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Title: Scientific American Supplement, No. 810, July 11, 1891
Author: Various
Language: English
As this book started as an ASCII text book there are no pictures available.
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.

*** Start of this Doctrine Publishing Corporation Digital Book "Scientific American Supplement, No. 810, July 11, 1891" ***

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[Illustration]



SCIENTIFIC AMERICAN SUPPLEMENT NO. 810



NEW YORK, JULY 11, 1891

Scientific American Supplement. Vol. XXXII, No. 810.

Scientific American established 1845

Scientific American Supplement, $5 a year.

Scientific American and Supplement, $7 a year.

       *       *       *       *       *



TABLE OF CONTENTS.


I.   BOTANY.--Cocos Pynaerti.--A new dwarf growing palm.--1 illustration.

II.  CHEMISTRY.--The Application of Electrolysis to Quantitative
     Analysis.--By CHARLES A. KOHN, B.Sc., Ph.D.--Applicability of
     these methods to poison determinations.

III. CIVIL ENGINEERING.--The Kioto-Fu Canal in Japan.--A
     Japanese canal connecting the interior of the country with the
     sea.--3 illustrations.

     The Iron Gates of the Danube.--An important engineering work,
     opening a channel in the Danube.--1 illustration.

     The New German Ship Canal.--Connection of the Baltic with
     the North Sea.--Completion of this work.--1 illustration.

     Transit in London, Rapid and Otherwise.--By JAMES A. TILDEN.
     --A practical review of London underground railroads and their
     defects and peculiarities.

IV.  ELECTRICITY.--An Electrostatic Safety Device.--Apparatus
     for grounding a circuit of too high potential.--1 illustration.

     Experiments with High Tension Alternating Currents.--Sparking
     distance of arc formed by a potential difference of 20,000 volts.
     --1 illustration.

     Laying a Military Field Telegraph Line,--Recent field trials in
     laying telegraph line in England.--3 illustrations.

     Some Experiments on the Electric Discharge in Vacuum Tubes.
     --By Prof. J.J. THOMSON, M.A., F.R.S.--Interesting experiments
     described and illustrated.--4 illustrations.

     The Electrical Manufacture of Phosphorus.--Note upon a new
     English works for this industry.

V.   GEOGRAPHY.--The Mississippi River.--By JACQUES W. REDWAY.
     --An interesting paper on the great river and its work and
     history.

VI.  MECHANICAL ENGINEERING.--How to Find the Crack.--
     Note on a point in foundry work.

     Riveted Joints in Boiler Shells.--By WILLIAM BARNET LE
     VAN.--Continuation of this practical and important paper.
     --10 illustrations.

VII. MEDICINE AND HYGIENE.--Influence of Repose on the Retina.
     --Important researches on the physiology of the eye.

     The Relation of Bacteria to Practical Surgery.--By JOHN B.
     ROBERTS, A.M., M.D.--A full review from the surgeon's standpoint
     of this subject, with valuable directions for practitioners.

VIII. MINERALOGY.--Precious and Ornamental Stones and Diamond
     Cutting.--By GEORGE FREDERICK KUNZ.--An abstract
     from a recent census bulletin, giving interesting data.

IX.  MINING ENGINEERING.--Mine Timbering.--The square system
     of mine timbering as used in this country in the Pacific coast
     mines and now introduced into Australia.--1 illustration.

X.   MISCELLANEOUS.--Freezing Mixtures.--A list of useful freezing
     mixtures.

     Sun Dials.--Two interesting forms of sun dials described.
     --3 illustrations.

     The Undying Germ Plasm and the Immortal Soul.--By DR. R.
     VON LENDENFELD.--A curious example of modern speculative
     thought.

XI.  NAVAL ENGINEERING.-The New British Battle Ship Empress
     of India.--A first class battle ship recently launched at
     Pembroke dockyard.

XII. TECHNOLOGY.--Composition of Wheat Grain and its Products
     in the Mill.--A scientific examination of the composition of
     wheat and its effect on mill products.

     Fast and Fugitive Dyes.--By Prof. J.J. HAMMEL.--Practical
     notes from the dyer's standpoint upon coloring agents.

       *       *       *       *       *



MINE TIMBERING.


The square system of timbering, in use in most of our large mines on
the Pacific coast, was first introduced in Australia by Mr. W.H.
Patton, who adopted it in the Broken Hill Proprietary mines, although
it does not seem to be so satisfactory to the people there as to our
miners, who are more familiar with it. The accompanying description
and plans were furnished by Mr. Patton to the report of the Secretary
of Mines for Victoria:

    "The idea is supposed to have originated in the German mines,
    but in a crude form. It was introduced among the mines of the
    Pacific coast of America some 20 years ago, by a gentleman
    named Diedesheimer. Its use there is universal, and experience
    has evolved it from the embryo state to its present
    perfection. The old system and its accompanying disadvantages
    are well known. A drive would be put in for a certain
    distance, when it had to be abandoned until it could be filled
    up with waste material and made secure. This process entailed
    much expense. The stuff had first to be broken on the surface,
    then sent below, trucked along the drives, and finally
    shoveled into place. Ventilation was impaired and the drives
    were filled with dust. The men worked in discomfort, and were
    not in a condition to perform a full measure of labor. Under
    the system as adopted in the Proprietary mine, these
    disadvantages disappear. The cost is one-third less,
    ventilation is perfect, and every portion of the faces are
    accessible at all times. Sawn timber is used throughout; the
    upright and cross pieces are 10 inches by 10 inches, and stand
    4 feet 6 inches apart; along the course of the drive, the
    cross pieces are five feet in length, and the height of the
    main drives and sill floor sets are 7 feet 2 inches in the
    clear. In blocking out the stopes, the uprights are 6 feet 2
    inches, just one foot shorter than those in the main drives.
    The caps and struts are of the same dimensions and timber as
    the sill floor. The planks used as staging are 9 inches by 2½
    inches; they are moved from place to place as required, and
    upon them the men stand when working in the stopes and in the
    faces. A stope resembles a huge chamber fitted with
    scaffolding from floor to roof. The atmosphere is cool and
    pure, and there is no dust. Stage is added to stage, according
    as the stoping requires it, and ladders lead from one floor to
    the other; the accessibility to all the faces is a great
    advantage.

    If, while driving, a patch of low grade ore is met with, it
    can be enriched by taking a higher class from another face,
    and so on. Any grade can be produced by means of this power of
    selection. Opinions have been expressed that this system of
    timbering is not secure, and that pressure from above would
    bring the whole structure down in ruins. But an opinion such
    as this is due to miscomprehension of the facts. If signs of
    weakening in the timbers become apparent, the remedy is very
    simple. Four or more of the uprights are lined with planks,
    and waste material is shot in from above, and a strong support
    is at once formed, or if signs of crushing are noticed, it is
    possible to go into the stope, break down ore, and at once
    relieve the weight."

[Illustration: THE SQUARE SYSTEM OF TIMBERING IN MINES.]

       *       *       *       *       *



TRANSIT IN LONDON, RAPID AND OTHERWISE.[1]

  [Footnote 1: Abstract from a paper read before the Boston Society
  of Engineers, in April, 1890.]

By JAMES A. TILDEN.


The methods of handling the travel and traffic in the city of London
form a very interesting subject for the study of the engineer. The
problem of rapid transit and transportation for a city of five
millions of inhabitants is naturally very complicated, and a very
difficult one to solve satisfactorily.

The subject may be discussed under two divisions: first, how the
suburban travel is accommodated, that is, the great mass of people who
come into the business section of the city every morning and leave at
night; second, how the strictly local traffic from one point to
another is provided for. Under the first division it will be noted in
advance that London is well provided with suburban railroad
accommodation upon through lines radiating in every direction from the
center of the city, but the terminal stations of these roads, as a
rule, do not penetrate far enough into the heart of the city to
provide for the suburban travel without some additional methods of
conveyance.

The underground railroad system is intended to relieve the traffic
upon the main thoroughfares, affording a rapid method of
transportation between the residential and business portions, and in
addition to form a communicating link between the terminals of the
roads referred to. These terminal stations are arranged in the form of
an irregular ellipse and are eleven in number.

One of the most noticeable features of the underground system in
London is that it connects these stations by means of a continuous
circuit, or "circle," as it is there called. The line connecting the
terminal stations is called the "inner circle." There is also an
extension at one end of this elliptical shaped circle which also makes
a complete circuit, and which is called the "middle circle," and a
very much larger circle reaching the northern portions of the city,
which is called the "outer circle." The eastern ends of these three
circles run for a considerable distance on the same track. In addition
to this the road branches off in a number of directions, reaching
those parts of the city which were not before accommodated by the
surface roads, or more properly the elevated or depressed roads, as
there are no grade crossings.

With regard to the accommodation afforded by this system: it is a
convenience for the residents of the western and southern parts of
London, especially where they arrive in the city at any of the
terminal stations on the line of the "circle," as they can change to
the underground. They can reach the eastern end of the "circle," at
which place is located the bank and the financial section of London,
in a comparatively short time. For example, passengers arriving at
Charing Cross, Victoria or Paddington stations, can change to the
underground, and in ten, fifteen and thirty minutes respectively,
reach the Mansion House or Cannon street stations, which are the
nearest to the Bank of England. In a similar manner those arriving at
Euston, St. Pancras or King's Cross on the northern side of the
"circle," can reach Broad Street station in ten or fifteen minutes,
which station is nearest the bank on that side of the "circle."

In a number of cases the underground station is in the same building
or directly connected by passages with the terminal stations of the
roads leading into the city. Examples of this kind would be such
stations as Cannon Street, Victoria or Paddington. They are not,
however, sufficiently convenient to allow the transference of baggage
so as to accommodate through passengers desiring to make connection
from one station to another across the city. Hand baggage only is
carried, about the same as it is on the elevated road in New York. The
method of cross town transfer, passengers and baggage, is invariably
done by small omnibuses, which all the railroads maintain on hand for
that special purpose. A very large proportion of the travel, however,
if not the largest, is obtained by direct communication by means of
the "circle" on branch lines with the various residential portions of
north, west and south London.

Approximately on the underground railroad the fare is one cent per
mile for third class, one cent and a half for second class, and two
cents for first class, but no fare is less than a penny, or two cents.
Omnibus fares in some instances are as low as a penny for two miles.
This is not by any means the rule, and is only to be found on
competing lines. The average fare would be a penny a mile or more.

The fares on the main lines which accommodate the suburban traffic are
somewhat higher than on the underground, perhaps 50 per cent. more. In
every case, on omnibus, tram cars or railroads, the rates are charged
according to distance. The system such as in use on our electric,
cable and horse cars and on the elevated road in New York, of charging
a fixed fare, is not in use anywhere.

The ticket offices of the underground roads are generally on a level
with the street. In some instances both the uptown and downtown trains
are approached from one entrance, but generally there is an entrance
at either side of the railroad, similar to the elevated railroad
system. In purchasing a ticket, the destination, number of the class,
and whether it is a single or return ticket have to be given. The
passenger then descends by generally well lighted stairways to the
station below, and his ticket is punched by the man at the gate. He
then has to be careful about two things; first, to place himself on
that part of the platform where the particular class which he wishes
to take stops, and secondly, to get on to the right train. In the
formation of the train the first class coaches are placed in the
center, the second and third class respectively at the front and rear
end. There are signs which indicate where passengers are to wait,
according to the class. There is a sign at the front end of the
engine, which to those initiated sufficiently indicates the
destination of the train. The trains are also called out, and at some
stations there is an obscure indicator which also gives the desired
information. The stations are from imperfectly to well lighted,
generally from daylight which sifts down from the smoky London
atmosphere through the openings above. The length of the train
averages about eight carriages of four compartments, each compartment
holding ten persons, making a carrying capacity of 320 passengers. The
equipment of the cars is very inferior. The first class compartments
are upholstered and cushioned in blue cloth, the second class in a
cheaper quality, while most of the third class compartments have
absolutely nothing in the way of a cushion or covering either on the
seat or back, and are little better than cattle pens. The width of the
compartment is so narrow that the feet can easily be placed on the
opposite seat, that is, a very little greater distance than would be
afforded by turning two of our seats face to face. The length of the
compartment, which is the width of the car, is about a foot and a half
less than the width of our passenger cars, about equal to our freight
cars. Each compartment is so imperfectly lighted by a single lamp put
into position through the top of the car that it is almost impossible
to read.

The length of time which a train remains at a station is from thirty
to forty seconds, or from three to four times the length of time
employed at the New York elevated railroad stations. The reason for
this is that a large proportion of the doors are opened by passengers
getting in or out, and all these have to be shut by the station porter
or guard of the train before the train can start. If the train is
crowded one has to run up and down to find a compartment with a vacant
seat, and also hunt for his class, and as each class is divided into
smoking and non-smoking compartments, making practically six classes,
it will be observed that all this takes time, especially when you add
the lost time at the ticket office and gate.

The ventilation of the tunnels and even the stations is oftentimes
simply abominable, and although the roads are heavily patronized there
is a great amount of grumbling and disfavor on this account. The
platforms of the stations are flush with those of the cars, so that
the delay of getting in or out is very small, but the doors are so low
that a person above the average height has to stoop to get in, and
cannot much more than stand upright with a tall hat on when he is once
in the car. The monitor roof is unknown.

The trains move with fair speed and the stations are plainly and
liberally marked, so that the passenger has little difficulty in
knowing when to get out. There are two signs in general use on English
railroads which are very simple and right to the point, namely, "Way
Out" and "Way In," so that when a passenger arrives at a station he
has no question how to get out of it. The ticket is given up as the
passenger leaves the station. There is nothing to prevent a passenger
with a third class ticket getting into a first class compartment
excepting the ominous warning of 40 shillings fine if he does so, and
the liability of having his sweet dreams interrupted by an occasional
inspector who asks to see the denomination of his ticket. All
compartments intended for the use of smokers are plainly marked and
are to be found in each class. Almost the entire part of the railroads
within the thickly settled portions of the city run in closed tunnels.
Outside of this they frequently run in open cuttings, and still
further out they run on to elevated tracks.

With regard to the equipment of the suburban or surface lines not
belonging to the underground system the description is about the same.
The cars are generally four compartments long and sometimes not
exceeding three. They are coupled together with a pair of links and
fastened to the draw bar on one car and the other thrown over a hook
opposite and brought into tension by a right and left hand screw
between the links. This is obviously very inconvenient for shunting
purposes, especially as the cars are not provided with hand brakes and
no chance to get at them if there were any. Consequently it appears
that when a train is made up it stays so for an indefinite period. A
load of passengers is brought into the station and the train remains
in position until it is ready to go out. As the trains run very
frequently this appears to be a very economical arrangement, as no
shunting tracks are needed for storage. The engine which brings the
train in of course cannot get out until the train goes out with the
next load. Turn tables for the locomotives are but very little used,
as they run as double enders for suburban purposes.

In conclusion it will be safe to say that the problem of rapid transit
for a city as large as London is far from solved by the methods
described. Although there are a great many miles of underground lines
and main lines, as they have been called throughout the paper, and
although grade crossings have been entirely abolished, allowing the
trains to run at the greatest speed suitable to their frequency, still
there are a great many sections which have to depend entirely upon the
omnibus or tram car. The enormous expense entailed by the construction
of the elevated structures can hardly be imagined. We have but one
similar structure in this country, which is that running from the
Schuylkill River to Broad Street station, in Philadelphia. The
underground system is even more expensive, especially in view of the
tremendous outlay for damages. This goes to show that money has not
been spared to obtain rapid transit.

After all, the means to be depended upon when one desires to make a
rapid trip from one part of the city to another is the really
admirable, cheap, always ready, convenient and comfortable London
hansom; while the way to see London is from the top of an omnibus, the
most enjoyable, if not the most expeditious, means of conveyance.

       *       *       *       *       *

[Continued from SUPPLEMENT, NO. 809, page 12930.]



RIVETED JOINTS IN BOILER SHELLS.[1]

  [Footnote 1: A paper read at a meeting of the Franklin Institute.
  From the journal of the Institute.]

By WILLIAM BARNET LE VAN.


[Illustration: FIG. 11.]

Fig. 11 represents the spacing of rivets composed of steel plates
three-eighths inch thick, averaging 58,000 pounds tensile strength on
boiler fifty-four inches diameter, secured by iron rivets
seven-eighths inch diameter. Joints of these dimensions have been in
constant use for the last fourteen years, carrying 100 pounds per
square inch.

_Punching Rivet Holes._--Of all tools that take part in the
construction of boilers none are more important, or have more to do,
than the machine for punching rivet holes.

That punching, or the forcible detrusion of a circular piece of metal
to form a rivet hole, has a more or less injurious effect upon the
metal plates surrounding the hole, is a fact well known and admitted
by every engineer, and it has often been said that the rivet holes
ought all to be drilled. But, unfortunately, at present writing, no
drilling appliances have yet been placed on the market that can at all
compare with punching apparatus in rapidity and cheapness of working.
A first-class punching machine will make from forty to fifty holes per
minute in a thick steel plate. Where is the drilling machine that will
approach that with a single drill?

The most important matter in punching plates is the diameter of the
opening in the bolster or die relatively to that of the punch. This
difference exercises an important influence in respect not only of
easy punching but also in its effect upon the plate punched. If we
attempt to punch a perfectly cylindrical hole, the opening in the die
block must be of the same diameter as the point of the punch, or, at
least, a very close fit. The point of the punch ought to be slightly
larger in diameter than the neck, or upper part, as shown in Figs. 12
and 13, so as to clear itself easily. When the hole in the bolster or
die block is of a larger diameter than the punch, the piece of metal
thrust out is of larger diameter on the bottom side, and it comes out
with an ease proportionate to the difference between the lower and
upper diameters; or, in other words, it produces a taper hole in the
plate, but allows the punching to be done with less consumption of
power and, it is said, with less strain on the plate.

[Illustration: FIG. 12.]

[Illustration: FIG. 13.]

As to the difference which should exist between the diameter of the
punch and the die hole, this varies a little with the thickness of the
plate punched, or should do so in all carefully executed work, for it
is easy to understand that the die which might give a suitable taper
in a three-fourths inch plate would give too great a taper in a
three-eighths inch plate. There is no fixed rule; practical experience
determines this in a rough and ready way--often a very rough way,
indeed, for if a machine has to punch different thicknesses of plate
for the same size of rivets, the workman will seldom take the trouble
to change the die with every variation of thickness. The maker of
punches and dies generally allows about three sixty-fourths or 0.0468
of an inch clearance.

The following formula is also used by punch and die makers:

    Clearance = D = d + 0.2t

where
    D = diameter of hole in die block;
    d = diameter of cutting edge of punch;
    t = thickness of plate in fractions of an inch;

that is to say, the diameter of the die hole equals diameter of punch
plus two-tenths the thickness of the plate to be punched.

_Example_.--Given a plate 3/8 or 0.375 of an inch thick, the diameter
of the punch being 13/16 or 0.8125 of an inch, then the diameter of
the die hole will be as follows:

  Diameter of die hole = 0.8125 + 0.375 X 0.2 = 0.8875 inch diameter,
    or say 7/8 or 0.875 inch diameter.

Punches are generally made flat on their cutting edge, as shown in
Fig. 12. There are also punches made spiral on their cutting edge, as
shown in Fig. 13. This punch, instead of being flat, as in Fig. 12, is
of a helical form, as shown in Fig. 13, so as to have a gradual
shearing action commencing at the center and traveling round to the
circumference. Its form may be explained by imagining the upper cutter
of a shearing machine being rolled upon itself so as to form a
cylinder of which its long edge is the axis. The die being quite flat,
it follows that the shearing action proceeds from the center to the
circumference, just as in a shearing machine it travels from the
deeper to the shallower end of the upper cutter. The latter is not
recommended for use in metal of a thickness greater than the diameter
of the punch, and is best adapted for thicknesses of metal two-thirds
the diameter of the punch.

Fig. 14 shows positions of punch and attachments in the machine.

[Illustration: FIG. 14.]

It is of the greatest importance that the punch should be kept sharp
and the die in good order. If the punch is allowed to become dull, it
will produce a fin on the edge of the rivet hole, which, if not
removed, will cut into the rivet head and destroy the fillet by
cutting into the head. When the punch is in good condition it will
leave a sharp edge, which, if not removed, will also destroy the
fillet under the head by cutting it away.

Punching possesses so many advantages over drilling as to render it
extremely important that the operation should be reduced to a system
so as to be as harmless as possible to the plate. In fact, no plate
should be used in the construction of a boiler that does not improve
with punching, and further on I will show by the experiments made by
Hoopes & Townsend, of Philadelphia, that good material is improved by
punching; that is to say, with properly made punches and dies, by the
upsetting around the punched hole, the value of the plate is increased
instead of diminished, the flow of particles from the hole into the
surrounding parts causing stiffening and strengthening.

_Drilling Rivet Holes._--In the foregoing I have not referred to the
drilling of rivet holes in place of punching. The great objection to
drilling rivet holes is the expense, from the fact that it takes more
time, and when drilled of full rivet size we are met with the
difficulty of getting the rivet holes to correspond, as they are when
punched of full rivet diameter. When two plates are drilled in place
together, the drill will produce a _burr_ between the two plates--on
account of their uneven surfaces--which prevents them being brought
together, so as to be water and steam tight, unless the plates are
afterward separated and the burr removed, which, of course, adds
greatly to the expense.

The difference in strength between boiler plates punched or drilled of
full rivet size may be either greater or less than the difference in
strength between unperforated plates of equal areas of fracture
section. When the metal plates are very soft and ductile, the
operation of punching does no appreciable injury. Prof. Thurston says
he has sometimes found it actually productive of increased strength;
the flow of particles from the rivet hole into the surrounding parts
causing stiffening and strengthening. With most steel and hard iron
plates the effect of punching is often to produce serious weakening
and a tendency to crack, which in some cases has resulted seriously.
With first class steel or iron plates, punching is perfectly
allowable, and the cost is twenty-five per cent. less than drilling;
in fact, none but first class metal plates should be used in the
construction of steam boilers.

In the original punching machines the die was made much larger than
the punch, and the result was a conical taper hole to receive the
rivet. With the advanced state of the arts the punch and die are
accurately fitted; that is to say, the ordinary clearance for a rivet
of (say) three-fourths of an inch diameter, the dies have about three
sixty-fourths of an inch, the punch being made of full rivet size, and
the clearance allowed in the diameter of the die.

Take, for example, cold punched nuts. Those made by Messrs. Hoopes &
Townsend, Philadelphia, when taken as specimens of "commercial," as
distinguished from merely experimental punching, are of considerable
interest in this connection, owing to the entire absence of the
conical holes above mentioned.

When the holes are punched by machines properly built, with the punch
accurately fitted to the die, the effect is that the metal is made to
flow around the punch, and thus is made more dense and stronger. That
some such action takes place seems probable, from the appearance of
the holes in the Hoopes & Townsend nuts, which are straight and almost
as smooth as though they were drilled.

Therefore I repeat that iron or steel that is not improved by proper
punching machinery is not of fit quality to enter into the
construction of steam boilers.


              STRENGTH OF PUNCHED AND DRILLED IRON BARS.

                          HOOPES & TOWNSEND.

----------------+------------------+----------------+----------------+
Thickness of bar|Thickness outside |  Punched bars  |  Drilled bars  |
   in inches.   |of hole in inches.|broke in pounds.|broke in pounds.|
----------------+------------------+----------------+----------------+
  3/8 or 0.375  |   3/8 or 0.375   |     31,740     |     28,000     |
  3/8 or 0.375  |   3/8 or 0.375   |     31,380     |     26,950     |
  5/8 or 0.625  |   1/4 or 0.25    |     18,820     |     18,000     |
  5/8 or 0.625  |   1/4 or 0.25    |     18,750     |     17,590     |
  5/8 or 0.625  |  3/16 or 0.1875  |     14,590     |     13,230     |
  5/8 or 0.625  |  3/16 or 0.1875  |     15,420     |     13,750     |
  5/8 or 0.625  |   1/8 or 0.125   |     10,670     |      9,320     |
  5/8 or 0.625  |   1/8 or 0.125   |     11,730     |      9,580     |
---------------------------------------------------------------------+


It will be seen from the above that the punched bars had the greatest
strength, indicating that punching had the effect of strengthening
instead of weakening the metal. These experiments have given results
just the reverse of similar experiments made on boiler plates; but the
material, such as above experimented upon, is what should be placed in
boilers, tough and ductile, and the manner of, and care taken in,
punching contribute to these results.

It is usual to have the rivet holes one-sixteenth of an inch in
diameter larger than the rivets, in order to allow for their expansion
when hot; it is evident, however, that the difference between the
diameters of the rivet hole and of the rivet should vary with the size
of the rivet.

The hole in the die is made larger than the punch; for ordinary work
the proportion of their respective diameters varies from 1:1.5 to 1:2.

As I have before stated, the best plate joint is that in which the
strength of the plate and the resistance of the rivet to shearing are
equal to each other.

In boilers as commercially made and sold the difference in quality of
the plates and rivets, together with the great uncertainty as to the
exact effect of punching the plates, have, so far, prevented anything
like the determination either by calculation or experiment of what
might be accepted as the best proportions of riveted joints.

In regard to steel plates for boilers Mr. F.W. Webb, of Crewe,
England, chief engineer of the London and Northwestern Railway, has
made over 10,000 tests of steel plates, but had only two plates fail
in actual work; these failures he thought were attributable solely to
the want of care on the part of the men who worked the plates up.

All their rivet holes for boilers were punched in a Jacquard machine,
the plates then annealed, and afterward bent in rolls; they only used
the reamer slightly when they had three thicknesses of plate to deal
with, as in butt joints with inside and outside covering strips. These
works turn out two locomotive boilers every three days.

The Baldwin Locomotive Works, which turn out on an average three
locomotives per day, punch all their rivet holes one sixteenth inch
less in diameter and ream them to driven rivet size when in place.
They also use rivets with a fillet formed under head made in solid
dies.

_Rivets._--Rivets of steel or iron should be made in solid dies.
Rivets made in open dies are liable to have a fin on the shank, which
prevents a close fit into the holes of the plates. The use of solid
dies in forming the rivet insures a round shank, and an accurate fit
in a round hole. In addition, there is secured by the use of solid
dies, a strong, clean fillet under the head, the point where strength
is most needed.

Commencing with a countersunk head as the strongest form of head, the
greater the fillet permissible under the head of a rivet, or bolt, the
greater the strength and the decrease in liability to fracture, as a
fillet is the life of the rivet.

If rivets are made of iron, the material should be strong, tough, and
ductile, of a tensile strength not exceeding 54,000 pounds per square
inch, and giving an elongation in _eight inches_ of not less than
twenty-five per cent. The rivet iron should be as ductile as the best
boiler plate when cold. Iron rivets should be annealed and the iron in
the bar should be sufficiently ductile to be bent cold to a right
angle without fracture. When heated it should be capable of being
flattened out to one-third its diameter without crack or flaw.

[Illustration: FIG. 15. Solid Die Rivet.]

[Illustration: FIG. 16. Open Die Rivet.]

If rivets are made of steel they must be low in carbon, otherwise they
will harden by chilling when the hot rivets are placed in the cold
plates. Therefore, the steel must be particularly a low grade or mild
steel. The material should show a tensile strength not greater than
54,000 pounds per square inch and an elongation in _eight inches_ of
thirty per cent. The United States government requirements are that
steel rivets shall flatten out cold under the hammer to the thickness
of one-half their diameter without showing cracks or flaws; shall
flatten out hot to one-third their diameter, and be capable of being
bent cold in the form of a hook with parallel sides without cracks or
flaws. These requirements were thought at first to be severe, but the
makers of steel now find no practical difficulty in meeting these
specifications.

The forming of the head of rivets, whether of steel or iron, and
whether the heads are conical or semi-spherical, should not be changed
by the process of riveting. The form of the head is intended to be
permanent, and this permanent form can only be retained by the use of
a "hold fast," which conforms to the shape of the head. In the use of
the flat hold fast (in general use in a majority of boiler shops) the
form of the head is changed, and if the rivet, by inadequate heating,
requires severe hammering, there is danger that the head of the rivet
may be "punched" off. By the use of a hold fast made to the shape of
the rivet head, this danger is avoided and the original form of the
head is retained. This feature of the use of proper rivet tools in
boiler shops has not received the attention it deserves. Practical use
of the above named hold fast would soon convince the consumers of
rivets of its value and efficiency.

The practice of driving rivets into a punched rivet hole from which
the fin or cold drag, caused by the movement of the punch, has not
been removed by reaming with a countersunk reamer, or better still a
countersunk set, should be condemned, as by driving the hot rivet head
down against the fin around the hole in the cold plate caused by the
action of punching the countersunk fillet is not only destroyed, but
it is liable to be driven into the head of the rivet, partially
cutting the head from the shank. If the rivet is driven into a hole
that has been punched with a sharp punch and sharp die, the result is
that the fillet is cut off under the head, and the riveted end is also
cut, and does not give the clinch or hold desired. That is to say,
rivet holes in plates to be riveted should have the burr or sharp edge
taken off, either by countersinking, by reamer, or set.

_Heating of Rivets._--Iron rivets are generally heated in an ordinary
blacksmith's or rivet fire having a forced blast; they are inserted
with the points down into the fire, so that the heads are kept
practically cool.

Steel rivets should be heated in the hearth of a reverberatory furnace
so arranged that the flame shall play over the top of the rivets, and
should be heated uniformly throughout the entire length of the rivet
to a cherry red. Particular attention must be given to the thickness
of the fire in which they are heated.

Steel, of whatever kind, should never be heated in a thin fire,
especially in one having a forced blast, such as an ordinary
blacksmith's or iron rivet furnace fire. The reason for this is that
more air passes through the fire than is needed for combustion, and in
consequence there is a considerable quantity of free oxygen in the
fire which will oxidize the steel, or in other words, burn it. If free
oxygen is excluded steel cannot burn; if the temperature is high
enough it can be melted and will run down through the fire, but
burning is impossible in a thick fire with a moderate draught.

This is an important matter in using steel rivets and should not be
overlooked; the same principle applies to the heating of steel plates
for flanging.

_Riveting._--There are four descriptions of riveting, namely:

    (1) Hammered or hand riveting.

    (2) Snapped or set.

    (3) Countersunk.

    (4) Machine.

For good, sound work, machine riveting is the best.

Snapped riveting is next in quality to machine riveting.

Countersunk riveting is generally tighter than snapped, because
countersinking the hole is really facing it; and the countersunk rivet
is, in point of fact, made on a face joint. But countersinking the
hole also weakens the plate, inasmuch as it takes away a portion of
the metal, and should only be resorted to where necessary, such as
around the front of furnaces, steam chests or an odd hole here and
there to clear a flange, or something of that sort.

Hammered riveting is much more expensive than machine or snapped
riveting, and has a tendency to crystallize the iron in the rivets,
causing brittleness.

In the present state of the arts all the best machine riveters do
their work by pressure, and not by impact or blow.

The best machines are those of the hydraulic riveting system, which
combines all of the advantages and avoids all the difficulties which
have characterized previous machine systems; that is to say, the
machine compresses without a blow, and with a uniform pressure at
will; each rivet is driven with a single progressive movement,
controlled at will. The pressure upon the rivet after it is driven is
maintained, or the die is retracted at will.

[Illustration: FIG. 17.]

Hydraulic riveting has demonstrated not only that the work could be as
well done without a blow, but that it could be _better done without a
blow_, and that the riveted material was stronger when so secured than
when subjected to the more severe treatment under impact.

What is manifestly required in perfect riveting is that the metal of
the rivet while hot and plastic shall be made to flow into all the
irregularities of the rivet holes in the boiler sheets; that the
surplus metal be formed into heads as large as need be, and that the
pressure used to produce these results should not be in excess of what
the metal forming the boiler shall be capable of resisting.

It is well known that metals, when subjected, either cold or hot, to
sufficient pressure, will obey almost exactly the same laws as fluids
under similar conditions, and will flow into and fill all the crevices
of the chamber or cavity in which they are contained. If, therefore, a
hot rivet is inserted into the holes made in a boiler to receive it,
and is then subjected to a sufficient pressure, it will fill every
irregularity of the holes, and thus fulfill one of the conditions of
perfect riveting. This result it is impossible to accomplish with
perfection or certainty by ordinary hand riveting, in doing which the
intermittent blows of an ordinary hammer are used to force the metal
into the holes. With a hydraulic riveting machine, however, an
absolutely uniform and continuous pressure can be imparted to each
rivet, so as to force the hot metal of the rivet into all the
irregularities of the holes in the same way as a hydraulic ram will
cause water to fill any cavity, however irregular.

[Illustration: FIG. 18.]

In order to illustrate the relative advantages of machine over hand
riveting, two plates were riveted together, the holes of which were
purposely made so as not to match perfectly. These plates were then
planed through the center of the rivets, so as to expose a section of
both the plates and rivets. From this an impression was taken with
printer's ink on paper and then transferred to a wooden block, from
which Figs. 17 and 18 were made.

The machine-driven rivet is marked _a_, and _b_ represents the
hammered rivet.

It will be observed that the machine rivet fills the hole completely,
while the hand rivet is very imperfect. This experiment was tried
several times, with similar results each time.

The hand rivet, it will be observed, filled up the hole very well
immediately under the head formed by the hammer; but sufficient
pressure could not be given to the metal--or at least it could not be
transferred far enough--to affect the metal at some distance from the
driven head. So great is this difficulty that in hand riveting much
shorter rivets must be used, because it is impossible to work
effectively so large a mass of metal with hammers as with a machine.
The heads of the machine rivets are, therefore, larger and stronger,
and will hold the plates together more firmly than the smaller
hammered heads.

To drive rivets by hand, two strikers and one helper are needed in the
gang, besides the boy who heats and passes the rivets; to drive each
five-eighths inch rivet, an average of 250 blows of the hammer is
needed, and the work is but imperfectly done. With a machine, two men
handle the boiler, and one man works the machine; thus, with the same
number of men as is required in riveting by hand, five rivets are
driven each minute.

The superior quality of the work done by the machine would alone make
its use advantageous; but to this is added greatly increased amount of
work done.

The difference in favor of the riveting machine over hand riveting is
at least _ten_ to _one_.

In a large establishment a record of the number of rivets driven by
the hand-driving gang, also by the gang at the steam-riveting machine
for a long period of time, in both cases making no allowances of any
kind of delays, the rivets driven per month by each was--for the hand
driven rivets at the rate of twelve rivets per hour, and for the
machine driven rivets, 120 per hour. In the case of the hand driven
rivets the boiler remains stationary and the men move about it, while
the machine driven rivets require the whole boiler to be hoisted and
moved about at the riveting machine to bring each hole to the position
required for the dies. Notwithstanding the trouble involved in
handling and moving the boiler, it shows that it is possible to do ten
times as much work, and with less skilled labor, by the employment of
the riveting machine.

_Calking._--One great source of danger in boiler making is excessive
joint calking--both inside and out--where a sharp nosed tool is
employed, and for the reason that it must be used so close to the
inner edge of plate as to indent, and in many cases actually cut
through the skin of the lower plate. This style of calking puts a
positive strain upon the rivets, commencing distortion and putting
excessive stress upon rivets--already in high tension before the
boiler is put in actual use. It is, I hope, rapidly becoming a thing
of the past.

With a proper proportion of diameter and pitch of rivet, all that is
required is the use of a light "fuller tool" or the round-nosed tool
used in what is known to the trade as the "Connery system."

There is but little need of calking if means are taken to secure a
clean metal-to-metal face at the joint surfaces. When the plates are
put together in ordinary course of manufacture, a portion of the mill
scale is left on, and this is reduced to powder or shaken loose in the
course of riveting and left between the plates, thus offering a
tempting opening for the steam to work through, and is really cause of
the heavy calking that puts so unnecessary a pressure on both plate
and rivet. A clean metallic joint can be secured by passing over the
two surfaces a sponge wet with a weak solution of sal-ammoniac and hot
water, an operation certainly cheap enough both as to materials and
labor required.

[Illustration: FIG. 19]

The above cut, Fig. 19, gives an illustration of calking done by
sharp-nosed and round nosed tools, respectively. It will be seen by
Fig. 20 that the effect of a round-nosed tool is to divide the plate
calked, and as the part divided is well driven toward the rivets, a
bearing is formed at _a_, from one-half to three-fourths of an inch,
which increases the strength of joint, and will in no way cut or
injure the surface of the under plate. A perfect joint is thus
secured.

[Illustration: Fig. 20.]

       *       *       *       *       *



THE NEW BRITISH BATTLE SHIP EMPRESS OF INDIA.


The launching of this first-class battle ship was successfully carried
out at Pembroke Dockyard on May 7. She is the second of a class of
eight battle ships built and building under the Naval Defense Act of
1889, which were specially designed to take part in general fleet
actions in European waters. The leading dimensions are: Length,
between perpendiculars, 380 ft.; breadth, extreme, 75 ft.; mean
draught of water, 27 ft. 6 in.; and displacement at this draught,
14,150 tons, which surpasses that of any other ship in the navies of
the world. Previous to the launching of the Royal Sovereign--a sister
vessel--which took place at Portsmouth in February last, the largest
war ships in the British navy were the Nile and Trafalgar, each of
12,500 tons, and these were largely exceeded in displacement by the
Italia, of 13,900 tons, and the Lepanto, of 13,550 tons, belonging to
the Italian navy.

The Empress of India is built throughout of mild steel, the stem and
stern post, together with the shaft brackets, being of cast steel.
Steel faced armor, having a maximum thickness of 18 in., extends along
the sides for 250 ft. amidships, the lower edge of the belt being 5
ft. 6 in. below the normal water line. The belt is terminated at the
fore and after ends by transverse armored bulkheads, over which is
built a 3 in. protective steel deck extending to the ends of the
vessel and terminating forward at the point of the ram. Above the belt
the broadside is protected by 5 in. armor, the central battery being
inclosed by screen bulkheads of the same thickness. The barbettes,
which are formed of armor 17 in. thick, rise from the protective deck
at the fore and after ends of the main belt. The principal armor
throughout is backed by teak, varying in thickness from 18 in. to 20
in., behind which is an inner skin of steel 2 in. thick. The engines
are being constructed by Messrs. Humphreys, Tennant & Co, London, and
are of the vertical triple expansion type, capable of developing a
maximum horse power of 13,000 with forced draught and 9,000 horse
power under natural draught, the estimated speeds being 16 and 17½
knots respectively at the normal displacement. The regular coal supply
is 900 tons, which will enable the ship to cover a distance of 5,000
knots at a reduced speed of ten knots and about 1,600 knots at her
maximum speed. The main armament of the Empress will consist of four
67 ton breechloading guns mounted in pairs _en barbette_. The
secondary armament includes ten 6 in. 100 pounder quick firing guns,
four being mounted on the main deck and six in the sponsons on the
upper deck, sixteen 6 pounder and nine 3 pounder quick-firing guns, in
addition to a large number of machine guns.

The largest guns at present mounted in any British warship are the 110
ton guns mounted in the Benbow class, and the difference between these
weapons and those to be carried by the Empress of India is very
marked.

The projectile fired from either of the Benbow's heavy gun weighs
1,800 lb., and is capable of penetrating 35 in. of unbacked wrought
iron at a distance of 1,000 yards. The projectile fired from the 67
ton guns of the Empress of India will have much less penetrating
power, being only equal to 27 in. of wrought iron with a full charge
of 520 lb. of prismatic brown powder, the missile weighing 1,250 lb.
or about one-half less than the weight of the shot used with the 110
ton gun. It will thus be seen that the ordnance of the Benbow can
penetrate armor that would defy the attack of the guns of the Empress.
It should be said, however, that the heavy artillery of the latter
vessel is capable of penetrating any armor at present afloat, and is
carried at a much greater height above the designed load water line
than in any existing battle ship, either in the British or foreign
navies. The armor being of less weight, too, enables the new ship, and
others of her class, to carry an auxiliary armament of unprecedented
weight and power.

The Empress will be lighted throughout by electricity, the
installation comprising some 600 lights, and will be provided with
four 25,000 candle power search lights, each of which will be worked
by a separate dynamo. The ship has been built from the designs of Mr.
W.H. White, C.B., Director of Naval Construction, and will be fitted
out for the use of an admiral, and when commissioned her complement of
officers and men will number 700.--_Industries._

       *       *       *       *       *



THE "IRON GATES" OF THE DANUBE.


The work of blowing up the masses of rock which form the dangerous
rapids known as the Iron Gates, on the Danube, was inaugurated on
September 15, 1890, when the Greben Rock was partially blown up by a
blast of sixty kilogrammes of dynamite, in the presence of Count
Szapary, the Hungarian premier; M. Baross, Hungarian minister of
commerce; Count Bacquehem, Austrian minister of commerce; M. Gruitch,
the Servian premier; M. Jossimovich, Servian minister of public works;
M. De Szogyenyi, chief secretary in the Austro-Hungarian ministry of
foreign affairs; and other Hungarian and Servian authorities. Large
numbers of the inhabitants had collected on both banks of the Danube
to witness the ceremony, and the first explosion was greeted with
enthusiastic cheers. The history of this great scheme was told at the
time the Hungarian Parliament passed the bill on the subject two years
ago. It is known that the Roman Emperor Trajan, seventeen centuries
ago, commenced works, of which traces are still to be seen, for the
construction of a navigable canal to avoid the Iron Gates.

For the remedy of the obstruction in the Danube, much discussed of
late years, there were two rival systems--the French, which proposed
to make locks, and the English and American, which was practically
the same as that of Trajan, namely, blasting the minor rocks and
cutting canals and erecting dams where the rocks were too crowded. The
latter plan was in principle adopted, and the details were worked out,
in 1883, by the Hungarian engineer Willandt. The longest canal will be
that on the Servian bank, with a length of over two kilometers and a
width of eighty meters. It will be left for a later period to make the
canal wider and deeper, as was done with the Suez Canal. For the
present it is considered sufficient that moderate sized steamers shall
be able to pass through without hindrance, and thus facilitate the
exchange of goods between the west of Europe and the east.

The first portion of the rocks to be removed, and of the channels to
be cut, runs through Hungarian territory; the second portion is in
Servia. The new waterway will, it is anticipated, be finished by the
end of 1895, and then, for the first time in history, Black Sea
steamers will be seen at the quays of Pesth and Vienna, having, of
course, previously touched at Belgrade. The benefit to Servian trade
will then be quite on a par with that of Austria-Hungary. Even Germany
will derive benefit from this extension of trade to the east. These,
however, are by no means the only countries which will be benefited by
the opening of the great river to commerce. Turkey, Southern Russia,
Roumania, and Bulgaria, not to speak of the states of the west of
Europe, will reap advantage from this new departure. England, as the
chief carrier of the world, is sure to feel the beneficial effects of
the Danube being at length navigable from its mouth right up to the
very center of Europe.

The removal of the Iron Gates has always been considered a matter of
European importance. The treaty of Paris stipulated for freedom of
navigation on the Danube. The London treaty of 1871 again authorized
the levying of tolls to defray the cost of the Danube regulation; and
article 57 of the treaty of Berlin intrusted Austria-Hungary with the
task of carrying out the work. By these international compacts the
European character of the great undertaking is sufficiently attested.

[Illustration: THE "IRON GATES" OF THE DANUBE]

The work of blasting the rocks will be undertaken by contractors in
the employ of the Hungarian government, as the official invitation for
tenders brought no offers from any quarter. The construction of the
dams, however, and the cutting of several channels to compass the most
difficult rocks and rapids, will be carried out by an association of
Pesth and other firms. The cost, estimated altogether at nine million
florins, will be borne by the Hungarian exchequer, to which will fall
the tolls to be levied on all vessels passing through the Gates until
the original outlay is repaid.

Very few persons know, says the _American Architect_, what an enormous
work has been undertaken at the Iron Gates of the Danube, where
operations are rapidly progressing, mainly in accordance with a plan
devised many years ago by our distinguished countryman, Mr. McAlpine.
The total length of that part of the river to be regulated is about
two hundred and fifty miles, so that the enterprise ranks with the
cutting of the Panama and Suez canals as one of the greatest
engineering feats ever attempted. Work has been begun simultaneously
at three points: at Greben, where there are reefs to be taken care of;
at the cataract, near Jucz, and at the Iron Gate proper, below Orsova.
At Greben, where the stream is shallow, but swift, a channel two
hundred feet wide is to be blasted out of the rock, and below it a
stone embankment wall is to be built more than four miles long. From a
reef which projects into the river a piece is to be blasted away,
measuring five hundred feet in length, and about nine feet in depth.
The difficulties of working in this part of the river are very great.
Not only is the current extremely rapid, but in certain places ridges
of rock barely covered at low water alternate with pools a hundred
and forty feet deep, which give rise, in the rapid current, to
frightful whirlpools and eddies. These deep pools are to be filled at
the same time that the reefs are cut away, and it is estimated that
nearly three million cubic feet of loose stonework will be needed for
this purpose alone. In addition to the excavation, artificial banks
and breakwaters, for modifying the course of the stream, are to be
built; so that it is estimated that the masonry to be executed in this
section will amount to about five and one-half million cubic feet.

In the cataract section, at Jucz, a channel two hundred feet wide, and
more than half a mile long, is to be blasted out of the rock, and a
breakwater built, to moderate the suddenness of the fall. This
breakwater is to be about two miles long, and ten feet thick at the
top, increasing in thickness toward the bottom. The rock in which the
channel must be cut at this point is partly serpentine greenstone,
partly chrome iron ore, and is intensely hard. In the section of the
Iron Gate, the work to be done consists in "canalizing" the river for
a distance of a mile and a half, by building a wall on each side, and
excavating the bed of the river between. The channel between the walls
will be two hundred and fifty feet wide. It is estimated that nearly
three million cubic feet of rock will have to be excavated here, all
of which will be used to fill in behind the embankment walls. Of
course, the greater part of the rock will be removed by means of
blasting with high explosives, but some of it is to be attacked with a
novel instrument, which was first tried, on a small scale, on the
Panama Canal, and is to be used for serious work here. This
instrument, as it is to be employed on the Danube, consists of an
enormous steel drill, thirty-three feet long, and weighing ten tons.
By means of a machine like a pile driver, this monstrous tool is
raised to a height of about fifty feet, and allowed to drop, point
first. So heavy a mass of metal, falling from a considerable height,
meets with comparatively little resistance from the water, and the
point shatters and grinds up the rock on which it strikes. Fifty or
sixty blows per minute can be struck with a tool of this kind, and ten
thousand blows in all can be inflicted before the tool is so worn as
to be past service. Several of these drills will be at work at the
same time, and to remove the fragments of rock which they break off, a
huge dredge of three hundred and fifty horse power is to be employed.
For excavating by means of explosives, arrangements have been made for
drilling the holes for the cartridges with the greatest possible
rapidity, as on this depends the celerity with which the work can be
pushed forward. Much of the work will be done by means of diamond
drills, which are mounted on boats. Five of these boats have been
provided, each with seven diamond drills, arranged so as to work
perfectly in twenty feet of water. Other boats are fitted with
pneumatic drills, which are operated by means of air, compressed to a
tension of seven hundred and fifty pounds to the square inch. The
pressure of the compressed air is transmitted by means of water to the
drills, which act by percussion, and work very rapidly. These drills
are curiously automatic in their operation. After boring the holes to
the allotted depth, the machine automatically sets in each a tube,
washes out the dust, inserts a dynamite cartridge, withdraws the tube,
and connects the wire of the electric fuse in the cartridge with the
battery wire in the boat. The cartridges are charged with a pound of
dynamite to each. In hard rock only one charge is fired at a time, but
in softer material four are fired at once. If the water over the work
is deep, the boat is not moved from its position, but in shallow water
it is towed a few yards away from the spot where the explosion is to
take place. The drill holes are about six feet deep, and are spaced at
the rate of about one to every three square feet, something, of
course, depending upon the character of the rock. The whole work is
now under contract, the mechanical engineering firm of Luther, of
Brunswick, having undertaken to complete it in five years, for a
payment of less than four million dollars.

       *       *       *       *       *



THE NEW GERMAN SHIP CANAL.


The gates which admit the water into the new canal which is to connect
the Baltic with the North Sea have been recently opened by the Emperor
William. This canal is being constructed by the German government
principally for the purpose of strengthening the naval resources of
Germany, by giving safer and more direct communication for the ships
of the navy to the North German ports. The depth of water will be
sufficient for the largest ships of the German navy. The canal will
also prove of very great advantage to the numerous timber and other
vessels trading between St. Petersburg, Stockholm, Dantzic, Riga, and
all the North German ports in the Baltic and this country. The passage
by the Kattegat and Skager Rack is exceedingly intricate and very
dangerous, the yearly loss of shipping being estimated at half a
million of money. In addition to the avoidance of this dangerous
course, the saving in distance will be very considerable. Thus, for
vessels trading to the Thames the saving will be 250 miles, for those
going to Lynn or Boston 220, to Hull 200, to Newcastle or Leith 100.
This means a saving of three days for a sailing vessel going to Boston
docks, the port lying in the most direct line from the timber ports of
the Baltic to all the center of England. The direction of the canal is
shown by the thick line in the accompanying sketch map of the North
Sea and Baltic. Considering that between 30,000 and 40,000 ships now
pass through the Sound annually, the advantage to the Baltic trade is
very apparent.

[Illustration: THE NEW GERMAN SHIP CANAL.]

The new canal starts at Holtenau, on the north side of the Kiel Bay,
and joins the Elbe fifteen miles above the mouth. From Kiel Bay to
Rendsborg, at the junction with the Eider, the new canal follows the
Schleswig and Holstein Canal, which was made about one hundred years
ago, and is adapted for boats drawing about eight feet; thence it
follows the course of the Eider to near Willenbergen, when it leaves
that river and turns southward to join the Elbe at Brunsbuttel, about
forty miles below Hamburg. The canal is 61 miles long, 200 ft. wide at
the surface, and 85 ft. at the bottom, the depth of water being 28 ft.
The surface of the water in the two seas being level, no locks are
required; sluices or floodgates only being provided where it enters
the Eider and at its termination. The country being generally level
there are no engineering difficulties to contend with, except a boggy
portion near the Elbe; the ground to be removed is chiefly sandy loam.
Four railways cross the canal and two main roads, and these will be
carried across on swing bridges. The cost is estimated at £8,000,000.
About six thousand men are employed on the works, principally Italians
and Swiss.--_The Engineer._

       *       *       *       *       *



THE KIOTO-FU CANAL, IN JAPAN.


Japan is already traversed by a system of railways, and its population
is entering more and more into the footsteps of western civilization.
This movement, a consequence of the revolution of 1868, is extending
to the public works of every kind, for while the first railway lines
were being continued, there was in the course of excavation (among
other canals) a navigable canal designed to connect Lake Biwa and the
Bay of Osaka, upon which is situated Kioto, the ancient capital of
Japan.

The work, which was begun in 1885, was finished last year, and one of
our readers has been kind enough to send us, along with some
photographs which we herewith reproduce, a description written by Mr.
S. Tanabe, engineer in chief of the work.

The object of the Kioto-Fu Canal is not only to provide a navigable
watercourse, putting the interior of the country in connection with
the sea, but also to furnish waterfalls for supplying the water works
of the city of Kioto with the water necessary for the irrigation of
the rice plantations, and that employed for city distribution. It
starts from the southwest extremity of Lake Biwa, the largest lake in
Japan, and the area of which is 800 square kilometers. This lake,
which is situated at 84 meters above the level of the sea, is 56
kilometers from the Bay of Osaka. As this bay is already in
communication with Kioto by a canal, the Kioto-Fu forms a junction
with the latter after a stretch of 11 kilometers and a difference of
level of 45 meters between its extremities.

[Illustration: FIG. 1.--EXTREMITY OF LAKE BIWA AND BEGINNING OF THE
CANAL.]

The lake terminates in a marshy plain (Fig. 1), in which the first
excavation was made. This is protected by longitudinal dikes which
lead back the water to it in case of freshets. At the end of this
cutting, which is 100 meters in length, begins the canal properly so
called, with a width of 5.7 meters, at the surface, and a depth of 1.5
meters, for a length of 540 meters. It then reaches the first tunnel
for crossing the Nagara-yama chain. This tunnel is 2,500 meters in
length, 4.8 in width and 4.2 in height. The water reaches a depth of
1.8 meters upon the floor. It was pierced through very varied
materials, such as clay, schists, sandstone and porphyry, and is lined
throughout with brick masonry. The construction was effected by means
of a working shaft 45 meters in depth, sunk in the axis of the work,
at a third of its length from the west side. At the upper extremity
are established sluices that permit of securing to the canal a
constant discharge of 8.5 cubic meters per second. Fig. 2 represents
the head of this work.

[Illustration: FIG. 2.--HEAD OF THE PRINCIPAL TUNNEL.]

Starting from the tunnel, the canal extends in the open air for a
length of 4,500 meters. To reach the basin of Kioto, it traverses the
Hino-oko-yama chain of hills, through two tunnels of the same section
and construction as the one just mentioned, and of the respective
lengths of 125 and 841 meters. Traction in the tunnels is to be
effected by means of an immersed chain.

On leaving tunnel No. 3, at about 8,400 meters from its origin, the
canal divides into two branches. The first of these, which is designed
to serve as a navigable way, has a slope 0.066 per meter for a length
of 540 meters. It is a true inclined plane, which the boats pass over
by means of a cradle carried by trucks and drawn by a cable actuated
by the fall furnished by the other branch. At the foot of the inclined
plane, the canal widens out to 18 meters at the surface, with a depth
of 1.5 meter, and, through a sluice, joins the Osaka Bay Canal, after
a stretch of 2 kilometers.

[Illustration: FIG. 3.--AQUEDUCT OVER THE VALLEY OF THE TOMBS OF THE
EMPERORS.]

The second branch traverses a small tunnel, crosses the valley of the
emperors' tombs upon an aqueduct of 14 arches (Fig. 3), and reaches
Kogawa, a faubourg north of Kioto, after a stretch of 8 kilometers.
Its slope is greater than that of the main canal, from which it
derives but 1.4 cubic meter. The 7 cubic meters remaining may be
employed for the production of motive power under a fall of 56 meters.
It is proposed to utilize a portion of it, at the point of bifurcation
and at the top of the inclined plane, in a hydraulic installation that
will drive electric machines. The total cost of the work was one
million dollars, a third of which was furnished by the imperial
treasury, a quarter by the central government, and the rest by various
taxes.--_La Nature._

       *       *       *       *       *


HOW TO FIND THE CRACK.--Most mechanics know that by drilling a hole at
the inner end of a crack in cast metal its extension can be prevented.
But to find out the exact point where the crack ends, the _Revue
Industrielle_ recommends moistening the cracked surface with
petroleum, then, after wiping it, to immediately rub it with chalk.
The oil that has penetrated into the crack will, by exudation,
indicate the exact course and end of the crack.

       *       *       *       *       *



FAST AND FUGITIVE DYES.[1]

  [Footnote 1: A paper recently read before the Society of Arts,
  London.]

By Prof. J.J. HUMMEL.


As it is with many other arts, the origin of dyeing is shrouded in the
obscurity of the past; but no doubt it was with the desire to attract
his fellow that man first began to imitate the variety of color he saw
around him in nature, and colored his body or his dress.

Probably the first method of ornamenting textile fabrics was to stain
them with the juices of fruits, or the flowers, leaves, stems, and
roots of plants bruised with water, and we may reasonably assume that
the primitive colors thus obtained would lack durability.

By and by, however, it was found possible to render some of the dyes
more permanent, probably in the first instance by the application of
certain kinds of earth or mud, as we know to be practiced by the Maori
dyers of to-day, and in this way, as it appears to me, the early dyers
learnt the efficacy of what we now call "mordants," which I may
briefly describe as fixing agents for coloring matters.

At a very remote period therefore, I imagine, the subject of fast and
fugitive dyes engaged the attention of textile colorists.

Our European knowledge of dyeing seems to have come to us from the
East, and although at first indigenous dyestuffs were largely
employed, with the discovery of new countries many of these fell
slowly and gradually into disuse, giving way to the newly imported
dyestuffs of other lands, which possessed some advantage, being either
richer in coloring matter, yielding brighter or faster colors, or
being capable of more easy application. Thus kermes gave way to
cochineal, woad to indigo, and so on.

Down to about the year 1856, natural dyestuffs alone, with but one or
two exceptions, were employed by dyers; but in that year a present
distinguished member of this Society, Dr. Perkin, astonished the
scientific and industrial world by his epoch-making discovery of the
coal tar color mauve. From that time down to the present, the textile
colorist has had placed before him an ever increasing number of
coloring matters derived from the same source.

Specially worthy of notice are the discoveries of artificial alizarin,
in 1868, by Graebe and Liebermann, and of indigotin, in 1878, by Adolf
Baeyer, both coloring matters being identical with the respective dyes
obtained from plants.

In view of the vast array of coal tar colors now at our disposal, and
their almost universal application in the decoration of all manner of
textile fabrics, threatening even the continued use of well known
dyestuffs of vegetable origin, it becomes of the greatest importance
to examine most thoroughly, and to compare the stability of both old
and new coloring matters.

The first point in discussing this question of fast and fugitive dyes
is to define the meaning of these terms "fast" and "fugitive."
Unfortunately, as frequently employed, they have no very definite
signification. The great variety of textile fabrics to which coloring
matters are applied, the different stages of manufacture at which the
coloring matter is applied, and the many uses to which the fabrics are
ultimately put, all these are elements which cause dyed colors to be
exposed to the most varied influences.

The term a "fast color," then, may convey a different meaning to
different individuals. To one it implies that the color will not fade
when exposed to light and atmospheric conditions; to another that it
is not impoverished by washing with soap and water; to a third it may
indicate that the color will withstand the action of certain
manufacturing operations, such as scouring, milling, stoving, etc.;
while a fourth person might be so exacting as to demand that a fast
color should resist all the varied influences I have named.

It is well to state at once that no dyed color is absolutely fast,
even to a single influence, and it certainly cannot pass unscathed
through all the operations to which it may be necessary to submit
individual colors applied to this or that material. Many colors are
fast to washing or milling, and yet very fugitive to light; others are
fast to light, but fugitive toward milling; while others again are
fast to both influences. In short, each color has its own special,
characteristic properties, so that colors may be classified with
respect to each particular influence, and may occupy a very different
rank in the different arrangements.

It is, however, by no means necessary to demand absolute fastness from
any color. A color may "bleed" in milling, and therefore be very
unsuitable for tweeds, and yet be most excellent for curtains and
hangings, because of its fastness to light. So, too, a dye capable of
yielding rich or delicate tints, but only moderately fast to light,
may still be perfectly well adapted for the silks and satins of the
ball room, or even the rapidly changing fashion, although it would be
quite inadmissible for the pennon at the masthead.

The colors of carpets, curtains, and tapestry should certainly be fast
to light, but no one expects them to undergo the fatigue of the weekly
washtub; and just as little as we look for the exposure of flannels
and hosiery, day by day and week by week, to the glare of sunlight,
much as we desire that the colors shall not run in washing.

For all practical purposes, then, it seems reasonable to define a
"fast color" as one which will not be materially affected by those
influences to which, in the natural course of things, it will be
submitted. Hence, in speaking of a fast color, it becomes necessary to
refer specially to the particular influences which it resists before
the term acquires a definite meaning. To be precise, one should say
that a color is "fast to light," or "fast to washing," or "fast to
light and washing," and so on. Further, it is necessary, as we shall
see afterward, to give always the name of the fiber to which the color
is applied.

All that I have said with respect to the term "fast" may be applied
with equal propriety to the term "fugitive." This, too, has no very
definite meaning until a qualifying statement, such as I have referred
to, gives it precision.

The most important question to be considered is


THE ACTION OF LIGHT ON DYED COLORS.

That light can effect radical changes in many substances was known to
the ancients. Its destructive action on artists' pigments, e.g., the
blackening of vermilion, was recorded 2,000 years ago by Vitruvius.
Since that time it has been well established, by numerous observations
and experiments, that light possesses, in a high degree, the power of
exerting chemical action, i.e., causing the combination or
decomposition of a large number of substances. The union of chlorine
with hydrogen gas, the blackening of silver salts, the reduction of
bichromate of potash and of certain ferric salts in contact with
organic substances, are all familiar instances of the action of light.
In illustration of this, I show here some calico prints produced by
first preparing the calico with a solution of potassium bichromate,
then exposing the dried calico under a photographic negative, and,
after washing, dyeing with alizarin or some similar coloring matter.
During the exposure under the negative, the light has reduced and
fixed the chromium salt upon certain parts of the fiber as insoluble
chromate of chromium (Cr_{2}O_{3}CrO_{3}) in the more protected
portions, the bichromate remains unchanged, and is subsequently
removed by washing. During the dyeing process, the coloring matter
combines with the chromium fixed on the fiber, and thus develops the
colored photograph.

The prints in Prussian blue are produced in a similar manner, the
sensitive salt with which the calico is prepared being ammonium
ferricitrate, and the developer potassium ferricyanide.

Investigation has shown that the most chemically active rays are those
situated at the blue end of the solar spectrum; and although all the
rays absorbed by a sensitive colored body affect its change, it is
doubtless the blue rays which are the chief cause of the fading of
colors. Experiments are on record, indeed, which prove this.

Depierre and Clouet (1878-82) exposed a series of colors, printed and
dyed on calico, to light which had passed through glasses stained red,
orange, yellow, green, blue, and violet, corresponding to definite
parts of the spectrum. They found that the blue light possessed the
greatest fading power, red light the least.

More recently (1886-88) Abney and Russell exposed water colors under
red, green, and blue glass, and came to the same conclusion.

But the chemical energy of the sun's rays is not the sole cause of the
fading of colors. There are certain contributory causes as important
as the light itself.

About fifty years ago, Chevreul showed what these accessory causes
are, by exposing to light a number of dyed colors under varied
conditions, e.g., in a vacuum, in dry and moist hydrogen, dry and
moist air, water vapor, and the ordinary atmosphere. He found that
such fugitive colors as orchil, safflower, and indigo-carmine fade
very rapidly in moist air, less rapidly in dry air, and that they
experience little or no change in hydrogen or in a vacuum. The general
conclusion arrived at was, that light, when acting alone, i.e.,
without the aid of air and moisture, exercises a very feeble
influence. Further, it was determined that the air and moisture,
without aid of light, have also comparatively little effect on dyed
colors. Abney and Russell, in their experiments with water colors,
obtained similar results.

These conclusions are exactly in accordance with our common knowledge
of the old fashioned method of bleaching cotton and linen, in which
the wetted fabric is exposed to light on the grass, and frequently
sprinkled with water. If the material becomes dry through the absence
of dew or rain, or the want of sprinkling, little or no bleaching
takes place.

The one color which Chevreul found to behave abnormally was Prussian
blue. This faded even in a vacuum; but, strange to say, on keeping the
faded color in the dark, and exposed to air, the color was restored.
It was shown that, during the exposure to light, the color lost
cyanogen, or hydrocyanic acid, while in the dark and exposed to the
air, oxygen was absorbed. Chevreul concluded, therefore, that the
fading of Prussian blue was due to a process of reduction.

The prevailing opinion, however, is that the fading of colors is a
process of oxidation, caused by the ozone, or hydrogen peroxide, which
is probably formed in small quantity during the evaporation of the
moisture present, and both these substances are powerful bleaching
agents.

It would be extremely convenient to have some rapid method of testing
colors for fastness to light, and I believe it is the custom with some
to apply certain chemical tests with this object in view. The results
of my own experiments in this direction lead me to the conclusion that
at present we have no sufficient substitute for sunlight for this
purpose, since I have not found any oxidizing or reducing substance
which affects dyed colors in all respects like the natural
color-fading agencies; further, I am inclined to the opinion that the
action of light varies somewhat with the different coloring matters,
according to their chemical constitution and the fiber upon which they
are applied.

With respect to this last point, Chevreul actually found that colors
are faster to light on some fibers than on others, and this fact,
which is generally known to practical men, is abundantly shown in the
diagrams on the wall. As a rule we may say that colors are most
fugitive on cotton and most permanent on wool, those on silk holding
an intermediate position. Still there are many exceptions to this
order, especially as between silk and wool.

Since the time of Chevreul, the action of light on dyed colors has not
been seriously and exhaustively studied. From time to time, series of
patterns dyed with our modern colors have been exposed to light, e.g.,
by Depierre and Clouet, Joffre, Muller, Kallab, Schmidt, and others;
but the published results must at best be considered as more or less
fragmentary. Under the auspices of the British Association, and a
committee appointed at its last meeting in Leeds, I hope to have the
pleasure during the next few years of studying this interesting
subject.

To-night I propose to give you some of the prominent results already
obtained in past years, in the dyeing department of the Yorkshire
College, where it has been our custom to expose to light and other
influences the patterns dyed by our students. Further, I wish to give
you an ocular demonstration of the action of light or dyed colors, by
means of these silk, wool, and cotton patterns, portions of which have
been exposed for 34 days and nights on the sea coast near Bombay,
during the month of February of this year.

I may remark that this test has been a very trying one, for I estimate
that it is equal to more than a year's exposure in this country.
During the whole period there was cloudless sunshine, without any
rain, and each evening heavy dew. I have pleasure in acknowledging the
services of Mr. W. Reid, a former student, who superintended the
exposure of the patterns, and from time to time took notes of the rate
at which individual patterns faded.

These diagrams contain, perhaps, the most complete series of both old
and new dyes, on the three fibers, which have been simultaneously
exposed to sunlight, and they form an instructive object lesson.

Let me first direct your attention to the diagram containing the
_natural coloring matters_--those dyestuffs which were in use previous
to 1856. Broadly speaking, they are of two kinds; those which dye
textile materials "direct," and those which give no useful color
without the aid of certain metallic salts, called "mordants."

Now, among the natural coloring matters, these "mordant dyes," as they
may be conveniently termed, are much more numerous than the "direct
dyes;" but be it observed, we have fast and fugitive colors in both
classes.

Referring first to the wool patterns and to the "direct dyes," we find
that the only really fast colors are Prussian blue and Vat indigo
blue. Turmeric, orchil, catechu, and indigo carmine are all extremely
fugitive.

As to the "mordant dyes," some yield fast colors with all the usual
mordants, e.g., madder, cochineal, lac dye, kermes, viz., reds with
tin and aluminum, claret browns with copper and chromium, and dull
violets with iron.

Other dyestuffs, like camwood, brazilwood, and their allies, also
young fustic, give always fugitive colors whatever mordant be
employed; others again, e.g., weld, old fustic, quercitron bark,
flavin, and Persian berries, give fast colors with some mordants and
fugitive colors with others; compare, for example, the fast olives of
the chromium, copper, and iron mordants with the fugitive yellows
given by aluminum and tin. A still more striking case is presented by
logwood, which gives a fast greenish-black with copper and very
fugitive colors with aluminum and tin. Other experiments have shown
that the chromium and iron logwood blacks hold an intermediate
position. Abnormal properties are found to be exhibited by camwood and
its allies, with aluminum and tin, the colors at first becoming
darker, and only afterward fading in the normal manner.

When we examine the silk patterns, we find, generally speaking, a
similar degree of fastness among the various natural dyes, as with
wool; in some instances the colors appear even faster, notice, for
example, the catechu brown and the colors given by brazilwood and its
allies, with iron mordant.

On examining the cotton patterns, we are at once struck with the
marked fugitive character of nearly all the natural dyes. The
exceptions are: the madder colors, especially when fixed on
oil-prepared cotton, as in Turkey red; the black produced by logwood,
tannin, and iron; and a few mineral colors, e.g., iron buff, manganese
brown, chromate of lead orange, etc., and Prussian blue. Cochineal and
its allies, which are such excellent dyes for wool and silk, give only
fugitive colors on cotton.

The main point which arrests our attention in connection with the
natural dyes seems to me to be the comparatively limited number of
fast colors. Very remarkable is the total absence of any really fast
yellow vegetable dye, and it is probably on this account that gold
thread was formerly so much introduced into textile fabrics. Notice
further the decided fastness of Prussian blue, especially on wool and
silk; while we cannot but remark the comparatively fugitive character
of vat indigo blue on cotton, and even on silk, compared with the
fastness of the same color when fixed on wool.

Now, let us turn our attention to the _artificial coloring matters_,
derived with few exceptions from coal tar products.

Here again we have two classes, "mordant dyes" and "direct dyes." Both
classes are somewhat numerous, but whereas the former may be
conveniently shown on a single diagram sheet, it requires a
considerable number to display the latter.

First let us examine the wool patterns dyed with the "mordant dyes."

We find there a few yellow dyes quite equal in fastness to those of
natural origin, or even somewhat surpassing them, e.g., two of the
alizarin yellows, viz., those marked R and G G W. Except in point of
fastness and mode of application, I may say that these are not true
alizarin colors, neither are they analogous to the natural yellow
dyestuffs, for they are incapable of giving dark olives with iron
mordants. Truer representatives of the natural yellow dyes appear,
however, to exist in galloflavin and the alizarin yellows marked A and
C, and, as you see, they are of about the same degree of fastness.

Among the red dyes we have alizarin and its numerous allies, and these
are certainly fit representatives of the madder root, which indeed
they have almost entirely displaced. The most recent additions to this
important class are the various alizarin Bordeaux. The only dyes in
this group which appear somewhat behind the rest in point of fastness
are purpurin and alizarin maroon.

On this same diagram we notice, also, fast blues and dark greens, of
which we have no similar representatives among the natural coloring
matters. I refer to alizarin blue, alizarin cyanin, alizarin indigo,
alizarin green, and coerulin.

Further, an excellent group of coloring matters, giving fast browns
and greens with copper and iron mordants respectively, is formed by
naphthol green, resorcinol green, gambin, and dioxin.

The only fugitive dyes of the class now under consideration are some
of the yellows, gallamin blue and gallocyanin.

If we now turn to examine the colors given by these artificial
"mordant dyes" on silk, we notice, also, a good series of fast colors
similar to those which they give on wool; and even on cotton we see
many fast colors, of which we have no representatives among the
dyewoods.

If we were not prepared to find so few really fast natural dyes,
surely we cannot but be surprised to find what a considerable number
of fast dyes are to be met with among the coal tar coloring matters
requiring the aid of mordants.

On these diagrams, the first vertical column shows the stain given by
the coloring matter alone; the remaining columns show the colors
obtained when the same coloring matters are applied in conjunction
with the several mordants--chromium, aluminum, tin, copper, and iron.

It was formerly held that the office of a mordant was merely to fix
the coloring matter upon the fiber; we now know, however, and it is
plainly illustrated by these diagrams, that this view is erroneous,
for the mordant not only fixes but also develops the color; the
mordant and coloring matter chemically combine with each other, and
the resultant compound represents the really useful pigment or dye. If
a coloring matter is combined with different mordants, the dyes thus
obtained represent distinct chemical products, and it is quite
natural, therefore, to find them differing from each other in color,
and their resistance toward light.

Knowing this, it is clearly the duty of the dyer to apply each
coloring matter of this class with a variety of mordants, and to
select the particular combination which gives him the desired color
and fastness. By adopting this method, however, his selection would
ultimately comprise a large number of coloring matters paired with a
great variety of mordants. In order, therefore, to avoid the intricacy
involved in the use of several mordants, and to simplify the process
of dyeing, especially when dyeing compound shades, the dyer prefers to
limit himself as far as possible to the use of a single mordant, and
to employ along with it a mixture of several coloring matters.

Now the woolen dyer has largely adopted an excellent mordant in
bichromate of potash; it is cheap, easily applied, and not perceptibly
injurious to the fiber. It is his desire, therefore, to have a good
range of red, yellow, blue, and other coloring matters, all giving
fast dyes with this mordant. This action and desire on the part of the
dyer has more and more placed the problem of producing fast colors
upon the shoulders of the color manufacturer or chemist, and right
well has the demand been met, for in the diagram on the wall we see
how, in the alizarin colors and their allies, he has already furnished
the dyer with a goodly number of dyestuffs yielding fast dyes with
this chosen mordant of the woolen dyer. Since, however, they yield
fast colors with other useful mordants, and upon other fibers than
wool, these alizarin colors prove of the greatest value to the dyer of
textile fabrics generally. Let us not forget the fact, then, that it
is among the "mordant dyes," the very class to which belong most of
the natural coloring matters, that we find our fastest coal tar dyes.

When we examine the results of actual exposure experiments, such as
are here shown on these four diagram sheets, surely we have no
hesitation in declaring how utterly false is the popular opinion that
all coal tar colors are fugitive to light, while the good
old-fashioned natural dyes are all fast. The very opposite indeed is
here shown to be the case. For myself, I feel persuaded that at the
present time the dyer has at his command a greater number of fast dyes
derived from coal tar than from any other source, and I believe it
possible to produce with dyes obtained from this source alone, if need
be, tapestries, rugs, carpets, and other textile fabrics which shall
vie successfully in point of color and duration of color with the best
productions of the East, either of this or any other age.

How, then, does it happen that these coal tar colors have been so long
and so seriously maligned by the general public? Apart from the fact
that public opinion has been based upon an imperfect knowledge of the
subject, we shall find a further explanation when we examine the
diagrams showing the "direct dyes" obtained from coal tar. According
to their mode of application I have here arranged them in three large
groups, viz., basic, acid, and Congo colors. A fourth group,
comprising comparatively few, is made up of those colors which are
directly produced upon the fiber itself.

The "basic colors" have a well known type in magenta. They are usually
applied to wool and silk in a neutral or slightly alkaline bath; on
cotton they are fixed by means of tannate of antimony or tin. The
"acid colors" are only suitable for wool and silk, to which they are
applied in an acid bath. A typical representative of this group is
furnished by any one of the ordinary azo scarlets which in recent
years have come into prominence as competitors of cochineal. The
"Congo colors" are comparatively new, and are conveniently so named
from the first coloring matter of the group which was discovered,
viz., Congo red. They are applicable to wool, silk, and cotton,
usually in a neutral or slightly alkaline bath. Of the dyes produced
directly upon the fiber itself, one may take aniline black and also
primulin as a type, the latter a dye somewhat recently introduced by
Mr. A.G. Green, of this city.

Our first impression, in looking at these "direct dyes," is that they
are more numerous and more brilliant than the "mordant dyes," and that
they are for the most part fugitive. Still, if we examine the
different series in detail, we shall find here and there, on the
different fibers, colors quite equal in fastness to any of the
"mordant dyes."

Among the "basic colors" we search in vain, however, for a really fast
dye on any fiber. Still, Magdala red, perhaps, appears faster than the
rest on silk, and among the greens and blues we find a few dull blues
on cotton, which, for this fiber, have been recommended as substitutes
for indigo, viz., Indophenin, paraphenylene, blue, cinerein, Meldola's
blue, etc. The azine greens, also, appear tolerably fast on cotton and
on silk, but although possessing some body of color, after exposure,
the original dark green has changed to a decided drab.

When we examine the "acid colors," however, we meet with a number of
scarlets, crimsons, and clarets, possessing considerable fastness both
on wool and on silk. Some, indeed, appear almost, if not entirely, as
fast as cochineal scarlet, e.g., Biebriech scarlet, brilliant crocein,
etc.

Among the "acid oranges and yellows," we also find a goodly number
which are of medium fastness. About ten, either on wool or on silk,
may even be accounted really fast, and are fit, apparently, to rank
with alizarin colors. Note, for example, on wool: Crocein orange,
aurantia, orange crystal, tartrazin, milling yellow, palatine orange;
on silk, acid yellow D, brilliant yellow, azo acid yellow, metanil
yellow, curcumin S, etc. I may remark that these are some of the
fastest yellows on wool and silk with which we are acquainted. It is
interesting to note the decided fugitive character, on silk, of
tartrazin, aurantia, orange crystal, etc., compared with their great
fastness on wool. Observe, also, how, on wool, the pale lemon yellow
of picric acid has changed to a full reddish brown.

Among the "acid greens and blues," all the colors are fugitive, both
on wool and on silk. Patent blue appears slightly better than the
rest. Of the "acid blacks and violets," a few colors are of medium
fastness, both on wool and silk, e.g., naphthol black, naphthylamine,
black, resorcinol brown, fast brown, etc.

When we examine the Congo colors, amid a number of very fugitive
colors, we find a few which are satisfactorily fast. Among the reds,
for example, diamine fast red is quite remarkable for its fastness,
both on wool and silk, and may certainly rank with alizarin; but on
cotton, it is quite as fugitive as the rest. Of medium fastness on
wool are brilliant Congo G and R, Congo G R; and on silk, diamine
scarlet B, deltapurpurin 5 B, and brilliant Congo R.

Among the "Congo oranges and yellows," we find some of the fastest on
cotton of this class of colors. Still they deserve only the rank of
medium fastness. They are Mikado orange 4 R, R, G. Hessian yellow,
curcumin S, chrysophenin. On wool, we have about half a dozen of
medium fastness, viz., benzo-orange, Congo orange R, chrysophenin G,
chrysamin R, brilliant yellow. On silk, however, we find in this group
about a dozen of the fastest oranges and yellows with which we are
acquainted for this fiber, viz., Congo orange R, chrysophenin G,
diamine yellow N, brilliant yellow, curcumin W, benzo orange, Hessian
yellow, chrysamin R and G, cresotin yellow R and G, cotton yellow G,
and carbazol yellow.

Does it not appear somewhat remarkable that we should find among this
generally fugitive group of coloring matters colors which are so
eminently fast on silk, and which we entirely fail to meet with among
those groups which usually furnish our fast colors, e.g., the alizarin
group?

Passing on to the "Congo violets, blues, and purples," we find few
colors worthy of particular notice for fastness. Diamine violet N
appears, perhaps, of medium fastness on wool and silk, while
sulphonazurin, benzo-black blue, and direct gray may claim the same
distinction on silk.

In the small group of colors which are produced directly upon the
fiber, none seems to call for special notice, except aniline black,
which, notwithstanding its direct derivation from aniline, is probably
the fastest color we have upon any fiber.

Now, in classifying the whole range of coal tar coloring matters into
"mordant dyes" and "direct dyes," and the latter into acid, basic,
Congo colors, etc., I have looked at them from the point of view of
the dyer and arranged them according to color and mode of application.
The chemist, however, classifies them quite differently, viz.,
according to their chemical constitution, i.e., the arrangement of the
atoms of which they are composed, and thus we have nitro colors,
phthaleins, azines, and so on.

In studying the action of light on the coal tar colors from this point
of view, we find that whereas the members of some groups are for the
most part fugitive, the members of other groups are nearly all fast,
and it becomes at once apparent that the chemical constitution of a
coloring matter exercises a profound influence upon its behavior
toward light. Members of the rosaniline group are all similarly
fugitive, while those of the alizarin group possess generally the
quality of fastness. Particularly fugitive are the eosins, and yet
some of these, by a slight modification of constitution, e.g., the
introduction of an ethyl group, as in ethyl-eosin, are rendered
distinctly faster.

In the azo group some colors are fugitive, others are moderately fast,
and it is generally recognized that certain classes of the tetrazo
compounds are distinctly faster than the ordinary diazo colors.

By a careful study of the influence of the atomic arrangement upon the
stability of colors, information useful to the color manufacturer may
possibly be gained, but at present my facts are not yet sufficiently
tabulated to enable one to recognize any generally pervading law in
this direction.

It is scarcely necessary to say that the fastness to light of a color
is independent of its commercial value, this being mainly determined
by the price of the raw material from which it is manufactured, the
working expenses, and the profit desired by the manufacturer. Neither
must we suppose that facility of application necessarily interferes
with its fastness to light, for some of our fastest coal tar colors on
wool, e.g., diamine fast red, tartrazin, etc., are applied in the
simplest possible manner. On the other hand, the intensity or depth of
a color has considerable influence on its fastness. Dark full shades
invariably appear faster than pale ones produced from the same
coloring matter, simply because of the larger body of pigment present.
A pale shade of even a very fast color like indigo will fade with
comparative rapidity. The fugitive character of many of the coal tar
colors is, in my opinion, rendered more marked, because, owing to
their intense coloring power, there is often such an infinitesimal
amount of coloring matter on the dyed fiber. Hence it is that in the
Gobelin tapestries pale shades on wool are frequently obtained by the
use of more or less unchangeable metallic oxides and other mineral
colors, to the exclusion of even fast vegetable dyes.

It is interesting to examine what is the action of light upon compound
colors. Is a fugitive color rendered faster by being applied along
with a fast color?

My own opinion, based upon general observation, is that it is not, and
that when light acts upon a compound color the unstable color fades,
while the stable color remains behind. A woaded color, for example, is
only fast in respect of the vat indigo which it contains, and yet how
frequent is the custom to unite with the indigo such dyes as barwood,
orchil, and indigo-carmine, the fugitive character of which I have
pointed out.

Having thus rapidly surveyed these numerous coal tar colors, both in
their dyed and exposed conditions, I again ask why are they so
generally regarded as altogether fugitive?

First, because we have, especially among these "direct dyes," a very
large number which are undoubtedly very fugitive.

Moreover, all the earlier coal tar dyes--mauve, magenta, Nicholson
blue, etc., belonged to a class which, even up to the present time,
has only furnished us with fugitive colors. They were indeed prepared
from aniline, and it appears to me that the defects of these early
aniline colors, as well as their designation, have been handed down to
their successors without due discrimination, so that in the popular
mind the term "aniline color" has become, as a matter of habit,
synonymous with "fugitive color." But science is progressive, fields
of investigation other than aniline have been opened up, so that now,
although a large number of fugitive dyes are still manufactured from
coal tar, there are others, as we have seen, which are as fast and
permanent as we have ever had from natural sources.

Finally, and perhaps this is the most important cause of all, many of
the fugitive coal tar colors are gifted, I will not say with fatal
beauty, but with a facility of application, and such comparative
cheapness in consequence of their intense coloring power, that the
dyer, tempted by competition, applies them not unfrequently to
materials for which, because of their ultimate uses, they are
altogether unsuited; and so it comes about that we find the most
fugitive colors applied indiscriminately and without due discretion.

As we look upon these multitudinous colors, one other thought cannot
fail to cross our minds. Is there not surely an overproduction of
these fugitive coal tar colors? Is not the dyer bewildered with an
_embarras de richesses_, so that he knows not where to choose?

There is indeed much truth in this. With rare skill and ingenuity an
army of chemists is busy elaborating these wonderful dyes; but in such
quick succession are they introduced into the dye house that the busy
dyer has no time sufficiently to prove them, and it is not surprising
therefore that he is liable to commit errors in their application.

But if there is an over-production of fugitive colors, there is also
at work, as in the organic world around us, the counteracting
influence of the law of the survival of the fittest. Sooner or later,
the fugitive colors must give way to those which are more permanent,
and already the number of coal tar colors which have been discarded,
for one reason or another, is considerable.

Not unfrequently one is asked the question, Is there no method whereby
these fugitive colors can be made fast? Knowing the efficacy of
mordants with certain coloring matters, is there no mordant which we
can generally apply with this desirable object in view? The discovery
of such a universal mordant I believe to be somewhat chimerical, and
yet, curiously enough, a number of experiments have been recorded in
recent years, which almost seem to point in the direction of selecting
for such a purpose ordinary sulphate of copper.

Some of these diagrams before you this evening show clearly the
fastness to light generally of the lakes formed with copper mordant.
This peculiarity of the copper compounds has not escaped the notice of
other observers. Dr. Schunck, for example, during the progress of his
research on chlorophyl, noticed the very permanent green dye which
this otherwise fugitive coloring matter gives in combination with
copper.

Then there is the assertion of practical dyers, that the use of copper
sulphate in dyeing catechu brown on cotton assists materially in
rendering this color fast to light.

The use of copper mordant with phenolic coloring matters is perfectly
natural. Some time ago, however, it was successfully applied, for the
purpose of rendering more permanent, to certain of the Congo colors on
cotton, e.g., benzo-azurine, etc., in the application of which,
metallic salts had not hitherto been deemed necessary.

Noelting and Herzberg have also observed that the fastness to light,
even of basic colors, e.g., magenta, methyl violet, malachite green,
etc., is increased by a subsequent treatment of the dyed fabric with
copper sulphate solution, although in many cases the color is much
soiled thereby.

Still more recently, A. Scheurer records that by impregnating or
padding certain dyed fabrics with an ammoniacal solution of copper
sulphate, the colors gain considerably in fastness to light. As the
result of his experiments Scheurer concludes that this protective
influence of copper on dyed colors is a general fact, apparently
applicable to all colors; that it is not necessarily due to its action
as a lake-forming substance, since intimate union between the coloring
matter and the copper salt is not necessary. He seems rather inclined
to ascribe its efficacy to the light being deprived of its active rays
during its passage through the oxide of copper.

Knowing, however, the strong reducing action of light in many cases,
and with the absence of positive knowledge concerning the cause of the
fading of colors, it seems to me that the beneficial influence of the
copper may just as probably be due to its well known oxidizing power,
which counteracts the reducing action of the light.

It is interesting to note, in connection with Scheurer's view, that,
many years ago, Gladstone and Wilson (1860) proposed to impregnate
colored materials with some colorless fluorescent substance, e.g.,
sulphate of quinine, evidently with the idea of filtering off the
active ultra-violet rays. How far some such method as this might prove
successful I cannot say, but since we cannot keep our dyed textile
materials in a vacuum, as Chevreul did, nor is it desirable to
impregnate them with mastic varnish for the purpose of excluding air
and moisture, as Mr. Laurie proposes, in order to preserve the colors
of oil paintings, it is perhaps well to bear in mind the principle
here alluded to as a possible solution of the difficulty.

I have dwelt rather long on this important question of the action of
light on dyed colors, but I have done so because I thought it would
most interest you. With the remaining portions of my subject I must be
more brief.

(_To be continued._)

       *       *       *       *       *


To introduce free fat acids from an oil, it must be decomposed. This
may be done by the use of lead oxide and water or by analogous
processes. To clarify an oil, expose to the sun in leaden trays. Often
washing with water will answer the purpose.

       *       *       *       *       *



COMPOSITION OF WHEAT GRAIN AND ITS PRODUCTS IN THE MILL.


Probably the most striking difference in the average mineral
composition of the grain of wheat is the very much lower proportion of
phosphoric acid, and of magnesia also, in the dry substance of the
best matured grain; and it is now known that these characteristics
point to a less proportion of bran to flour, or, in other words, of a
greater accumulation of starch in the process of ripening, and
consequently of a whiter and better quality of bakers' flour. The
study of the chemical composition of wheat and its products in the
mill, therefore, and of the amount of fertilizing matters (nitrogen,
phosphoric acid and potash) removed from the soil by the crop, becomes
of direct interest not only to the producer from whose soil these
ingredients are removed, but to the consumer of the byproducts as
well, who desires to know what proportion of these elements of
fertility he is returning to his own soil in the different products he
may use as animal food. It is desirable also to determine what is the
average composition of wheats and the flour made from them, in order
to see in what direction efforts should be turned, by the selection of
seed wheats, to improve the present varieties for the production of
the best quality of flour. This can only be done after we determine
what variation there is for different years due to climatic influences
and variations of soil, for it has been shown in our former papers
that environment very largely influences the quality of wheat grain,
and also of the flour. When these have been determined, than we may
hope to be able to determine which factors under our control enter in
to permanently improve the better flour-producing quality of wheats.

A mixture, in equal proportions, was made of Clawson, Mediterranean,
and early amber wheats, and submitted to the mill, using the Hungarian
roller process. From this mixture for each one bushel of the grain of
60 lb. weight was furnished the following proportion of products:

                                Lb. per
                                Bushel.      Per cent.
  Flour.                          44           73.3
  Middlings.                       4            6.7
  Shipstuff.                       2            3.3
  Bran.                           10           16.7
                                  --          -----
      Total.                      60          100.0


These data furnish us a means of estimating the amount of the
different ingredients removed in the various products in one bushel of
wheat with the foregoing component parts.


FLOUR.

The analysis of the flour shows us that the 44 lb. obtained from the
one bushel of grain would contain the following ingredients:

                                         Lb. per Bushel
                                          of Wheat.
  Water.                                   5.834
  Ash.                                     0.167
  Albuminoids.                             4.620
  Woody fiber.                             0.532
  Carbo-hydrates (starchy matters).       33.391
  Fat.                                     0.453


WHEAT MIDDLINGS.

The middlings form the inner coating of the wheat grain, next the
floury or starchy portion, and contain particles of the germ and a
larger percentage of carbohydrates than either shipstuff or bran, and
a less proportion of fiber, while the percentage of albuminoids
usually stands between that of shipstuff and bran. The following data
are obtained from the 4 lb. procured from a bushel of wheat:

                                         Lb. per Bushel
                                          of Wheat.
  Water.                                   0.562
  Ash.                                     0.138
  Albuminoids.                             0.657
  Woody fiber.                             0.142
  Carbo-hydrates (starchy matters).        2.307
  Fat.                                     0.193


SHIPSTUFF.

That part separated and known as shipstuff is a very thin layer next
outside of the middlings, and contains the germ not found in the
middlings or left as a part of the flour. The quantity produced, 2 lb.
from a bushel of wheat, is very small and rarely kept separate from
the bran. The following shows the analysis:

                                         Lb. per Bushel
                                          of Wheat.
  Water.                                   0.282
  Ash.                                     0.101
  Albuminoids.                             0.349
  Woody fiber.                             0.160
  Carbo-hydrates (starchy matters).        1.088
  Fat.                                     0.099


BRAN.

Bran, the outer coating of the wheat, contains twice or three times as
much fiber as does either of the other products from wheat, and
proportionately less of each of the other ingredients except ash,
which is greater, perhaps partly due to foreign matter adhering to the
kernel. The following analysis shows the amount of constituents
removed by the bran (10 lb.) from one bushel of wheat:

                                         Lb. per Bushel
                                          of Wheat.
  Water.                                   1.459
  Ash.                                     0.506
  Albuminoids.                             1.416
  Woody fiber.                             1.000
  Carbo-hydrates (starchy matters).        5.277
  Ash.                                     0.342

From the foregoing milling products obtained from one bushel of wheat
of 60 lb. in weight, the ash on analysis gave the following
constituents, which shows the amount that was abstracted from the soil
by its growth:

  _____________________________________________________
                                                       |
    CONSTITUENTS FROM ONE BUSHEL OF WHEAT.             |
  _____________________________________________________|
              |         |          |         |         |
              |Nitrogen.|Phosphoric| Potash. |  Lime.  |
              |         |  Acid.   |         |         |
              |         |          |         |         |
              +---------+----------+---------+---------+
              |         |          |         |         |
  Flour.      |  0.739  |  0.092   |  0.054  |  0.013  |
  Middlings.  |  0.105  |  0.064   |  0.024  |  0.002  |
  Shipstuff.  |  0.056  |  0.044   |  0.021  |  0.003  |
  Bran.       |  0.228  |  0.251   |  0.083  |  0.012  |
              +---------+----------+---------+---------+
    Totals.   |  1.118  |  0.454   |  0.182  |  0.030  |
  ____________|_________|__________|_________|_________|


Or we may express the results in another form, the amount contained in
one ton of straw, and the products of 30 bushels of wheat, which may
be reckoned as an average crop, expressing the amounts in pounds as
follows:


    AMOUNTS OF SELECTED CONSTITUENTS IN THIRTY
      BUSHELS OF WHEAT AND ITS PROPORTION OF
      STRAW.
  _____________________________________________________
              |         |          |         |         |
              |Nitrogen.|Phosphoric| Potash. |  Lime.  |
              |         |    Acid. |         |         |
              |         |          |         |         |
              +---------+----------+---------+---------+
              |         |          |         |         |
  Straw.      |  11.20  |    2.67  |  13.76  |   6.20  |
  Flour.      |  22.17  |    2.76  |   1.62  |   0.39  |
  Middlings.  |   3.15  |    2.01  |   0.72  |   0.06  |
  Shipstuff.  |   1.68  |    1.32  |   0.63  |   0.09  |
  Bran.       |   6.84  |    7.53  |   2.49  |   0.36  |
              +---------+----------+---------+---------+
    Totals.   |  45.04  |   16.29  |  19.22  |   7.10  |
  ____________|_________|__________|_________|_________|


From numerous investigations it has been found that in regard to the
nitrogen and the ash constituents, there is striking evidence of the
much greater influence of season than of manuring on the composition
of a ripened wheat plant, and especially of its final product--the
seed. Further, under equal circumstances the mineral composition of
the wheat grain, excepting in cases of very abnormal exhaustion, is
very little affected by different conditions as to manuring, provided
only that the grain is well and normally ripened. Again, it is found
that the composition may vary very greatly with variations of season,
that is, with variations in the conditions of seed formation and
maturation, upon which the organic composition of the grain depends.
In other words, differences in the mineral composition of the ripened
grain are associated with differences in its organic composition, and
hence the great value of proper selection both for seed and for
milling purposes.


AMERICAN WHEATS.

In a comprehensive treatise on the composition of American wheats, Mr.
Clifford Richardson says we cannot attribute the poverty of American
wheats in nitrogen as a whole to an enhanced starch formation, and for
the following reasons: An enhanced formation of starch, there being no
poverty of nitrogen in the soil, increases the weight of the grain and
diminishes the relative percentage of nitrogen. Were this the cause of
the relatively low percentage of nitrogen in the American wheats, the
grain from the Eastern States, which are poorest in this respect,
would be heavier than those from the middle West, which are richer in
albuminoids; but this is not the case. Formation of starch is
attributed by Messrs. Lawes & Gilbert to the higher ripening
temperature in America, but Clifford Richardson has found that there
is scarcely any difference in composition or weight between wheats
from Canada and Alabama, and if anything those from Canada contain
more starch than those from the South, and the spring wheat from
Manitoba with its colder climate more than those from Dakota and
Minnesota, with its milder temperature. In Oregon is found a striking
example of the formation of starch and increase in the size of the
grain, at the relative expense of the nitrogen, due to climate, but
not to high ripening temperature. The average weight per hundred
grains of wheat from this State has been found to be 5.044 grains, and
the relative percentage of nitrogen 1.37, equivalent to 8.60 per cent.
of albuminoids. These are the extremes for America, and are due, as
has been said, to the enhanced formation of starch. This, however, is
said to be not owing to high ripening temperature, because most of the
specimens examined were grown west of the Cascade Range, which has an
extremely moist climate and a summer heat not exceeding 82 deg. F. for
any daily mean. The climate in another way, however, is, of course,
the cause, by producing luxuriant growth, as illustrated by all the
vegetation of the country. Numerous other analyses form illustrations
of the important effect of surroundings and season upon the storing up
of starch by the plant, and consequent relative changes in the
composition of the grain.

As a whole, the poverty of American wheats in nitrogen, decreasing
toward the less exhausted lands of the West, seems to be due more to
influences of soil than of climate, while locally the influence of
season is found to be greater than that of manure, confirming the
conclusions of Messrs. Lawes & Gilbert. Also from the analyses of the
ash of different parts of the grain, as from the analyses of roller
milling products, we learn that a large percentage of ash
constituents, other things being equal, is indicative of large
proportion of bran, and consequently of a low percentage of
flour.--_The Miller._

       *       *       *       *       *



PRECIOUS AND ORNAMENTAL STONES AND DIAMOND CUTTING.[1]

  [Footnote 1: Abstract from Census Bulletin No. 49, April, 1891.]

By GEORGE FREDERICK KUNZ.


The statistics of this report are divided into two sections: First,
the discoveries and finds of precious stones in the United States and
the mineral specimens sold for museums and private collections or for
bric-a-brac purposes; second, the diamond cutting industry.


DISCOVERIES OF PRECIOUS STONES.

Up to the present time there has been very little mining for precious
or semi-precious stones in the United States, and then only at
irregular periods. It has been carried on during the past few years at
Paris, Maine; near Los Cerrillos, New Mexico; in Alexander County,
North Carolina, from 1881 until 1888; and on the Missouri River near
Helena, Montana, since the beginning of 1890. True beryls and garnets
have been frequently found as a by-product in the mining of mica,
especially in Virginia and North Carolina. Some gems, such as the
chlorastrolite, thomsonite, and agates of Lake Superior, are gathered
on beaches, where they have fallen from rock which has gradually
disintegrated by weathering and wave action.

_Diamond._--A very limited number of diamonds have been found in the
United States. They are met with in well-defined districts of
California, North Carolina, Georgia, and recently in Wisconsin, but up
to the present time the discoveries have been rare and purely
accidental.

_Sapphire._--Of the corundum gems (sapphire, ruby, and other colored
varieties), no sapphires of fine blue color and no rubies of fine red
color have been found. The only locality which has been at all
prolific is the placer ground between Ruby and Eldorado bars, on the
Missouri River, sixteen miles east of Helena, Montana. Here sapphires
are found in glacial auriferous gravels while sluicing for gold, and
until now have been considered only a by-product. Up to the present
time they have never been systematically mined. In 1889 one company
took the option on four thousand acres of the river banks, and several
smaller companies have since been formed with a view of mining for
these gems alone or in connection with gold. The colors of the gems
obtained, although beautiful and interesting, are not the standard
blue or red shades generally demanded by the public.

At Corundum Hill, Macon County, North Carolina, about one hundred gems
have been found during the last twenty years, some of good blue color
and some of good red color, but none exceeding $100 in value, and none
within the past ten years.

_Beryl Gems._--Of the beryl gems (emerald, aquamarine, and yellow
beryl) the emerald has been mined to some extent at Stony Point in
Alexander County, North Carolina, and has also been obtained at two
other places in the county. Nearly everything found has come from the
Emerald and Hiddenite mines, where during the past decade emeralds
have been mined and cut into gems to the value of $1,000, and also
sold as mineralogical specimens to the value of $3,000; lithia
emerald, or hiddenite, to be cut into gems, $8,500, and for
mineralogical specimens, $1,500; rutile, cut and sold as gems, $150,
and as specimens, $50; and beryl, cut and sold as gems, $50.

At an altitude of 14,000 feet, on Mount Antero, Colorado, during the
last three years, material has been found which has afforded $1,000
worth of cut beryls. At Stoneham, Maine, about $1,500 worth of fine
aquamarine has been found, which was cut into gems.

At New Milford, Connecticut, a property was extensively worked from
October, 1885, to May, 1886, for mica and beryl. The beryls were
yellow, green, blue, and white in color, the former being sold under
the name of "golden beryl." No work has been done at the mine since
then. In 1886 and 1887 there were about four thousand stones cut and
sold for some $15,000, the cutting of which cost about $3,000.

_Turquoise._--This mineral, which was worked by the Aztecs before the
advent of the Spaniards, and since then by the Pueblo Indians, and
largely used by them for ornament and as an article of exchange, is
now systematically mined near Los Cerrillos, New Mexico. Its color is
blue, and its hardness is fully equal to that of the Persian, or
slightly greater, owing to impurities, but it lacks the softness of
color belonging to the Persian turquoise.

From time immemorial this material has been rudely mined by the
Indians. Their method is to pour cold water on the rocks after
previously heating them by fires built against them. This process
generally deteriorates the color of the stone to some extent, tending
to change it to a green. The Indians barter turquoise with the Navajo,
Apache, Zuni, San Felipe, and other New Mexican tribes for their
baskets, blankets, silver ornaments, and ponies.

_Garnet and Olivine (Peridot)._--The finest garnets and nearly all the
peridots found in the United States are obtained in the Navajo Nation,
in the northwestern part of New Mexico and the northeastern part of
Arizona, where they are collected from ant hills and scorpion nests by
Indians and by the soldiers stationed at adjacent forts. Generally
these gems are traded for stores to the Indians at Gallup, Fort
Defiance, Fort Wingate, etc., who in turn send them to large cities in
the East in parcels weighing from half an ounce to thirty or forty
pounds each. These garnets, which are locally known as Arizona and New
Mexico rubies, are the finest in the world, rivaling those from the
Cape of Good Hope. Fine gems weighing from two to three carats each
and upward when cut are not uncommon. The peridots found associated
with garnets are generally four or five times as large, and from their
pitted and irregular appearance have been called "Job's tears." They
can be cut into gems weighing three to four carats each, but do not
approach those from the Levant either in size or color.

_Gold Quartz._--Since the discovery of gold in California, compact
gold quartz has been extensively used in the manufacture of jewelry,
at one time to the amount of $100,000 per annum. At present, however,
the demand has so much decreased that only from five to ten thousand
dollars' worth is annually used for this purpose.

In addition to the minerals used for cabinet specimens, etc., there is
a great demand for making clocks, inkstands, and other objects.

_Quartz._--During the year 1887 about half a ton of rock crystal, in
pieces weighing from a few pounds up to one hundred pounds each, was
found in decomposing granite in Chestnut Hill township, Ashe County,
North Carolina. One mass of twenty and one-half pounds was absolutely
pellucid, and more or less of the material was used for art purposes.
This lot of crystal was valued at $1,000.

In Arkansas, especially in Garland and Montgomery Counties, rock
crystals are found lining cavities of variable size, and in one
instance thirty tons of crystals were found in a single cavity. These
crystals are mined by the farmers in their spare time and sold in the
streets of Hot Springs, their value amounting to some $10,000
annually. Several thousand dollars' worth are cut from quartz into
charms and faceted stones, although ten times that amount of paste or
imitation diamonds are sold as Arkansas crystals.

Rose quartz is found in the granitic veins of Oxford County, Maine,
and in 1887, 1888, and 1889 probably $500 worth of this material was
procured and worked into small spheres, dishes, charms, and other
ornamental objects.

The well-known agatized and jasperized wood of Arizona is so much
richer in color than that obtained from any other known locality that,
since the problem of cutting and polishing the large sections used for
table tops and other ornamental purposes was solved, fully $50,000
worth of the rough material has been gathered and over $100,000 worth
of it has been cut and polished. This wood, which was a very prominent
feature at the Paris Exposition, promises to become one of our richest
ornamental materials.

Chlorastrolite in pebbles is principally found on the inside and
outside shores of Rock Harbor, a harbor about eight miles in length on
the east end of Isle Royale, Lake Superior, where they occur from the
size of a pin head to, rarely, the size of a pigeon's egg. When larger
than a pea they frequently are very poor in form or are hollow in
fact, and unfit for cutting into gems. They are collected in a
desultory manner, and are sold by jewelers of Duluth, Petoskey, and
other cities, principally to visitors. The annual sale ranges from
$200 to $1,000.

Thomsonite in pebbles occurs with the chlorastrolite at Isle Royal,
but finer stones are found on the beach at Grand Marais, Cook County,
Minnesota. Like the chlorastrolites, they result from the weathering
of the amygdaloid rock, in which they occur as small nodules, and in
the same manner are sold by jewelers in the cities bordering on Lake
Superior to the extent of $200 to $1,000 worth annually.


THE DIAMOND CUTTING INDUSTRY.

In New York there are sixteen firms engaged in cutting and recutting
diamonds, and in Massachusetts there are three. Cutting has also been
carried on at times in Pennsylvania and Illinois, but has been
discontinued. The firms that were fully employed were generally the
larger ones, whose business consisted chiefly in repairing chipped or
imperfectly cut stones or in recutting stones previously cut abroad,
which, owing to the superior workmanship in command here, could be
recut at a profit, or in recutting very valuable diamonds when it was
desired, with the certainty that the work could be done under their
own supervision, thus guarding against any possible loss by exchange
for inferior stones.

The industry employed 236 persons, of whom 69 were under age, who
received $148,114 in wages. Of the 19 establishments, 16 used steam
power. The power is usually rented. Foot power is only used in one
establishment. Three of the firms are engaged in shaping black
diamonds for mechanical purposes, for glass cutters and engravers, or
in the manufacture of watch jewels.

The diamonds used in this industry are all imported, for, as already
stated, diamonds are only occasionally found in the United States.

The importation of rough and uncut diamonds in 1880 amounted to
$129,207, in 1889 to $250,187, and the total for the decade was
$3,133,529, while in 1883 there were imported $443,996 worth, showing
that there was 94 per cent. more cutting done in 1889 than 1880, but
markedly more in 1882 and 1883. This large increase of importation is
due to the fact that in the years 1882 to 1885 a number of our
jewelers opened diamond cutting establishments, but the cutting has
not been profitably carried on in this country on a scale large enough
to justify branch houses in London, the great market for rough
diamonds, where advantage can be taken of every fluctuation in the
market and large parcels purchased, which can be cut immediately and
converted into cash; for nothing is bought and sold on a closer margin
than rough diamonds.

There has been a remarkable increase in the importation of precious
stones in this country in the last ten years. The imports from 1870 to
1879, inclusive, amounted to $26,698,203, whereas from 1880 to 1889,
inclusive, the imports amounted to $87,198,114, more than three times
as much as were imported the previous decade.

       *       *       *       *       *



SOME EXPERIMENTS ON THE ELECTRIC DISCHARGE IN VACUUM TUBES.[1]

  [Footnote 1: From a recent communication made to the Physical
  Society, London.]

By Prof. J.J. THOMSON, M.A., F.R.S.


[Illustration: FIG. 1.--Coil of Glass Tube for Vacuum Discharge
Experiments. The primary coils are filled with mercury, the secondary
coils form continuous closed circuits.]

The phenomena of vacuum discharges were, he said, greatly simplified
when their path was wholly gaseous, the complication of the dark space
surrounding the negative electrode and the stratifications so commonly
observed in ordinary vacuum tubes being absent. To produce discharges
in tubes devoid of electrodes was, however, not easy to accomplish,
for the only available means of producing an electromotive force in
the discharge circuit was by electromagnetic induction. Ordinary
methods of producing variable induction were valueless, and recourse
was had to the oscillatory discharge of a Leyden jar, which combines
the two essentials of a current whose maximum value is enormous, and
whose rapidity of alternation is immensely great.

[Illustration: FIG. 2.--Exhausted Bulb Surrounded by Primary Spiral
Consisting of a Coiled Glass Tube Containing Mercury.]

[Illustration: FIG. 3.--Exhausted Bulb Surrounded by Primary Coils,
Inclosed in Bell Jar.]

The discharge circuits, which may take the shape of bulbs, or of tubes
bent in the form of coils, were placed in close proximity to glass
tubes filled with mercury, which formed the path of the oscillatory
discharge. The parts thus corresponded to the windings of an induction
coil, the vacuum tubes being the secondary and the tubes filled with
the mercury the primary. In such an apparatus the Leyden jar need not
be large, and neither primary nor secondary need have many turns, for
this would increase the self-induction of the former and lengthen the
discharge path in the latter. Increasing self-induction of the primary
reduces the E.M.F. induced in the secondary, while lengthening the
secondary does not increase the E.M.F. per unit length. Two or three
turns (Fig. 1) in each were found to be quite sufficient, and on
discharging the Leyden jar between two highly polished knobs in the
primary circuit, a plain uniform band of light was seen to pass round
the secondary. An exhausted bulb (Fig. 2) containing traces of oxygen
was placed within a primary spiral of three turns, and, on passing the
jar discharge, a circle of light was seen within the bulb in close
proximity to the primary circuit, accompanied by a purplish glow,
which lasted for a second or more. On heating the bulb the duration of
the glow was greatly diminished, and it could be instantly
extinguished by the presence of an electromagnet. Another exhausted
bulb (Fig. 3), surrounded by a primary spiral, was contained in a bell
jar, and when the pressure of air in the jar was about that of the
atmosphere the secondary discharge occurred in the bulb, as is
ordinarily the case. On exhausting the jar, however, the luminous
discharge grew fainter, and a point was reached at which no secondary
discharge was visible. Further exhaustion of the jar caused the
secondary discharge to appear outside the bulb. The fact of obtaining
no luminous discharge either in the bulb or jar the author could only
explain on two suppositions, viz., that under the conditions then
existing the specific inductive capacity of the gas was very great, or
that a discharge could pass without being luminous. The author had
also observed that the conductivity of a vacuum tube without
electrodes increased as the pressure diminished until a certain point
was reached, and afterward diminished again, thus showing that the
high resistance of a nearly perfect vacuum is in no way due to the
presence of the electrodes. One peculiarity of the discharges was
their local nature, the rings of light being much more sharply defined
than was to be expected. They were also found to be most easily
produced when the chain of molecules in the discharge were all of the
same kind. For example, a discharge could be easily sent through a
tube many feet long, but the introduction of a small pellet of mercury
in the tube stopped the discharge, although the conductivity of the
mercury was much greater than that of the vacuum. In some cases he had
noticed that a very fine wire placed within a tube on the side remote
from the primary circuit would prevent a luminous discharge in that
tube.

[Illustration: FIG. 4.--Exhausted Secondary Coil of One Loop
Containing Bulbs. The discharge passed along the inner side of the
bulbs, the primary coils being placed within the secondary.]

       *       *       *       *       *



THE ELECTRICAL MANUFACTURE OF PHOSPHORUS.


Dr. Readman, at the May meeting of the Glasgow Section of the Society
of Chemical Industry, gave a description of the new works and plant
which have been erected at Wolverhampton for the manufacture of
phosphorus by the Readman-Parker patents. The process consists in
decomposing the mixture of phosphoric acid, or acid phosphates and
carbon, by the heat of the electric arc embedded in the mass.

       *       *       *       *       *



LAYING A MILITARY FIELD TELEGRAPH LINE.


The 1st Division of the Royal Engineers, Telegraph Battalion, now
encamped at Chevening, close to Lord Stanhope's park, as a summer
exercise is engaged in running a military telegraph field line from
Aldershot to Chatham. Along the whole of the line the wire is
supported on light fir and bamboo poles. The work has been carried out
with unusual celerity. From Aldershot to Chevening, a distance of
fifty miles, the line was erected in a day and a quarter, or under
thirty hours, the detachments employed having worked or marched all
night. This is, it is said, the greatest length of telegraph line ever
laid within so short a time. The result cannot fail to be useful, for
by the new line communication is now established both by telegraph and
telephone between Aldershot and Chatham. For laying such telegraph
lines to accompany calvary, a light cable is made use of. This is
carried on reels on a wheeled cart, and can be laid at the rate of six
to seven miles an hour. The Telegraph Battalion of the Royal Engineers
comprises two divisions. One is employed in time of peace under the
Post Office in the construction and maintenance of postal lines; the
other, stationed at Aldershot, is equipped with field telegraph
material.--_Daily Graphic._

[Illustration: LAYING A MILITARY FIELD TELEGRAPH LINE.]

       *       *       *       *       *



AN ELECTROSTATIC SAFETY DEVICE.


This device, as shown in the accompanying illustration, is a glass
cylinder fixed on an ebonite base, and closed at the top by an ebonite
cap. A solid brass rod runs from top to bottom, and near the bottom,
and at right angles to it, is fixed a smaller adjustable rod,
terminating in a flat head. Opposite to this flat disk there is a
brass strip secured to the ebonite cap. From the top of this brass
strip hangs a gold or aluminum foil. The foil and strip are placed to
earth, and the solid brass rod is connected to the circuit to be
protected. Should the difference of potential between the foil and the
terminal opposite to it attain more than a certain amount,
electrostatic attraction will cause the foil to touch the disk and
place the circuit to earth. The apparatus, which is a modification of
the Cardew earthing device, is constructed by Messrs. Drake & Gorham,
of Victoria Street.--_The Electrician_.

[Illustration.]

       *       *       *       *       *



EXPERIMENTS WITH HIGH TENSION ALTERNATING CURRENTS.


Messrs. Siemens and Halske, of Berlin, recently invited the members of
the Elektrotechnische Verein of that city to their works to witness
the demonstration of a series of experiments on alternating currents
under a pressure of 20,000 volts. In order to show that the desired
pressure was really _en evidence_, the high tension was conducted
through a pair of wires of only 0.2 mm. diameter to a battery of 200
100-volt incandescent lamps, all connected up in series. An ordinary
Siemens electric light cable was inserted, and broke down at a
pressure of some 15,000 volts.

At the end of the meeting a few experiments on the formation of the
arc under this enormous pressure were shown. The sparking distance
varied considerably, according to the shape of the electrodes. At
20,000 volts a spark jumped from a ball to a ball about 10
millimeters, while between two points a sparking distance of 30
millimeters, and sometimes even more, was reached. This arc is shown
half size in the accompanying engraving.

[Illustration: A 20,000 VOLT ALTERNATING ARC (half size).]

The arc which followed the jumping over of a spark made a loud humming
and clapping noise, and flapped about, being easily carried away by
the slightest draught. The arc could be drawn out horizontally to
something like 100 millimeters distance between the electrodes, and
even to a distance of 150 millimeters, when carbon pencils were used
as electrodes, but it always remained standing up in a point.
--_Electrical Engineer._

       *       *       *       *       *



THE RELATION OF BACTERIA TO PRACTICAL SURGERY.[1]

  [Footnote 1: The address in surgery delivered before the Medical
  Society of the State of Pennsylvania, June 4, 1890.]

By JOHN B. ROBERTS, A.M., M.D., Professor of Surgery in the Woman's
Medical College and in the Philadelphia Polyclinic.


The revolution which has occurred in practical surgery since the
discovery of the relation of micro-organisms to the complications
occurring in wounds has caused me to select this subject for
discussion. Although many of my hearers are familiar with the germ
theory of disease, it is possible that it may interest some of them to
have put before them in a short address a few points in bacteriology
which are of value to the practical surgeon.

It must be remembered that the groups of symptoms which were formerly
classed under the heads "inflammatory fever," "symptomatic fever,"
"traumatic fever," "hectic fever," and similar terms, varying in name
with the surgeon speaking of them, or with the location of the
disease, are now known to be due to the invasion of the wound by
microscopic plants. These bacteria, after entering the blood current
at the wound, multiply with such prodigious rapidity that the whole
system gives evidence of their existence. Suppuration of wounds is
undoubtedly due to these organisms, as is tubercular disease, whether
of surgical or medical character. Tetanus, erysipelas, and many other
surgical conditions have been almost proved to be the result of
infection by similar microscopic plants, which, though acting in the
same way, have various forms and life histories.

A distinction must be made between the "yeast plants," one of which
produces thrush, and the "mould plants," the existence of which, as
parasites in the skin, gives rise to certain cutaneous diseases. These
two classes of germs are foreign to the present topic, which is
surgery; and I shall, therefore, confine my remarks to that group of
vegetable parasites to which the term bacteria has been given. These
are the micro-organisms whose actions and methods of growth
particularly concern the surgeon. The individual plants are so minute
that it takes in the neighborhood of ten or fifteen hundred of them
grouped together to cover a spot as large as a full stop or period
used in punctuating an ordinary newspaper. This rough estimate applies
to the globular and the egg-shaped bacteria, to which is given the
name "coccus" (plural, cocci). The cane or rod shaped bacteria are
rather larger plants. Fifteen hundred of these placed end to end would
reach across the head of a pin. Because of the resemblance of these
latter to a walking stick they have been termed bacillus (plural,
bacilli).

The bacteria most interesting to the surgeon belong to the cocci and
the bacilli. There are other forms which bacteriologists have dubbed
with similar descriptive names, but they are more interesting to the
physician than to the surgeon. Many micro-organisms, whether cocci,
bacilli, or of other shapes, are harmless, hence they are called
non-pathogenic, to distinguish them from the disease-producing or
pathogenic germs.

As many trees have the same shape and a similar method of growing, but
bear different fruits--in the one case edible and in the other
poisonous--so, too, bacteria may look alike to the microscopist's eye,
and grow much in the same way, but one will cause no disease, while
the other will produce perhaps tuberculosis of the lungs or brain.

Many scores of bacteria have been, by patient study, differentiated
from their fellows and given distinctive names. Their nomenclature
corresponds in classification and arrangement with the nomenclature
adopted in different departments of botany. Thus we have the
pus-causing chain coccus (streptococcus pyogenes), so-called because
it is globular in shape, because it grows with the individual plants
attached to each other, or arranged in a row like a chain of beads on
a string, and because it produces pus. In a similar way we have the
pus-causing grape coccus of a golden color (staphylococcus pyogenes
aureus). It grows with the individual plants arranged somewhat after
the manner of a bunch of grapes, and when millions of them are
collected together, the mass has a golden yellow hue. Again, we have
the bacillus tuberculosis, the rod-shaped plant which is known to
cause tuberculosis of the lungs, joints, brain, etc.

It is hardly astonishing that these fruitful sources of disease have
so long remained undetected, when their microscopic size is borne in
mind. That some of them do cause disease is indisputable, since
bacteriologists have, by their watchful and careful methods, separated
almost a single plant from its surroundings and congeners, planted it
free from all contamination, and observed it produce an infinitesimal
brood of its own kind. Animals and patients inoculated with the plants
thus cultivated have rapidly become subjects of the special disease
which the particular plant was supposed to produce.

The difficulty of such investigation becomes apparent when it is
remembered that under the microscope many of these forms of vegetable
life are identical in appearance, and it is only by observing their
growth when in a proper soil that they can be distinguished from each
other. In certain cases it is quite difficult to distinguish them by
the physical appearances produced during their growth. Then it is only
after an animal has been inoculated with them that the individual
parasite can be accurately recognized and called by name. It is known
then by the results which it is capable of producing.

The various forms of bacteria are recognized, as I have said, by their
method of growth and by their shape. Another means of recognition is
their individual peculiarity of taking certain dyes, so that special
plants can be recognized, under the microscope, by the color which a
dye gives to them, and which they refuse to give up when treated with
chemical substances which remove the stain from, or bleach, all the
other tissues which at first have been similarly stained.

The similarity between bacteria and the ordinary plants with which
florists are familiar is, indeed, remarkable. Bacteria grow in animal
and other albuminous fluids; but it is just as essential for them to
have a suitable soil as it is for the corn or wheat that the farmer
plants in his field. By altering the character of the albuminous fluid
in which the micro-organism finds its subsistence, these small plants
can be given a vigorous growth, or may be actually starved to death.
The farmer knows that it is impossible for him to grow the same crop
year after year in the same field, and he is, therefore, compelled to
rotate his crops. So it is with the microscopic plants which we are
considering.

After a time the culture fluid or soil becomes so exhausted of its
needed constituents, by the immense number of plants living in it,
that it is unfit for their life and development. Then this particular
form will no longer thrive; but some other form of bacterium may find
in it the properties required for functional activity, and may grow
vigorously. It is probable that exhaustion or absence of proper soil
is an important agent in protecting man from sickness due to infection
from bacteria. The ever-present bacteria often gain access to man's
blood through external wounds, or through the lungs and digestive
tracts; but unless a soil suited for their development is found in its
fluids, the plants will not grow. If they do not grow and increase in
numbers, they can do little harm.

Again, there are certain bacteria which are so antagonistic to each
other that it is impossible to make them grow in company, or to
co-exist in the blood of the same individual. For example, an animal
inoculated with erysipelas germs cannot be successfully inoculated
immediately afterward with the germs of malignant pustule. This
antagonism is illustrated by the impossibility of having a good crop
of grain in a field overrun with daisies.

On the other hand, however, there are some micro-organisms which
flourish luxuriantly when planted together in the same fluid, somewhat
after the manner of pumpkins and Indian corn growing between the same
fence rails. Others seem unwilling to grow alone, and only flourish
when planted along with other germs. It is very evident, therefore,
that bacteriology is a branch of botany, and that nature shows the
same tendencies in these minute plants as it does in the larger
vegetable world visible to our unaided eyes.

As the horticulturist is able to alter the character of his plants by
changing the circumstances under which they live, so can the
bacteriologist change the vital properties and activities of bacteria
by chemical and other manipulations of the culture substances in which
these organisms grow. The power of bacteria to cause pathological
changes may thus be weakened and attenuated; in other words, their
functional power for evil is taken from them by alterations in the
soil. The pathogenic, or disease producing, power may be increased by
similar, though not identical, alterations. The rapidity of their
multiplication may be accelerated, or they may be compelled to lie
dormant and inactive for a time; and, on the other hand, by exhausting
the constituents of the soil upon which they depend for life, they may
be killed.

It is a most curious fact, also, that it is possible by selecting and
cultivating only the lighter colored specimens of a certain purple
bacterium for the bacteriologist to obtain finally a plant which is
nearly white, but which has the essential characteristics of the
original purple fungus. In this we see the same power which the
florist has to alter the color of the petals of his flowers by various
methods of selective breeding.

The destruction of bacteria by means of heat and antiseptics is the
essence of modern surgery. It is, then, by preventing access of these
parasitic plants to the human organism (aseptic surgery), or the
destruction of them by chemical agents and heat (antiseptic surgery),
that we are enabled to invade by operative attack regions of the body
which a few years ago were sacred.

When the disease-producing bacteria gain access to the tissues and
blood of human and other animals by means of wounds, or through an
inflamed pulmonary or alimentary mucous membrane, they produce
pathological effects, provided there is not sufficient resistance and
health power in the animal's tissues to antagonize successfully the
deleterious influence of the invading parasitic fungus. It is the
rapid multiplication of the germs which furnishes a _continuous_
irritation that enables them to have such a disastrous effect upon the
tissues of the animal. If the tissues had only the original dose of
microbes to deal with, the warfare between health and disease would be
less uncertain in outcome. Victory would usually be on the side of the
tissues and health. The immediate cause of the pathogenic influence is
probably the chemical excretions which are given out by these
microscopic organisms. All plants and animals require a certain number
of substances to be taken into their organisms for preservation of
their vital activities. After these substances have been utilized
there occurs a sort of excretion of other chemical products. It is
probably the excretions of many millions of micro-organisms,
circulating in the blood, which give rise to the disease
characteristic of the fungus with which the animal has been infected.
The condition called sapræmia, or septic intoxication, for example, is
undoubtedly due to the entrance of the excretory products of
putrefaction bacteria into the circulation. This can be proved by
injecting into an animal a small portion of these products obtained
from cultures of germs of putrefaction. Characteristic symptoms will
at once be exhibited.

Septicæmia is a similar condition due to the presence of the
putrefactive organisms themselves, and hence of their products, or
ptomaines, also in the blood. The rapidity of their multiplication in
this albuminous soil and the great amount of excretion from these
numerous fungi make the condition more serious than sapræmia.
Clinically, the two conditions occur together.

The rapidity with which symptoms may arise after inoculation of small
wounds with a very few germs will be apparent, when it is stated that
one parasitic plant of this kind may, by its rapidity of
multiplication, give rise to fifteen or sixteen million individuals
within twenty-four hours. The enormous increase which takes place
within three or four days is almost incalculable. It has been
estimated that a certain bacillus, only about one thousandth of an
inch in length, could, under favorable conditions, develop a brood of
progeny in less than four days which would make a mass of fungi
sufficient to fill all the oceans of the world, if they each had a
depth of one mile.

Bacteria are present everywhere. They exist in the water, earth, air,
and within our respiratory and digestive tracts. Our skin is covered
with millions of them, as is every article about us. They can
circulate in the lymph and blood and reach every tissue and part of
our organisms by passing through the walls of the capillaries.
Fortunately, they require certain conditions of temperature, moisture,
air, and organic food for existence and for the preservation of their
vital activities.

If the surroundings are too hot, too cold, or too dry, or if they are
not supplied with a proper quantity and quality of food, the bacterium
becomes inactive until the surrounding circumstances change; or it may
die absolutely. The spores, which finally become full-fledged
bacteria, are able to stand a more unfavorable environment than the
adult bacteria. Many spores and adults, however, perish. Each kind of
bacterium requires its own special environment to permit it to grow
and flourish. The frequency with which an unfavorable combination of
circumstances occurs limits greatly the disease-producing power of the
pathogenic bacteria.

Many bacteria, moreover, are harmless and do not produce disease, even
when present in the blood and tissues. Besides this, the white blood
cells are perpetually waging war against the bacteria in our bodies.
They take the bacteria into their interiors and render them harmless
by eating them up, so to speak. They crowd together and form a wall of
white blood cells around the place where the bacteria enter the
tissue, thus forming a barrier to cut off the blood supply to the
germs and, perhaps, to prevent them from entering the general blood
current.

The war between the white blood cells and the bacteria is a bitter
one. Many bacteria are killed; but, on the other hand, the life of
many blood cells is sacrificed by the bacteria poisoning them with
ptomaines. The tissue cells, if healthy, offer great resistance to the
attacks of the army of bacteria. Hence, if the white cells are
vigorous and abundant at the site of the battle, defeat may come to
the bacteria; and the patient suffer nothing from the attempt of these
vegetable parasites to harm him. If, on the other hand, the tissues
have a low resistive power, because of general debility of the
patient, or of a local debility of the tissues themselves, and the
white cells be weak and not abundant, the bacteria will gain the
victory, get access to the general blood current, and invade every
portion of the organism. Thus, a general or a local disease will be
caused; varying with the species of bacteria with which the patient
has been affected, and the degree of resistance on the part of the
tissues.

From what has been stated it must be evident that the bacterial origin
of disease depends upon the presence of a disease-producing fungus and
a diminution of the normal healthy tissue resistance to bacterial
invasion. If there is no fungus present, the disease caused by such
fungus cannot develop. If the fungus be present and the normal or
healthy tissue resistance be undiminished, it is probable that disease
will not occur. As soon, however, as overwork, injury of a mechanical
kind, or any other cause diminishes the local or general resistance of
the tissues and individual, the bacteria get the upper hand, and are
liable to produce their malign effect.

Many conditions favor the bacterial attack. The patient's tissues may
have an inherited peculiarity, which renders it easy for the bacteria
to find a good soil for development; an old injury or inflammation may
render the tissues less resistant than usual; the point, at which
inoculation has occurred may have certain anatomical peculiarities
which make it a good place in which bacteria may multiply; the blood
may have undergone certain chemical changes which render it better
soil than usual for the rapid growth of these parasitic plants.

The number of bacteria originally present makes a difference also. It
is readily understood that the tissues and white blood cells would
find it more difficult to repel the invasion of an army of a million
microbes than the attack of a squad of ten similar fungi. I have said
that the experimenter can weaken and augment the virulence of bacteria
by manipulating their surroundings in the laboratory. It is probable
that such a change occurs in nature. If so, some bacteria are more
virulent than others of the same species; some less virulent. A few of
the less virulent disposition would be more readily killed by the
white cells and tissues than would a larger number of the more
virulent ones. At other times the danger from microbic infection is
greater because there are two species introduced at the same time; and
these two multiply more vigorously when together than when separated.
There are, in fact, two allied hosts trying to destroy the blood cells
and tissues. This occurs when the bacteria of putrefaction and the
bacteria of suppuration are introduced into the tissues at the same
time. The former cause sapræmia and septicæmia, the latter cause
suppuration. The bacteria of tuberculosis are said to act more
viciously if accompanied by the bacteria of putrefaction.
Osteomyelitis is of greater severity, it is believed, if due to a
mixed infection with both the white and golden grape-coccus of
suppuration.

I have previously mentioned that the bacteria of malignant pustule are
powerless to do harm when the germs of erysipelas are present in the
tissues and blood. This is an example of the way in which one species
of bacteria may actually aid the white cells, or leucocytes, and the
tissues in repelling an invasion of disease-producing microbes.

Having occupied a portion of the time allotted to me in giving a crude
and hurried account of the characteristics of bacteria, let me
conclude my address by discussing the relation of bacteria to the
diseases most frequently met with by the surgeon.

Mechanical irritations produce a very temporary and slight
inflammation, which rapidly subsides, because of the tendency of
nature to restore the parts to health. Severe injuries, therefore,
will soon become healed and cured if no germs enter the wound.

Suppuration of operative and accidental wounds was, until recently,
supposed to be essential. We now know, however, that wounds will not
suppurate if kept perfectly free from one of the dozen forms of
bacteria that are known to give rise to the formation of pus.

The doctrine of present surgical pathology is that suppuration will
not take place if pus-forming bacteria are kept out of the wound,
which will heal by first intention without inflammation and without
inflammatory fever.

In making this statement I am not unaware that there is a certain
amount of fever following various severe wounds within twenty-four
hours, even when no suppuration occurs. This wound fever, however, is
transitory; not high; and entirely different from the prolonged
condition of high temperature formerly observed nearly always after
operations and injuries. The occurrence of this "inflammatory,"
"traumatic," "surgical," or "symptomatic" fever, as it was formerly
called, means that the patient has been subjected to the poisonous
influence of putrefactive germs, the germs of suppuration, or both.

We now know why it is that certain cases of suppuration are not
circumscribed but diffuse, so that the pus dissects up the fascias and
muscles and destroys with great rapidity the cellular tissue. This
form of suppuration is due to a particular form of bacterium called
the pus-causing "chain coccus." Circumscribed abscesses, however, are
due to one or more of the other pus-causing micro-organisms.

How much more intelligent is this explanation than the old one that
diffuse abscesses depended upon some curious characteristic of the
patient. It is a satisfaction to know that the two forms of abscess
differ because they are the result of inoculation with different
germs. It is practically a fact that wherever there is found a diffuse
abscess there will be discovered the streptococcus pyogenes, which is
the name of the chain coccus above mentioned.

So, also, is it easy now to understand the formation of what the old
surgeons called "cold" abscesses, and to account for the difference in
appearance of its puriform secretion from the pus of acute abscesses.
Careful search in the fluid coming from such "cold" abscesses reveals
the presence of the bacillus of tuberculosis, and proves that a "cold"
abscess is not a true abscess, but a lesion of local tuberculosis.

Easy is it now to understand the similarity between the "cold abscess"
of the cervical region and the "cold abscess" of the lung in a
phthisical patient. Both of them are, in fact, simply the result of
invasion of the tissues with the ubiquitous tubercle bacillus; and are
not due to pus-forming bacteria.

Formerly it was common to speak of the scrofulous diathesis, and
attempts were made to describe the characteristic appearance of the
skin and hair pertaining to persons supposed to be of scrofulous
tendencies. The attempt was unsuccessful and unsatisfactory. The
reason is now clear, because it is known that the brunette or the
blond, the old or the young, may become infected with the tubercle
bacillus. Since the condition depends upon whether one or the other
become infected with the generally present bacillus of tubercle, it is
evident that there can be no distinctive diathesis. It is more than
probable, moreover, that the cutaneous disease so long described as
lupus vulgaris is simply a tubercular ulcer of the skin, and not a
special disease of unknown causation.

The metastatic abscesses of pyæmia are clearly explained when the
surgeon remembers that they are simply due to a softened blood clot
containing pus-causing germs being carried through the circulation and
lodged in some of the small capillaries.

A patient suffering with numerous boils upon his skin has often been a
puzzle to his physician, who has in vain attempted to find some cause
for the trouble in the general health alone. Had he known that every
boil owed its origin to pus bacteria, which had infected a sweat gland
or hair follicle, the treatment would probably have been more
efficacious. The suppuration is due to pus germs either lodged upon
the surface of the skin from the exterior or deposited from the
current of blood in which they have been carried to the spot.

I have not taken time to go into a discussion of the methods by which
the relationship of micro-organisms to surgical affections has been
established; but the absolute necessity for every surgeon to be fully
alive to the inestimable value of aseptic and antiseptic surgery has
led me to make the foregoing statements as a sort of _résumé_ of the
relation of the germ theory of disease to surgical practice. It is
clearly the duty of every man who attempts to practice surgery to
prevent, by every means in his power, the access of germs, whether of
suppuration, putrefaction, erysipelas, tubercle, tetanus, or any other
disease, to the wounds of a patient. This, as we all know, can be done
by absolute bacteriological cleanliness. It is best, however, not to
rely solely upon absolute cleanliness, which is almost unattainable,
but to secure further protection by the use of heat and antiseptic
solutions. I am fully of the opinion that chemical antiseptics would
be needless if absolute freedom from germs was easily obtained. When I
know that even such an enthusiast as I myself is continually liable to
forget or neglect some step in this direction, I feel that the
additional security of chemical antisepsis is of great value. It is
difficult to convince the majority of physicians, and even ourselves,
that to touch a finger to a door knob, to an assistant's clothing, or
to one's own body, may vitiate the entire operation by introducing one
or two microbic germs into the wound.

An illustration of how carefully the various steps of an operation
should be guarded is afforded by the appended rules, which I have
adopted at the Woman's Hospital of Philadelphia for the guidance of
the assistants and nurses. If such rules were taught every medical
student and every physician entering practice as earnestly as the
paragraphs of the catechism are taught the Sunday school pupil (and
they certainly ought to be so taught) the occurrence of suppuration,
hectic fever, septicæmia, pyæmia, and surgical erysipelas would be
practically unknown. Death, then, would seldom occur after surgical
operations, except from hemorrhage, shock, or exhaustion.

I have taken the liberty of bringing here a number of culture tubes
containing beautiful specimens of some of the more common and
interesting bacteria. The slimy masses seen on the surfaces of jelly
contained in the tubes are many millions of individual plants, which
have aggregated themselves in various forms as they have been
developed as the progeny of the few parent cells planted in the jelly
as a nutrient medium or soil.

With this feeble plea, Mr. President and members of the Society, I
hope to create a realization of the necessity for knowledge and
interest in the direction of bacteriology; for this is the foundation
of modern surgery. There is, unfortunately, a good deal of abominable
work done under the names of antiseptic and aseptic surgery, because
the simplest facts of bacteriology are not known to the operator.

_Rules to be observed in Operations at Dr. Roberts' Clinic at the
Woman's Hospital of Philadelphia._--After wounds or operations high
temperature usually, and suppuration always, is due to blood
poisoning, which is caused by infection with vegetable parasites
called bacteria.

These parasites ordinarily gain access to the wound from the skin of
the patient, the finger nails or hands of the operator or his
assistants, the ligatures, sutures, or dressings.

Suppuration and high temperature should not occur after operation
wounds if no suppuration has existed previously.

Bacteria exist almost everywhere as invisible particles in the dust;
hence, everything that touches or comes into even momentary contact
with the wound must be germ-free--technically called "sterile."

A sterilized condition of the operator, the assistant, the wound,
instruments, etc., is obtained by removing all bacteria by means of
absolute surgical cleanliness (asepsis), and by the use of those
chemical agents which destroy the bacteria not removed by cleanliness
itself (antisepsis).

Surgical cleanliness differs from the housewife's idea of cleanliness
in that its details seem frivolous, because it aims at the removal of
microscopic particles. Stains, such as housewives abhor, if germ-free,
are not objected to in surgery.

The hands and arms, and especially the finger nails, of the surgeon,
assistants, and nurses should be well scrubbed with hot water and
soap, by means of a nail brush, immediately before the operation. The
patient's body about the site of the proposed operation should be
similarly scrubbed with a brush and cleanly shaved. Subsequently the
hands of the operator, assistants, and nurses, and the field of
operation should be immersed in, or thoroughly washed with, corrosive
sublimate solution (1:1,000 or 1:2,000). Finger rings, bracelets,
bangles, and cuffs worn by the surgeon, assistants, or nurses must be
removed before the cleansing is begun; and the clothing covered by a
clean white apron, large enough to extend from neck to ankles and
provided with sleeves.

The instruments should be similarly scrubbed with hot water and soap,
and all particles of blood and pus from any previous operation removed
from the joints. After this they should be immersed for at least
fifteen minutes in a solution of beta-naphthol (1:2,500), which must
be sufficiently deep to cover every portion of the instruments. After
cleansing the instruments with soap and water, baking in a temperature
a little above the boiling point of water is the best sterilizer.
During the operation the sterilized instruments should be kept in a
beta-naphthol solution and returned to it when the operator is not
using them.

[The antiseptic solutions mentioned here are too irritating for use in
operations within the abdomen and pelvis. Water made sterile by
boiling is usually the best agent for irrigating these cavities, and
for use on instruments and sponges. The instruments and sponges must
be previously well sterilized.]

Sponges should be kept in a beta-naphthol or a corrosive sublimate
solution during the operation. After the blood from the wound has been
sponged away, they should be put in another basin containing the
antiseptic solution, and cleansed anew before being used again. The
antiseptic sutures and ligatures should be similarly soaked in
beta-naphthol solution during the progress of the operation.

No one should touch the wound but the operator and his first
assistant. No one should touch the sponges but the operator, his first
assistant, and the nurse having charge of them. No one should touch
the already prepared ligatures or instruments except the surgeon and
his first or second assistants.

None but those assigned to the work are expected to handle
instruments, sponges, dressings, etc., during the operation.

When any one taking part in the operation touches an object not
sterilized, such as a table, a tray, or the ether towel, he should not
be allowed to touch the instruments, the dressings, or the ligatures
until his hands have been again sterilized. It is important that the
hands of the surgeon, his assistants, and nurses should not touch any
part of his own body, nor of the patient's body, except at the
sterilized seat of operation, because infection may be carried to the
wound. Rubbing the head or beard or wiping the nose requires immediate
disinfection of the hands to be practiced.

The trailing ends of ligatures and sutures should never be allowed to
touch the surgeon's clothing or to drag upon the operating table,
because such contact may occasionally, though not always, pick up
bacteria which may cause suppuration in the wound.

Instruments which fall upon the floor should not be again used until
thoroughly disinfected.

The clothing of the patient, in the vicinity of the part to be
operated upon, and the blanket and sheets used there to keep him warm,
should be covered with dry sublimate towels. All dressings should be
kept safe from infection by being stored in glass jars, or wrapped in
dry sublimate towels.

       *       *       *       *       *



INFLUENCE OF REPOSE ON THE RETINA.


Some interesting researches have lately been published in an Italian
journal concerning the influence of repose on the sensitiveness of the
retina (a nervous network of the eye) to light and color. The
researches in question--those of Bassevi--appear to corroborate
investigations which were made some years ago by other observers. In
the course of the investigations the subject experimented upon was
made to remain in a dark room for a period varying in extent from
fifteen to twenty minutes. The room was darkened, it is noted, by
means of heavy curtains, through which the light could not penetrate.
After the eyes of the subject had thus been rested in the darkness, it
was noted that the sensitiveness of his sight had been increased
threefold. The mere sense of light itself had increased eighteen
times. It was further noted that the sensitiveness to light rays,
after the eye had been rested, was developed in a special order; the
first color which was recognized being red, then followed yellow,
while green and blue respectively succeeded. If color fatigue was
produced in the eye by a glass of any special hue, it was found that
the color in question came last in the series in point of recognition.
The first of these experiments, regarded from a practical point of
view, would appear to consist in an appreciation of the revivifying
power of darkness as regards the sight. The color purple of the retina
is known to become redeveloped in darkness; and it is probable,
therefore, that the alternation of day and night is a physical and
external condition with which the sight of animals is perfectly in
accord.

       *       *       *       *       *



SUN DIALS.


An article on the subject, recently published by us, has gained for us
the communication of two very interesting sun dials, which we shall
describe. The first, which we owe to the kindness of General Jancigny,
is of the type of the circular instrument, of which we explained the
method of using in our preceding article. The hour here is likewise
deduced from the height of the sun converted into a horary angle by
the instrument itself; but the method by which such conversion
operates is a little different. Fig. 1 shows the instrument open for
observation. We find here the meridian circle, M, and the equator E,
of the diagram shown in Fig. 3 (No. 4); but the circle with alidade is
here replaced by a small aperture movable in a slide that is placed in
a position parallel with the axis of the world. Upon this slide are
marked, on one side, the initials of the names of the months and on
the other side the corresponding signs of the zodiac. The sun
apparently describing a circle around the axis, PP¹, the rays passing
through a point of the axis (small aperture of the slide) will travel
over a circular cone around such axis. If, then, the apparatus be so
suspended that the circle, M, shall be in the meridian, the slide
parallel with the earth's axis, and the circle, E, at right angles
with the slide, the pencil of solar light passing through the aperture
will describe, in one day, a cone having the slide for an axis; that
is to say, concentric with the equator circle. If, moreover, the
aperture is properly placed, the luminous pencil will pass through the
equator circle itself; to this effect, the aperture should be in a
position such that the angle, a (Fig. 3, No. 4), may be equal to the
declination of the sun on the day of observation. It is precisely to
this end that the names of the months are inscribed upon the slide....

[Illustration: FIG. 1.--TRAVELER'S SUN DIAL.]

The accessories of the instrument are as follows: A ring with a pivot
for suspending the meridian circle, and the position of which, given
by a division in degrees marked upon this circle, must correspond with
the latitude of the place; two stops serving to fix the position of
the equator circle; finally the latitude of various cities. The
instrument was constructed at Paris, by Butterfield, probably in the
last quarter of the eighteenth century.

The second instrument, which is of the same nature as the cubical sun
dial--that is to say, with horary angle--is, unlike the latter, a true
trinket, as interesting as a work of art as it is as an astronomical
instrument. It is a little mandolin of gilded brass, and is shown of
actual size in Fig. 2. The cover, which is held by a hook, may be
placed in a vertical position, in which it is held by a second hook.
It bears in the interior the date 1612. This is the only explicit
historic datum that this little masterpiece reveals to us. Its maker,
who was certainly an artist, and, as we shall see, also a man of
science, had the modesty not to inscribe his name in it.

[Illustration: FIG. 2.--SUN DIAL IN THE FORM OF A MANDOLIN,
CONSTRUCTED IN 1612.]

No. 2 of Fig. 3 represents the instrument open. It rests upon the tail
piece and neck of the mandolin. The cover is exactly vertical. The
bottom of the mandolin is closed by a horizontal silver plate,
beneath which is soldered the box of a compass designed to put the
instrument in the meridian, and carrying upon its face an arrow and
the indications S. OR. M. OC., that is to say, "Septentrion" (north),
"Orient" (east), "Midi" (south), "Occident" (west). One of the ends of
the needle of the compass is straight, while the other is forked. It
is placed in a position in which it completes the arrow, thus
permitting of making a very accurate observation (Fig. 2, No. 3).
Around the compass, the silver plate carries the lines of hours. It is
perfectly adjusted, and held in place by a screw that traverses the
bottom of the instrument. In front of the compass it contains a small
aperture designed to permit of the passage of the indicating thread,
which, at the other end, is fastened to the cover. The silver plate is
not soldered, in order that the thread may be replaced when it chances
to break. On the inner part of the cover are marked in the first place
the horary lines, traversed by curves that are symmetrical with
respect to the vertical and having the aspect of arcs of hyperbolas.
At the extremity of these lines are marked the signs of the zodiac. At
the top, a pretty banderole, which appears at first sight to form a
part of the _ensemble_ of the curves, completes the design. Such is
this wonderful little instrument, in which everything is arranged in
harmonious lines that delight the eye and easily detract one's
attention from a scientific examination of it. Let us enter upon this
drier part of our subject; we shall still have room to wonder, and let
us take up first the higher question.

[Illustration: FIG. 3.--DIAGRAM EXPLANATORY OF THE MANDOLIN SUN DIAL.]

Let us consider a horizontal plane (Fig. 3, No. 2)--a plane
perpendicular to the meridian, and a right line parallel with the axis
of the world. Let P be a point upon this line. As we have seen, such
point is the summit of a very wide cone described in one day by the
solar rays. At the equinox this cone is converted into a plane, which,
in a vertical plane, intersects the straight line A B. Between the
vernal and autumnal equinoxes the sun is situated above this plane,
and, consequently, the shadow of P describes the lower curves at A B.
During winter, on the contrary, it is the upper curves that are
described. It is easily seen that the curves traced by the shadow of
the point P are hyperbolas whose convexity is turned toward A B. It
therefore appears evident to us that the thread of our sun dial
carried a knot or bead whose shadow was followed upon the curves. This
shadow showed at every hour of the day the approximate date of the day
of observation. The sun dial therefore served as a calendar. But how
was the position of the bead found? Here we are obliged to enter into
new details. Let us project the figure upon a vertical plane (Fig. 3,
No. 1) and designate by H E the summits of the hyperbolas
corresponding to the winter and summer solstices. If P be the position
of the bead, the angles, P H H¹, P E E¹, will give the height of the
sun above the horizon at noon, at the two solstices. Between these
angles there should exist an angle of 47°, double the obliquity of the
ecliptic, that is to say, the excursion of the sun in declination: now
P E E¹-P H H¹ = E P H = 47°.

Let us carry, at H and E, the angles, O H E = H E O = 43° = 90°-47°;
the angle at 0° will be equal to 180-86 = 94°. If we trace the
circumference having O for a center, and passing through E and H, each
point, Q, of such circumference will possess the same property as the
angle, H Q E = 47°. The intersection, P, of the circumference with the
straight line, N, therefore gives the position of the bead.

Let us return to our instrument. We have traced upon a diagram the
distance of the points of attachment of the thread, at the
intersection of the planes of projection. We have thus obtained the
position of the line, N S. Then, operating as has just been said, we
have marked the point, P. Now, accurately measuring all the angles, we
have found: N S R = 50°; P H H¹ = 18°; P E E¹ = 65°. The first shows
that the instrument has been constructed for a place on the parallel
of 50°, and the others show that, at the solstices, the height of the
sun was respectively 18° and 65°, decompounded as follows:

  18° = polar height of the place -23½°.
  65° = "     "      "      "     +23½°.

The polar height of the place where the object was to be observed
would therefore be 41½°, that is to say, its latitude would be 48½°.

Minor views of construction and measurement and the deformations that
the instrument has undergone sufficiently explain the divergence of
1½° between the two results, which comprise between them the latitude
of Paris.

After doing all the reasoning that we have just given at length, we
have finally found the means by which the hypothetic bead was to be
put in place. A little beyond the curves, a very small but perfectly
conspicuous dot is engraved--the intersection of two lines of
construction that it was doubtless desired to efface, but the scarcely
visible trace of which subsists. Upon measuring with the compasses the
distance between the insertion of the thread and this dot, we find
exactly the distance, N P, of our diagram. Therefore there is no doubt
that this dot served as a datum point. The existence of the bead upon
the thread and the use of it as a rude calendar therefore appears to
be certain.

The compass is to furnish us new indications. After dismounting it--an
operation that the quite primitive enchasing of the face plate renders
very easy--we took a copy of it, which we measured with care. The
arrow forms with the line O C-O R an angle of 90° + 8°. The compass
was therefore constructed in view of an eastern declination of 8°.

Now, here is what we know with most certainty as to the magnetic
declination of Paris at the epoch in question:

  Years.     Declinations.
  1550.         8° east.
  1580.        11.30
  1622.         6.30
  1634.         4.16

On causing the curve (Fig. 3, No. 3) to pass through the four points
thus determined, we find, for 1612, the declination 8½°. This is, with
an approximation closer than that of the measurements that can be made
upon the small compass, the value that we found. From these data as a
whole we draw the two following conclusions: (1) The instrument was
constructed at Paris; and (2) the inventor was accurately posted in
the science of his time.

Certain easily perceived retouchings, moreover, show that this sun
dial is not a copy, but rather an original. We are therefore in an
attitude to claim, as we did at the outset, that the constructor of
this pleasing object was not only an artist, but a man of science as
well.

Let us compare a few dates: In 1612, Galileo and Kepler were still
living. Thirty years were yet to lapse before the birth of Newton.
Modern astronomy was in its tenderest infancy, and remained the
privilege of a few initiated persons.--_C.E. Guillaume, in La Nature._

       *       *       *       *       *

[MIND.]



THE UNDYING GERM PLASM AND THE IMMORTAL SOUL.

By Dr. R. VON LENDENFELD.

[The following article appeared originally, last year, in the German
scientific monthly, _Humboldt_. It, is reproduced here (by
permission)--the English from the hand of Mr. A.E. Shipley--as a
specimen of the kind of general speculation to which modern biology is
giving rise.--EDITOR.]


To Weismann is due the credit of transforming those vague ideas on the
immortality of the germ plasma which have been for some time in the
minds of many scientific men, myself among the number, into a clear
and sharply-defined theory, against the accuracy of which no doubt can
be raised either from the theoretical or from the empirical
standpoint. This theory, defined as it is by Weismann, has but
recently come before us, and some time must elapse before all the
consequences which it entails will be evident. But there is one
direction which I have for some time followed, and indeed began to
think out long before Weismann's remarkable work showed the importance
of this matter. I mean the origin of the conception of the immortal
soul.

Before I approach the solution of this problem, it may be advisable to
recall in a few words to my readers the theory of the immortality of
the germ plasm.

All unicellular beings, such as the protozoa and the simpler algæ,
fungi, etc., reproduce themselves by means of simple fission. The
mother organism may split into two similar halves, as the amoeba does,
or, as is more common in the lowest unicellular plants, it may divide
into a great number of small spores. In these processes it often
happens that the whole body of the mother, the entire cell, may
resolve itself into two or more children; at times, however, a small
portion of the mother cell remains unused. This remnant, in the
spore-forming unicellular plants represented by the cell wall, is then
naturally dead.

From this it follows that these unicellular beings are immortal. The
mother cell divides, the daughter cells resulting from the first
division repeat the process, the third generation does the same, and
so on. At each division the mother cell renews its youth and
multiplies, without ever dying.

External circumstances can, of course, at any moment bring about the
death of these unicellular organisms, and in reality almost every
series of beings which originate from one another in this way is
interrupted by death. Some, however, persist. From the first
appearance of living organisms on our planet till to-day, several such
series--at the very least certainly one--have persisted.

The immortality of unicellular beings is not at any time absolute, but
only potential. Weismann has recently directed attention to this
point. External occurrences may at any moment cause the death of an
individual, and in this way interrupt the immortal series; but in the
intimate organization of the living plasma there exist no seeds of
death. The plasma is itself immortal and will in fact live forever,
provided only external circumstances are favorable.

Death is always said to be inherent in the nature of protoplasm. This
is not so. The plasm, as such, is immortal.

But a further complication of great importance affects the
reproduction and the rejuvenescence of these unicellular organisms;
this is the process of conjugation. Two separate cells, distinct
individuals, fuse together. Their protoplasmic bodies not only unite
but intermingle, and their nuclei do likewise; from two individuals
one results. A single cell is thus produced, and this divides. As a
rule this cell seems stronger than the single individual before the
union. The offspring of a double individual, originated in this way,
increase for some time parthenogenetically by simple fission without
conjugation, until at length a second conjugation takes place among
them. I cannot consider further the origin of this universally
important process of conjugation. I will only suggest that a kind of
conjugation may have existed from the very beginning and may have been
determined by the original method of reproduction, if such existed.

At any rate conjugation has been observed in very many plants and
animals, and is possibly universally present in the living world.

Conjugation does not affect the theory of immortality. The double
individual produced from the fusion of two individuals, which divides
and lives on in its descendants, contains the substance of both. The
conjugating cells have in no way died during the process of
conjugation; they have only united.

If we examine a little more closely the history of such a "family" of
unicellular beings from one period of conjugation to the next, we see
that a great number of single individuals, that is, single cells, have
proceeded from the double individual formed by conjugation. These may
all continue to increase by splitting in two, and then the family tree
is composed of dichotomously branching lines; or they may resolve
themselves into numerous spores, and then the family tree exhibits a
number of branches springing from the same point.

The majority of these branches end blindly with the death, caused by
external circumstances, of that individual which corresponds with the
branch. Only a few persist till the next period of conjugation, and
then unite with other individuals and afford the opportunity for
giving rise to a new family tree.

All the single individuals of such a genealogical table belong to one
another, even though they be isolated. Among certain infusoria and
other protista, they do, in fact, remain together and build up
branching colonies. At the end of each branch is situated an
infusorian (vorticella), and the whole colony represents in itself the
genealogical family tree.

In the beginning, there existed no other animal organisms than these
aggregations of similar unicellular beings, all of which reproduced
themselves. Later on, division of labor made its appearance among the
individuals of the animal colony, and it increased their dependence
upon one another, so that their individuality was to a great extent
lost, and they were no longer able to live independently of one
another.

By the development of this process, multicellular metazoa arose from
the colonies of similar protozoa, and at length culminated in the
higher animals and man.

If we examine the human body, its origin and end, in the light of
these facts, we shall see that a comparison between the simple
immortal protozoa and man leads us to the result that man himself, or
at least a part of him and that the most important, is immortal.

When we turn to the starting point of human development, we find an
egg cell and a spermatozoon, which unite and whose nuclei intermingle.
Thus a new cell is produced. This process is similar to the
conjugation of two unicellular beings, such as two acinetiform
infusoria, one of which, the female ([Symbol: Female]), is larger than
the other, the male ([Symbol: Male]). This difference of size in the
conjugating cell is, however, without importance.

From this double cell produced by conjugation many generations of
cells arise by continual cell division in divergent series. Among the
infusoria these are all immortal, but many of them are destroyed, and
only a few persist till conjugation again takes place. The same is the
case with man. Numerous series of cell families arise, which are all
immortal: of these but few--strictly speaking, only one--live till the
next period of conjugation and then give the impulse which results in
the formation of a new diverging series of cells. The difference
between man and the infusorian is only that in the former the cells
which originate from the double cell (the fertilized ovum) remain
together and become differentiated one from another, while in the
latter the cells are usually scattered but remain alike in appearance,
etc.

The seeds of death do not lie, as Weismann appears to assume, in the
differentiation of the cells of the higher animals. On the contrary,
all the cell series, not only those of the reproductive cells, are
immortal. As a matter of fact all must die; not because they
themselves contain the germs of death and have contained them from the
beginning, but because the structure which is built up by them
collectively finally brings about the death of all. The living plasm
in every cell is itself immortal. It is the higher life of the
collective organism which continually condemns countless cells to
death. They die, not because they cannot continue to exist as such but
because conditions necessary for their preservation are no longer
present.

Thus, while the cells are themselves immortal, the whole organism
which they build up is mortal. The complex inter-dependence between
the single cells, which, since they have adapted themselves to
division of labor, has become necessary, carries with it, from the
beginning, the seeds of death. The mutual dependence ceases to work,
and the various cells are killed.

The death of the individual is a consequence of the defective
precision in the working of the division of labor among the cells.
This defect, after a longer or shorter time, causes the death of all
the cells composing the body. Only those which quit the body retain
their power of living.

Of all those countless cells which, in the course of a lifetime, are
thrown off from the body, only one kind is adapted for existence
outside the body, namely, the reproductive cells.

Among the lower animals the reproductive cells often leave the body of
their parents only after the death of the latter. This is not the case
in man.

All the cell series which do not take part in the formation of
reproductive cells, as well as all the reproductive cells without
exception, or with only a few exceptions, die through unfavorable
external conditions; just as all, or almost all, of the infusoria
which arose from the double cell die before they can conjugate again.

At times, however, some of the infusoria persist till the next period
of conjugation, and in the same way, from time to time, some of the
human reproductive cells succeed in conjugating, and from them a new
individual arises.

A man is the outgrowth of the double cell produced from the
conjugation of two human reproductive cells, and consists of all the
cells which arise from this and remain in connection with each other.
The human individual originates at the moment of the mingling of the
nuclei of the reproductive cells; and the details of this mingling
determine his individual peculiarities.

The end of man is manifestly to preserve, to nourish, and to protect
the series of reproductive cells which are continually developing
within him, to select a suitable mate and to care for the children
which he produces. His whole structure is acquired by means of
selection with this one object in view, the maintenance of the series
of reproductive cells.

From this standpoint the individual loses his significance and
becomes, so to speak, the slave of the reproductive cells. These are
the important and essential and also the undying parts of the
organism. Like raveled threads whose branches separate and reunite,
the series of reproductive cells permeate the successive generations
of the human race. They continually give off other cell series which
branch out from this network of reproductive cells, and, after a
longer or shorter course, come to an end. Twigs from these branches
represent the human individuals, and any one who considers the matter
must recognize that, as was said above, apart from the preservation of
the reproductive cell series the individuals are purposeless.

It is on this basis that the moral ordering of the world must place
itself if it is to stand on any basis at all. It is an easy and a
pleasant task to interpret the facts of history from this standpoint.
Everything fits together and harmonizes, and each turn in the
historical development of civilization when observed from this point
of view acquires a simple and a clear causality.

I cannot enlarge on this topic, engaging as it is, but here a further
question obtrudes itself. May there not be some connection between the
actual immortality of the germ cells, the continuity of their series
and the importance of the part they play, and the origin of the idea
of an immortal soul? May not the former have given rise to the latter?

As a matter of fact, the series of reproductive cells possess the
essential attributes of the human soul; they are the immortal living
part of a man, which contain, in a latent form, his spiritual
peculiarities. The immortality of the reproductive cells is only
potential and is essentially different from that absolute eternal life
which certain religions ascribe to the soul.

We must not, however, forget that at the time when the conception of a
soul arose among men, owing to a defective knowledge of the laws of
logic, no clear distinction was made between a potential immortality
and an absolute life without end.

Herbert Spencer has pointed out that all religions have their origin
in reverence paid to ancestors. Each religion must have a true
foundation, and the deification of our forefathers has this true and
natural foundation inasmuch as they belong to the same series of
reproductive cells as their descendants. Of course our barbaric
ancestors who initiated the ancestor worship had no idea of this
motive for their religion, but that in no way disproves that this and
this alone was the _causa efficiens_ of the origin of such religions.
It is indeed typical of a religion that it depends upon facts which
are not discerned and which are not fully recognized.

With the origin and development of every religion the origin and
development of the conception of the soul progresses step by step.

We find the justification of ancestor worship in the immortality of
the reproductive cells, and in the continuity of their series. This
should also take a part in the origin of the conception of the soul.

Spencer derives the conception of the existence of the soul from
dreams, and from the imagination of the mentally afflicted. The savage
dreams he is hunting, and wakes up to find himself at home. In his
dream he talks with friends who are not present where he sleeps; he
may even in the course of his dream encounter the dead. From this he
draws the conclusions--(1) that he himself has two persons, one
hunting while the other sleeps; (2) that his acquaintances also have a
double existence; and, from those cases in which he met with the dead,
(3) that they are not only double persons, but that one of the persons
is dead while the other continues to live.

Thus, according to Spencer, the idea arises that man consists of two
separable thinking parts, and that one of these can survive the other.

When a person faints and recovers, we say he comes to himself. That
is, a part of his person left him and has returned. But in this case,
as in the dream, the body has not divided, so that in a swoon the
outgoing portion is not corporeal.

The savage will think that this is what remains alive after death,
for he is incapable of distinguishing between a swoon and death. Then
he will associate the part which leaves the body during a swoon with
that which gives life, and some will regard the heart, which fails to
beat after death, and others the breath, which ceases when life does,
as this life-giving part or soul.

Thus far I am quoting from Spencer.

The conception of the soul, which has thus arisen, has been utilized
by astute priests to obtain power over their fellow-men; while the
genuine founders of religions have made use of it, and by threats of
punishment, and promises of reward, have tried to induce mankind to
live uprightly.

With this purpose in view, the teachers of religion have changed the
original conception of the soul and have added to it the attribute of
absolute immortality and eternal duration, an attribute which is in no
way connected by people in a low state of development with their
conception of the soul.

At the present time among the religions of all civilized people the
undying soul plays an extraordinarily important part.

I start from the position that no doctrine can receive a general
acceptation among men which does not depend on a truth of nature. The
various religions agree on one point, and this is the doctrine of the
immortal soul. Such a point of universal agreement, I am convinced,
cannot have been entirely derived from the air. It must have had some
foundation in fact, and the question arises, What was this foundation?
Dreams and phantasms, as Spencer believes? No; there must have been
something real and genuine, and the path we have entered upon to find
traces of this true foundation of the conception of the soul cannot be
distrusted.

We must compare the conception of the soul as held by various related
religions, and strip off from it all those attributes which are not
common to all. But those which all the various religions agree in
ascribing to the soul we may regard as its true attributes.

It would take too long to go into the details of this examination of
the conception of the soul. As the general result of a comparison of
the various views of the soul we may put down the following
characteristics which are invariably ascribed to it:

    (1) The soul is living.

    (2) It survives the body, and can continue to exist without
    it.

    (3) During life it is contained in the body, but leaves it
    after death.

    (4) The soul participates in the conduct of the body: after
    the death of the latter, causality (retribution) can still
    affect the soul.

The characteristics (1) to (3) hold also for the series of
reproductive cells continually developing within the body; and these
attributes of the germ cells may well be the true but unrecognized
cause of the origin of those conceptions of the soul's character.

This like holds true for (4), although the connection is not so
obvious. For this reason it will be advisable to consider the point in
more detail.

It has been already indicated that the founders of religions have made
use of the survival of the soul after death to endeavor to lead
mankind to live righteously, by threats of punishments or promises of
reward, which will affect the soul after the death of the body.

It is precisely on this point that in the most highly developed
religions there is the greatest falling off from the original
conception of the after-effect of human conduct on the soul, and the
most astounding things are inculcated by the Koran and other works
with respect to this.

But here again we may separate the true kernel from the artificial
shell, and reach the conclusion that good conduct is advantageous for
the soul after the death of the body, and that bad conduct is
detrimental. In no other way can the Mohammedan paradise or the
Christian hell be explained than as sheer anthropomorphic realizations
of these facts, which can appeal even to the densest intellect.

What then is good conduct, or bad?

The question is easily asked, but without reference to external
circumstances impossible to answer. _Per se_ there is no good or bad
conduct. Under certain circumstances a vulgar, brutal murder may
become a glorious and heroic act, a good deed in the truest sense of
the word; as, for example, in the case of Charlotte Corday. Nor must
the view of one's fellow creatures be accepted as a criterion of good
or bad conduct, for different parties are apt to cherish diametrically
opposed opinions on one and the same subject. There remains then only
one's own inner feeling or conscience. Good conduct awakes in this a
feeling of pleasure, bad conduct a feeling of pain. And by this alone
can we discriminate. Now let us further ask. What sort of conduct
produces in our conscience pleasure and what sort of conduct induces
pain? If we investigate a great number of special cases, we shall
recognize that conduct which proves advantageous to the individual, to
the family, to the state, and finally to mankind, produces a good
conscience, and that conduct which is injurious to the same series
give rise to a bad conscience. If a collision of interests arise, it
is the degree of relationship which determines the influence of
conduct on the conscience. As, for instance, among the clans in
Scotland, a deed which is advantageous for the clan produces a good
conscience, even if it be injurious to the state and to mankind.

The conscience is one of the mental faculties of man acquired by
selection and rendered possible by the construction and development of
the commonwealth of the state. Conscience urges us to live rightly,
that is, to do those things which will help ourselves and our family,
whereby our fellow creatures according to their degree of relationship
may be benefited. These are good deeds, and they will merit from the
teachers of religion much praise for the soul. We find, therefore,
that the only possible definition of a good deed is one which will
benefit the series of germ cells arising from one individual, and
further which will be of use to others with their own series of germ
cells, and that in proportion to the degree of connection
(relationship).

It is clear that in this point also the ordinary conception of the
future fate of the soul agrees fundamentally with the result of
observation on the prosperity of the series of germ cells.

As all the forces of nature, known to the ignorant barbarian only by
their visible workings, call forth in him certain vague and,
therefore, religious ideas, which are but a reflection of these forces
in an anthropomorphically distorted form, so the apparently
enigmatical conception of the eternal soul is founded on the actual
immortality and continuity of the germ plasma.

       *       *       *       *       *



COCOS PYNAERTI.


This is an acquisition to the dwarf growing palms, and a graceful
table plant. It first appeared in the nurseries of M. Pynaert, Ghent,
and is evidently a form of C. Weddelliana, having similar character,
though, as shown by the accompanying illustration, it is quite
distinct. The leaves are gracefully arched, the pinnules rather
broader than in the type, more closely arranged, and of a deep tone of
rich green. Such a small growing palm possessing elegant and distinct
character should become a favorite.--_The Gardener's Magazine_.

[Illustration: COCOS PYNAERTI--A NEW PALM.]

       *       *       *       *       *



THE MISSISSIPPI RIVER.[1]

  [Footnote 1: Read May 17, 1890, before the Engineers' Club of
  Philadelphia.]

By JACQUES W. REDWAY.


INTRODUCTION.

The purport of the following paper is to show that corrosion of its
banks and deposition of sediment constitute the legitimate business of
a river. If the bed of the Mississippi were of adamant, and its
drainage slopes were armored with chilled steel, its current would do
just what it has been doing in past ages--wear them away, and fill the
Gulf of Mexico with the detritus.

Many thoughts were suggested by Mr. S.C. Clemens, erstwhile a
Mississippi pilot, and by Mr. D.A. Curtis. Both of these gentlemen
_know_ the river.


GENERAL GEOGRAPHY.

The Mississippi River, as ordinarily regarded, has its head waters in
a chain of lakes situated mainly in Beltrami and Cass counties,
Minnesota. The lake most distant from the north is Elk Lake, so named
in the official surveys of the U.S. Land Office. A short stream flows
from Elk Lake to Lake Itaska, a beautiful sheet of water, considerably
larger than Elk Lake. From Lake Itaska it flows in a general
northeasterly direction, receiving the waters of innumerable springs
and ponds, among them Lake Bemidji, a body of water equal in size to
Lake Itaska. After a course of 135 miles the steam flows into Cass
Lake, absorbing in the meantime the waters of another chain of lakes,
discharged through Turtle River. From Cass Lake the waters flow a
distance of twenty miles, and are poured into Lake Winnibigoshish. The
latter has an area of eighty square miles; it is twice the size of
Cass Lake and more than six times that of Lake Itaska. From Lake
Winnibigoshish to the point where it receives the discharge of Leech
Lake, the river flows through an open savannah, from a quarter of a
mile to a mile in width. Forty miles beyond are Pokegama Falls. Here
the river flows from Pokegama Lake, falling about fourteen feet before
quiet water is reached. All the country about the headwaters is
densely wooded with Norway pine on the higher ground, and with birch,
maple, poplar and tamarack on the lower ground. Between Pokegama Falls
and the Falls of St. Anthony, the river receives the waters of a
number of other similar streams, all flowing from the lake region.

At St. Paul the navigable stage of the river practically begins,
although there is more or less navigable water above the falls at
certain seasons. From St. Paul to Cairo the river flows between
bluffs, the terraces of Champlain times, from ten to fifty miles
apart. Between the bluffs are the bottom lands, often coincident with
the flood plain, along which the river channel wanders in a devious
course of 1,100 miles. The soil of the bottom lands is, of course,
alluvial, and was deposited by the river during past ages; that beyond
the bluffs is a part of the great intermontane plain, and is
sedentary--that is, it has not been materially disturbed since the
plain was raised above the sea level by the uplift of the continent.

From Cairo, at the junction of the Ohio River, the plain to the
southward is nearly all made land, and in a few spots only does the
river touch soil which it has not itself made. Here the Lower
Mississippi proper begins, and here, at some not far distant time in
the past,[2] was the head of the Gulf of Mexico. A fuller description
of the Lower Mississippi is unnecessary here, inasmuch as the
following pages are mainly devoted to this part alone.

  [Footnote 2: Estimated at from 100,000 to 150,000 years. Such
  estimates, however, are but little better than guesses.]


HISTORICAL.

Nearly three and a half centuries have elapsed since De Soto, that
prince among explorers, traversed the broad prairies that lie between
the border highlands of the Western continent, and beheld the stream
which watered the future empire of the world. His chroniclers tell us
that he was raised to an upright position, so that he could catch a
fleeting glimpse of the restless, turbulent flood; for even then the
hand of death was upon him, and soon its waters were to enshroud his
mortal remains. "His soldiers," says Bancroft, "pronounced his eulogy
by grieving for their loss, and the priests chanted over his body the
first requiems ever heard on the Mississippi. To conceal his death,
his body was wrapped in a mantle, and, in the stillness of midnight,
was silently sunk in the middle of the stream." Just across the river
the Arkansas was pouring in its tumultuous flood, and its confluence
was the site of the future town of Napoleon, which in coming years was
to be historic ground.

Worn by suffering, hardships and peril, and racked by the pestilential
fever that still hovers about the river lowlands, De Soto paid the
debt of nature, and his thrice decimated followers made their way back
to France. It seemed a strange, incredible story that they told, for
such a mighty river, with its vast plain, was beyond conception. Its
source, they said, was in the north--among the eternal snows--farther
than it had ever been given to man to penetrate. Its waters, they
thought, were poured into the Gulf of California, or perhaps into the
great Virginia Sea. Its flood, they said, was so great that if all the
rivers of Europe were gathered into one channel, they would not be a
tithe as large. But the people who heard these wonderful accounts were
unconcerned. The French monarch knew naught but to debauch his
heritance; the French courtier intrigued and plundered; the French
peasant, dogged and sullen in his long suffering, dragged out his
miserable existence. The flood of waters rolled on, and a hundred and
thirty years must come and go before the next white man should see the
sheen of its rippling.

Let us cast a retrograde glance to the history of this period. It was
only fifty years before that Columbus had dropped anchor off the coral
reef of Samana Cay, and thrilled the Old World by announcing the
discovery of the New. Elizabeth, the virgin Queen of England, was a
proud, haughty girl just entering her teens, all unmindful of her
eventful future. Mary Queen of the Scots was a tiny infant in
swaddling clothes. The labors of Rafael Sanzio were still fresh in the
memory of his surviving pupils. Michael Angelo was in the zenith of
his fame, bending his energies to the beautifying of the great
cathedral. Martin Luther was in the sere old age of his life, waiting
for the command of the Master, which should bid him lay down his
armor. A hundred years were to elapse before Charles I. of England
must pay with his life the price of his folly.

Joliet, a French trader, was a man possessed of far more brains than
marked the average men of his times. He had not only the indomitable
courage which is essential to the successful explorer, but he had also
the rare ability to manage men; and we find him in 1672 with a
commission from the French king directing him to explore the valley
which was to be a part of New France. The lands which he visited must
be his fee to the king; certain rights of trade he wisely secured to
himself. So, with Pere Marquette, a Jesuit priest, he undertook the
mission, which we may doubt whether to call a journey of discovery or
an errand of diplomacy. Crossing the ocean, their route lay along the
St. Lawrence River to the Great Lakes; through the Great Lakes to the
country of the Illini; down the Illinois to the Mississippi, and down
the Mississippi to its junction with the Arkansas. Here they encamped
near the site of Napoleon. Everywhere along their route they had won
the hearts of the savage Illini. They possessed that rare tact which
was born in French travelers, and which no English explorer ever had.
When they had reached the junction of the Arkansas, "they were kindly
received by the Indian tribes." They held a council with the various
chiefs, with whom they made a treaty. The treaty was celebrated by a
feast, and, if we may believe the record thereof, libations of wine
were freely poured forth to pledge the stipulations of the business
transaction. For a heavenly possession in the uncertain future, the
Indian acknowledged, by the cross raised in commemoration, that he had
bartered away his earthly kingdom. The title by which the Indian held
the soil wrested from the Mound-builder may not have been perfect;
that of the wily Joliet may have been equally defective. But Joliet
builded more wisely than he knew, for to this day, fraud, treachery
and broken faith are the chief witnesses to our treaties with the
aboriginal owners of the land.

Nine years after the business venture of Joliet, La Salle received
letters extraordinary from the King of France, directing him to make
additional explorations along the course of the great river. He
organized an expedition, crossed the ocean, and made his way rapidly
to the scene of his explorations. Preparing his canoes and launches,
he followed the sinuous course of the river to Napoleon. His arrival
was celebrated by another feast and post-prandial business agreement,
and New France began its brief existence. Never in the history of the
world had such an empire been founded--such another could not be
formed until the domains of this had been widened from sea to sea, and
the energy of Saxon, Teuton and Kelt mingled to build a greater.

To La Salle belongs the honor of tracing the true course of the
Mississippi river. He charted it with a faithfulness and accuracy that
would do credit to the surveys of the present day. He seemed to have
noted all the important feeders and tributaries, correctly locating
their points of confluence. He did not cease his work until he reached
the Gulf of Mexico.[3] So not only was La Salle the most indefatigable
explorer of this region, but he also earned the credit of having made
the most important discovery.

  [Footnote 3: From the best information I can gather I am unable to
  decide to my own satisfaction whether or not La Salle discovered
  the Red River. It is not improbable that he never saw this stream,
  for it is more than likely that at that time, Red River poured its
  waters directly into the Gulf of Mexico, through Atchafalaya and
  Cocoudrie Bayous. That these were formerly a part of the channel
  of Red River, there can be no doubt. The sluggish swale that now
  leads from the river to the Gulf is a silted channel that was
  formerly large enough to carry the whole volume of Red River. Such
  changes in the channel of a river, when the latter flows through
  "made" soil, are by no means infrequent. It is only a few years
  since the Hoang River, "the sorrow of Han," broke through its
  restraining banks, and poured its flood into the Gulf of
  Pe-chee-lee, 350 miles distant from its former mouth.]

With La Salle's exploration the future importance of the Mississippi
began; and though the railway has of late years largely supplanted it
as a commercial highway, yet, with the possible exception of the
Ganges, no other river in the world transports yearly a greater
tonnage of merchandise. The early traders were content to carry their
supplies back and forth in canoes. As settlement and business
increased, the canoe gave place to the raft, and the raft yielded to
the flatboat. In the course of time, steam was applied to the
propulsion of boats, and the flatboat yielded to the inevitable: the
palatial steamboat was supreme. But the days of the steamboat were
numbered when the civil war cast its blight over the land; and when
the years of strife were over, so also was the river traffic which had
created the floating palaces of the Mississippi. There were several
things that operated to prevent the reorganization of the fleet of
steamboats which for size, beauty and capacity were found in no other
part of the world. Many of these boats had been destroyed, and the
companies that owned them were financially ruined. Most of those
remaining were purchased or confiscated for military purposes, and
rebuilt either as transports or as gunboats. A period of unparalleled
railway construction began at the close of the war, and most of the
traffic was turned to the railway. Finally, it was discovered that a
puffy, wheezy tug, with its train of barges, costing but a few
thousand dollars, and equipped with half a score of men, could, at a
much less rate, tow a vastly greater cargo than the river steamer.
That discovery was the knell of the old-time steamboat, and the
beginning of a new era of navigation. Powerful as the railway may be,
we cannot shut our eyes to the fact that a tug and train of barges
will carry a cargo of merchandise from St. Paul to St. Louis for
one-tenth the sum the consignee must pay for railway transportation.
So, to-day, the river is just as important as a highway of commerce as
it was in the palmy days of the floating palace and river greyhound.
Railway traffic has enormously increased, but river traffic along the
most wonderful of streams has not materially lessened.

The Mississippi is certainly a wonderful river. From Elk Lake to the
Gulf of Mexico it has a variable length of about 2,800 miles; from
Pass à l'Outre to the head of the Missouri its extent is nearly 4,200
miles--a length not equaled by any other river in the world. It is
evident, by a moment of reflection, that a river which traverses a
great extent of latitude offers much greater facilities for commerce
and settlement than a longitudinal river. The Mississippi traverses a
greater breadth of latitude than any other river, except the Nile, for
its sources are in regions of almost arctic cold, while its delta is
in a land that is practically tropical. The volume of its flood is
surpassed by the Amazon and, perhaps, the Yukon. It discharges,
however, three times as much water as the Danube, twenty-five times as
much as the Rhine, and almost three hundred and fifty times as much as
the Thames. It has several hundred navigable tributaries, and its
navigable waters, stretched in a straight line, would reach nearly
three-fourths the distance around the earth. It is one of the most
sinuous of rivers. In one part of its course it flows in a channel
nearly 1,400 miles long to accomplish, as the crow flies, the distance
of 700 miles. In more than one place the current forms a loop ten,
twenty and even thirty miles around, rather than to cut through a neck
perhaps not half a mile in width. It is one of the most capricious of
rivers, for its channel rarely lies in the same place during two
successive seasons. The river manifests a strong inclination to move
east; and were La Salle to repeat his memorable voyage, he would touch
in scarcely half a score of places the course he formerly traveled; or
if he were to go over exactly the same course, he must of necessity
have his boats dragged over the ground, for almost the entire course
over which he traveled is now dry land. Since that time the river has
deserted almost all of its former channel, as if to repudiate its
connection with the after-dinner treaties of two hundred years lang
syne; in places its channel lies to the west, but for the greater
extent it is to the eastward.[4]

[Footnote 4: "The bed of the river is so broad that the channel
meanders from side to side within the bed, just as the bed itself
meanders from bluff to bluff; and, as by erosions and deposits, the
river, in long periods of time, traverses the valley, so the channel
traverses the bed from bank to bank, justifying the remark often
heard, that 'not a square rod of the bed could be pointed out that had
not, at some time, been covered by the track of steamboats.'"--J.H.
SIMPSON, _Col. Eng., Brevet Brig.-Gen., U.S.A._]


PHYSICAL.

The lower Mississippi is among the muddiest streams in the world.
During the average year it brings down 7,500,000,000 cubic yards of
sediment, discharging it along the lower course, or pushing it into
the Gulf. As one thinks of the small amount of sediment held in a
gallon or two of river water, a comprehension of this vast amount of
silt is impossible. It is enough to cover a square mile in area to a
depth of 268 feet. In five hundred years it would build above the sea
level a State as large and as high as Rhode Island. Thus, by means of
this sediment, the river has pushed its mouths fifty miles into the
sea, confining its flow within narrow strips of land--natural levees
made by the river itself.

The Mississippi is notable for its varying length. Within the memory
of the oldest pilot the length of the river between St. Louis and New
Orleans has varied more than one hundred and fifty miles, being
sometimes longer and sometimes shorter, as the year may be one of
drought or of excessive rainfall. Occasionally the river will shorten
itself a score of miles at a single leap. The shortening invariably
takes place at one of its long sinuous curves for which it is so
remarkable. At a season when the volume of water begins to increase,
the narrow neck of the loop gives way little by little under the
continuous impact of the strengthening current. Narrower and narrower
it grows as the water ceaselessly cuts away the bank. Finally the
barrier is broken; there is a tumultuous meeting of waters; the next
steamboat that comes along goes through a new cut; and a moat or
ox-bow lake is the only reminder of the former channel.[5]

[Footnote 5: One of the most noteworthy examples of these cut-offs is
Davis'. This cut-off occurred at Palmyra Bend, eighteen miles below
Vicksburg. The mid-channel distance around the bend was not far from
twenty miles; the neck was only twelve hundred feet across. The fall
of the river, measured around the bend, was about four inches per
mile; the slope, measured across the neck, was about five and one-half
feet, nearly twenty feet per mile. Inasmuch as the soil in the neck
was wholly alluvial, the current cut its new channel with exceedingly
great rapidity, soon clearing it out a mile in width and more than one
hundred feet in depth. The water rushed through the channel with such
a velocity that steamboats could not breast its flow for many weeks,
while the roaring of its flood could be heard many miles away. The
influence of the cut-off was felt both above and below Vicksburg for
several years after. The rate of erosion has been perceptibly
increased above Vicksburg: and it is not unlikely that the cut-off
which occurred a few years later at Commerce, about thirty miles below
Memphis, was a result of Davis' Cut. Other recent cut-offs have
occurred near Arkansas City, below Greenville, near Duncansby, below
Lake Providence at Vicksburg, and at Kienstra. The latter place is
below Natchez; all the others are between Natchez and Memphis. A
double cut-off is strongly threatened at Greenville.]

In 1863 the city of Vicksburg was situated on the outer curve of such
a loop. At that time General Grant and his army were on the opposite
side of the river, and the whole power of the Federal government was
directed upon devising how the army might cross it and capture the
long-beleagured city. So an army engineer conceived the idea of
turning the river around the rear of the army. Accordingly, a canal
was cut across the loop, in order to make an artificial channel
through which its current might run. But the river steadfastly refused
to accept any channel it had not itself made, and the ditch soon
silted up. Twelve years or more afterward there was trouble; for the
river, which had all this time so persistently ignored the canal, one
stormy night, when its current was considerably swollen, took a notion
to adopt the canal that it had so long refused. Next morning the good
people of Vicksburg woke to find their metropolis, not on the river
channel, but practically an inland town overlooking a stagnant mud
flat. The town of Delta, which, the night before, was three miles
below Vicksburg, was, in the morning, two miles above it. Since that
time, energy and intelligence have conspired in its behalf, and
Vicksburg is still an important river port; but the channel of the
river is persistent, and constant effort and watchfulness alone keep a
depth of water sufficient for the needs of navigation before the
wharves.

The average inhabitant of the flood plain of the Mississippi is not
surprised at this capriciousness of the river, for long experience has
taught him to look for it. During seasons of mean or of low water,
there is little or no trouble; but when floods begin to swell the
current, then it is high time to be on the alert, for no one knows
what a day or even an hour may bring forth. Perhaps a snag, loosened
from the bank above, may come floating down the stream. It strikes a
shallow place somewhere in the river, and thereupon anchors in
mid-channel. Directly it does, a small riffle or bar of silt will form
around it, and this, in turn, sends an eddying current over against
the bank. By and by the latter begins to be chipped away, little by
little. Perhaps the corrosion of the bank might not be noticed except
by a bottom land planter or a riverman. But there is no time to be
lost. If some unfortunate individual happens to possess belongings in
that vicinity, he simply lays aside his coat and works as if he were a
whole legion doing Cæsar's bidding; he well knows that in a very few
hours the river will be swallowing up his real estate at the rate of
half an acre to the mouthful. It is certainly hard to see one's
earthly possessions disappear before the angry flood of the river, but
the bottom land planter does not complain, because the experience of
generations has taught him that he must expect it. A queer fortune
befell Island No. 74.

Between the States of Arkansas and Mississippi there is a large
island, which, for want of a name, is commonly known as Island No.
74.[6] This slip of insular land is probably the only territory within
the United States and not of it, for this island is without the
boundaries of either State, county or township. It is not under
control of the government, because it is in the possession of an owner
whose claim is acknowledged by the government. The anomalous position
of the island as to political situation is due to the erosion of the
river as an active and the defects of statutory law as a passive
agent. According to the enactment whereby the States of Arkansas and
Mississippi were created, the river boundary of the former extends to
_mid-stream_; that of the latter to _mid-channel_. Herein is the
difficulty. A dissipated freshet turned the current against the
Mississippi bank, and shifted the former position of mid-channel many
rods to the eastward, so that the fortunate or unfortunate owner found
his possessions lying beyond both the mid-river point of Arkansas and
the mid-channel line of Mississippi. The owner of the plantation may
be unhappy at time of election, for he is practically a non-resident
of any political division. His grief, however, is somewhat assuaged
when the tax gatherer calls, for, being outside of all political
boundaries, he has no taxes to pay.

[Footnote 6: For convenience to navigation, the islands in the lower
Mississippi, beginning at St. Louis, are numbered. Many of them,
however, have local names by which they are frequently known.]

Within a few years the town of Napoleon, which has already been
mentioned as the site which beheld the cross erected by Marquette and
the seizure of La Salle, was the scene of still another chapter in
history. Almost two hundred years from the time when Joliet and
Marquette beheld the historic ground, the river turned its current
against the banks, and in a few hours the crumbling walls of an old
stone building, half a mile or more from the river banks, were the
surviving monument that marked the former location of the town.

The Mississippi is indeed a grand study, and the people who have lived
in its valley during past ages have seen the river doing just what it
is doing to-day; and as race has succeeded race, each in turn has seen
the landmarks of its predecessors swept away by its angry flood and
buried beneath its sediment. Ever since the crests of the Appalachian
and Rocky Mountains were thrust up above the sea, the river has been
wearing them away, and bearing the scourings to the vast plain below.
In the time of its building it has made the greatest and the richest
valley on the face of the earth; next to that of the Amazon it is the
largest, covering an area of one and one-quarter million square miles.
The river and its tributaries drain twenty-eight States and
Territories--an area equal to that of all Europe except Russia. This
basin includes half the area of the United States, exclusive of
Alaska. It is five times as large as Austria-Hungary, six times the
size of France or Germany, nine times the area of Spain, and ten times
that of the British Isles. Measured by its grain-producing capacity,
this valley is capable of supporting a larger population than any
other physical region on the face of the earth. Already it is the
foremost region in the world in the production of grain, meat and
cotton. The rich soil, sedentary on the prairie and alluvial in the
bottomlands, is almost inexhaustible in its nutritious qualities. The
soil cannot be "worn out" in the bottomlands, for nature restores its
vitality by bringing fresh supplies from the highlands as fast or
faster than the seed crop exhausts it. Sixty bushels of wheat or two
bales of cotton may be harvested from an acre of bottom lands. So vast
in proportions is the yearly crop of food stuffs that more than three
hundred thousand freight cars and about two thousand vessels are
required to move the crop from farm to market. One hundred and
twenty-five thousand miles of railway, fifteen thousand miles of
navigable water, exclusive of the Great Lakes, and several thousand
miles of canals are insufficient to transport this enormous
production; thousands of miles of railway are therefore yearly built
in order to keep pace with the growth of population and the settlement
of new lands. To the natural resources of the soil add the enormous
mineral wealth hidden but a few feet below the surface, and wonder
grows to amazement. Coal fields surpassing in extent all the remaining
fields in the world; iron ore sufficient to stock the world with iron
and steel for the next thousand years; copper of the finest quality;
zinc, lead, salt, building stone and timber, all in quantities
sufficient for a population a hundred times as great. Is it strange
that wise economists point to this territory and say, "Behold the
future empire of the world"? Where in the wide world is another valley
in which climate, latitude and nature have been so liberal?

It is only a few years since the Indian and the bison divided between
them the sole possession of this region. What a change hath the hand
of destiny wrought! What a revelation, had some unseen hand lifted the
curtain that separated the past from the future! Iron, steam and
electricity have in them more of mysterious power than ever oriental
fancy accredited to the genii of the lamp, and the future of the basin
of the Mississippi will be a greater wonder than the past.

The feast of La Salle was the death warrant of the Indian, and the
Aryan has crowded out the Indian, just as the latter evicted the mound
builder--just as the mound builder overcame the people whose monuments
of burned brick and cut stone now lie fifty feet below the surface.
Only a few centuries have gone by since these happenings; can we
number the years hence when rapacious hordes from another land shall
drive out the effete descendants of the now sturdy Aryan?

(_To be continued_.)

       *       *       *       *       *



FREEZING MIXTURES.


The following selection of mixtures causing various degrees of cold,
the starting point of the cooling being indicated in the first column,
will probably serve many purposes. It should be stated that the amount
of depression in temperature will practically be the same, even if the
temperature to start from is higher. Of course in the case of snow it
cannot be higher than 0° C. (32° F.) But in some cases it is necessary
to start at a temperature below 0° C. For instance, the temperature of
-49° C. may be reached by mixing 1 part of snow with ½ part of dilute
nitric acid. But then the snow must have the temperature -23° C. If it
were only at 0° C., the depression would be only to about -26° C.:

  _________________________________________________________________
                                         |
                                         |  The temperature sinks
    Substances to be mixed in parts by   |-------------------------
                 weight.                 |    from    |     to
  _______________________________________|____________|____________
                                         |            |
  1.  Water.                       1     |   +10° C.  |   -15.5° C.
       Ammonium nitrate.           1     |            |
  2.  Dil. hydrochloric acid.     10     |   +10      |   -17.8
       Sodium sulphate.           16     |            |
  3.  Dil. hydrochloric acid.      1     |   +10      |   -16
       Sodium sulphate.            1½    |            |
  4.  Snow.                        1     |   + 0      |   -32.5
       Sulphuric acid.             4     |            |
       Water.                      1     |            |
  5.  Snow.                        1     |   - 7      |   -51
       Dil. sulphuric acid.        1     |            |
  6.  Snow.                        1     |   -23      |   -49
       Dil. nitric acid.            ½    |            |
  7.  Snow.                        1     |     0      |   -17.8
       Sodium chloride.            1     |            |
  8.  Snow.                        1     |     0      |   -49
       Calcium chloride.           1.3   |            |
  9.  Snow.                        1     |     0      |   -33
       Hydrochloric acid.          0.625 |            |
  10. Snow.                        1     |     0      |   -24
       Sodium chloride.            0.4   |            |
       Ammon. chloride.            0.2   |            |
  11. Snow.                        1     |     0      |   -31
       Sodium chloride.            0.416 |            |
       Ammon. nitrate.             0.416 |            |
  _______________________________________|____________|____________

       *       *       *       *       *



THE APPLICATION OF ELECTROLYSIS TO QUALITATIVE ANALYSIS.

By CHARLES A. KOHN, B.Sc., Ph.D., Assistant Lecturer in Chemistry,
University College, Liverpool.


The first application of electrolysis to chemical analysis was made by
Gaultier de Claubry, in 1850, who employed the electric current for
the detection of metals when in solution. Other early workers followed
in this direction, and in 1861 Bloxam published two papers (J. Chem.
Soc., 13, 12 and 338) on "The application of electrolysis to the
detection of poisonous metals in mixtures containing organic matters."
In these papers a description is given of means for detecting small
quantities of arsenic and of antimony by subjecting their acidulated
solutions to electrolysis. The arsenic was evolved as hydride and
recognized by the usual reactions, while the antimony was mainly
deposited as metal upon the cathode. The electrolytic method for the
detection of arsenic, in which all fear of contamination from impure
zinc is overcome, has since been elaborated by Wolff, who has
succeeded in detecting as little as 0.00001 grm. arsenious oxide by
this means (this Journal, 1887, 147).

In a somewhat different manner the voltaic current is made use of in
ordinary qualitative analysis for the detection of tin, antimony,
silver, lead, arsenic, etc., by employing a more electro-positive
metal to precipitate a less electro-positive one from its solution.

The quantitative electrolytic methods of analysis, some of which I had
the honor of bringing before the notice of the Society some time back
(this Journal, 1889, 256), have placed a number of methods of
determination and separation of metals in the hands of chemists, which
can be employed with advantage in qualitative analysis, especially in
case of medical and medico-legal inquiry. These methods are not
supposed to supersede in any way the ordinary methods of qualitative
analysis, but to serve as a final and crucial means of identification,
and thus to render it possible to detect very small quantities of the
substances in question with very great certainty. As such they fulfill
the required conditions admirably, being readily carried out,
comparatively free from contamination with impure reagents, and
capable of being rendered quantitative whenever desired.

In conjunction with Mr. E.V. Ellis, B.Sc., I have examined the
applicability of the electrolytic methods for the detection of the
chief mineral poisons (with the exception of arsenic, an electrolytic
process for the detection of which has already been devised, as
described), viz., antimony, mercury, lead, and copper.

_Antimony_.--The method employed in the case of antimony is that
adopted in its quantitative estimation by means of electrolysis, a
method which insures a complete separation from those metals with
which it is precipitated in the ordinary course of analysis--arsenic
and tin. This fact is of considerable importance in reference to the
special objects for which these methods have been worked out.

The precipitated sulphide is dissolved in potassium sulphide, and the
resultant solution, after warming with a little hydrogen peroxide to
discolorize any poly-sulphides that may be present, electrolyzed with
a current of 1.5-2 c.c. of electrolytic gas per minute (10.436 c.c. at
0° and 760 mm. = 1 ampere), when the antimony is deposited as metal
upon the negative electrode. One part of antimony (as metal) in
1,500,000 parts of solution may be thus detected, a reaction thirty
times more delicate than the deposition by means of zinc and
potassium. The stain on the cathode, which latter is best used in the
form of a piece of platinum foil about 1 sq. cm. in diameter, is
distinct even with a solution containing 1/28 mgrm. of antimony; and
by carefully evaporating a little ammonium sulphide on the foil, or
by dissolving the stain in hot hydrochloric acid and then passing a
few bubbles of sulphureted hydrogen gas into the solution, the orange
colored sulphide is obtained as a satisfactory confirmatory test. The
detection of 0.0001 grm. of metal can be fully relied on under all
conditions, and one hour is sufficient to completely precipitate such
small quantities.

_Mercury_.--Mercury is best separated from its nitric acid solution on
a small closely wound spiral of platinum wire. The solution to be
tested is acidified with nitric acid and electrolyzed with a current
of 4-5 c.c. (c.c. refer to c.c. of electrolytic gas per minute). The
deposition is effected in half an hour. The deposited metal is removed
from the spiral by heating the latter gently in a test tube, when the
mercury forms in characteristic globules on the upper portion of the
tube. As a confirmatory and very characteristic test, a crystal of
iodine is dropped into the tube, and the whole allowed to stand for a
short time, when the presence of mercury is indicated by the formation
of the red iodide. 0.0001 grm. of mercury in 150 c.c. of solution can
be clearly detected.

Wolff has applied this test under similar conditions, using a special
form of apparatus and a silver-coated iron anode (this Journal, 1888,
454).

_Lead_.--Lead is precipitated either as PbO_{2} at the anode from a
nitric acid solution or as metal at the cathode from an ammonium
oxalate solution. In both cases a current of 2-3 c.c. suffices to
effect the deposition in one hour.

Here, again, 0.0001 grm. of metal in 150 c.c. of solution can be
easily detected. With both solutions this amount gives a distinct
discoloration to the platinum spiral, on which the deposition is best
effected. As a confirmatory test the deposited metal is dissolved in
nitric acid and tested with sulphureted hydrogen, or the spiral may be
placed in a test tube and warmed with a crystal of iodine, when the
yellow iodide is formed. This latter reaction is very distinct,
especially in the case of the peroxide.

Of the above two methods, that in which an ammonium oxalate solution
is used is the more delicate, although it cannot be employed
quantitatively, owing to the oxidation of the metal that takes place.

An addition of 1 grm. of ammonium oxalate to the suspected solution is
sufficient.

_Copper_.--0.00005 grm. of copper can be very readily detected by
electrolyzing an acid solution in the usual way. A spiral of platinum
wire is employed as the cathode, and the presence of the metal
confirmed for by dissolving it in a little nitric acid, diluting with
water and adding potassium ferrocyanide.

To detect these metals in cases of poisoning, the organic matter with
which they are associated must first be destroyed in the usual way by
means of hydrochloric acid and potassium chlorate, and the
precipitates obtained in the ordinary course of analysis, then
subjected, at suitable stages, to electrolysis. As the solutions thus
obtained will be still contaminated by some organic matter, it is
necessary to pass the current for a longer time than indicated above.
On the other hand, _urine_ can be tested directly for these poisons.

The presence of mercury or of copper may be detected by acidifying the
urine with 2-3 c.c. of nitric acid (conc.), and electrolyzing as
described. 0.0001 grm. of metal in 30 c.c. of urine can be detected
thus, or 1 part in 300,000 of urine.

Lead does not separate well as peroxide from urine, but if ammonium
oxalate be added, and the lead deposited as metal, the reaction is
quite as delicate as in aqueous solution, and 0.0001 grm. of lead can
be thus detected.

With antimony it is advisable to precipitate it first as sulphide, but
it can be detected directly, though not so satisfactorily, by
acidifying the urine with 2-3 c.c. of sulphuric acid (dil.), and
electrolyzing with a current of 1-5 to 2 c.c. In this case also it is
precipitated as metal upon the cathode (cp. Chittenden, Proceedings
Connecticut Acad. Science, Vol. 8).

In the presence of urine it is advisable to continue the passage of
the current for about twice the time required in the case of aqueous
solutions.

That an approximately quantitative result can be obtained under the
above conditions was shown in several cases in which deposition of
0.001 grm. of metal was confirmed with considerable accuracy, the
spiral or foil being weighed before and after the experiment.

A comparison of the delicacy of these tests with the ordinary
qualitative tests for antimony, mercury, lead, and copper by means of
sulphureted hydrogen, showed that the two were equally delicate in the
case of antimony and of copper, but that in that of mercury and of
lead the electrolytic test was at least eight times the more delicate.
These comparisons were made in aqueous solutions. In testing urine the
value of the electrolytic method is still more evident, for here the
color of the liquid interferes materially with the reliability of the
ordinary qualitative tests when only very small quantities of the
metals referred to are present.

Beyond the detection of mineral poisons, qualitative electrolysis can
only offer attraction to analysts in special cases, and the data on
the subject are to be found in the many electrolytic methods already
published. Beyond testing for gold and silver in this manner, I have
not therefore examined the applicability of these methods further.

The detection of small quantities of gold and silver is of
considerable importance, and advantage can be taken of the ease with
which they are separated from potassium cyanide solution by the
electric current for this purpose.

_Silver_.--Silver is obtained as chloride in the course of analysis.
To confirm for the metal electrolytically, this precipitate is
dissolved in potassium cyanide and the resulting solution electrolyzed
with a current of 1-1.5 c.c. A spiral of platinum wire is employed as
the anode, from which the silver may be dissolved by means of nitric
acid, and tested for by hydrochloric acid or by sulphureted hydrogen.
0.0001 grm. of silver in 150 c.c. of solution can be detected thus,
and one hour is sufficient for the deposition.

_Gold_.--Gold is deposited under similar conditions to silver from
cyanide solutions. The deposit, which is rather dark colored, can be
dissolved in aqua regia and confirmed for by the Cassius' purple test.
Here again 0.0001 grm. of metal in 150 c.c. of solution can be
detected without any difficulty.

As gold and silver are both extracted from quartziferous ores by
treatment with potassium cyanide solution according to the
MacArthur-Forrest process of gold extraction (this Journal, 1890,
267), this electrolytic method should prove very useful. By
electrolyzing the resulting solution a mixture of gold and silver will
be deposited upon the cathode, which can then be parted by nitric acid
and tested for as described.


DISCUSSION.

The chairman said that there was little doubt but that further
investigation into electrolytic methods of chemical analysis would
give even more valuable results than those already obtained.
Systematic investigations of the subject, such as have been given by
Dr. Kohn, would go far to prove the adaptability of this method as a
substitute for or aid in ordinary qualitative examinations. The
remarks of Dr. Kohn respecting quantitative examinations were very
interesting, and well worth following up by other practical work.

Professor Campbell Brown said that Dr. Kohn had shown that electricity
brought the same kind of elegance, neatness, and simplicity into
analysis that it did into lighting and silver plating.

In its applications to the detection of poisons, he understood Dr.
Kohn to say that the poisons must first be extracted by chemical
means. That would not be sufficient, and he had no doubt that if the
subject was pursued farther they would have a paper from him (Dr.
Kohn) some day, indicating that he had obtained arsenic and such
poisons without the previous separation of the metal from organic
matter. It was a very great desideratum to have a method for detecting
arsenic and separating it from the contents of the stomach and food
directly without previous destruction of the organic matter, and he
hoped Dr. Kohn would pursue his work in that direction.

Dr. Hurter said he was about to construct a new laboratory, and he
would assure them that one of its arrangements would be the
installation of electricity, by which to carry out researches similar
to those described. He was very glad to learn that the presence of
arsenic, etc., could be readily proved by means of electrolysis.

       *       *       *       *       *


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