
only had to remain hidden away under the surface for ages and ages
until a little man who could live but a hundred years at the utmost
solved the deepest secrets of the earth's formation.

Thus, to obtain pure metals the oxygen must be removed from the
oxide. In other words, it must be reduced. Plainly such reduction
was a problem of smelting, but Doctor Goldschmidt in his efforts to
obtain purity was working along lines of smelting, in his little
German laboratory, very different from the ones in general use.

His first object was to reduce iron oxides. First, he knew that
aluminum has a great affinity for oxygen, or, in other words, when
the two are heated will absorb oxygen like a sponge will absorb
water, only more forcibly and more violently than any such comparison
even faintly suggests. In yet other words, aluminum wants oxygen
more than any other metal does. Of course no chemical changes would
occur if a piece of iron oxide and a piece of aluminum were set side
by side, any more than we would have gunpowder if we set a chunk of
saltpetre, a chunk of sulphur, and a chunk of charcoal all in a row.
The iron oxide and the aluminum would have to be mixed by cutting
or filing them into small pieces and making a coarse powder. Still
nothing would happen without heat to start it.

If you collected some flakes of iron oxide in the palm of your hand
they wouldn't look to you like very promising material for a bonfire,
and you wouldn't be in any danger of an explosion, but you would
have something in your hand that would burn, nevertheless. If you
sprinkled your iron filings over a gas flame, Welsbach burner, or
over a common lamp chimney the heat would cause them to splutter and
fly out with all the brilliancy you know so well when the blacksmith
gives the redhot horseshoe the first pound.

Of course Doctor Goldschmidt knew all this, just as he knew that
the way the aluminum would take the oxygen away from the iron oxide
was through heating the coarse powder of filings to a very high
temperature. But this was attended with serious troubles and many
times the German scientist came near losing his life in explosions in
his laboratory.

At first he failed to get the mixture hot enough and nothing
happened. Bit by bit he increased the heat under the crucible
containing the filings until it reached about 3,000 degrees
Fahrenheit. At this point the metals were hot enough to fuse or run
together and the whole thing reacted with such violence that it
amounted to an explosion. What really happened was that the mass
reached the temperature where the aluminum could take the oxygen
from the iron oxide, and it did so with such force that an explosion
resulted.

Doctor Goldschmidt then saw his problem. It was that of devising some
way of heating the mixture to a temperature sufficient to gain the
reaction, but without an explosion.

After trying everything that he could think of, he conceived the plan
of leaving the crucible in the open air and starting the heat at just
one point first, instead of heating the whole thing in a furnace.
He did this with a pinch of ignition powder placed on the top of
his pile of iron oxide and aluminum. The ignition powder was simply
lighted with a match.

What happened?

Thermit was discovered.

The heat, or reaction started at one point, gradually spread through
the whole mass, and reduced it to white-hot molten material.

In other words the application of intense heat at one point in the
mixture was sufficient to fuse the metals and start the battle
between the iron oxide on one side and the aluminum on the other, in
the immediate vicinity of the point where the heat was applied. As
the few particles set off by the ignition powder struggled for the
oxygen they themselves generated heat--terriffic heat--which gave
a high enough temperature to start the particles that were their
next-door neighbours to struggling for the oxygen. These in turn
generated heat to set off their own neighbours, and so it went.

In far less time than it takes to read this, Doctor Goldschmidt
saw the whole crucible of dead mineral particles take on life and
become white-hot liquid metal. Scientifically speaking, the reaction
had spread through the whole mass in less than a minute, but what
Doctor Goldschmidt saw was a blinding white light, more intense than
any arc lamp, throwing off a little cloud of white smoke or vapour.
Apparently the whole thing was burning up. He only heard a little
hissing as the metals battled for the precious oxygen.

There was no explosion, there was no violent scattering of molten
particles, and there were no noxious life-destroying gases such as
come from the explosion of gunpowder, dynamite, or even the burning
of coal. And yet the seething, molten metals in the crucible reached
a temperature second or third to the highest ever registered by man.
Five thousand four hundred degrees--think of it!--more than half as
hot as science tells us is the sun which makes this world of ours
habitable.

But what was the result of this temperature which staggers the
imagination?

Just this. Doctor Goldschmidt knew that the aluminum had won the
prize of battle and had paid the price of victory.

The conquered iron was at the bottom of the crucible, a molten mass
of pure metal, while the victorious aluminum, seething on the top,
was nothing but slag (aluminum oxide).

Perhaps there may be a little lesson in this drama of the metals,
because while the iron was vanquished it emerged from the stress of
conflict purified and fitted for its high service to mankind, while
the more aggressive aluminum came to the top an almost useless
product, ruined by the prize for which it had fought.

Another interesting point about this reaction is that the heat
produced by a certain quantity of the mixture is no greater in total
volume than the heat that would be produced by the burning of an
equal amount of anthracite coal. The difference is that the thermit
process concentrates all the heat in a few seconds whereas the coal
gives off its heat bit by bit for a long period of time.

The mixture of filings used in this process is called thermit. A
technical definition of the product is as follows: "Thermit is a
mixture of finely divided aluminum and iron oxide. When ignited in
one spot, the combustion so started continues throughout the entire
mass without supply of heat or power from outside and produces
superheated liquid steel and superheated liquid slag (aluminum
oxide)."

Thus the makers of thermit call the pure metal that results from the
combustion, thermit steel.

For the boy who has studied chemistry the simple equation by which
the scientist described the process to his young friend will mean as
much as his long explanation. The equation is:

Fe_{2}O_{3} + 2Al = Al_{2}O_{3} + 2Fe.

The scientist simply went on to say that Fe_{2}, iron, and O_{3},
oxygen, in the equation means iron oxide, while 2Al means aluminum.
Thus we have iron oxide plus aluminum, heated to 5,400 degrees
Fahrenheit, equals aluminum oxide, Al_{2}O_{3}, plus pure iron,
2Fe. These signs are simply the abbreviations scientists use for
expressing processes in the terms of mathematical equations.

With this general outline of the principle of the thermit process
in mind its actual application will seem a simple matter. Suppose
that a great steel ship ploughing her way through a storm breaks her
sternframe. This is the steel framework upon which the rudder post is
mounted, and naturally a fracture puts the rudder out of commission.
Repairs must be made before the ship can make another trip. Quick
repairs are desired by the owners. Perhaps the ship is a passenger
steamer due to leave port in a few days with passengers and mail, so
to put the liner in drydock, wait for the steel mills to cast a new
sternframe, wait for it to come by freight, and then wait for the
steelworkers to fit the piece in the place of the broken one is a
matter of weeks, perhaps more.

With the thermit process at hand this is not necessary. The company
that manufactures and sells thermit has big plants in several cities
in various parts of the world, but if there is steel repairing to be
done elsewhere the company will send its materials and expert workmen
on a minute's notice. So if the crippled ship limps into the port
where there is a thermit plant the repairs can begin at once, but
there need be only a little delay otherwise, because the captain of
the ship can notify his owners of the damage by wireless while still
out at sea, and long before he reaches the port he is making for they
can have a complete thermit outfit on the way.

One of the biggest advantages of the thermit process of repairing
machinery or structural steel is that the welding in a great many
cases can be made without taking the complicated parts to pieces.
Consequently after the ship is in drydock the workmen build a wooden
scaffolding about the broken sternframe, so that they can work the
better.

The next step is the preparation of the broken parts for welding.
Most boys know how the doctor has to put splints on a broken arm so
that it will knit properly. It is something like that with a thermit
weld.

The broken parts are supported in exact alignment by heavy blocks of
concrete, and the fractured ends sliced off clean by the oxygen-gas
torch. This leaves a space of from one inch to two and a half inches
between the fractured ends, just according to the size of the piece
to be welded. After the parts are all thoroughly cleaned the workmen
are ready to take the next step.

This is the preparation of the mould for the weld. First, a pattern
of the weld, as it will appear when completed, is put on the fracture
with beeswax. The space between the broken ends is filled in and a
thick "collar" of wax is packed around the parts, so that when this
is done the pattern looks like a swelling on the frame. The mould is
then built around this wax pattern.

The inventor of the thermit process had to make a number of
experiments before he found a material refractory enough to stand
the terrific heat to which the mould had to be exposed. Finally he
decided upon an equal mixture of fire brick, fire clay, and fire sand.

With this material, then, the workmen go about making the mould. It
is solid, with the exception of three apertures or tunnels, which are
left by inserting in the moulding clay, wooden models of the size
and shape desired. These are a gate, or place into which the molten
welding material is to be poured, a "riser" or larger hole into
which the surplus material can run for the overflow, and a heating
aperture. The gate runs from the top of the mould down to the lowest
point of the wax pattern, while the "riser" extends from the top of
the wax pattern to the top of the mould. Thus we really have a small
inlet and large outlet, although it is always arranged so that the
surplus metal remains in the riser, and as little as possible runs
over. The heating aperture is a small hole in the side of the mould
extending to the bottom of the wax pattern.

With the mould complete the wooden models of the gate, riser, and
heating aperture are pulled out and the first step in the process
of welding is taken. The long pipe of a specially constructed
gasoline compressed-air torch is inserted in the heating aperture
and the process called preheating started. The gasoline torch, of
course, quickly melts the beeswax, and leaves the space occupied by
the pattern clear for the molten metal that is to be introduced to
make the weld. The blast from the torch is continued through this
heating aperture until the parts to be welded have reached a red
heat, because if this were not done the cold steel would so chill the
molten thermit steel that the weld could not be accomplished. The
length of time taken by this preheating is governed, of course, by
the size of the parts to be welded. Sometimes it is many hours.

Everything is now ready for the thermit. There has been some
elaborate preparation of the thermit too. The coarse powder or grains
of iron oxide and aluminum previously have been prepared according
to the job to be done. In very large welds, or welds where very hard
steel is required, certain additions, to be explained later, are made
to the thermit.

The amount of thermit to be used is an important factor, of course,
as there must be plenty to fill the mould, and yet not so much that
it will overflow the riser. To decide on the amount takes a careful
calculation because in large operations there are certain additions
to the thermit which have to be considered. In general, however, the
engineer must remember that he must have just twice as much molten
thermit steel as he needs to fill the space left by the melting
of the wax pattern. The surplus flows up into the riser, heating
aperture, and gate, effectually closing all of them. The calculation,
then, is that it takes four and a half ounces of steel to fill a
cubic inch. It takes nine ounces of thermit to produce four and a
half ounces of steel, so the engineer directing the weld must figure
on eighteen ounces of thermit to each cubic inch in the wax pattern,
including the space between the parts to be welded.

After seeing that the proper amount of thermit is measured out the
engineer must see that the crucible in which the reaction is to take
place is ready to contain the strenuous battle that is to be fought
in it.

As before mentioned there are very few products that can withstand
the heat of the fire produced by thermit. Ordinary fire brick and
mortar would melt or be burned to powder in a few seconds. Metal
would go the same way that the metal in the crucible goes. Science,
however, has established that magnesia tar is not affected by the
thermit fire, so the crucible in which the thermit is reduced is
heavily lined with magnesia tar. The crucible itself is shaped like
a cone with the point downward. At the bottom is a magnesia stone,
which has a conical-shaped hole for the "thimble." This "thimble"
also is made of magnesia stone, and has a hole through it for the
molten thermit steel to run through after the reaction has taken
place. Before filling the crucible with the thermit, however, the
pouring hole is very carefully plugged up by a special process, with
a little steel pin protected by fire sand and fire clay. This pin
extends below the lowest point of the crucible a couple of inches,
and by knocking it upward the molten metal is allowed to flow out.
The upper end of this little plug that otherwise would be melted
instantaneously by contact with the burning thermit, as indicated
above, has to be protected by a layer of fire sand. The hole through
which the metal flows is never more than half an inch in diameter.

With the crucible, mould, and thermit prepared, the next thing is
to put the thermit in the crucible and put the crucible in place.
There are many ways of placing the crucible. In some cases, it is
hung by a chain and in others it is supported by a tripod or wooden
scaffolding. The latter is the better because, though the wood always
catches fire from the heat, it can be kept standing by throwing on
water, whereas steel or iron would be eaten in two in an instant
by the touch of a few sparks of flying thermit. The point is to
support the crucible so that the pouring hole is directly over the
entering gate, or pouring gate of the mould.

  [Illustration: THERMIT WELD ON STERNFRAME OF A STEAMSHIP

  Notice metal left above weld, where it flowed up into the riser.]

  [Illustration: A LARGE SHAFT WELDED BY THE THERMIT PROCESS

  Protruding metal is that which flowed up into gate and riser. It
  is cut away by the gas torch to leave a neat weld.]

  [Illustration:

    Courtesy of the _American Machinist_

  CUTTING UP THE OLD BATTLESHIP MAINE WITH AN OXY-ACETYLENE GAS
  TORCH

  Picture shows end of boat crane over exploded magazine, which was
  cut off in fifteen minutes.]

  [Illustration:

    Courtesy of the _American Machinist_

  CUTTING AWAY THE DECKS

  Oxygen and acetylene generators can be seen on top of
  after-turret.]

Things move with a rush now, for all these arrangements are made
ahead of time, and as soon as the workmen are sure that the parts in
the mould are redhot the heating aperture is carefully plugged with
fire sand and the thermit is ignited. From a mere pinch to half a
teaspoonful of the ignition powder is put into a little hollow in the
thermit so that the heat may be communicated at once to as much of
the thermit as possible. This is then set off with a storm match. The
workman quickly withdraws his hand, slams the lid on to the crucible
and gets out of the way of flying sparks.

There is a hiss, a puff of white smoke, a blinding glare from the
hole in the top of the crucible, and that is all, beside a few
sparks, to indicate that a heat second only to that of the sun is
being generated within.

One cannot help but marvel at the wonders of science as this
inconceivable heat is being produced, the process is seemingly so
simple, so easily handled, and so accessible for all kinds of work
where steel welding is necessary.

Half a minute to a minute (according to the amount of thermit used)
after the match has been applied a workman holding at arm's length a
long tool called a "tapping spade" gives a few upward knocks to the
little metal pin extending down from the closed pouring aperture.
He jumps back for the heat is enough to set his clothes afire, even
at a considerable distance, and a few flying particles of the molten
thermit would inflict a serious burn.

Down through the little hole the thermit, that a minute before had
been only a coarse dark gray powder like metal filings, seemingly the
last thing on earth that would catch fire, flows into the pouring
gate of the mould in a steady stream of white-hot liquid steel. The
white glow from the metal is brighter than any electric light. It is
so intense that although the workmen wear heavy dark goggles, they
shade their eyes and turn their heads away.

Now you will be wondering, if you know anything about steel and its
wonderful properties, how it is that this can be good steel when it
is all mixed up with the aluminum oxide or slag. The reason it is of
best quality is that as soon as the reaction reduces the whole mass
to a molten liquid the heavier steel, set free, as the scientists
say, but as we have chosen to think of it, robbed of the aluminum,
sinks to the bottom, while the lighter aluminum oxide rises to the
top. Consequently the steel goes into the mould to make the weld
while the slag, having risen to the top, will be found at the top of
the pouring gate, and only around the outer edges of the weld.

When the pour is completed the workmen go away and leave it to cool.
It is usually left over night, sometimes as long as forty hours,
when the weld is a very large one.

Finally the mould is broken down and the weld is found complete, with
big extensions of the steel extending from the weld, in just the
shape of the pouring gate "riser" and heating aperture.

The molten thermit steel rushing in at the bottom of the mould has
risen between the heated broken ends, and all around them, in just
the shape left by the wax pattern. As the scientists say, the thermit
steel has united the broken sternframe and formed a homogeneous mass
with it. In other words the terrific heat of the thermit rushing on
the heated ends has resulted in the two parts becoming one with the
added thermit steel.

After the mould is broken down the oxygen-gas torch comes into use
again to cut away the ends of steel sticking up where they had cooled
in the pouring gate, "riser" and heating aperture. After this the
weld looks like a great swelling upon the sternframe, and if the
swelling is where it will not interfere with the working of the
rudder or steamer propellers, nothing more need be done. On the other
hand, if the swelling is in the way, it can be reduced to the size of
the frame, and squared off with machines built for the purpose.

Thus the ship is repaired and is ready to be taken out of drydock for
her next trip, as good as new.

About the same plan is followed out on all kinds of welding except
pipes and rails. Locomotives can be repaired without taking the
complicated machinery apart just by working around until the crucible
can be so hung, and the pouring gate so arranged that the metal
can be poured into the place designed for it. The chief difference
lies in the size of the weld to be made and the consequent amount
of thermit to be used. Welds have been made where as much as 2,000
pounds of thermit--enough to make 1,000 pounds of steel--have been
run into a mould. In these very big welds a certain percentage of
steel "punchings," or small pieces of steel, and a little pure
manganese are used to give the additional hardness to the weld.

Without going into details as to the manner in which the principle
of the thermit process is applied on rails or pipes, it will be
enough to say that in welding rails three different systems are used.
The first is done by building the mould around the ends of the two
rails to be welded together and letting the thermit steel run in
and completely surround the rails and the space between them. This
gives one continuous rail just as far as the welding is carried on,
and one through which the electric current of an electric road can
pass without any trouble at all. It is plain, then, why this system
is used so much on third rails of electric roads. The trouble with
it is that the swelling on the top and inside of the rails must be
machined down to present a smooth running surface to the wheels.

The next system, which is now almost out of date, is one in which two
moulds are used so that the thermit does not come up over the running
surface of the rails. This relieves the engineers of the necessity of
machining the welded joints.

The third system is a mixture of the joining by plates and the
thermit process. This is called the "Clark joint," after the name of
Chief Engineer Charles H. Clark of the Cleveland, (Ohio) Electric
Company, who formulated the plan. The rails are joined with plates
and bolted, or riveted together in the old way, but a thermit weld
is made at the base of the rail, welding the bases of the two rails
together and to the plate.

The method of welding steel pipes is an exact reversal of the
principle of welding together solid pieces of steel or iron. After
the pipes are cut off clean, the mould, which is made of cast iron,
is placed around them with specially constructed clamps to force
the two ends closer together after the thermit has been poured in.
The thermit is then set off in a flat-bottomed crucible like a
long-handled ladle, and poured into the mould by hand as if from a
ladle. As the slag rises to the top it goes into the mould first and
coats the pipes. The thermit steel does not touch the pipes, but
merely supplies the heat to weld them perfectly, so that they are as
strong as the piping itself. Just after the pour has been made, the
clamps are tightened up and the white-hot pipe ends forced together.
They are thus held until cold, when the mould is broken away. The
slag coats the outside of the pipes and this is chipped away, leaving
a perfect weld.

Another interesting use of thermit is in the great foundries where
cauldrons of metal have to be kept at a very high temperature. To
help keep the mass in a liquid state thermit can be introduced in
it either by throwing it into the cauldrons in bags, with a little
ignition powder so fixed that it will be touched off by the heat
of the boiling metal, or by putting it in especially designed cans
affixed to the ends of long rods. By these rods the thermit can be
plunged to the bottom of the cauldron before it "burns." The reaction
of the thermit, with the intense heat caused by it, helps to keep the
mass at the proper temperature.

Also thermit is used in the same way with a small amount of titanium
oxide, to purify iron and steel. The metal becomes much more liquid,
and a commotion like boiling is started. This is the result of the
titanium driving out the impure gases and driving other impurities
such as metallic oxides and sulphur contents to the top. Chemically
what happens when the titanium is introduced by the thermit process
is that the titanium combines with the nitrogen in the molten iron,
giving it a much finer grain, and making it a much lighter colour,
more like steel, than previously.

One of the things thermit is not extensively used for is the
repairing of gray iron castings. The first reason is that gray iron
is cheaper than steel, and a new casting often can be turned out by
the mills quickly.

Another and a more interesting reason is that gray iron melts in a
much lower temperature than does thermit steel and consequently has a
lower shrinkage. Therefore when the molten thermit, with its terrific
heat, cools there is a large shrinkage. Thermit steel being much
stronger than gray iron, its shrinking sometimes strains and cracks
the iron casting.

In spite of this difficulty very successful repairs have been made
on cast-iron and it has been found that by mixing 2 per cent. of
ferro-silicon and 1 per cent. pure manganese with the thermit for
welding, a thermit steel is formed which is very soft and comes close
to the properties of gray iron. By using this mixture important
welds have been made on cast-iron flywheels, water wheels, and other
cast-iron parts with great success.

While industry is making progress with all these uses of thermit,
science is experimenting all the time to add to the scope of the
process. As was pointed out before, many other metals can be reduced
to a high degree of purity with this process and in the laboratories
they are always trying new ones and working out new formulas. Of
the pure metals that can be reduced by the thermit process there
are chromium, which is 98 to 99 per cent. pure; manganese, which
is 96 per cent. pure; and molybdenum, which is 98 to 99 per cent.
pure. These are used in the manufacture of very hard steel, such as
armour plate, and "high speed steel." Among the alloys, or mixtures
of metals, there are chromium-manganese, manganese titanium,
ferro-titanium, ferro-vanadium, and ferro-boron, all of which have
uses in industry and help us to travel faster and more safely by
railroad, electric train, and steamship.

It may have occurred to some bright boy that, since this heat is
so intense and so handy, it might be a good way to make steam in
locomotive boilers, or cook our meals, but it will be remembered
that the heat is all over within a few minutes. In other words,
where a terrific heat is required for a few seconds, thermit will
fill the bill, but where a continuous heat for many hours is needed,
electricity, gas, coal, coke, oil, or wood are better. The high cost
of aluminum would probably prevent the thermit process coming into
use in the manufacture of steel for our armour plate, ship plate, or
structural steel, at least for a good many years.

Earlier in this chapter I said that the slag, or aluminum oxide, from
the thermit process was an almost useless product. This is not the
precise scientific truth, for the slag becomes a black powder such as
is used in making emery wheels, but the slag from thermit is never
actually used for this. Another use for the slag from the thermit
process in which chromium is used has been discovered. Potters use a
material called corundum, which this slag resembles, except that it
is superior to natural corundum in pottery manufacturing because of
its freedom from metallic impurities. The slag can be mixed with clay
and baked. It is especially useful in chemical apparatus that must
withstand great extremes of temperature, because its experience has
so tempered it that nothing less than a heat equal to that of the sun
would give it much concern.

Another interesting thing about the slag from chromium thermit is
that small rubies have been found in it. The scientific explanation
is that they are nothing but crystallized alumina, coloured with
chromium. The jewels usually are too small for any commercial purpose
but serve as a very striking example of the intensity of the thermit
fire. All the real jewels, diamonds, rubies, emeralds, amethysts, and
so on, were formed by the terrific heat in the bosom of the earth
millions of years ago when it was cooling down from gases hotter
than anything we can possibly conceive of, to a molten ball, then
to a solid redhot mass and then to a globe sufficiently cool on the
outside to be crusted over. That they can be made in this little
chemical furnace shows how far science has gone in imitation of the
wonders of nature.


AUTOGENOUS WELDING AND CUTTING

"Now," said the scientist, after he and his young friend had finished
some experiments, and were ready to talk about autogenous welding,
"imagine a little white flame no bigger than a pencil point at the
end of a brass pipe about the size, and not entirely unlike in
appearance the old-fashioned taper holder with which you used to
light the gas, and you have before you in the rough, a picture of
one of the oxy-acetylene torches that will in a few minutes weld two
pieces of almost any metal, or in a few seconds cut a solid plate of
the hardest steel of several inches thickness almost as fast and easy
as a carpenter could saw a board, and yet without taking the temper
out of the metal."

Picking up what seemed to be a little brass rod bent at the end, the
man turned a valve, applied a match, and as the gas burned up with a
beautiful little flame of dazzling whiteness, he continued:

"This tiny flame, so easily controlled, is hotter than any produced
by man except that generated by the electrical furnace, for it
reaches a temperature of about 6,300 degrees Fahrenheit. Previous to
the invention of these wonderful torches the oxy-hydrogen was the
hottest gas flame, but it only reached a temperature of 4,000 degrees
Fahrenheit."

"How do you use it?" asked the boy.

"Well, for instance, Uncle Sam is enabled to weld and cut steel
plate in building his battleships, steelworkers to carry on their
gigantic tasks, and wreckers to clear away tangled masses of steel
beams far more quickly and easily than with the older methods.

"If you had visited one of the navy yards, a shipyard or any place
where big work in iron and steel was being carried on as short a
time as three years ago, you would have seen a man sitting for hours
sawing away on the end of a steel beam, for instance, trying to cut
it down to the required length. He would dull many saws, use a great
deal of energy, and an appalling amount of the most valuable thing in
the world--time. Again, you would have seen them welding pieces of
iron and steel by the old blacksmith method, or riveting other pieces
that could not be joined by heating them and pressing them together.

"To-day you would see fewer of these processes because autogenous
welding and cutting by the powerful little oxy-acetylene torches
is revolutionizing certain methods of working with metals. Instead
of squatting at the end of the beam and sawing away like an
old-fashioned carpenter, the modern iron worker takes up his little
torch, turns a valve in the handle and concentrates the flame on the
steel beam that he wishes cut. Almost instantly a shower of sparks on
the under side of the beam shows him that the flame has burned its
way through. Then he slowly moves the flame along the line where he
desires to cut and the trick is done."

Illustrating with his own little laboratory torch, the scientist
continued his explanation, saying that cutting is only one of the
many uses to which this modern invention in steel working is put.
Not quite so spectacular but every bit as useful is the autogenous
welding by means of these magic wands. Welding metals has ever been
more or less unsatisfactory. The old process of heating the two
ends and then beating them together is cumbersome and practically
impossible in many cases. Consequently inventors have sought other
welding processes with wider application and greater facility ever
since the first metal workers of earliest times forged crude chains
and weapons. With this modern device two pieces of steel or other
metal are brought to within a small fraction of an inch of each other
and by the use of the oxy-acetylene torch and a thin strip or rod of
metal are melted and fused together.

Although the acetylene flame gives off a far greater proportion of
light than heat, it is a very powerful gas and Le Chetalier, a French
inventor, was sure that he could put it to other uses than furnishing
lights for automobiles, etc. To this end he tried mixing acetylene
gas with oxygen, for there can be no fire or combustion without
oxygen. He very properly figured that by introducing pure oxygen
into the acetylene, the burning, or combustion, would be greater,
and the heat of the flame greatly intensified. His experiments were
ultimately successful, and it was then only a short step to the
time when three different oxy-acetylene torches were in use. In
France there were developed low pressure, medium pressure, and high
pressure torches; but the last named has not been found commercially
practicable in the United States, where the "medium pressure" torch
is sometimes called the high pressure. As we are dealing entirely
with the American use of the invention we also will call the two
kinds of torches used here the low pressure and the high pressure.

The general principle of the torch is, as we see, the mixture of
oxygen with acetylene in order to obtain a hotter flame, but right
here we come to the difference between the low-pressure and the
high-pressure tools. Both are made of brass pipes, terminating in the
burning tip and connected at the rear of the handle with rubber tubes
which run to the separate tanks holding the acetylene gas and the
oxygen, but the method by which these gases are combined in the torch
constitutes the principle differences in the two systems, with the
consequent greater or less efficiency claimed by the manufacturers.
Without going into the technical details, which are a matter of
controversy between scientists as well as the various commercial
concerns interested in the torches, it will be sufficient to say
that in the low-pressure torch the acetylene gas is only used under
a pressure of a few ounces, with the oxygen under a much heavier
pressure, while in the high-pressure torches, the acetylene and
oxygen both are under an appreciable pressure of several pounds.

Thus in the low-pressure torch invented by Fouché, the oxygen is
forced out of the nozzle by the pressure and the outrush sucks
out the acetylene in the proper quantities. The two gases mix in
a chamber at the end of the torch just above the tip and flow out
into the air in this mixed form. The proportions of the gases in the
low-pressure tool are about 1.7 of oxygen to 1.0 of acetylene.

The high-pressure torch, which has largely taken the place of the
low-pressure one in France, and which we also see most frequently in
this country, has a different method of mixing the gases, due to the
fact that they both are under pressure. According to many authorities
the tip where the gases are mixed is by far the most important
factor in the success or failure of the tool. In the high-pressure
torch the oxygen enters the tip from a hole in the centre, while
the acetylene enters it from two holes, one on each side. They meet
under high pressure at the upper end of the tip, and have the length
of the hollow tip in which to mix, before they strike the air. The
long, narrow hole in the tip is called the mixing chamber. Those who
are interested in the high-pressure torch declare that it is the
fact that the gases are positively mixed in proper proportion in
the detachable tip, that so greatly adds to the efficiency of the
tool. They declare that by allowing the acetylene to enter the tip
laterally, at right angles with the oxygen, the blast of the oxygen
is broken as it mixes with the acetylene, and the tendency of an
oxygen flame to oxidize any metal with which it comes in contact by
reason of an excess of oxygen in the flame is largely done away with.
This, with the small diameter of the mixing chamber and the friction
with the walls, gives a perfect mixture, according to the claims of
the high-pressure torch enthusiasts. Moreover, the small hole which
is the mixing chamber, effectually prevents serious accidents by
flash-backs of the highly explosive acetylene, and also provides a
much easier method of control. Each outfit has several different
sizes of tips for various kinds of work.

The pressure under which the two gases are used is the other big
difference between the high-pressure and the low-pressure torches, as
said before. In the the high-pressure tool the oxygen is compressed
about the same as in the low-pressure torch, while the acetylene is
under several pounds pressure, just in accordance with the size of
the tip used. In the low-pressure torch the pressure on the acetylene
is only about ten ounces to the square inch, or only enough to keep
it flowing. On account of this difference in the pressure making the
big difference in the mixture of the gases, scientists have chosen
to call the low-pressure torches injector mixture types, from the
fact that the acetylene is sucked into the tip by an injector system,
while the high-pressure torches are called positive mixture types,
because the gases are mixed directly by pressure. In the latest
high-pressure tool the mixture of gases is 1.14 parts of oxygen to 1
part of acetylene, while the low-pressure torch takes a proportion of
1.7 parts of oxygen to 1 part of acetylene.

The torches also vary in size from the little 8-ounce "jeweller's"
torch, that the scientist used, to nineteen to twenty inches long and
a weight of two and a quarter pounds. The average size, however, is
twelve inches long with a weight of one pound. The welding torch is
made up of two brass tubes, one for the acetylene and the other for
the oxygen, connected at the two ends. At the nozzle end there is
a sharp turn in the piping so that the tip is very nearly at right
angles to the main pipes. At the handle end, are the connections for
the rubber tubes that lead to the gas tanks, and the little valves by
which the operator can control the flow of gas. The pipes carrying
the gases to the tip are the same size the whole length, but at one
end are enclosed in a larger tube, which serves as a handle.

Now that we have seen the general construction of the oxy-acetylene
torches, we will assume that the tanks, which look like large
soda-water reservoirs, are filled with pure oxygen and acetylene
gas, and transported to some convenient point in a railroad repair
shop where great forges are spurting flames, and one can hardly hear
the talk of a man beside him for the roar of the hammers and the
compressed air riveters. Assume that some large expensive steel part
of a locomotive has been broken and must be repaired quickly so that
the engine can go out on the road to help haul an accumulation of
freight.

In the old days an engine would have to be taken apart, a new
part turned out at the steel mill, shipped to the shops, and the
locomotive put together again. Nowadays it is only necessary to take
enough of the machinery apart for the workmen to get at the broken
parts. After cutting off the edges to be welded so that they make a
small V, and supporting them within the fraction of an inch apart
in the exact position and shape that they are to be repaired, the
workman selects a rod of steel or iron, to use in somewhat the same
way the tinker uses a strip of solder when he wants to repair a break
in a kettle with solder and soldering iron.

The selection of this filling rod, or wire, is all-important, for
the skilful and successful iron worker uses a piece of metal that
will fuse well with the parts to be repaired, at about the same
temperature at which they themselves will fuse. Mild steel or Norway
iron which is 90 per cent. pure is frequently used, but there are no
hard and fast rules because every master mechanic has his own ideas
about such things, and would not take the word of any manufacturing
company.

Then the operator turns on his torch, lights it with a match, takes
it in one hand, and the rod of welding steel in the other. Holding
the end of the steel rod at the thin crack or bevelled edges between
the pieces to be welded the operator directs the small flame on the
point, holding the tip of the torch about a quarter to a half inch
from the metal. It only takes a few seconds for the terrific heat of
the flame to melt the strip of steel and the edges of the parts to be
welded so that they all are fused together in one perfect mass.

Strange as it may seem, the brass tip of the torch does not melt in
this heat because the pressure behind the gases forces them out with
such velocity that the flame is far enough removed from the tip to
do it no injury, just so long as the operator does not put the tip
square against the metal and drive the flame back against it. This
not only would melt the tip but probably would cause a flash-back in
the torch.

As the end of the strip melts into the crack the operator moves
up the steel, and moves his torch along the crack until the whole
operation is complete. At the end the weld is very rough but when it
is machined down it may be so perfect that it is difficult to tell
where it was made, and the strength is equal to that of any other
part of the piece.

In other words, the weld becomes homogenous with the parts repaired.
From this fact autogenous welding takes its name. Autogenous is
defined as "self produced," or independent of outside materials.

Thus, we see that the autogenous process is a system of putting on
new material, without either heating, compression, or adding flux
(molten material) to the broken parts. In the foregoing paragraphs we
have taken up the welding of steel parts, but the process can be as
well applied to steel pipe, steel plate, iron, cast-iron, aluminum,
copper, and other materials with only slight variations in the manner
of using the torch.

The cutting process is even more spectacular because while the
welding proceeds quietly, the cutting is accompanied by just enough
fireworks to show us the progress of the tiny flame through the
hardest and thickest of metals.

The cutting torch is the same as the welding torch with the exception
of an additional pipe from which flows a jet of pure oxygen to give
the flame the necessary cutting property. The greater the supply
of oxygen the greater the combustion, and the more penetrating the
flame. The acetylene gas flame heats up the steel--"fills the office
of a preheater," said the scientist--while the oxygen jet follows
close behind and makes a thin cut through the hot metal.

The extra pipe is the same size as the others and extends down to the
end of the torch at an angle where its tip is clamped alongside the
main tip. The rear end of the third tube is connected with a rubber
hose like the others, which extends to the oxygen tank. The flow of
oxygen is under higher, and individual working pressure, controlled
by a valve. In a new style torch the extra hose is done away with and
the separation of the oxygen is done in the torch.

When the modern steel carpenter wants to cut a hole, or saw off a
strip from a piece of steel, no matter whether it be a steel beam,
steel plate, or almost any other form of iron (except cast-iron), he
attaches the cutting pipe, lights his torch and sets to work. Holding
the tool about half an inch from the surface he directs the little
blue flame, which is no more than three quarters of an inch long,
and a quarter of an inch thick, against the spot where he desires
to start cutting. He holds it there a few seconds, then there is a
shower of sparks on the under side of the steel plate, indicating
that the flame has eaten its way all the way through. The operator
next moves the torch along the line where he wants to cut. The speed
with which he can move is governed by the thickness of the steel to
be cut. Half-inch ship steel, for instance, could be cut at a rate of
more than a foot a minute. The heat of the flame melts a little of
the steel, which drops down in molten particles, but the edge that
is cut is sharp and clean, and its temper is as perfect as if the
cutting were done with one of the laborious old-fashioned steel saws.

  [Illustration: AN OXY-ACETYLENE GAS TORCH WELD

  Note the little torch in the man's left hand, the filling metal
  in his right, and the inserted picture of the apparatus.]

  [Illustration: TINY 200-HORSEPOWER TURBINE

  This engine could almost be covered by a derby hat. A part of the
  casing is removed to show the smooth disks.]

  [Illustration: THE TESLA TURBINE PUMP

  Driven by a 1/12-horsepower motor. The little pump here shown is
  delivering 40 gallons of water per minute against a 9-foot head.]

This cutting process is of especial value to navy yards, shipyards,
and wreckers, where there is a great deal of steel to be cut.
Uncle Sam uses it at most of his navy yards, for in building his
battleships there are thousands and thousands of holes to be cut
in steel plates, plates to be shaped, and beams to be cut off to
required lengths.

When the scientist and his young friend visited the Brooklyn Navy
Yard to see this process in operation the naval constructors had made
considerable headway on the framework of the great Dreadnaught _New
York_, in course of building there. The huge steel ribs of the ship
towered upward amid the scaffolding nearly as high as a five-story
building. In laying this steel framework, and shaping the plates that
will make the hull, bulkheads, and decks, there will be millions
of holes to be cut, and virtually miles and miles of plates to be
shaped. Instead of sawing these the workmen were cutting them with
the oxy-acetylene torches.

Half a dozen men were at work, all cutting as fast as possible, and
the great steel plates, and beams were coming and going as quickly
as ever boards were passed along by a carpenter. The lines that were
to be cut were all marked out in advance so the men never put out
their torches. The only cessation in the work was when one of them
stopped for a minute or so, to wipe his eyes, for in spite of the
dark goggles worn by all operators of the oxy-acetylene process the
intense flame is very hard on the eyes.

One reason why the cutting process is so popular in shipyards is
because in making steel ships, holes are cut in the plates, ribs, and
beams, wherever possible without lessening the strength, to lighten
the frame.

Probably the most picturesque use of the cutting device is by
wreckers of steel structures. Nowadays whenever there is a bad fire
the building is left a tangled mass of steel pipes and girders that
can only be cleared away with the greatest risk of life, and the
greatest difficulty. The process always was a long, tedious one until
the oxy-acetylene cutting came into use.

Thousands of New York boys saw the device in use during the winter
of 1911-1912 when they visited the ruins of the Equitable Life
Assurance Society fire. The sight is unmistakable. Far up in the
ruins you see a man bending over a great twisted steel beam that it
might take weeks to pull out of the débris. Soon there is a shower
of sparks, and the part that is sticking out is cut off and ready to
be sent to the street and hauled away. The device has been used in
the ruins of a large number of disastrous fires, lately, particularly
where men have been entombed in the collapse of ceilings, and haste
means everything in getting out their bodies. Also, it was very
successfully used in cutting up the old battleship _Maine_ before the
hull was removed from Havana harbour.



CHAPTER VIII

THE TESLA TURBINE

   DR. NIKOLA TESLA TELLS OF HIS NEW STEAM TURBINE ENGINE A MODEL
   OF WHICH, THE SIZE OF A DERBY HAT, DEVELOPS MORE THAN 110
   HORSEPOWER


"How would you like to have an engine for your motor boat that you
could almost cover with a man's derby hat and yet which would give
110 horsepower?" asked the scientist of his young friend one day when
they had been talking about boats and engines.

"I never heard of any real engine as small as that," said the boy. "I
used to play with toy engines, but they wouldn't give anywhere near
one horsepower, much less 110."

"Well, I think I can show you a little engine that, for mechanical
simplicity and power is about the most wonderful thing you ever have
seen, if you would like to make another visit to Dr. Nikola Tesla,
who told us all about his invention for the wireless transmission of
power the other day. Doctor Tesla invented this little engine and he
is going to do great things with it."

Of course the boy jumped at the opportunity, for what real boy would
miss a chance to find out all about a new and powerful engine?

"Is it a gasoline engine?" he asked.

"No, it is a steam turbine, but if you know anything at all about
turbines you will see that it is entirely different from any you ever
have seen, for Doctor Tesla has used a principle as old as the hills
and one which has been known to men for centuries, but which never
before has been applied in mechanics."

After a little more talk the scientist promised to arrange with Tesla
to take the young man over to the great Waterside power-house, New
York, where the inventor is testing out his latest invention. We will
follow them there and see what this wonderful little turbine looks
like.

Picking his way amid the powerful machinery and the maze of
switchboards, the scientist finally stopped in front of a little
device that seemed like a toy amid the gigantic machines of the
power-house.

"This is the small turbine," says Tesla. "It will do pretty well for
its size."

The little engine looked like a small steel drum about ten inches in
diameter and a couple of inches wide, with a shaft running through
the centre. Various kinds of gauges were attached at different
points. Outside of the gauges and the base upon which it was mounted,
the engine almost could have been covered by a derby hat. The whole
thing, gauges and all, practically could have been covered by an
ordinary hat box.

Yet when Tesla gave the word, and his assistant turned on the steam,
the small dynamo to which the turbine shaft was geared, instantly
began to run at terrific speed. Apparently the machine began to run
at full speed instantly instead of gradually working up to it. There
was no sound except the whir of well-fitted machinery. "Under tests,"
said Tesla, "this little turbine has developed 110 horsepower."

Just think of it, a little engine that you could lift with one hand,
giving 110 horsepower!

"But we can do better than that," added the inventor, "for with a
steam pressure of 125 pounds at the inlet, running 9,000 revolutions
per minute, the engine will develop 200 brake-horsepower."

Nearby was another machine a little larger than the first, which
seemed to be two identical Tesla turbines with the central shafts
connected by a strong spring. Gauges of different kinds, to show
how the engine stood the tests, were attached at various places.
When Tesla gave the word to open the throttle on the twin machines
the spring connecting the shafts, without a second's pause, began
to revolve, so that it looked like a solid bar of polished steel.
Outside of a low, steady hum and a slight vibration in the floor,
that steadied down after the engine had been running a little while,
there was no indication that enough horsepower to run machinery a
hundred times the weight and size of the turbine was being generated.

"You see, for testing purposes," said Doctor Tesla, "I have these
two turbines connected by this torsion spring. The steam is acting
in opposite directions in the two machines. In one, the heat energy
is converted into mechanical power. In the other, mechanical power
is turned back into heat. One is working against the other, and by
means of this gauge we can tell how much the spring is twisted and
consequently how much power we are developing. Every degree marked
off on this scale indicates twenty-two horsepower." The beam of light
on the gauge stood at the division marked "10."

"Two hundred and twenty horsepower," said Doctor Tesla. "We can do
better than that." He opened the steam valves a trifle more, giving
more power to the motive end of the combination and more resistance
to the "brake" end. The scale indicated 330 horsepower. "These
casings are not constructed for much higher steam pressure, or I
could show you something more wonderful than that. These engines
could readily develop 1,000 horsepower.

"These little turbines represent what mechanical engineers have
been dreaming of since steam power was invented--the perfect rotary
engine," continued Doctor Tesla, as he led the way back to his
office. "My turbine will give at least twenty-five times as much
power to the pound of weight as the lightest weight engines made to
date. You know that the lightest and most powerful gasoline engines
used on aeroplanes nowadays generally develop only one horsepower to
two and one half pounds of weight. With that much weight my turbine
will develop twenty-five horsepower.

"That is not all, for the turbine is probably the cheapest engine
to build ever invented. Its mechanical simplicity is such that any
good mechanic could build it, and any good mechanic could repair
such parts as get out of order. When I can show you the inside of
one of the turbines, in a few moments, however, you will see that
there is nothing to get out of order such as most turbines have, and
that it is not subjected to the heavy strains and jerks that all
reciprocating engines and other turbines must stand. Also you will
see that my turbine will run forward or backward, just as we desire,
will run with steam, water, gas, or air, and can be used as a pump or
an air compressor, just as well as an engine."

"But most of your research has been in electricity," Tesla was
reminded, for no one can forget that Tesla's inventions largely
have made possible most of the world's greatest electrical power
developments.

"Yes," he answered, "but I was a mechanical engineer before I was
an electrical engineer, and besides, this principle was worked out
in the course of my search for the ideal motor for airships, to be
used in conjunction with my invention for the wireless transmission
of electrical power. For twenty years I worked on the problem, but
I have not given up. When my plan is perfected the present-day
aeroplanes and dirigible balloons will disappear, and the dangerous
sport of aviation, as we know it now with its hundreds of accidents,
and its picturesque birdmen, will give way to safe, seaworthy
airships, without wings or gas bags, but supported and driven by
mechanical means.

"As I told you before when we were talking of the wireless
transmission of power, the mechanism will be a development of
the principle on which my turbine is constructed. It will be so
tremendously powerful that it will make a veritable rope of air above
the great machine to hold it at any altitude the navigators may
choose, and also a rope of air in front or in the rear to send it
forward or backward at almost any speed desired. When that day comes,
airship travel will be as safe and prosaic as travel by railroad
train to-day, and not very much different, except that there will
be no dirt, and it will be much faster. One will be able to dine in
New York, retire in an aero Pullman berth in a closed and perfectly
furnished car, and arise to breakfast in London."

Tesla's plans for the airship are far in the future, but his turbine
is a thing of the present, and it has been declared by some of the
most eminent authorities in the world in mechanical engineering
to be the greatest invention of a century. The reason for this is
not altogether on account of the wonderful feats of Tesla's model
turbines, but because in them he has shown the world an entirely
unused mechanical principle which can be applied in a thousand useful
ways.

James Watt discovered and put to work the expansive power of steam,
by which the piston of an engine is pushed back and forth in the
cylinder of an engine, but it has remained for Nikola Tesla to prove
that it is not necessary for the steam to have something to push
upon--that the most powerful engine yet shown to the world works
through a far simpler mechanism than any yet used for turning a gas
or a fluid into the driving force of machinery.

"How did you come to invent your turbine while you were busy with
your wonderful electrical inventions?" Tesla was asked.

"You see," he answered, "while I was trying to solve the problem
of aerial navigation by electrical means, the gasoline motor was
perfected; and aviation as we know it to-day became a fact. I
consider the aeroplane as it has been developed little more than a
passing phase of air navigation. Aeroplaning makes delightful sport,
no doubt, but as it is now it can never be practical in commerce.
Consequently I abandoned for the time being my attempts to find the
ideal airship motor in electricity, and for several years studied
hard on the problem as one of mechanics. Finally I hit upon the
central idea of the new turbine I have just been showing you."

"What is this principle?"

"The idea of my turbine is based simply on two properties known to
science for hundreds of years, but never in all the world's history
used in this way before. These properties are adhesion and viscosity.
Any boy can test them. For instance, put a little water on a sheet of
metal. Most of it will roll off, but a few drops will remain until
they evaporate. The metal does not absorb the water so the only thing
that makes the water remain on the metal is adhesion--in other words,
it adheres, or sticks to the metal.

"Then, too, you will notice that the drop of water will assume a
certain shape and that it will remain in that form until you make it
change by some outside force--by disturbing it by touch or holding it
so that the attraction of gravitation will make it change.

"The simple little experiment reveals the viscosity of water, or, in
other words, reveals the property of the molecules which go to make
up the water, of sticking to each other. It is these properties of
adhesion and viscosity that cause the 'skin friction' that impedes
a ship in its progress through the water, or an aeroplane in going
through the air. All fluids have these qualities--and you must keep
in mind that air is a fluid, all gases are fluid, steam is fluid.
Every known means of transmitting or developing mechanical power is
through a fluid medium.

"It is a surprising fact that gases and vapours are possessed of this
property of viscosity to a greater degree than are liquids such as
water. Owing to these properties, if a solid body is moved through a
fluid, more or less of the fluid is dragged along, or if a solid is
put in a fluid that is moving it is carried along with the current.
Also you are familiar with the great rush of air that follows a
swiftly moving train. That simply means that the train tends to carry
the air along with it, as the air tries to adhere to the surface of
the cars, and the particles of air try to stick together. You would
be surprised if you could have a picture of the great train of moving
air that follows you about merely as you walk through this room.

"Now, in all the history of mechanical engineering, these properties
have not been turned to the full use of man, although, as I said
before, they have been known to exist for centuries. When I hit upon
the idea that a rotary engine would run through their application, I
began a series of very successful experiments."

Tesla went on to explain that all turbines, and in fact all engines,
are based on the idea that the steam must have something to
push against. We shall see a little later how these engines were
developed, but it will suffice for the moment to listen to Doctor
Tesla's explanation.

"All of the successful turbines up to the time of my invention," he
says, "give the steam something to push upon. For instance"--taking a
pencil and a piece of paper--"we will consider this circle, the disk,
or rotor of an ordinary turbine. You understand it is the wheel to
which the shaft is attached, and which turns the shaft, transmitting
power to the machinery. Now it is a large wheel and along the outer
edge is a row of little blades, or vanes, or buckets. The steam is
turned against these blades, or buckets, in jets from pipes set
around the wheel at close intervals, and the force of the steam
on the blades turns the wheel at very high speed and gives us the
power of what we call a 'prime mover'--that is, power which we can
convert into electricity, or which we can use to drive all kinds of
machinery. Now see what a big wheel it is and what a very small part
of the wheel is used in giving us power--only the outer edge where
the steam can push against the blades.

"In my new turbine the steam pushes against the whole wheel all at
once, utilizing all the space wasted in other turbines. There are no
blades or vanes or sockets or anything for the steam to push against,
for I have proved that they hinder the efficiency of the turbine
rather than increase it."

Comparing his turbine to other engines Tesla says, "In reciprocating
engines of the older type the power-giving portion--the cylinder,
piston, etc.--is no more than a fraction of 1 per cent. of the total
weight of material used in construction. The present form of turbine,
with an efficiency of about 62 per cent., was a great advance, but
even in this form of machine scarcely more than 1 per cent. or 2 per
cent. is used in actually generating power at a given moment. The
only part of the great wheel that is used in actually making power is
the outside edge where the steam pushes on the buckets.

"The new turbine offers a striking contrast using as it does
practically the entire material of the power-giving portion of the
engine. The result is an economy that gives an efficiency of 80 per
cent. to 90 per cent. With sufficient boiler capacity on a vessel
such as the _Mauretania_, it would be perfectly easy to develop,
instead of some 70,000 horsepower, 4,000,000 horsepower in the same
space--and this is a conservative estimate.

"You see this is obtained by the new application of this principle in
physics which never has been used before, by which we can economize
on space and weight so that the most of the engine is given over to
power producing parts in which there is little waste material."

Tesla then went on to explain the details of his new turbine. Leading
the way to a small model in his office he unscrewed a few bolts and
lifted off the top half of the round steel drum or casing. Inside
were a number of perfectly smooth, circular disks mounted upon one
central shaft--the shaft that extends through the machine, and
corresponds to the crankshaft of an ordinary engine. The disks all
were securely fastened to the rod so that they could not revolve
without making it also turn in its carefully adjusted bearings. The
disks, which were only about one sixteenth of an inch in thickness,
and which he said were constructed of the finest quality of steel,
were placed close together at regular intervals, so that a space of
only about an eighth of an inch intervened between them. They were
solid with the exception of a hole close to the centre. The set of
disks is called the rotor or runner.

When the casing is clamped down tight, the steam is sent through
an inlet or nozzle at the side, so that it enters at the periphery
or outside edge of the set of disks, at a tangent to the circle
of the rotor. Of course the steam is shot into the turbine under
high pressure so that all its force is turned into speed, or what
the scientists call velocity-energy. The steel casing of the rotor
naturally gives the steam the circular course of the disks, and as
it travels around the disks the vapour adheres to them, and the
particles of steam adhere to each other. By the law that Tesla has
invoked, the steam drags the disks around with it. As the speed of
the disks increases the path of the steam lengthens, and at an
average speed the steam actually travels a distance of twelve to
fifteen feet. Starting at the outside edge of the disks it travels
around and around in constantly narrowing circles as the steam
pressure decreases until it finally reaches the holes in the disks
at their centre, and there passes out. These holes, then, we see act
as the exhaust for the used-up steam, for by the time the steam,
which was shot into the turbine by the nozzle under high pressure,
reaches the exhaust, it registers no more than about two pounds gauge
pressure.

  [Illustration: DIAGRAM OF THE TESLA TURBINE

  A--Steam Inlet. B--Disks. C--Path of the Steam. D,D´D´´--Exhaust.
  E--Reverse Inlet. F--Shaft.]

For reasons which will be explained later, ordinary turbines cannot
be reversed, but Tesla's invention can run backward just as easily
as forward. The reverse action is accomplished simply by placing
another nozzle inlet on the other side of the rotor so that the
steam can be turned off from the right side of the engine, for
instance, and turned into the left side, immediately reversing its
direction, with the change in the direction of the steam. The action
is instantaneous, too, for as we saw in the experiments Tesla showed
us, the turbine began to run at practically top speed as soon as the
steam was turned on.

The disks in the little 110-horsepower engine which we saw, were only
a little larger than a derby hat were only nine and three quarter
inches in diameter, while in his larger turbines he simply increases
the diameter of the disks.

Tesla further explained that the 110-horsepower turbine represented
a single stage engine, or one composed simply of one rotor. Where
greater power is required he explained that it would be easy to
compound a number of rotors to a double, or triple or even what he
calls a multi, or many stage, turbine. In engineering the single
stage is called one complete power unit, and a large engine could be
made up of as many units as needed, or practicable.

"Then do you mean to say," Tesla was asked, "that the only thing that
makes the engine revolve at this tremendous speed is the passage of
steam through the spaces between those smooth disks?"

"Yes, that is all," he answered, "but as I explained before, the
steam travels all the way from the outer edge to the centre of
the disks, working on them all the time; whereas in the ordinary
turbines the steam only works on the outside edge, and all the rest
of the wheel is useless. By the time it leaves the exhaust of my
engine practically all the energy of the steam has been put into the
machine."

This is only one of the many advantages that Tesla points out in his
invention, for the turbine is the exemplification of a principle, and
hence more than a mechanical achievement. "With a 1,000-horsepower
engine weighing only 100 pounds, imagine the possibility in
automobiles, locomotives, and steamships," he says.

Explaining the large engines that he is testing, one against the
other, at the power plant, the inventor said:

"Inside of the casings of the two larger turbines the disks are
eighteen inches in diameter and one thirty-second of an inch thick.
There are twenty-three of them, spaced a little distance apart, the
whole making up a total thickness of three and one half inches. The
steam, entering at the periphery, follows a spiral path toward the
centre, where openings are provided through which it exhausts. As the
disks rotate and the speed increases the path of the steam lengthens
until it completes a number of turns before reaching the outlet--and
it is working all the time.

"Moreover, every engineer knows that, when a fluid is used as a
vehicle of energy, the highest possible economy can be obtained only
when the changes in the direction and velocity of movement of the
fluid are made as gradual and easy as possible. In previous forms
of turbines more or less sudden changes of speed and direction are
involved.

"By that I mean to say," explained Doctor Tesla, "that in
reciprocating engines with pistons, the power comes from the backward
and forward jerks of the piston rod, and in other turbines the steam
must travel a zigzag path from one vane or blade to another all the
whole length of the turbine. This causes both changes in velocity and
direction and impairs the efficiency of the machine. In my turbine,
as you saw, the steam enters at the nozzle and travels a natural
spiral path without any abrupt changes in direction, or anything to
hinder its velocity."

But the Tesla turbine engine, claims the inventor, will work just
as well by gas as by steam, for as he points out gases have the
properties of adhesion and viscosity just as much as water or steam.

Further, he says that if the gas were introduced intermittently in
explosions like those of the gasoline engine, the machine would
work as efficiently as it does with a steady pressure of steam.
Consequently Tesla declares that his turbine can be developed for
general use as a gasoline engine.

The engine is only one application of the principle of Tesla's
turbine, because he has used the same idea on a pump and an air
compressor as successfully as on his experimental engines. In his
office in the Metropolitan Tower he has a number of models. Pointing
to a little machine on a table, which consisted of half a dozen small
disks three inches in diameter, he said: "This is only a toy, but
it shows the principle of the invention just as well as the larger
models at the power plant." Tesla turned on a small electric motor
which was connected with a shaft on which the disks were mounted, and
it began to hum at a high number of revolutions per second.

"This is the principle of the pump," said Tesla. "Here the electric
motor furnishes the power and we have these disks revolving in the
air. You need no proof to tell you that the air is being agitated and
propelled violently. If you will hold your hand down near the centre
of these disks--you see the centres have been cut away--you will feel
the suction as air is drawn in to be expelled from the outer edges.

"Now, suppose these revolving disks were enclosed in an air-tight
case, so constructed that the air could enter only at one point and
be expelled only at another--what would we have?"

"You'd have an air pump," was suggested.

"Exactly--an air pump or a blower," said Doctor Tesla. "There is one
now in operation delivering ten thousand cubic feet of air a minute."

But this was not all, for Tesla showed his visitors a wonderful
exhibition of the little device at work. "To make a pump out of this
turbine," he explained; "we simply turn the disks by artificial means
and introduce the fluid, air or water at the centre of the disks,
and their rotation, with the properties of adhesion and viscosity
immediately suck up the fluid and throw it off at the edges of the
disks."

The inventor led the way to another room, where he showed his
visitors two small tanks, one above the other. The lower one was full
of water but the upper one was empty. They were connected by a pipe
which terminated over the empty tank. At the side of the lower tank
was a very small aluminum drum in which, Tesla told his visitors,
were disks of the kind that are used in his turbine. The shaft of a
little one twelfth horsepower motor adjoining was connected with the
rotor through the centre of the casing. "Inside of this aluminum case
are several disks mounted on a shaft and immersed in water," said
Doctor Tesla. "From this lower tank the water has free access to the
case enclosing the disks. This pipe leads from the periphery of the
case. I turn the current on, the motor turns the disks, and as I open
this valve in the pipe the water flows."

  [Illustration: THE MARVELLOUS TESLA TURBINE

  The 200-horsepower engine, which a man could lift with one hand.

  How the Tesla Turbine compares in size with a man.]

  [Illustration: THOMAS A. EDISON AND HIS CONCRETE FURNITURE

  The white cabinet is a piece of Edison's poured concrete
  furniture, while the other one is the ordinary wooden phonograph
  cabinet.]

  [Illustration: MODEL OF EDISON POURED CONCRETE HOUSE

  This little house, which stands on a table in Edison's
  laboratory, shows what he expects to do with the poured concrete
  house.]

He turned the valve and the water certainly did flow. Instantly a
stream that would have filled a barrel in a very few minutes began to
run out of the pipe into the upper part of the tank and thence into
the lower tank.

"This is only a toy," smiled the inventor. "There are only half a
dozen disks--'runners,' I call them--each less than three inches in
diameter, inside of that case. They are just like the disks you saw
on the first motor--no vanes, blades or attachments of any kind.
Just perfectly smooth, flat disks revolving in their own planes and
pumping water because of the viscosity and adhesion of the fluid.
One such pump now in operation, with eight disks, eighteen inches in
diameter, pumps 4,000 gallons a minute to a height of 360 feet.

"From all these things, you can see the possibilities of the new
turbine," he continued. "It will give ten horsepower to one pound of
weight, which is twenty-five times as powerful as many light weight
aeroplane engines, which give one horsepower of energy for every two
and one half pounds of weight.

"Moreover, the machine is one of the cheapest and simplest to build
ever invented and it has the distinct advantage of having practically
nothing about it to get out of order. There are no fine adjustments,
as the disks do not have to be placed with more than ordinary
accuracy, and there are no fine clearances, because the casing does
not have to fit more than conveniently close. As you see, there are
no blades or buckets to get broken or to get out of order. These
things, combined with the easy reversibility, simplicity of the
machine when used either as an engine, a pump or an air compressor,
and the possibility of using it either with steam, gas, air, or water
as motive power, all combine to afford limitless possibilities for
its development."

Doctor Tesla calls the invention the most revolutionary of his
career, and it certainly will be if it fulfils the predictions that
so many eminent experts are making for it.

It is interesting to think that although this latest and most modern
of all steam engines is a turbine, the first steam engine ever
invented, also was a turbine.

Though most of us usually think of James Watt as the inventor of
the steam engine, he was not the first by any means, for the very
first of which history gives us any record was a turbine, which was
described by Hero of Alexandria, an ancient Egyptian scientist, who
wrote about 100 B.C.

Hero's engine was a hollow sphere which was made to turn by the
reaction of steam as it escaped from the ends of pipes, so placed
that they would blow directly upon the ball.

Centuries later--in 1629, about the time the New England States
were being colonized--a scientist named Branca made use of the
oldest mechanical principle in the world--the paddle-wheel--which,
turned by the never-ceasing river, goes on forever in the service
of mankind. Branca's invention was simply a paddle-wheel turned by
a jet of steam instead of by a water current. The engine was really
a turbine, for that type is simply a very high development of this
idea--the pushing power of a fluid on a paddle-wheel.

The picture of Branca's crude machine shows the head and shoulders
of a great bronze man suspended over a blazing wood fire. Evidently
it is intended to convey the idea that the figure's lungs are filled
with boiling water, for he is pictured breathing a jet of steam on to
the blades of a paddle-wheel, the revolving of which sets some crude
machinery in motion.

After Branca, however, the turbine dropped from view and what
few inventors did experiment with steam worked on the idea of a
reciprocating engine.

The principle of the reciprocating engine, as most boys know from
their own experiments with toy steam engines, and as was discovered
by Watt, is simply the utilization of the power of steam for
expanding with great force when let into first one side, and then the
other side of the cylinder. Thus, as the steam expands, it pushes the
piston back and forth at a high rate of speed, transmitting motion to
shafts and flywheels.

In 1888 the world was ready for a bigger and more powerful type of
steam engine; and C. A. Parsons, an Englishman, and Dr. G. de Laval
of Stockholm, brought forth successful turbines at about the same
time.

The machines were developed to a high state of efficiency, and are
still in general use, although most turbines for driving heavy
electrical machinery in the United States are the great Curtiss
engines, which are a combination of the principles of both the De
Laval and Parsons machines. All of them are run by the old principle
of the water-wheel. Instead of the steam being turned into a cylinder
to push the piston, it is turned into a steel drum or casing in which
wheels or disks are mounted on the central shaft. All along the edge
of these wheels are hundreds of little vanes or blades or buckets
against which the steam flows from many nozzles placed all around the
inside of the casing. The steam flows with great force, and naturally
pushing against the blades, starts the wheels and the engine shaft
to revolving. After expending its force on the blades that turn the
steam passes on to a set of stationary blades which then shoot it out
against the next set of moving blades.

In the Curtiss turbine the wheels at one end of the shaft are smaller
than those at the other, and the steam enters at the small end,
where it is under heavy pressure. After having expended its force
on the blades of the first wheel, the steam passes through holes in
a partition at the side and zigzags back so that it strikes the
vanes or blades on the next larger disk. It then repeats the process,
expands a little, and goes to a larger disk. Finally, by the time
the steam has expanded to its full capacity, the greater part of its
force has been expended against the disks of the turbine.

  [Illustration: THE CURTISS TURBINE

  Diagram of Steam Diaphragm Showing Nozzles and Fixed and Moving
  Blades

  A--Single stage turbine wheel. B--Steam nozzles.

  B´--Steam exhausts. C--Moving blades. D--Stationary blades.]

From this we see the main points of difference between reciprocating
engines and turbines, and between most turbines and Tesla's invention.

While most turbines take advantage of the expansive power of steam,
the main idea is to make use of the velocity of the vapour as it is
driven from a set of nozzles around the turbine wheel, under high
pressure.

Also it will be seen that Tesla's invention is a turbine in form, but
that it is entirely different from either of the two earlier types,
because instead of giving the steam something to push against, it is
allowed to follow its own natural course around between the smooth
disks, and drag them after it.

Some kind of a crank motion is necessary in all reciprocating
engines, to convert the backward and forward movement of the piston
to the rotary motion of the shaft, but this is done away with
entirely in the turbine. What engineers call a "direct drive" is
substituted in its place. In other words, the turbine wheels or
disks, fastened to the shaft, turn it, and drive the machinery
directly from the source of power. The speed of the machine is
regulated by gears.

The great advantage of the "direct drive," particularly for big
steamships and for turning big electric dynamos, will be plain to
every boy when he thinks of the long narrow body of a ship in which
can lie the turbine engines working directly on the propeller shafts
(with the exception of certain gears, of course, for regulating the
speed) instead of the big flywheels, and flying cranks of marine
reciprocating engines. Also with dynamos it is just as important
to have the power applied directly to save space and increase the
general efficiency of the machine.

The greatest disadvantage of the usual kinds of turbines for most
machinery, including steamships, is the fact that they cannot be
reversed. To solve this difficulty, all the great ocean and coast
liners, battleships, cruisers, and torpedo boats that are equipped
with turbines have two sets of engines, one for straight ahead and
one for backward.

With the Tesla turbine this disadvantage, as we have seen, is
entirely done away with, and the one turbine can be reversed as
easily and simply as it can be started.

And so, while we are waiting for the world-moving wireless
transmission of power and for the completion of Tesla's invention for
safe and stable airships, we can look for the speedy development of
his turbine in practically all departments of mechanical engineering.



CHAPTER IX

THE ROMANCE OF CONCRETE

   THE ONE-PIECE HOUSE OF THOMAS A. EDISON, AND OTHER USES OF THE
   NEWEST AND YET THE OLDEST BUILDING MATERIAL OF CIVILIZED PEOPLES
   SEEN BY THE BOY AND HIS SCIENTIFIC FRIEND


While we are looking around at all these epoch-making inventions let
us follow our friendly scientist and his boy companion to one of
the big cement shows held in the various large cities of the United
States every year, for a glance at some of the uses of reinforced
concrete in modern engineering and building. For the boy who intends
to become a civil engineer this wonderful material will have an
especial interest, because its successful use in all of the greatest
engineering works going on to-day has brought it to the front as
the modern substitute, in a great many cases, for wood, brick, or
expensive stone and steel structures.

  [Illustration: WHAT ONE SET OF BOYS DID WITH CONCRETE

  This Indian tepee of concrete was made by the boys of Dr. W. A.
  Keyes' summer school, at Sebasco, Maine.

  The picture on the left shows the method of construction.]

  [Illustration: MASSIVE CONCRETE WORK

  Completed side walls of solid concrete in the Gatun Locks of the
  Panama Canal.]

  [Illustration: A LEVEL STRETCH OF CATSKILL AQUEDUCT

  Showing completed section as well as forms for the concrete.]

On entering the cement show our friends saw on every side long rows
of booths showing models of structures and articles that could
be made of concrete. There were models of houses, subways, dams,
bridges, dock works, retaining walls, sewers, bridges, pavements
and even boats and furniture. In fact, so the men in the exhibition
booths said, concrete can be used for practically every building
purpose where strength, lasting qualities, and resistance to heat and
cold are needed. "This is the concrete age," they declared. "Concrete
is fireproof, waterproof, sanitary, and resists frost when properly
used. Our timber supply is decreasing, the supply of iron ore for
structural steel is limited, and stone is expensive; so concrete,
reinforced with steel, and used by engineers who understand their
business, will be the greatest building material of the future."

These are the things that the enthusiasts at all the concrete shows
say, but they admit that there are certain kinds of construction in
which concrete is not as effective as steel or granite. Also they
say that the use of reinforced concrete requires the highest type of
engineering skill, and a complete understanding of the technicalities
of the subject.

One of the places where we know concrete best is in pavements and
sidewalks, and several of the booths exhibited samples of such work.
To show its strength the men in charge piled on weights, struck the
slabs with hammers, or subjected them to any kind of hard usage
suggested by the crowd. Then, too, there were sections of concrete
buildings, and exhibitions of various systems of reinforced concrete
construction. With these there were concrete chimneys, portable
concrete garages, railroad ties, and what not.

"Oh, but look here," broke out the boy as he led his older friend
about. "Here's a perfect model of a house."

"Yes," answered the man, "that is a model of the famous Edison poured
cement, or 'one-piece' house, the latest invention of our great
American inventor."

There the little building stood, perfect in every way, surrounded
by a model concrete wall, a beautiful lawn, and approached by fine
concrete walks and driveways.

"This model," explained the scientist, "represents what Thomas
A. Edison is trying to get time to accomplish for workingmen and
their families. Instead of being built piece by piece, the house is
supposed to be made all at one time by pouring the concrete into a
complete set of moulds. This house is so interesting that we shall
look at it much closer a little later on."

"And here," said the boy; "what's this?"

He had paused before a perfect model of the Gatun locks of the Panama
Canal, where the world's greatest work in concrete, or any other
kind of masonry, is being carried on. The work is greater than the
Pyramids of Egypt or the Great Wall of China. Though we will not
bother ourselves much with figures, it will give an idea of the
size of the job on the canal when we realize that it will require
8,000,000 cubic yards of concrete, and more then 900,000 tons of
Portland cement.

In all there will be six great locks for the transportation of our
ships from the Atlantic to the Pacific and back. Three of these locks
are at Gatun on the Atlantic side of the canal, one at Pedro Miguel,
and two at Miraflores. Each lock will be 1,000 feet long, 110 feet
wide, and 45 feet deep--and practically all of this is done with
concrete. So massive is most of the work that steel reinforcement
is only necessary in certain parts of the project. The problem of
sinking the great retaining walls to bedrock, and making them strong
enough to hold in the face of the tremendous floods of the Chagres
River, alone makes one of the most stupendous engineering works ever
undertaken by man. Were it not for the use of concrete the cost
of the work would be so great as to make it almost impossible of
accomplishment.

The model of the Gatun locks showed the boy everything, just as it
will be when the canal is opened for traffic in 1913. There was the
wide Gatun lake, surrounded by the tropical forests, the great Gatun
dam, and the series of locks in one solid mass of concrete. These
locks when completed will be 3,800 feet long, and their tremendous
height and thickness can be seen from the pictures of the work as it
is actually being carried on. In the model there were perfect little
ships on the lake and going through the locks.

Besides the many present day uses of cement some of the concrete
enthusiasts are suggesting that heavily reinforced concrete be used
in place of steel in making bank vaults, as they declare that the
material will resist the keen tools and the powerful explosives of
bank robbers even more successfully than the hardest steel.

Then too, at the cement show, the boy saw, besides models of big
works and examples of all kinds of concrete construction, exhibits of
the various methods of placing steel bars and steel network in the
cement to make it stronger, and the different machines used in mixing
concrete and in making Portland cement, which is the binding element
in concrete.

As concrete is a material that can be mixed by an amateur and used
for a great many purposes, the booths where mixing and simple uses
were demonstrated attracted a great deal of attention. For instance,
in the last few years the farmers have found out that they can make
watering troughs, drains, floors for stables, hen houses, and even
fence posts, of concrete just as easily as they can of wood or iron.
Moreover, the articles thus made will last practically forever. All
that is needed is a supply of Portland cement, and a little careful
study as to the best way of mixing it with the proper amounts of sand
and gravel. The amateur has best results if he starts modestly and
takes up the use of reinforced concrete after learning how to use
the material in its simple form.

One of the most interesting uses of reinforced concrete for the
amateur who has learned something of the craft is in making a good,
seaworthy rowboat, or even a small motor boat. Poured boats are
strong, graceful, and durable. If they are properly made there never
is any danger of their leaking, and by a little extra pains it is
possible to make them with air-tight compartments so that they are
non-sinkable.

The usual method of making concrete boats is very simple. The kind of
boat to be duplicated is borrowed and hung on the shore so that it
swings free of the ground. Then a mould of clay is built all around
it. A strong bank of sand is heaped around the clay, to hold it firm.
Then the boat is worked a little each way so that a space of about an
inch and a half is left all around between the outside of the boat
and the clay. The space between the boat and the clay is the space
into which the concrete is poured for sides and bottom after the
reinforcing rods have been properly inserted. After the whole thing
has stood a day or so the inside boat is taken out and the clay mould
broken down, revealing a complete concrete hull.

Thus, we see that concrete can be used as a building material in
practically any kind of construction, that it is easily handled
since all that is necessary is to pour it into the moulds after the
engineers have properly placed the reinforcement, and that it can be
cast in practically any decorative design just as easily as plain.
Add to this the fact that concrete is cheaper than stone or steel,
and that it is practically indestructible when properly handled, and
it is easy to see the reason for calling this the cement age, and
concrete _the_ building material of the future.

After the Panama Canal, the greatest engineering feat in which
concrete figures as one of the chief materials used, is the Catskill
aqueduct, by which water from four watersheds in the Catskill
Mountains of New York State is to be piped to all five boroughs of
New York City. The Ashokan reservoir, near Kensington, N. Y., was
the first part of the work to be taken up, together with the Kensico
storage reservoir twenty-five miles from New York, several smaller
reservoirs, and the aqueducts to carry this water from the mountains
to every home in greater New York. The dam and containing walls of
the Ashokan reservoir are all made of reinforced concrete, and the
size of the lake and the strength of the walls can be appreciated
when one thinks that the 130,000,000,000 gallons of water it holds
in check would cover all Manhattan Island with twenty-eight feet of
water. A large part of the aqueduct proper, through which this great
stream of water is carried from the mountains, under the Hudson
River, and to the city where it runs more than a hundred feet below
the street level, is made of reinforced concrete.

For other examples of the use of this material in big engineering
works a boy has only to look around him. There are the tunnels under
the rivers around New York, the New York subways, the Philadelphia
and Boston subways, the Detroit River tunnel, bridges, culverts, big
piers and other dock works, miles of concrete snowsheds along the
lines of the railroads that cross the continental divide of the Rocky
Mountains, and in fact practically every big structural undertaking.

Almost anywhere we look these days we see a big machine crushing
rock, mixing it with sand and mortar, and turning out concrete to be
shovelled into a hole and perhaps used far below the surface by "sand
hogs" working under compressed air, or hoisted to the towering walls
of some great office building or factory that is being constructed of
the artificial stone.

We are familiar with the falsework of a concrete building under
construction. It is all, apparently, a maze of wooden beams that
look like scaffoldings, and yet they seem to make the outlines of
the building. This maze of woodwork, seemingly so lacking in plan or
system, as a matter of fact is a triumph of engineering skill, for it
is the mould for the building, and was all built by the most careful
plans as to strains, stresses, floor loads, etc.

First, however, before building the mould for a residence, school,
theatre, office building, or factory, the engineer decides what
strength his foundations must have. The foundation for a small
residence is an easy matter, but when it comes to a big factory, or
an office building of a dozen stories or so, the most careful work
must be done beforehand. In the old days, when it was desired to
sink the foundations of a building down to bedrock, they used steel
or wooden piles, but these will rust or rot, and the modern way is
to use concrete piles. Either the great poles are moulded first and
sunk like the ordinary wooden ones, or a pipe with a sharpened point
is sunk and the concrete deposited in it by buckets designed for the
purpose. Once these piles are driven, they are there for all time,
if the work is done properly, and the engineer can be sure that his
building is as good as if resting on bedrock.

From then on the erection of a reinforced concrete building is a
most intricate matter, because while concrete in itself is a very
simple substance, its use in buildings is a highly developed science.
Of course there are many different methods of using concrete,
and each one prescribes a different kind of steel network for
the reinforcement. Then, too, some engineers cast parts of their
buildings separately and put them in place after they have set, while
others run the concrete for beams, floors, and walls into moulds,
built right where those parts are to be in the finished structure.
In laying the steel reinforcing rods, before the concrete is poured,
the engineer sees that they make a perfect network so as to take
care of all the strains, just as they will be put upon the building
when it is completed. It is in the proper placing of reinforcement
that the greatest engineering knowledge is needed in this kind of
building.

As the wooden moulds for the first foundation beams and girders are
completed and the reinforcement is placed, the concrete is poured in.
The subcellar or cellar floor mould then is laid, the reinforcement
placed and the concrete run in. Next the moulds for the cellar walls
are built and perhaps the moulds for the beams and girders for the
first floor. The reinforcing rods are placed in these moulds and the
concrete run in, and so on, a story at a time, or a small section
at a time, until the structure reaches the height called for in
the plans, and it stands completed. As the building progresses and
the concrete on the lower floor sets, the moulds can be taken down
and used on higher stories. Concrete is even used for the roofs of
buildings, as it can be moulded right in place or set up in slabs
that can be later cemented together.

When properly used reinforced concrete is absolutely fireproof, so
it is coming into extensive use in the construction of schools,
theatres, warehouses, factories, and all other such buildings where a
great height is not required. So far, none of the great skyscrapers
has been built of reinforced concrete, although office buildings of
sixteen stories have been erected with complete success.

There is still another method of using concrete as a building
material. This is in the form of building blocks, and doubtless all
who read this will recall seeing many beautiful residences built of
blocks of stone that on closer inspection proved to be concrete. The
blocks can be cast in any size or form and used in just the same way
as structural stone.

Now, after having looked about the city and having seen the numerous
ways that concrete is used as a building material, we come back
to the very latest thing in the use of this man-made stone--the
"one-piece" or poured house.

For a good view of it let us take a little jaunt out to West Orange,
N. J., with the scientist and look into the library of Thomas A.
Edison's laboratory, where we will see a perfect model of this marvel
of invention. It is practically the same as the one at the cement
show. Standing in the centre of the great room where Edison works
is this perfect little cottage, about the size of a large doll's
house. It represents not only Edison's latest invention, but also his
favourite scheme. In years to come, when the boys who read this are
grown men, it will probably be no novelty to build houses by pouring
them all at once into a steel mould, but just at present it is one of
the most startling developments in an age of epoch-making inventions.

Every boy knows that Edison has never followed the ideas of others in
working out his inventions, and the poured house is no exception to
his rule. It will be interesting to take a little look back over a
part of Edison's life and see how he came to enter the cement-making
business, and how, when he had his process down to a fine point, he
said to himself, "It is cheap and easy to build a house or an office
building of concrete in sections, why not build it all in one piece?"

We shall see that no sooner had he asked himself this startling
question than he began by making models, and satisfied himself that
it was not only possible, but one of the cheapest and best methods
of making small, simply arranged houses, such as could be bought or
rented for a small sum.

Although Edison has within the last few years brought his idea to a
state where it can be put to practical use, he himself is not trying
to push it commercially, as he has his other great inventions like
the phonograph, storage battery, and the motion-picture machine. In
fact, he is content to let it be worked out by others just so long
as it fulfills his idea of giving to workingmen good houses at a low
price.

"Years ago, long before Edison had retired from active business
affairs to give his whole attention to scientific research," said the
scientist, as he and the boy walked about the laboratory, "he became
interested in metallurgy, just as he was and always is interested in
every other science where great difficulties must be overcome. In
those days iron and steel were not used as extensively as they are
now, but the scientists and leaders in the big industries saw that
the day was coming when far, far greater quantities of iron ore would
be needed to supply the great demand for steel to build skyscrapers,
ships, machinery, and so on. Men were going farther and farther away
in their search for iron ore, but Edison, with his never failing
originality, said to himself that it was likely there was plenty of
iron ore right around his laboratory in New Jersey if he only knew
how to get at it.

"For one thing," continued the boy's friend, "Edison had seen on
the ocean beaches great stretches of white sand with millions and
millions of little black particles sprinkled through them. He knew
that the specks were pure iron ore. You can prove this to yourself
by simply holding a good magnet close to a pile of such sand, and
watching the iron particles collect."

It was Edison's idea to concentrate the iron ore found in the earth,
in just this way, for he had sent out a corps of surveyors who had
reported vast quantities of low-grade ore in most of the Atlantic
Coast States. Low-grade ore is that which contains only a small
percentage of the metal desired, and hence it does not pay to smelt
it, unless a very cheap process can be found. Edison thought he had
a process cheap enough, for he simply intended to grind the mountains
to sand and take out the particles of iron by running it through a
hopper with a high-power magnet at the mouth.

The process sounds simple, but the machinery required was very
complicated, to say nothing of being extremely heavy. Edison set up
his mill in the mountains of New Jersey and started to blast down the
cliffs of low-grade ore and run them through a series of gigantic
crushers that ground them to a fine powder. The iron particles,
called concentrates, after being extricated were pressed into
briquets ready for delivery to the foundry.

After having spent close to $2,000,000 on the experiment, and
satisfactorily proving its mechanical success, the discovery of vast
quantities of high-grade ore in the Messaba range of Minnesota forced
Edison to close his plant. "This would have been a crushing failure
to most men," added the scientist, "but Edison's only comment was
a whimsical smile. Indeed, even on his way home after closing his
plant, Edison was planning new and more important activities, for
with his experience at rock crushing he was satisfied he could enter
the field as a maker of the building material called Portland cement."

At that time cement and concrete were even less used than were steel
and iron, but Edison for many years had seen that in the future they
would take the place of wood, stone, and brick.

"Well-made concrete, employing a high grade of Portland cement,"
said Edison on one occasion, "is the most lasting material known.
Practical confirmation of this statement may be found abundantly in
Italy at the present time, where many concrete structures exist, made
of old Roman cement, constructed more than a thousand years ago, and
are still in a good state of preservation.

"Concrete will last as long as granite and is far more resistant to
fire than any known stone."

But Edison had something more than a successful business in mind when
he returned from his rock-crushing plant, for he intended setting
up cement-making machinery such as had never before been seen. With
this end in view he began to read up on the subject, just as we have
seen the Wright brothers read up on aviation. Incidentally, as an
indication of the manner in which this wizard works, it may be said
that all this time Edison was perfecting his new storage battery.

One big improvement upon the usual process in the manufacture of
cement, planned by Edison, was that the grinding should be so fine
that 65 per cent. of the ground clinker should pass through a
200-mesh screen instead of only 75 per cent. as is the usual rule.
Thus, Edison made into cement 10 per cent. more material that other
manufacturers sent back to be ground over again.

The success of Edison's Portland cement plant is not matter for our
attention here, so we will pass over those busy years to the time of
Edison's retirement to devote all his time to scientific research.

For many years he had watched the cities grow, had seen the great
tenements become more crowded, and less comfortable each year. He
had seen the children playing in the streets, and had compared their
lives to the happy lives of the children whose parents could afford
to live away from the great cities, where boys could have yards to
play in. He decided that the boys of the city streets would have a
far better time, that their mothers and fathers would have a far more
cheerful life if they could live in comfortable little houses in the
country with yards, and gardens, and plenty of room for every one.

Edison saw that what was needed was a building material cheap enough,
and a method of using it cheap enough, so that dwellings could be put
up at a cost that would place them within the means of workingmen and
their families.

Concrete, he decided, was the material to solve the problem, and
Edison set himself to the task of making houses poured complete into
one mould so as to make the cost of labour as low as possible. The
"one-piece" house was an assured thing from that time on. All that
remained was for the "Wizard of Orange," as he is called, to work
out the difficult details of a properly mixed cement and a practical
system of moulds.

An incident that occurred at the time of the failure of his ore
crushing plant in the New Jersey mountains was one of the things that
brought the whole situation home to him. When the plant was closed
and the buildings vacated, the fire insurance companies cancelled the
policies, declaring that the moral risk was too great.

The inventor's reply was short and to the point. He made no protest
against the cancellation of his policies, but simply said he would
need no more policies, as he would erect fireproof buildings in which
there would be no "moral risk."

This promise of Edison's, made at the time of his so-called failure
and pondered during the years of his tremendous activities, was
not redeemed until he had retired from the business of invention
as a means of gaining riches. "I am not making these experiments
for money," Edison has said many times. "This model represents the
character of the house which I will construct of concrete. I believe
it can be built by machinery in lots of 100 or more at one location
for a price which will be so low that it can be purchased or rented
by families whose total income is not more than $550 per annum. It is
an attempt to solve the housing question by a practical application
of science, and the latest advancement in cement and mechanical
engineering."

  [Illustration: HUGE CONCRETE MOULDS AT PANAMA

  These great locks are made as monoliths or in moulds of one
  piece, the whole making the greatest masonry work the world has
  ever seen.]

  [Illustration: CONCRETE LOCKS ON THE PANAMA CANAL

  The Gatun middle locks, east chamber, looking south from the east
  bank.]

Edison's plan, as we have seen before, was simply to make a set
of moulds in the shape of the house he desired to build, run the
concrete into them, let them stand until the material had settled,
and then take down the retaining surfaces, exposing to view the
finished house.

It was contrary to all the previous ideas in building, and was
ridiculed by many famous architects. Nevertheless, tremendous
obstacles are the stuff upon which Edison's genius feeds, and he only
worked the harder to produce a concrete that would be liquid enough
to fill all the intricate spaces and turns in the moulds and yet
sufficiently thick to prevent the sand or gravel in the concrete from
sinking to the bottom. Thus, it first had to run like thin mush and
then set in walls and floors harder than any brick or stone. Another
of the difficulties to be overcome was to discover a concrete that
would give perfectly smooth walls.

Although this may sound very simple, it has not yet been completely
worked out in this country, owing to the heavy demands on Edison's
time. The perfected process, however, will be made known just as soon
as the inventor can find time to complete certain small details that
he wants to clear up before giving the system to the world. A French
syndicate working along Edison's ideas for a poured house has made
some progress and it is reported they have constructed two attractive
dwellings with considerable success. One of these is at Santpoort,
Holland, and the other near Paris.

Whether the houses are poured completely in one mould, or whether
they are built a story at a time on different days, this newest form
of house building is carried on along about the same lines.

"Let us just suppose," said the scientist, "that we are standing on
a building site in some pretty suburb of a great city. We will also
suppose that an Edison poured house is to be erected there. Plans are
drawn beforehand for a small house of simple arrangement and a set
of steel moulds in convenient sizes are turned out. These moulds all
have connections so they can be set up and joined together in one
piece. First, we see that a solid concrete cellar floor, called the
'footing', has been laid down just the size and shape of the house.
A crowd of skilled workmen quickly set up the moulds on this footing
and lock them together. The moulds make one complete shell of the
house, from cellar to roof, just as it will appear when completed.
Reinforcing rods are placed in the mould so that they will be left in
the concrete walls, floors, etc., of the house after the steel shell
is taken away.

"Nearby we see a few more skilled workmen mixing the concrete in
great vats. When the mould and the material are ready we see the
concrete taken to a tank on the roof and poured into troughs which
carry the stuff to a number of different holes through which it
flows into the mould. We hear it splash, splash, splash as it
gradually fills every space in the shell, and finally after six hours
or so it overflows at the roof. The main part of the work is now done
and we can go away for a few days while the liquid in the shell sets,
or turns to the hardest kind of stone.

"After about six days we return to see the moulds unlocked, taken
down and the complete house standing ready with walls, floors,
stairways, chimneys, bathtubs, stationary tubs in the cellar,
electric-wire conduits, water, gas and heating pipes all complete. In
making the moulds the spaces for bathtubs, wash-tubs, electric wiring
and piping for gas, water, and heat, are just as carefully arranged
as walls and floors. The only work necessary after the concrete has
set is to put in the doors and windows, install the furnace and
necessary fixtures for heating, lighting and plumbing and connect
them up ready for use. No plaster is used in these houses, but the
walls can be tinted or decorated just as the landlord or occupant
desires."

The boy's friend went on to say that one might think that this
was about as far as science could carry the use of concrete, but
Edison said to himself: "If we can make houses, why can't we make
furniture?" and he set about experimenting with poured furniture. He
obtained some wonderful results with this newest use of concrete, and
in his Orange laboratory he has several cabinets, chairs, and other
articles of furniture that are every bit as attractive to look at as
wooden furniture and that are practically indestructible.

"And my concrete furniture will be cheap, as well as strong," says
Edison. "If I couldn't put it out cheaper than the oak that comes
from Grand Rapids, I wouldn't go into the business. If a newlywed
starts out with, say, $450 worth of furniture on the installment
plan, I feel confident that we can give him more artistic and more
durable furniture for $200. I'll also be able to put out a whole
bedroom set for $5 or $6."

At present the weight of this concrete furniture is about one third
greater than wooden furniture, but Edison is confident he can reduce
this excess to one quarter. The concrete surface can, of course,
be stained in imitation of any wood finish. The phonograph cabinet
shown at the left of Edison in the picture opposite page 281 has been
trimmed in white and gold. Its surface resembles enamelled wood. The
cabinet at his right is the old style wooden type.

This concrete cabinet easily withstood the hard usage of shipment by
freight for a long distance.

  [Illustration: THE WORLD-WIDE USE OF CONCRETE

    Courtesy of the Atlas Portland Cement Co.

  An eight-story all-concrete office building under construction in
  Portland, Maine.]

  [Illustration:

    Courtesy of the Atlas Portland Cement Co.

  A perfect little model of the great Gatun Locks of the Panama
  Canal.]

  [Illustration: THE CATSKILL AQUEDUCT, ONE OF THE WORLD'S GREATEST
  CONCRETE WORKS

  Laying a level section of the great concrete tunnel through which
  New York City is to get its drinking water.]

  [Illustration: THE AQUEDUCT DEEP UNDER GROUND

  A partially completed section showing the concrete work. Note the
  size of the tunnel.]

Of course, the poured concrete furniture is made in just the same
way as the houses except that it is a much simpler process. It is a
very easy matter to set up a steel mould for a chair, a cabinet, a
dresser, or a bedstead, whereas a house, with its tubs, conduits,
stairways, hallways, doorways, window frames, plumbing system, etc.,
is a most complex matter, requiring a set of moulds that could be put
together properly by only a man who combined the highest abilities
of an architect, a builder, an engineer, and a mechanic. Although
concrete has been used for many years in making garden furniture,
Edison's plan for making finished indoor pieces with it is entirely
new.

But to return to the houses; Edison says it is just as easy to make
poured dwellings in decorative designs as in plain ones. It is
only necessary to have the moulds cast in the desired shape. It is
his idea to have all the poured houses pretty as well as perfectly
sanitary and substantial. He intends that there shall be many
different kinds of moulds, and also that each set of moulds shall be
so cast that it can be joined in different ways, in order to give the
houses a variety of appearance. Thus, in a small town where a large
number of poured houses were set up, there would be no two exactly
alike if the owners preferred to have them different.

According to the plans Edison now has on foot, the first complete
poured houses will have on the main floor two rooms, the living
room and dining room, while on the second floor there will be four
rooms, a bathroom and hallway. Of course as the main idea is to give
perfectly sanitary and comfortable houses, there will be plenty of
windows, for lots of fresh air and sunlight. Edison figures that
he can build a house of poured concrete for $1,200 that would cost
$30,000 if built of cut stone. Furthermore, he figures that the rent
ought to be about $10 per month, as he will only license reputable
concerns to use his patents, and his licenses will stipulate the
approximate rent that can be charged.

Thus, the high cost of living about which we all hear so much at the
family dinner table as well as everywhere else is being attacked by
science and invention through a new channel, and Edison's latest
invention can be expected soon to give good homes at low rents to
thousands of families now paying exorbitant prices for dark stuffy
city flats.

It was significant that at the celebration of Edison's sixty-fifth
birthday, February 10, 1912, the great American inventor should sit
at the head of the table surrounded by his family and associates
facing a perfect model of one of his poured cement houses. The chair
in which he sat, to all appearances was beautiful mahogany, but in
reality was cast in a mould of Edison concrete at the Edison plant.
At the place of each guest was a bronze paperweight, appropriately
engraved, with Edison's favourite motto:

"All things come to him who hustles while he waits."


HISTORY OF CONCRETE

Although concrete is in truth the newest building material in
our time, it is the oldest known to civilization because it was
the stuff with which the eternal buildings of ancient Rome were
constructed. Even before the Romans used concrete it was used by the
Eygptians, more than 4,000 years ago. Every boy will remember from
his history classes that the Egyptians, so far as we can learn, were
the first people in the history of the world to reach a high state of
civilization. Every boy also will remember that the only way we know
this is through the evidence of ruins of tombs and buildings. Many of
these buildings were made of a material very much like concrete that
must have been made in some such manner as concrete is made nowadays.

About 2,000 years later, long after the Egyptian civilization had
died, the men of Carthage discovered concrete for themselves and
built a marvellous aqueduct 70 miles long, through which water
was brought to their city. It was carried across a great valley
over about 1,000 arches, many of which are still standing in good
condition.

To the Romans, however, we are indebted for some of the best examples
of ancient concrete work. They used this material in their wonderful
city for buildings, bridges, sewers, aqueducts, water mains, and in
fact in a great many of the ways that we have seen it is used to-day.
The great Coliseum and the Pantheon at Rome are relics of the skill
of the ancient architects in the use of concrete.

Although many historians think that the secret of making cementious
building material was lost from the fall of Rome until the middle
of the eighteenth century, there are ruins of ancient castles which
stood in mediæval times in Europe which indicate at least some use of
concrete.

The real discoverer of natural cement in our modern times though,
was John Smeaton, who will be remembered by the readers of "The
Boy's Second Book of Inventions" as the man who built the first
rock lighthouse at Eddystone, England, in 1756. In his great work
he discovered a kind of limestone with which he could make a cement
that would set, or harden, under water. His discovery was hailed as
the recovery of the secret of the ancient Romans of making hydraulic
cement. It was so called because it would harden under water.

In 1796, Joseph Parker, another Englishman, made what he called Roman
cement. Several others followed, and in 1818 natural cement was
first made in the United States by Canvass White near Fayetteville,
N. Y. The material was made from natural rock and was used in the
construction of the Erie Canal.

All of these early cements are called natural cements by engineers
nowadays, because they were made from natural rock. It was only
necessary to find a clayey limestone which contained a certain
percentage of iron oxide and two other minerals known as silica and
alumina. The limestone was crushed to a convenient size and was
burned in a kiln. The heat turned the stuff into cinders which, when
ground to a fine powder and mixed with water, would make a cement
that would harden under either air or water very quickly, and last
for practically all time. Just for the sake of those who have studied
chemistry we will say that in this process the heat drives off the
carbon dioxide in the limestone, and the lime, combining with the
silica alumina and iron oxide, forms a mass containing mineral
properties called silicates, aluminates, and ferrites of lime. These
properties mixed with the water make natural cement. In the United
States, natural cement was called Rosendale cement, because it was
first made commercially in a town of New York State by that name.

The supply of natural cement, however, is limited, because the proper
kind of limestone is only found in a few places. Consequently, when
an artificial mortar called Portland cement was invented in 1824, the
world took a step forward that could not be measured in those days.

Most authorities give the credit for the invention to Joseph Aspdin,
a bricklayer of Leeds, England. He took out a patent on the material
and in 1825 set up a large factory. In 1828 Portland cement was used
in the Thames tunnel, making the first time that the material figured
in any big engineering work. In those days even the most enthusiastic
supporters of cement little dreamed that in this modern age it would
be the material that would make possible such tremendous victories
over the obstacles of nature as the Panama Canal, the tunnels under
the rivers that surround New York and the great dams that hold back
the waters all over the country.

Aspdin, however, is not given the credit for the invention of
Portland cement by all authorities, as some claim that Isaac Johnson,
also an Englishman, who early in 1912 died at the age of 104, was
really the first man to invent a practical, commercial, artificial
cement.

The advantage in Portland cement is that it can be made of a number
of different kinds of earth, to be found in many different parts
of the world, and makes a far stronger rock. It sets more slowly
than natural or hydraulic cement, but is more satisfactory for use
in reinforced concrete work. In the Lehigh Valley, where about two
thirds of the Portland cement used in the United States is made,
the raw material is a rock, called cement rock, and limestone. In
New York State they make Portland cement of limestone and clay;
in the Middle West they make it of marl and clay, while in other
Western States they make it of chalk and clay. In Europe slag is
sometimes used. The artificial product contains lime oxide, silica,
alumina, iron oxide, and other minerals in varying quantities, but
the necessary ones are silica, alumina, and lime. In making Portland
cement the raw material is ground into a fine powder and poured into
one end of a long cylindrical kiln which looks like a smokestack
lying on its side. Powdered coal is shot into the kiln, where it is
kept burning, at a heat of about 2,500 to 3,000 degrees Fahrenheit.
After the raw material has been burned thoroughly and is taken from
the kiln it looks like little cinders or clinkers about the size of
marbles. The cement clinker is then cooled and ground to a powder,
after which it is stored away for a little while to season.

The first Portland cement ever made in the United States was turned
out by David O. Saylor, of Coplay, Pa., in 1875, but the development
of the new industry was very slow, as builders and engineers seemed
to be blind to the great possibilities of the material that built
Imperial Rome. In 1890, nearly twenty years after the process was
introduced in America, only 335,500 barrels of Portland cement were
manufactured in this country. The country woke up to the situation a
few years later, and in 1905 there were manufactured in the United
States 35,246,812 barrels of Portland cement. In 1911 the industry
turned out the stupendous total of 77,877,236 barrels.

This was because the age of concrete had dawned on the world and man
had learned in those years that by mixing gravel and sand with cement
he could make a material cheaper, more easily handled, and far more
lasting than wood, brick or some stone.

As Edison once said to some of his associates:

"I think the age of concrete has started, and I believe I can prove
that the most beautiful houses that our architects can conceive
can be cast in one operation in iron forms at a cost, which, by
comparison with present methods, will be surprising. Then even the
poorest man among us will be enabled to own a home of his own--a home
that will last for centuries with no cost for insurance or repairs,
and be as exchangeable for other property as a United States bond."

The technical definition of concrete is as follows: "Concrete is
a species of artificial stone formed by mixing cement mortar with
broken stone or gravel. Cement is the active element called the
_matrix_ and the sand and stone forms the body of the mixture called
the _aggregate_."

The ingredients are mixed in different proportions for different
work. A common proportion is 1 part cement, 2 parts sand, and 5
parts broken stone or gravel. Cement users speak of this as a "1:
2: 5 mixture." Sometimes the gravel is left out and a mixture of 1
part cement to 3 or 4 parts sand is made. The cement binds the mass
together and sand fills up any little vacant spaces about the gravel,
making what is called a dense mixture.

  [Illustration: THE SILENT KNIGHT MOTOR

  Two views of the latest automobile engine. At the top can be seen
  the sliding sleeves, the inlets and outlets which do away with
  valves]

  [Illustration: A PORTABLE ARMY WIRELESS OUTFIT

  The Signal Service is rapidly increasing its wireless equipment
  for use on land.]

  [Illustration: THE WIRELESS IN THE NAVY

  Practically all of Uncle Sam's warships and Navy Yards now are
  equipped with wireless, and a regular navy wireless operators'
  school is maintained at the Brooklyn Navy Yard.]

From the use of concrete it was only a short step to reinforced
concrete, or, concrete braced on the inside with iron or steel rods.
It is sometimes called concrete steel, ferro-concrete, and armoured
concrete. If we asked an engineer the idea in using reinforced
concrete he might say to us that the steel when imbedded, united so
closely with the concrete as to form one single mass of very great
strength. Steel rods add to the _tensile_ strength of concrete which
alone has a tremendous strength under _compression_. In other words,
steel does not break nor stretch easily; that is, it has great
tensile strength. Concrete has great strength under compression;
that is, it will hold up an enormous weight without crushing. Thus,
a concrete beam alone might crack on the bottom, because it has not
as great tensile strength as steel. But, if we put steel rods into a
concrete mould, an inch or so from the bottom, turn out a reinforced
concrete beam, for instance, and place it in the building, with the
reinforcement at the bottom, we use a beam in which the strength
of the concrete and iron is combined. Thus, when a great weight is
placed on the top of the beam the concrete resists the compression
of the weight, and the reinforcement at the bottom, by its tensile
strength, prevents the beam from cracking where the strain of the
weight is greatest.

That is what the engineer might tell us is the theory of reinforced
concrete, and the practice requires the highest engineering skill
and technical knowledge, but in the simplest terms, it is concrete,
braced by an imbedded skeleton of steel. In actual practice the
reinforcing rods run both ways, or diagonally, just as the engineers
decide it is necessary to resist the particular kind of stress that
the wall or beam must withstand.

Reinforced concrete was first used, so far as known, by M. Lambot,
who exhibited a small rowboat made of that material at the World's
Fair in Paris, in 1855. The sides and bottom of the boat were 1-1/2
inches thick, with reinforcement of steel wires. The boat is still
in use at Merval, France. F. Joseph Monier, however, is called the
"father of reinforced concrete," as he took out the first patent on
it in France in 1865. Monier was a gardener and had experimented with
large urns for flowers and shrubs. He wanted to make his pots lighter
but just as strong, so he tried making some of concrete with a wire
netting imbedded in the material. But even then the world did not
realize that his accomplishment was more important to mankind than a
great many of the wars that had been fought, and little was done with
concrete as a building material until the Germans developed it.

Reinforced concrete was not used in the United States, according to
the best records, until 1875, when W. E. Ward, without having studied
the subject very carefully, built himself a house of it, in Port
Chester, N. Y. He made the whole thing, including foundation, outside
walls, cornices, towers, and roof of reinforced concrete, placing
the steel rods where his own good judgment told him they would do
the most good. About this time the Ransome Cement Company began to
use the material for building, and put up a great many strong and
beautiful structures, still to be seen in California and elsewhere.

Finally, bit by bit, in the face of opposition of all kinds,
reinforced concrete came to be recognized by architects, engineers,
and builders as one of the best materials for certain kinds of work.
To-day we find that most of the predictions of the early enthusiasts
have been fulfilled and that the age of concrete has dawned. That it
will be used even more extensively in the future, as men learn more
and more about this wonderful artificial stone, is certain.



CHAPTER X

THE LATEST AUTOMOBILE ENGINE

   OUR BOY FRIEND AND THE SCIENTIST LOOK OVER THE FIELD OF GASOLINE
   ENGINES AND SEE SOME BIG IMPROVEMENTS OVER THOSE OF A FEW YEARS
   AGO


While we are following the conversations of the scientist and his
young friend about new inventions, we must not overlook some of their
most interesting times in keeping abreast of the vast improvements
that are being made every year--almost every day--in the inventions
of a dozen years ago.

For instance, there is the gas engine. Ten years ago it was a very
imperfect machine, as every boy who has heard the old jokes about
"auto-go-but doesn't," "get a horse," etc., will remember.

Then there is the wireless telegraph. No invention of recent years
has shown a more remarkable development than that of Guglielmo
Marconi for sending messages without wires.

But these are only a few of the things that the two friends talked
about. They looked into the wonderful advancement in the art of
photography about which every boy knows something, and they
investigated the latest achievements of science in electric lighting.
Ten years is a very short time, even in this fast moving age of ours,
and we shall see that many inventions made years ago are still being
worked upon by the original inventors and others.

First, let us see a few of the ways the gas engine has been improved,
for we are all more or less familiar with it in automobiles, motor
boats, or the hundred and one other places that it has become an
invaluable aid to man in carrying on the world's work.

Our young friend brought up the subject one day when he asked the
scientist for a few pointers on getting better results with his
motor-boat engine.

"We will look it over together," said the man. "Of course you
know that every gasoline engine has its own peculiarities, and
crankinesses, so it's hard to tell just what's the matter with one
until you see it. I don't know very much about them; I wish I knew
more, but I have been talking with my automobile friends a good deal
lately about the new motor invented by Charles Y. Knight."

"Oh, I know," replied the boy, "it is called the 'Silent Knight'
motor because it doesn't make any noise, and it is used on a great
many high-priced automobiles."

"That's it. If you like we will go and have one of these engines
explained to us. At any rate the automobile man can tell you more
about your motor-boat engine than I can."

The expedition was made shortly after the conversation. "You
understand, of course," said the scientist on the way, "that the
Knight motor represents only one of the many, many improvements in
the gas engine, but it is what we call a fundamental improvement, as
it is a development in the main idea of the gasoline motor, rather
than merely an improvement of one of the parts. Most of the evolution
of gas engines has consisted merely of the improvement and perfection
of the various parts for more power, and more all around efficiency.

"You remember what you found out about gasoline motors in general
when we were spending so much time talking about aeroplanes. The high
speed motor, as we know it now, was invented, you know, by Gottlieb
Daimler, a German inventor, in 1885, and with the ordinary four-cycle
engine it takes four trips, or two round trips of the piston rod,
to exert one push on the crankshaft of the engine. In other words,
the explosion drives down the piston giving the power, and on its
return trip the piston forces out the burned fumes. On the next
downward stroke the fresh vapour is sucked into the cylinder and on
the fourth trip, or second upward trip, the gas is compressed for
the explosion. The carbureter on your motor-boat engine, and all
others, as you know, is the device that mixes the gasoline with air
and converts it into a highly explosive gas, and the sparking system
is the electrical device that ignites the gas in the cylinders for
each explosion which makes the 'pop, pop, pop' so familiar with all
gasoline engines.

"In the old gas engines the ignition was derived from a few dry-cell
batteries and some sort of a transformer coil, whereas nowadays the
magneto takes care of this work. As you know there are many kinds
of magnetos, and inventors have spent years working out better and
better ones. Also, in the old style motors the carbureter was more
or less of a makeshift, with a drip feed arrangement, and a hand
regulating shutter for admitting the air. Now a special automatic
device regulates this, so that it is no longer a toss up whether
the gas is mixed in the proper quantities or not. Then, too, the
oiling systems have been improved, so that the function is done
automatically. In short, the motor has been made a perfectly reliable
servant instead of a very capricious plaything.

"All these improvements made no fundamental change in the valves
through which the gas was admitted to the cylinders, and the
exhausted vapours expelled--and from your own experience you know
that you are just about as apt to have trouble with your valves as
with any other part of your machine.

"It is in these valves that the Knight motor departs from the usual
style, and by this it eliminates the well-known 'pop, pop, pop' by
which gas engines have been known all over the world."

As they looked over the engine, an expert in gasoline motors
explained all the parts of the "Silent Knight" and showed the
scientist and his boy friend just how the machine worked.

He said that the only big difference between the Knight motor and
other standard makes of engines is that the Knight substitutes for
the intake and exhaust valves an entirely new device composed of two
cylinders, one within the other, sliding upon each other so as to
regulate the flow of gas and the exhaust of fumes.

Early in his career as an inventor, while living in his home city of
Chicago, Knight decided that gasoline engines had entirely too many
parts--that they were too complicated--and he set about trying to
simplify them. For one thing, he made a careful study of valves, and
collected a specimen of every kind known to mechanics. The sliding
locomotive valve seemed to him to hold the greatest possibilities for
his work, and he began a series of experiments with sliding valves
until he finally brought out his first engine in 1902.

Strange as it may seem, Knight's work was not recognized in his own
country until after he had gone to Europe, where his engine was
taken up by some of the biggest automobile manufacturers of England,
France, Germany, Belgium, and Italy. After that it was taken up in
the United States, and only now is coming to be generally known. The
inventor now lives in England, where he was first successful, and he
is still at work on improvements of his engine.

The motor expert went on to explain that the advantage of the Knight
motor lay in the fact that the two sleeves or cylinders, which go
to make up the combustion chamber or engine cylinder, sliding up
and down upon one another, give a silent, vibrationless movement,
as against the noisy action of the old style poppet or spring valve
motors.

"But," interrupted the boy, "there are lots of other engines that run
without making a noise nowadays."

"That is true," the man answered, "but most of them run quietly only
when at low speed, or stationary. When they begin to hit the high
places the noise of the poppet valves is very noticeable. A few years
ago, when most engine builders were satisfied to make motors that
would run, regardless of noise, they paid no attention to some of the
finer mechanical problems, but since they have become more skilful,
they are cutting down on the noise. But, as I say, the explosions
are plainly heard when these engines are running at high speed. With
the 'Silent Knight' the only noise is that of the fan and magneto,
whether at low speed or the very fastest the motor can run. There can
be no noise, for there is nothing for the sleeves to strike against."

The expert then went on to explain the motor in detail. The
combustion chambers of the four or six-cylinder "Silent Knight," he
explained, are made up of two concentric cylinders or sleeves, or, in
other words, one cylinder within another. There is only the smallest
fraction of an inch between them, and as they are well oiled by an
automatic lubricating device they slide up and down upon each other
with perfect ease. Of course the sleeves, which are made of Swedish
iron, a very fine material for cylinder construction, are machined
down inside and out so that they are perfectly smooth to run upon
each other.

The two sleeves which go to make up one cylinder work up and down
upon each other by means of a small connecting rod affixed to the
bottom of each sleeve connected to an eccentric rod, which is driven
by a noiseless chain from the engine shaft.

The most important features are the slots cut in each side, and close
to the upper end of each sleeve, so that, as the sleeves move upon
one another the slot in the right-hand side of the inner one will
pass the slot of the right-hand side of the outer sleeve, and also
the same with the left-hand side.

Then when the left-hand slots of the outer sleeve open upon, or come
into register with the left-hand slots of the inner sleeve, a passage
into the cylinder is opened for the new gas to enter. When a charge
of gas has been drawn into the cylinder, one sleeve rises while the
other falls, so that the openings are separated and the passage is
tightly closed. The compression stroke then begins with the piston
rising to the top. At this juncture the igniting spark explodes
the compressed gas and the downward or power stroke takes place.
During the upward compression stroke and the downward impulse stroke
the slots have been closed, allowing no opportunity for the gas to
escape. When the explosion has taken place and the piston has been
driven to the bottom of its stroke, the right-hand openings in the
inner sleeve and those of the outer sleeve come together, providing a
passage for the exhausted gases to escape with the fourth or exhaust
stroke. Thus it is plain that the motor is of the four-cycle type and
it should not be confounded with two-cycle motors.

As the expert explained the motion he showed how it was carried out
on an engine from which the casing had been partly removed. The
careful mechanical adjustment of the eccentric shaft, which operated
the connecting rods that pull the sleeves of the cylinder up and
down so that the openings for the entrance of the fresh gas and the
expulsion of the exploded fumes come together at just the proper
second, was what took the boy's eye.

In connection with this the scientist handed the boy a magazine
to read. It was a copy of the _Motor Age_ in which an expert said
editorially:

   "Those who pin their faith to the slide-valve motor do so for
   many reasons, chief of which is that with this motor there is a
   definite opening and closing of the intake and exhaust parts, no
   matter at what motor speeds the car be operating. Two years ago
   one of the leading American engineers experimented with poppet
   valves and discovered that frequently at the high speeds the
   exhaust valves did not shut, there not being sufficient time
   owing to the inability of the valve spring to close the valve in
   the interval before a cam returned to open it again. With such a
   condition it is certain that the most powerful mixture was not
   obtained. With the sleeve valve such failure of operation cannot
   be, because no matter how fast the motor is operating there is a
   definite opening and closing for both intake and exhaust valve.

   "It is a well-known fact that with poppet valves the tension
   of the springs on the exhaust side varies after five or six
   weeks' use, and consequently the accuracy of opening and
   closing is interfered with. Carbon gets on the valve seatings
   and prevents proper closing of the valve, with the result that
   the compression is interfered with and the face of the valve
   injured. These troubles are, as far as can be learned, obviated
   in the sleeve valve."

The friends of the Knight motor claim that it is simpler than the
ordinary types of engines, having about one third less parts, that it
is economic, powerful, and, as previously pointed out, runs silently.
Beside these advantages, there are claimed for it many technical
virtues that we need not enter into here.

The lubricating system of the Knight motors is another interesting
point, as it serves to illustrate one more way in which the gasoline
engine has been improved upon of late years. The manner of oiling
used is known as the "movable dam" system. Located transversely
beneath the six connecting rods are six oil troughs hinged on a shaft
connected with the throttle. With the opening and closing of the
throttle these troughs are automatically raised and lowered. When the
throttle is opened, which raises the troughs, the points on the ends
of the connecting rods dip deep into the oil and create a splashing
of oil on the lower ends of the sliding sleeves. These sleeves are
grooved circularly on their outer surfaces in order to distribute the
oil evenly, while toward the lower ends holes are drilled to allow
for the passage of oil.

When the motor is throttled down, which lowers the troughs, the
points barely dip into the oil and a corresponding less amount of oil
is splashed. An oil pump keeps the troughs constantly overflowing.

The motor is cooled by a complete system of water jackets, and it is
fitted with a double ignition system, each independent of the other.

Of course in the adoption of the sliding sleeve type, mushroom
valves, cams, cam rollers, cam shafts, valve springs, and train of
front engine gears all are eliminated, the sliding parts fulfilling
their various functions.

Before Mr. Knight ever achieved success with his motor it was
subjected to some of the severest tests on record in the whole
automobile industry. In France, Germany, and England, it was only
accepted by the leading manufacturers after being tried out for
periods extending over several months of the hardest kind of usage.
Now, that it has proven itself a practical success, automobile men
declare that the sliding valve principle, never before applied to
gas engines until Knight began work, will undoubtedly have a lasting
effect on the whole industry.

The compact little two-cycle motors represent another big fundamental
development in the field of gas engines. There are many different
makes of two-cycle motors, of course, and all have their various
merits. They are used in practically all the work for which gas
engines are employed, including automobiles, motor boats, and
aeroplanes. It will not be necessary to describe these engines
further than to say that the name describes the fundamental
difference between them and the four-cycle motors. Instead of the
piston making four strokes for every explosion--that is, an, upward
stroke to clean out the burnt vapours, a downward stroke to suck
in the fresh gas, an upward stroke to compress it, and finally the
downward explosion or power stroke, all this work is done in two
strokes.

For the general development of the gasoline engine, it is only
necessary for a boy to look about him. Everywhere motors built on
the same ideas as laid down in earlier inventions, but improved in
every detail, are in use. Not only do we see them on fine pleasure
automobiles, motor boats, and aeroplanes, but on our biggest trucks,
fire engines, and in business establishments where light machinery is
to be run.



CHAPTER XI

THE WIRELESS TELEGRAPH UP TO THE MINUTE

   THE SCIENTIST TALKS OF AMATEUR WIRELESS OPERATORS--THE GREAT
   DEVELOPMENT OF WIRELESS THAT HAS ENABLED IT TO SAVE ABOUT THREE
   THOUSAND LIVES--LONG DISTANCE WORK OF THE MODERN INSTRUMENTS


While the inspiring stories of Jack Binns of the steamship
_Republic_, and of J. G. Phillips and Harold S. Bride of the
ill-fated _Titanic_ are fresh in our minds, it is not necessary
to say that within the last few years the wireless telegraph has
established itself as indispensable to the safe navigation of the
seas. The story of its development is a marvellous one when we
think that it was only in December of 1901 that Marconi received
the first signal ever transmitted across the Atlantic Ocean without
wires. Now, as every boy knows, all the big steamships are equipped
with wireless, all the governments of the world operate their own
stations to communicate with their warships, at sea, and thousands
upon thousands of boy amateurs operate their own little plants with
complete success.

More wonderful still is the story when we think that by the use of
this invention a total of about three thousand persons have been
saved from death in shipwrecks. Nowhere in the pages of all history
are there any more thrilling stories of heroism and devotion to duty
than those of the men who, in the face of death themselves, have
stuck by their keys sending out over the waves the "C. Q. D." and the
"S. O. S." signals, which as every boy knows are the wireless calls
for help.

The scientist and his boy friend never tired of talking of these
things, for the young man was one of the many amateurs who had
mastered the art, so that many a night as he sat at his receiver he
caught the messages of steamships far out on the broad Atlantic, and
heard the Navy Yard station transmitting orders to Uncle Sam's ships
at sea.

One day shortly after the _Titanic_ disaster the boy said to his
friend: "I saw by the paper to-day that they are talking of passing a
law to prevent the amateur wireless operators from working. I don't
think they ought to do that. I'm sure most amateurs never interfere
with any signals, as was said they did in connection with the
messages to and from ships that went to the rescue of the _Titanic_."

"So long as the amateurs do not have powerful sending apparatus,"
answered the scientist, "I don't think they will make any serious
trouble, for it makes no confusion to have them 'listening in'
on the passing radiographs. Of course with a powerful sender a
mischievous person could work irreparable damage by sending fake
messages of one kind or another. In fact there have been several
instances of messages that were thought to be fakes, but I am sure no
boy with the intelligence to rig up a wireless outfit, would be so
lacking in understanding of his responsibilities as to try to confuse
traffic.

"But it would be a shame to stop the amateurs altogether," he
continued, "for, no matter what the companies may say, the wireless
telegraph is still in an experimental stage, and we must look to the
bright boys who are studying it now, for its greatest development.
The marvellous strides in improving the apparatus, and solving the
mysteries of electro-magnetic currents, that have been made in the
last dozen years, should be eclipsed in the next decade, if young
men with some practical experience and a desire to get at the real
scientific basis of the art, work at it."

"What are some of the main improvements of the last few years?" asked
the boy.

For answer, the scientist and the boy made a journey down to the
steamship docks, and visited the wireless cabins of several of the
big transatlantic liners. They also went to the Brooklyn Navy Yard,
where there is a wireless school, that turns out Navy operators after
a thorough course in all the various branches of the art. While on
vacations to the seashore, the youth had visited some of the big
high-power stations that send and receive messages to and from the
ships at sea.

In talking to the operators and electricians the boy learned much
about the wide extent to which wireless is used nowadays. The law
passed by Congress in the United States in 1911, making it necessary
for every passenger steamer sailing from American ports with fifty
or more passengers, to carry a wireless outfit capable of working
at least 100 miles, in charge of a licensed operator, capable of
transmitting 20 or more words a minute, did a great deal to increase
the use of wireless. Also, not only the actions of one government but
the concerted action of all the civilized nations represented at the
various international wireless conferences have brought it to the
official notice of the whole world.

Thus it has become a commercial reality on the sea, and the Great
Lakes, and also it has become a big factor in war. All of the
nations, besides having their warships equipped with wireless, now
have wireless squads in the army, and have small compact apparatus
that can be transported in small wagons, or even on horses' backs.
These portable army wireless outfits are very valuable for the
communication between detachments of an army, particularly in
places where there are few disturbing elements to intercept the
electro-magnetic waves.

In the recent campaign in Tripoli, in the war between Italy and
Turkey, the wireless was extensively used by the Italian army in the
field, and it was found that the messages radiated over the desert
just about as well as over the sea. Of course as will be seen later,
it is not meant here to convey the idea that wireless cannot be sent
over the land, for the electro-magnetic waves travel through the
ether in every direction, and as the ether fills the whole universe,
mountains, buildings, or water just as well as the air, the waves
are thought to go through obstacles as well as over water. The
difficulty in sending over land, is that there are various electrical
disturbances that intercept and confuse the wireless waves. In other
words, wireless works through mere physical obstructions without
any difficulty, just so long as certain little known electrical
disturbances do not interfere. Just think of the thousands and
thousands of wireless messages that are passing through the ether
every hour of the day and night. And yet the scientists really know
very little about the laws that govern them!

One of the instances of the strange antics of wireless was told
to the boy by an operator who had been in charge of the wireless
outfit on a Hudson River boat. He said that he and the operators on
the other boats were able to communicate with a station on shore
until they had passed the Poughkeepsie bridge, and the great steel
and stone structure stretched between the boat and the station.
Immediately communication stopped short and all efforts failed to
get any response. A series of experiments proved that the obstruction
was at the bridge, but whether it was some electrical property in
the bridge itself, or in the hills on each side of the bridge, they
have never been able to find out, and the land station was finally
discontinued.

This is just an instance of what the scientists do _not_ know about
wireless, but it shows the many boy amateurs that there are still
worlds for them to conquer in scientific research.

The central principle upon which the wireless telegraph works now is
the same as it was when Marconi, through his marvellous invention,
first received a signal from the other side of the Atlantic Ocean,
but the inventors have learned much more about the details of the
theory and it is in the improvement of devices for applying these
laws of electricity that the development has been, rather than in the
discovery of new theories. Nikola Tesla's invention for the wireless
transmission of power by earth waves is a revolutionary departure
from the usual wireless practice, but as we saw in the earlier
chapter on this subject the Tesla invention has not yet been put in
practical operation.

Though Guglielmo Marconi did not discover the laws of electricity
upon which his invention is based, to him belongs all the credit
for making use of the discoveries of the scientists of his day, and
working out from them a practical system of wireless communication.

As many boys know, the wireless telegraph is possible through the
radiation of electric waves. For instance, if a stone is thrown into
a pool waves are started out in every direction from the point where
the water is disturbed. The water does not move except up and down,
and yet the waves pass on until they reach the side of the pool, or
their force is expended.

The scientists before Marconi found out that when an electric spark
was made to jump between two magnetic poles it started electric waves
in every direction, much like the stone thrown into the pool, except
at a speed that is reckoned at 186,000 miles per second.

Prof. Amos Dolbear, of Tufts College, Massachusetts, first made
use of these waves in 1880, and a few years later Doctor Hertz,
conducting experiments along the same lines, discovered them. Since
that time these waves have been called Hertzian waves.

For many years scientists had understood that electrical waves or
vibrations travelled through the ether in a copper wire, and that
gave us telegraphy by wires, but it was a new thing to think of the
waves travelling in every direction through space without wires.
These early investigators found out that they could detect these
waves by a device called a Hertzian loop, which was simply a copper
wire bent into a hoop with the two ends close together but not
touching. A spark would appear between the ends of the wire when the
electric waves were sent out.

Marconi began his work where these scientists left off, as a very
young man on his father's farm in Italy, but soon went to England, of
which country his mother was a native, and placed the results of his
experiments before the government authorities. Continuing his labors
he soon had his wireless apparatus worked out in the form in which it
first became known to the world.

It consisted of a transmitter, receiving machine or detector, and a
set of antennæ or aerial wires from which the electrical waves were
sent. For his transmitter, he created a spark between the two brass
knobs on the ends of two thick brass wires by closing and opening an
electrical circuit with a key, very much like, but somewhat larger
than the regulation telegraph key. The space between the knobs was
called the spark gap. For a dash he would hold down his key and
make a large spark, and for a dot he would release his key quickly
and make only a short one. Thus, he could send the regular Morse or
Continental telegraphic codes of dots and dashes. These impulses were
transmitted by wires to the aerial wires, or antennæ. The impulses
left the antennæ as electro-magnetic waves, and went forth in all
directions, only to be caught on the antennæ of another station
aboard a ship or on land.

Here is where the receiver did its work, and the problem was a far
more difficult one than the working out of the transmitter, for the
waves as received were too weak in themselves to register a dot
or a dash. In Marconi's first instruments he used a device called
the "coherer." This was a glass tube about as big around as a lead
pencil, and perhaps two inches long. It was plugged at each end with
silver, and the narrow space between the plugs was filled with finely
powdered fragments of nickel and silver, which possess the strange
property of being alternately very good and very bad electrical
conductors. The waves in Marconi's first experiments were received
on a suspended kite wire, exactly similar to the wire used in the
transmitter, but they were so weak that they could not of themselves
operate an ordinary telegraph instrument. They possessed strength
enough, however, to draw the little particles of silver and nickel
in the coherer together in a continuous metal path. In other words,
they made these particles "cohere," and the moment they cohered they
became a good conductor for electricity, and a current from a battery
near at hand rushed through the connection, operated the Morse
instrument, and caused it to print a dot or a dash; then a little
tapper, actuated by the same current, struck against the coherer, the
particles of metal were broken apart, becoming a poor conductor, and
cutting off the current from the home battery.

In Marconi's early experiments there was little or no attempt at
tuning the instruments for waves of certain lengths, but this art has
been developed to a high state in modern wireless telegraphy and we
shall see how the operator tunes his instruments to talk to any one
special station.

The distinguishing feature of the modern wireless transmitter, now
familiar to every boy who has ever taken a trip aboard a large ship,
or attended an electrical show, as it was in the old days, is the
"crack, crack, cr-r-r-ack, crack" of the spark as it flickers between
the brass knobs of the instrument, as the operator pounds away at
his key. In some of the great high-power land stations, where long
distance work is done the crash of the spark is like that of thunder,
the flame is as big around as a man's wrist and of such intensity
that it could not be looked at with unshaded eyes. On ships where the
crash is too loud it has become necessary to cover the spark gap with
a wooden muffler so as to deaden the noise.

While the simple spark gap of the early Marconi instruments was
enough to send out the Hertzian waves, the modern transmitter is a
marvel of electrical construction utilizing as it does the latest
discoveries in electrical apparatus.

The most noticeable difference in the sending apparatus is in the
arrangement of the two wires between which the spark flies. In the
early instruments the wires were set in a horizontal line, and
connected to an induction coil, but in the later ones the oscillator
was turned up lengthwise with the spark gap between the vertical
wings.

The different position of the spark gap is a change only in form, and
not in principle. In the Marconi apparatus used nowadays the current
comes from a dynamo of more than 110 volts, direct current. The two
terminals of the circuit are connected with an induction coil, and
from there to the two ends of the wires, making the terminals of the
spark gap. The upper wire runs from the spark gap to the aerial,
and the lower runs through a battery of Leyden jars, through a high
tension transformer (as does the other side of the circuit), and
thence to the ground. Aboard ship the ground connection is simply
made by attaching a wire to the hull of the ship, which is in
connection with the water, the best possible earth connection.

  [Illustration: MARCONI TRANSMITTER LAYOUT

    A--Key.
    B--Induction coil.
    C--Spark gap.
    D--Dynamo.
    E--Rheostat.
    F--Interrupter magnet.
    G--Aerial.
    H--High tension transformer.
    I--Ground wire.
    K--Battery of Leyden jars.]

  There are, of course, a great many different kinds of
  transmitters, but they are all worked out on the same general
  principle--a spark gap which creates electrical oscillations that
  are sent into the ether from the aerials.

  In some modern stations an alternating current is used at more
  than 100 volts and is stepped up through a transformer to about
  30,000 volts. This high power current then charges a condenser
  consisting of a battery of Leyden jars.

  When the operator presses his key he establishes a connection,
  which immediately sets up electrical waves oscillating at a
  rate of anywhere from 100,000 to 2,500,000 per second. These
  oscillations are carried to the antennæ where they pass into the
  ether and spread in all directions to be caught on the aerials of
  all stations within range.

  One of the improvements in wireless transmission which makes
  long distance work possible aboard ships is the use of what the
  engineers call "coupled circuits." The arrangement consists
  in connecting the aerial to an induction coil, and connecting
  the latter with a ground wire. Another coil is placed close to
  this and is connected with the spark gap, and a condenser. The
  period of oscillation of the antennæ circuit, and of the spark
  gap circuit are timed to be exactly the same. The two circuits
  are then called "coupled circuits," for while they are coupled
  together by induction only, the oscillation or spark gap circuit
  increases its capacity, and at the same time has a small spark
  gap.

  With these new devices for increasing the power of the
  oscillations, or in other words throwing a bigger stone into the
  pond, the electrical waves are sent out with far greater force,
  just as the water waves are sent farther in the pond, and will
  reach stations at a greater distance.

  "Crash, bang," goes the oscillator, and in less time than it
  takes to think it the oscillations have reached the antennæ of
  ships hundreds or thousands of miles away, or even those of
  another land station on the other side of the Atlantic Ocean.

  The next thing is to understand the apparatus used for receiving
  the faint electric waves transmitted through the ether, for the
  modern instruments are far different from the old style "coherer"
  explained before. As with the spark gaps, there are many
  different styles of receiving devices, all known by the general
  name of "detectors," as they detect the faint electro-magnetic
  waves radiating through the ether.

  Some of the latest Marconi experiments show a return to the
  "coherer" idea, very greatly improved upon, but the full details
  of the device have not been made public.

  [Illustration:

    Courtesy of the New York Edison Co.

  THE NAVY WIRELESS SCHOOL

  At top is the class in sending, while below is shown the class
  learning to receive messages.]

  [Illustration: AN AMATEUR WIRELESS OUTFIT

  Hundreds of boys are receiving and sending wireless messages with
  far less efficient apparatus than that shown here.]

  [Illustration: MARCONI DETECTOR LAYOUT

    A--Aerial.
    B--Condenser.
    C--Glass tube oscillator transformer.
    D--D´--Rollers.
    E--E´--Iron wire passing through oscillator transformer.
    F--F´--Magnets.
    G--G´--Ground wires.
    H--Telephone receiver.]

One of the detecting devices used by the Marconi system, after
the old-style "coherer" was done away with, was very simple
indeed in comparison to the cohering and tapping machines. It
was made up of a small glass tube wound with copper wire. One
end of this made the ground connection, and the other end led
to the aerial, and also to an earth connection through a tuning
inductance coil. Then another coil was wound around the first
one on the glass tube and connected with the head telephone
receivers which have taken the place of the Morse dot and dash
printing instrument in all the modern wireless instruments. Two
magnets were placed just above the glass tube, and a flexible
iron wire was made to move through it by means of a pair of
rollers a little way from each end. When the electro-magnetic
waves reached the aerial and made oscillations in the first coil
about the glass tube, the magnetic intensity of the iron wire
band was disturbed and the glass tube became an oscillation
transformer, setting up currents in the coil leading to the
telephone receivers. The impulses were manifested by ticks, just
the length of the dots and dashes being sent out by the operator
perhaps thousands of miles away.

Another form of detector is the "electrolytic" which consists of
a very fine platinum wire about one ten-thousandth of an inch in
diameter, which dips into a platinum cup filled with nitric acid.
When the invisible electro-magnetic waves impinge upon the wires
of the receiving station, and cause electrical surges to take
place in those wires, they in turn affect the detector, giving an
exact reproduction of the note of the transmitting spark at the
distant station.

This device has since been replaced by one of another type,
equally sensitive and much better suited for general work on
account of its greater stability and freedom from atmospheric
disturbances. This detector consists simply of a crystal of
carborundum supported between two brass points. When connected to
the antennæ it is affected by the oscillations caused by distant
transmitting stations as previously stated. These wireless
signals are reproduced in telephone receivers.

Another frequently used detector known as the Audion is composed
of a small incandescent lamp with filaments of carbon, tantalum,
or preferably tungsten, and one or more sheets or wings of
platinum secured near the filaments. The lamp is lighted by a
set of home batteries, and is connected with a ground wire, the
aerial, and the telephone receivers. The tungsten filament and
the platinum wing act as two electrodes, and the faint electric
oscillations received on the antennæ and transmitted to the
platinum plate are supposed to affect the discharge of negatively
electrified particles, or ions, between the two electrodes.
This affects the flow of the battery current, and consequently
registers the oscillations in the telephone receivers.

By diligent study of the subject the wireless experts also
have learned that the arrangement of the aerials is of great
importance, because much depends upon the send-off received by
the electrical oscillations. In Marconi's early experiments he
used a single wire attached to a kite, then changed to a single
wire stretched from the top of a high mast. Later, the system of
stretching the wires horizontally between two masts, as we see
them so often aboard passenger steamships, and at land stations,
came into general use. The old idea that the height of the aerial
wires had something to do with the efficiency of the apparatus
has passed, for science showed that the electro-magnetic waves
travelled in all directions irrespective of land, water,
mountains, or buildings. Whether, in sending messages across the
ocean, they actually pass through the globe, or follow the curve
of the surface, is more than the most careful wireless students
have been able to tell.

Another of the big improvements in wireless is in the tuning of
the instruments to certain wave lengths or rates of vibrations,
and in controlling the wave lengths by the sender. Science has
established that these waves usually vary from a few feet up
to 12,000 feet or more. The ordinary wave lengths for ships
is between 1,000 feet and 1,800 feet, but on the biggest land
stations and the transatlantic liners the full 12,000 feet is
used. Even greater lengths of waves are used by the big Marconi
stations transmitting messages between Clifden, on the west coast
of Ireland, and Glace Bay, Nova Scotia. The reason for this is
that with the same power messages can be sent greater distances
with long wave lengths than with shorter ones.

The wave length is controlled by an apparatus called the "helix,"
which may be seen in the picture of the wireless outfit. It looks
like a drum wound with a spiral of copper tubing, and although
it looks simple it presents some of the greatest problems in
connection with wireless.

On the receiving end is the instrument called the tuner, by which
the operator can adjust his detector to the wave lengths being
sent out by the station with which he wishes to talk. There are
various kinds of "tuners," all more or less complicated. The
device corresponds to the telephone exchange or the telegraph
switch-board. Of course a good receiving apparatus can be tuned
so that the operator can listen to any messages going through
the ether, within range, but all messages that are intended to
be secret are sent in code, just as all wire and cable messages
that are secret are sent in code.

In line with the advent of wireless telegraphy it is fitting that
we should have the wireless telephone. While this instrument is
still in the experimental stage, some very promising results have
been obtained. There are several experimental wireless telephone
stations in New York City, but the best results are obtained when
some one keeps up a steady conversation, so it is far easier to
connect the reproducer of a phonograph to the transmitter of the
wireless telephone. It is surprising how distinctly this music or
speech is received. In fact the ship operators nearing New York
are often entertained by strains of music from these wireless
telephones. The wireless telephones employ what are known as
undamped oscillations created by electric arcs, and it is very
easy to "tune out" such vibrations for musical effects.

Just as we have the motion-picture "newspaper," we have the
wireless newspaper published aboard the big transatlantic liners
every day. The news is sent out from certain land stations at
certain times in the day and night, and every ship within range
copies it, and publishes it just as our regular daily papers are
published. Of course, the paper is small, but it usually contains
most of the important news of the day, the big sporting items,
such as baseball scores, and the stock quotations.

In the United States the great station at Wellfleet, Cape Cod,
Mass., sends out the press matter each night from dispatches
prepared in the main offices of the big American press
associations. Ships as far as 1,600 miles distant frequently
receive this news matter, and by the time the ocean-going editor
is ready to get out his next day's edition he is in touch with
the wireless press station on the other side, and is receiving
the world's news from the English coast.

As our young friend found out when he was gathering up all the
information he could about aeroplanes, some success has been made
in the equipment of the fliers with wireless. The project offers
some serious difficulties, however, as on an aeroplane there is
no place for long aerials. Experiments have been tried with long
trailing wires, but these are dangerous to the aeroplane, and to
use the wires of the machine for antennæ endangers the operator
to electric shocks. One scheme tried by several aviators in the
United States with some success has been the stringing of aerials
in the rear framework.

The problem of equipping balloons and airships with wireless is
much simpler because it allows of long trailing wires to act as
the antennæ. Most boys will remember the success of the wireless
apparatus that was set up on the _America_ at the time Walter
Wellman made his famous attempt to cross the Atlantic in his
airship.

That wireless will take its place as one of the great forces in
civilization is the idea of Guglielmo Marconi, the inventor of
the wireless telegraph, expressed when he was in New York in the
spring of 1912.

"I believe," he said, "that in the near future a wireless message
will be sent from New York completely round the globe with no
relaying, and will be received by an instrument located in the
same office as the transmitter, in perhaps even less time than
Shakespeare's forty minutes.

"Most messages across the Atlantic will probably go by wireless
at a comparatively early date. In time of war wireless
connections will be invaluable. The enemy can cut cables and
telegraph wires; but it is difficult seriously to damage the
wireless service. The British Empire has realized this, and is
already equipping many of its outposts with wireless stations."



CHAPTER XII

MORE MARVELS OF SCIENCE

   COLOUR PHOTOGRAPHY, THE TUNGSTEN ELECTRIC LAMP, THE PULMOTOR,
   AND OTHER NEW INVENTIONS INVESTIGATED BY OUR BOY FRIEND


Before we leave our good friend the scientist and his young
companion, let us go over a few more of the things about which
they talked. To take up all of them would be to prolong this book
indefinitely, for the boy's mind was ever unfolding to the new things
of the world and with each subject mastered, or at least partially
understood, he was anxious to go on to the next. Not that he did not
have his special hobbies upon which he spent most of his time, for he
did, but that did not prevent his inquiring young mind from reaching
out for new and more wonderful things once he had come to realize the
world of marvels in which we live.

One of this youth's favourite pastimes was photography, and as an
amateur his work had attracted considerable attention from his
friends. One day in the summer, when all the trees, shrubs, and
flowers were at the height of their beauty, he came into the
laboratory where his scientific friend was working over an experiment.

"I have heard of a process of colour photography," he said, "and I
wonder if I couldn't make use of it to get some good pictures out in
the country, showing just exactly how it is."

"Certainly," replied his friend. "There are a number of systems of
colour photography now--all invented within the last few years.
None of them is perfect though, and you would have the added fun of
carrying on some experiments that might bring to light some valuable
knowledge.

"While it is possible to make coloured photographic prints now,
by means of a specially treated paper, colour photography is best
known as a means of making beautiful transparent glass plates and
lantern slides. When held up to the light, the transparencies give
an accurate picture of the scene in natural colours. The paper I
mention can be bought at the photographic houses, but the inventors
do not claim yet that their process is so perfect as to give exact
reproductions of all the shades of colours unless they are well
defined in the positive plates. The prints are made from the positive
transparencies in just the same way that photographic prints are made
from black and white photographic plates."

"Let's try some colour photographs," promptly said the boy. "Will you
go out into the country with me some Saturday and help me?"

"I certainly will be glad to go with you, but you are a better
photographer than I am, for you see, about the only kind of
photography I do now is with a microscope, such as you have looked
through here many times. Your own regular camera and tripod will be
all you will need, for I will buy the colour plates upon which the
pictures are to be taken."

They made their trip to the country on the first pleasant Saturday,
and while they were out the scientist explained many points about the
system.

"Years ago," he said, "even before that wonderful Frenchman,
Daguerre, invented light photography, scientists were trying to
discover some means of mechanically registering on paper, the
beautiful things they saw in nature, in their natural colours, as
well as in their natural form in black and white. All through the
years of the development of photography with light and shadow,
scientists never relaxed their search for some way of photographing
colours. Although many of them hit upon the colour screen idea by
which it finally was accomplished, there remained years and years
of patient experiment. Prof. James Clark Maxwell, Ducos du Hauron,
Doctor Konig, Sanger Shepherd, and, in later years, Frederick Eugene
Ives, of Philadelphia, all worked on the idea.

"In 1907, however, Antoine Lumiére, of the famous French photographic
house that bears his name, announced a system of colour photography
which has grown in popularity ever since. The system, which is known
as the autochrome, was the result of many years patient study and
research with his sons who are associated in business with him."

The scientist then went on to explain that in attacking the problem
the investigators first had to learn all they could about colours,
and how they are reflected by light rays. As we have seen in the
colour process for motion pictures there are really only three
fundamental or primary colours, and all other shades and tints are
made up from combinations of these. The three are blue-violet, green,
and orange-red, and a screen of these forms the foundation of all the
colour plates now used.

In the autochrome process the lowly potato, which we generally
think of merely as a common article of our food, forms the first
factor. The starch of the potato is ground down and sifted so that
the grains are the same size--not more than 0.0004 to 0.0005 of an
inch in diameter. These grains then are divided into three equal
portions, and each portion is dyed, respectively, blue-violet, green,
and orange-red. The three little piles of starch grains are then
mixed together in suitable amounts and dusted on to a plate, which
has previously been coated with a substance to make them stick. The
difficulty in dusting on the starch grains is great, for they must
cover the whole plate equally and yet not make any piles of starch
at any one point, for to have several grains on top of one another
would spoil the effect. The extreme delicacy of this operation will
be appreciated when it is realized that there are over five million
grains to the square inch. When the starch is all properly placed it
makes the colour screen, though in appearance the plate is a dark
gray.

The plate is next put through a rolling process so that all the
grains are flattened out to form a mosaic covering over the whole
surface. In spite of all the manufacturers can do there will still be
some microscopic spaces between the particles, and these are filled
up with a fine powder of carbon to prevent the passage of light.

The screen is then coated with a very thin layer of varnish and upon
this is laid a thin and extremely sensitive photographic emulsion.

"And so that is the way these autochrome plates we have here were
made," concluded the scientist. "Now our troubles begin, for we must
be careful to give them a fair trial with the proper kind of an
exposure and the proper kind of development."

As the plates are extremely sensitive to all kinds of light the
scientist cautioned the boy against loading the camera carelessly. It
is better, he said, to load in a dark room.

In putting the plates in the camera the plates are reversed and
instead of placing the sensitized side toward the lens, the uncoated
glass is put in front and the photograph is taken through the glass.
Thus, the image first passes through the glass, next, through the
grains of coloured starch, and, lastly, is recorded on the sensitive
photographic emulsion.

Before loading the camera, however, the scientist fitted a yellow
colour screen over the lens, explaining that this was necessary to
absorb some of the overactive blue-violet light rays, to which the
emulsion is extremely sensitive.

In exposing the plate what happens is this: Suppose a green field
is to be photographed. The green rays of light, reflected from
the field, pass through the lens, and through the glass support
of the plate. But when they reach the coloured starch, the green
rays pass through the green particles of starch, but not through
the violet-blue particles, or the orange-red particles, for the
grains of other colours absorb the green rays and hold them. Thus,
development would show that the green light rays passing through the
green starch particles caused the emulsion to darken under the green
particles in just the proportion in which the green light reached
them, and to record the image they carried. As the light would not
pass through the other coloured particles they would not record any
image. Thus a negative is produced, as we have seen, not the colour
we see in life but the complement. By treating the plate with a
solvent of silver the tiny black specks that were brought out behind
each green particle are removed and each starch grain is allowed to
transmit exactly the colour we see in life. In other words, we have
a positive.

This is just as true of all the shades and hues as it is of the three
fundamental colours, for the various rays of light will penetrate the
starch in just the proportion of the hues they represent in the scene
before our eyes. While the silver solvent will remove the dark images
built up by the penetration of green light, it will leave behind the
particles of red-orange, and blue-violet, backed up by the creamy
silver bromide of the emulsion. If above the green field we had a
blue sky, the blue-violet particles would let the blue-violet rays
penetrate them, and record the image of the sky.

After the negative has been treated and made a positive, a second
development reduces the silver bromide to opaque metallic silver,
preventing any light from passing through the grains through which a
part of the image did not pass. This second bath also brightens the
colours, while the hypo bath removes the unaltered silver bromide
ensuring permanency to the image.

"Of course in taking these colour photographs," went on the
scientist, "we must take into consideration a great many things, to
which the manufacturers will call your attention in their booklets.
The exposure is the most important part of all, for these plates are
necessarily slow and must be exposed for a much longer time than the
ordinary rapid plates. For instance, this field, with this bright
summer sunlight, will require a full second with this lens at U. S.
4."

The scientist then went on to give the boy directions for developing
his colour plates, as follows:

The whole process of development consists of three operations and but
two solutions are required, one of them being kept preferably in two
stock solutions. Apothecary weight is used.

STOCK DEVELOPER

    Water                                        30 ounces
    Metoquinone                                   3-1/2 drams
    Sodium sulphite (dry)                         3 ounces
    Ammonia (density 0.923 or 22 degrees B)       1 ounce
    Potassium bromide                             1-1/2 drams

Dissolve the metoquinone first in lukewarm water and then the other
chemicals in the order given.

STOCK REVERSING SOLUTIONS

    A. Water                                     25 ounces
      Potassium permanganate                     50 grains
    B. Water                                     25 ounces
      Sulphuric acid                              4 drams

Errors in exposure are to be corrected by varying the duration
of development and the amount of stock solution added after the
appearance of the image. Use the solutions at a temperature of 60
degrees Fahrenheit, and start development of a 5 × 7 plate in

    Water                         4 ounces
    Metoquinone stock solution    2 drams

Have ready two graduates, one containing 6 drams of the stock
developer, the other 2-1/4 ounces. Begin counting seconds upon
immersion of the plate in the weak developer and watch for the
outlines of the image, not considering the sky. If the time of
appearance is less than 40 seconds, add the smaller quantity of stock
solution; if more, add the greater. The total times of development
are given in the following table. Cover the tray for protection from
light as soon as the solution has been modified properly.

    ==================+==================+=======================
    TIME, IN SECONDS, |   QUANTITY OF    |   TOTAL DURATION OF
      OF APPEARANCE   |   METOQUINONE    | DEVELOPMENT, INCLUDING
        OF IMAGE,     |  STOCK SOLUTION  |   TIME OF APPEARANCE.
      DISREGARDING    |TO BE ADDED AFTER |---------+-------------
        THE SKY.      |  IMAGE APPEARS.  | Minutes.|  Seconds.
    ------------------+------------------+---------+-------------
         12 to 14     |     6 drams      |    1    |    15
         15 "  17     |        "         |    1    |    45
         18 "  21     |        "         |    2    |    15
         22 "  27     |        "         |    3    |    15
         28 "  33     |        "         |    3    |    30
         34 "  39     |        "         |    4    |    30
         --------     |   ------------   |   --    |    ---
         40 to 47     |   2-1/2 ounces   |    3    |
          Over 47     |     "     "      |    4    |
    ------------------+------------------+---------+-------------

As soon as development is finished rinse the plate briefly, immerse
in equal parts of the reversing solutions and carry the tray into
bright daylight. Gradually the image clears and the true colours are
seen by transmitted light. In three or four minutes the action will
be complete. Rinse the plate in running water for thirty or forty
seconds and immerse again, still in daylight, in the developer. In
three or four minutes the white parts of the image will be seen to
have turned entirely black. The plate may now be rinsed for three or
four minutes in running water and set away to dry without fixing.

To avoid frilling in summer, it is well to immerse the plate for two
minutes after reversal in

    Water                     5 ounces
    Chrome alum              25 grains

After a brief rinsing proceed with the second development as usual.

The completed transparency may be protected from scratches to a
certain extent by varnishing the film side, although this is not
necessary. The varnish consists of

    Benzole (crystallizable)      5 ounces
    Gum dammar                    1 ounce

It should be applied cold in the usual way, making sure that the
entire surface is covered, and then setting the plate on edge to dry.

The other colour processes now used with success also are based upon
the colour screen.

The process known as the omnicolore, which was brought out in France,
depends upon a screen consisting of a very fine network of violet
lines in one direction, crossed by red and green lines at right
angles. The usual sensitive emulsion is placed over these. The lines
run more than two hundred to the inch but they can be seen by close
examination of the plate.

In the Thames process which was brought out in England the colour
screen and the sensitive emulsion are on separate plates which must
be bound together during exposure and again placed in register or in
exactly the same relative position after development. This causes
some trouble, but reduces expense as the failures waste the sensitive
plates but not the colour screens. The primary colours instead of
being scattered at random, as in the autochrome system, are arranged
in a pattern to give the proper proportions to each. The red-orange
and green particles are arranged in circles, with the green a little
larger than the red ones, while the blue particles fill the spaces.


THE NEWEST ELECTRIC LIGHTS

One evening our boy friend entered the scientist's laboratory and
found it more brilliantly illuminated than it ever had been before.

"Oh, I know," he said looking up at the ceiling, "those new electric
lights up there are tungsten lamps. It certainly makes a difference
in the looks of this place."

"Lights up all the dingy corners, doesn't it?" answered his friend.
"You remember," he continued, "we talked last week about some of the
new kinds of electric light and that made me think that I might just
as well take advantage of what other scientists have done and install
this newest kind of electric lamps."

From the ceiling were suspended several stationary fixtures with
bright glass reflectors. The lamps the boy saw were somewhat larger
than the usual electric light bulbs, and gave off a beautiful white
light instead of the slightly yellowish illumination that comes
from the ordinary ones. He saw that the filament from which the
illumination came was not arranged in a series of horseshoe curves,
as in the case of the ordinary globes, but that it was strung
between the ends of cross trees, or "spiders," so that there was a
greater total length of filament in the same size bulb than in the
ones used before the invention of the tungsten lamp. It is a sight
familiar enough to most boys in these days of the rapid adoption of
new inventions, but it brought to the boy's mind a question that had
often occurred to him before.

"Who invented tungsten lights?" he asked.

"Well, it would hardly be right to say that any one individual
invented them, for they were really a development of science worked
out by many men, who studied the problem for many years. This caused
a number of very bitter lawsuits over the patents and brought about
the imprisonment of one United States patent office official who was
convicted of falsifying the records at Washington to help one of
the inventors. This inventor was John Allen Heany, and his patents
were rejected finally, the rights of the tungsten filament going to
the General Electric Company. The name 'tungsten' is taken from the
material of which filament, or the little wire which lights up in the
globe, is made."

"What is tungsten?" asked the boy.

"Tungsten is a metal that for a great many years some of our most
prominent chemists and scientific investigators declared could not be
put to the use we see it here," answered the man.

Noticing that the boy leaned forward in his chair, keen on his every
word, the boy's friend continued his description of this strange
metal that has been put to work lighting us in our march along the
road of life.

He explained that tungsten, or wolfram, was discovered in 1781 and
was named from the Swedish words "tung" (heavy) and "sten" (stone).
The mineral is not found in a pure state but rather in wolframite,
which is what the scientists call a tungstate of iron and manganese,
and also in schoolite which is calcium tungstate. Pure tungsten is
bright steel gray, very hard, and very heavy. It is one of the most
brittle of all the metals and for that reason was put to very few
uses before the invention of the tungsten lamp. It was most commonly
used, however, in various steel processes, to harden the metal.

From the time Edison invented the incandescent lamp in 1879, right up
to the present electricians have tried to get a better electric light
filament. A number of persons conceived the idea of making a filament
of tungsten on account of its peculiar characteristics, which seemed
to be just about the ones needed for the ideal electric light globe.

In its fundamental idea the tungsten lamp is not very greatly
different from the early Edison incandescent lamps, but in
the application of the principle there is half a century of
accomplishment packed into a little over a quarter of a century of
years. Edison saw that he must have a filament that would carry the
current of electricity, but yet one which would be of such high
resistance that it would not take up all the current fed to it. He
saw that he had to have a filament that would heat to incandescence
with the electrical current, and yet one that would stand a certain
amount of wear and tear, and which would not be consumed by the heat.
To obtain the latter effect he put his filament in an air-tight
glass globe from which the atmosphere was exhausted, leaving it in
a vacuum. As there was no air, there was no oxygen, and hence there
could be no oxidization, or, in other words, combustion of the
filament.

Edison thought that success lay in a carbon filament, and in these
early days when he was experimenting at his Menlo Park laboratory he
carbonized just about everything he could lay his hands on and tried
heating the result to incandescence in the vacuum globe. Finally,
on October 21, he carbonized a piece of cotton thread and put it
in his vacuum globe in the form of a horseshoe loop. On connecting
it with his electric circuit he was rewarded by seeing a brilliant
incandescent light that lasted without dimming for forty straight
hours.

What a dim, dingy little light it was in comparison to the world
famous lights that Edison now puts forth! And yet in one way it
was the most brilliant light that ever had shone in the world, for
it showed mankind the pathway toward a complete system of electric
lighting by incandescent lamps.

The carbonized cotton thread filament had many drawbacks, and Edison
continued carbonizing various fabrics and fibres, including, it is
said, some of the red hairs out of the beard of one of his loyal
staff! At last he hit upon a filament made of carbonized Japanese
bamboo that was very successful for a number of years, but this was
later superseded by a cellulose mixture mechanically pressed out by
dies.

Meanwhile, several investigators began work with tungsten and a
similar metal called tantalum because of their extremely high
melting points, high resistance, and other technical characteristics
favourable for an incandescent filament.

For years they had no success because the metal was so very brittle
that they could do nothing with it, but finally a filament of
pressed tungsten was brought out. In this type of lamp several
filament loops would be fused or welded together to make one complete
filament. The result was a very fine light, but the little wire was
too fragile to stand hard usage, and owing to the fact that the
various connected loops were not all of exactly the same thickness,
one frequently burned out far ahead of the others and caused early
lamp failure.

The next step, and the one which a great many scientists had declared
impossible, was the manufacture of a tungsten wire through a regular
process of drawing it out through dies to the desired length, and in
the desired thickness. The investigators had declared that in spite
of all they could do, tungsten was too brittle ever to be drawn into
wire. In the latest methods this is accomplished with such perfection
that tungsten wire of 0.0015 of an inch in diameter is produced.

"With the invention of a method for drawing out tungsten wire,"
continued the scientist, "an almost ideal lamp was practically
accomplished. The wire simply was strung on the spiders or cross
pieces, and a filament of almost any length giving almost any desired
candlepower light could be used.

"You see in an incandescent light the higher the melting point of
the filament the greater the quantity of light for the amount of
electricity used. Also tungsten has a low vapour tension, which
prevents discolouration of the globe by the evaporation of the
filament. It also has other advantages which are too technical for us
to go into.

"Of course, tungsten lamps still have the drawback of being rather
delicate. When not in use, and when the filament is cold, it is apt
to break with rough treatment, but when lighted the filament, being
at a white heat, is more durable. This delicacy of the tungsten lamp
is the reason the fixtures for most of them are placed in stationary
positions, rather than on swinging drop cords, as is the case with so
many carbon incandescent lights.

"While the tungsten lamp is far from perfect, it is a great advance
over other forms, and an advance in the right direction, for it gives
a better light with a smaller consumption of electricity than other
types. I think your father will agree with me that anything that will
help ever so little to reduce the high cost of living is a benefit."

"But," answered the boy, "there are other new kinds of electric
lights besides tungsten, aren't there?"

"Oh, of course, but they are hardly as generally used as the tungsten
light. There is the mercury light about which you read in 'The
Second Boys' Book of Inventions,' several new kinds of arc lights,
the Nernst light, the tantalum lamp (which we know is much like the
tungsten lamp with the exception that in the latter each loop of the
wire can be made longer), and the new carbon dioxide gas electric
light, which is a very good imitation of daylight.

"From all our little scientific journeys you have doubtless formed
the idea that light is not the simple thing it seems, and that the
rays of different kinds of light will bear a limitless amount of
study. Now some of the greatest scientists the world ever has known
have spent the best part of their lives trying to produce a light
that would duplicate the beautiful health-giving rays of the sun.
This light we are speaking of comes as near to it as any."

He picked up a long glass test tube and holding it between his
fingers said: "Now if this tube were exhausted of air to a vacuum,
and we had an ingenious little device at each end which would allow
just the right amount--no more, no less--of carbon dioxide gas to
enter it, and also we had electrodes at either end, and connected
them to an alternating current, we would have a rough model of the
light that duplicates daylight.

"In actual practice the vacuum tubes are long, and turn upon
themselves in many lengths. You have seen these lights in many
places, for photographers, lithographers, dye works, textile mills,
and all other places where the true light of day is necessary for the
judgment of colours are adopting them for their night work."

"But the light is a ghastly pale blue," interrupted the boy. "It
doesn't look like daylight to me."

"No, you are thinking of the mercury light, which also is strung
around in tubes. That has a blue-greenish tinge to it, and gives
people's faces a disagreeable greenish tinge, but this carbon dioxide
electric light is white with a salmon pink tinge. Of course it isn't
perfect, but the men who developed it from the work of others who
started on this idea years ago, are constantly at work trying to
improve it."


THE PULMOTOR

"My father read in the paper to-day about a new machine called the
pulmotor, which he said was one of the greatest inventions ever
brought out," said our boy friend one day in the winter of 1911-12.

"Yes, it is a great invention," replied the scientist, "and like so
many other big things it is so simple we wonder how it is no one was
bright enough to think of it before. I suppose most of us are too
busy trying to make money."

"My father said it would be a fine thing for humanity and that it
would save hundreds of lives every year."

"That is true, and the pulmotor is just about the newest invention
of our time, along those lines. When I first heard of it, I wrote to
a friend of mine in Chicago, where it was brought out, and asked him
about it."

"How does it work?" asked the boy, and ever willing to explain the
marvels of science to his young friend, the scientist took a pencil
and a piece of paper to illustrate as he talked.

As every boy knows, oxygen is the property in the air we breathe that
gives us life. Also, every boy knows that physicians and surgeons
use pure oxygen stored in iron tanks to restore respiration to the
lungs of their patients when breathing has almost stopped. Until
the invention of the pulmotor, how ever, this oxygen was simply
introduced into the patient's lungs by placing the tube in his mouth
and turning on the valve.

The pulmotor _makes_ the patient breathe--because it carries on the
function for him artificially. "In Chicago this winter," said the
boy's friend, "there were several cases where the pulmotor brought
back to life people who apparently were dead, from asphyxiation, or
gas poisoning. The machine is most successful where breathing has
stopped through some unnatural interference, and the rest of the
organs are physically intact, but of course it can be used in all
surgical cases just as the ordinary oxygen tank is used.

"One case, and probably the one about which your father was reading,"
continued the boy's friend, "was that of a family of three, father,
mother and little girl, who were asphyxiated, and were apparently
dead. The pulmotor pumped pure oxygen into their lungs until they
began to breathe naturally again."

When the pulmotor is unpacked from its little wooden box, about the
size of a suitcase, it looks like a confusion of rubber tubes and
bags. The oxygen is contained in the tank under high pressure, and
this pressure also furnishes the power to keep up the artificial
breathing.

  [Illustration: THE PULMOTOR

  A--Oxygen tank. B--Reducing valve. C--Inspirator.

  D-E--Inlet and outlet of controlling valve. F--Operating bellows.

  G--Dashpot bellows. H--Face cap.]

The oxygen flows from the tank through a reducing valve, which cuts
down the pressure, and into a controlling valve whence it flows by
a rubber tube to the face cap which fits tightly over the patient's
nose and mouth. The patient's tongue is kept from sliding back into
his throat by a pair of forceps placed for the purpose.

Thus, the oxygen is forced into the lungs by the pressure, but
when it reaches a certain degree, about what it would be in normal
breathing, a bellows connected with the controlling valve is pressed,
and the pressure is turned to suction so that the oxygen that has
been forced into the lungs is brought out, through the outlet,
causing the poisonous gases to be expelled from the lungs. After the
exhalation is complete the controlling valve works again and another
blast of pure oxygen is sent into the lungs, only to be withdrawn at
the proper moment. This is kept up until the patient's breathing is
normal.

We will leave the scientist and his young friend here, for already we
have spent more time in following their journeys and talks than we
set out to do. We have not touched upon every invention of the last
ten years or so, nor every important development, by a long ways, but
we have gone far enough to get a pretty fair idea as to the trend of
modern thought in inventive research.

This is the epoch of electricity, and of the utilization of all the
great forces of Nature that have been right here to our hands since
the world began, but which it has taken all these thousands of years
to discover and analyze. More and more man is coming to see that
Nature's own forces will carry on the big works of the world, if they
are properly led through an understanding of their laws. We have
aviation because man learned how to utilize the fact that air gives
support; we have wireless telegraphy, and we will have the wireless
transmission of power, because man learned that Nature has her own
perfect system of carrying electrical currents when they are properly
delivered to her, without any cumbersome system of wires; we have the
Tesla turbine because its inventor found out that Nature gave steam,
gas, water, and even air, certain properties that are intangible, and
yet stronger far than mere brute force; and so it goes:

Ever a greater familiarity with Nature leads to greater progress, and
a happier, more interesting world.


THE END



Transcriber's note:
    Minor spelling inconsistencies, mainly hyphenated words, have been
    harmonized. Obvious typos have been corrected. A "List of Diagrams"
    section  has been added as an aid for the reader. The tables in
    Chapter II have been split in order to meet width of line
    requirements. The first column has been duplicated in the second
    half of each table.





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