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Title: Old-Time Nautical Instruments
Author: Robinson, John H.
Language: English
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Copyright Status: Not copyrighted in the United States. If you live elsewhere check the laws of your country before downloading this ebook. See comments about copyright issues at end of book.

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  Nautical Instruments






  Old-Time New England

  APRIL, 1921

[Illustration: SHIP GRAND TURK, 1786]



_Curator of the Marine Room, Peabody Museum, Salem, Mass._

What sort of instruments did the Colonial ship-masters carry? What did
they have on the _Mayflower_? What did Columbus use? And, to come down
to comparatively recent times, what instruments were available and were
actually used on the vessels during the commercial-marine activities
following the American Revolution and up to the time of the appearance
of steamships?

These questions are often asked, not only by landsmen but by seafaring
men as well. The ship-master of today uses instruments so different
from those of Colonial times, or even of the earlier years of the
nineteenth century, that unless he has a penchant for research he
knows nothing about the earlier ones and certainly not how to use
them if by chance they come to his notice. Holding in his hand a
Davis quadrant, the skilful navigator of Salem's last square-rigger,
the ship _Mindoro_, which passed out of service in 1897, said to the
writer:--"I have no idea how to use it and I do not believe that there
is a ship-master sailing out of Boston today who does." The Davis
quadrant was in common use all through the eighteenth century and
probably later. It is figured and explained in a book on navigation in
1796. There are two in the Peabody Museum collection in Salem, dated
respectively, 1768 and 1773, and an undated one in the collection is
certainly older. Only the student of the history of navigation can
explain them or their uses. The English navigator, John Davis, the
inventor of this quadrant, in his "Seaman's Secrets", printed in 1594,
gives a list of instruments which should be taken on ships, but it is
to be feared few vessels carried them all or that owners were able to
provide them. It included,--sea-compass, cross-staff, chart, quadrant,
astrolabe, instrument to test compass variation, horizontal plane
sphere, and paradoxical compass.


Full size. From Museum of Fine Arts, Boston.]


Diameter 3-1/2 inches. Owned by Mr. Parker Kemble.]

No one knows exactly what instruments Columbus took with him on his
voyage in 1492. He undoubtedly had an astrolabe and a cross-staff.
The astrolabe was devised during the first millennium and Arabian
astronomers had perfected it as early as the year 700. It is really the
basis of all future instruments of its class,--cross-staff, quadrant,
sextant. Some of the most beautiful astrolabes preserved in museums are
those made for the Persian astronomers in the sixteenth and seventeenth
centuries. Columbus probably used the form devised by Martin Behaim
which had been adapted for use at sea about the year 1480. Observations
with the astrolabe required three persons, one to hold the instrument
plumb by the ring, another to sight the sun and adjust the arm, and the
third to read the scale. With these difficulties observations were, of
course, far from accurate, but approximate time and latitude could be
obtained. Another device was the ring-dial, or universal ring-dial as
the old works on navigation called it. This differed from the astrolabe
by having adjustable rings with the hours and scales engraved upon
them. Both of these instruments are now rare.

No original cross-staff is known to the writer in any collection in
this country. It consisted of a rod thirty-six inches long on which
another of twenty-six inches was centered and arranged to slide up and
down at right angles to it. By sighting from the end of the longer rod
and moving the sliding bar until the sun was seen at one end of it and
the horizon at the other, the figure on the scale at the junction of
the rods indicated the sun's altitude and from this the latitude was


From Seller's "Practical Navigation," London, 1676]


From Seller's "Practical Navigation," London, 1676]

Based on this instrument, by laying out the circle on a table, John
Davis, the explorer, devised his quadrant in 1586. At first the
observer used it by facing the sun, as the cross-staff had been
used, but a better form was made later where the observer had the
sun at his back. This instrument has been called by sailors "jackass
quadrant" and, supposedly from its shape, "hog-yoke." In early books on
navigation it is called "sea-quadrant." The earlier form used by the
observer standing back to the sun had a solid "shade vane" which slid
along the smaller arc of the instrument. By adjusting this a little
short of the supposed altitude of the sun and sighting the horizon
through the minute hole in the "sight vane" until it was seen through
the "horizon vane" at the apex of the instrument, and then gradually
moving the "sight vane" along the larger arc until the shadow of the
"shade vane" met the horizon line, the sum of the degrees on the two
scales indicated the sun's altitude. This was really the second form of
the Davis quadrant. In the third, the solid "shade vane" was replaced
by one with a low-power lens inserted in it arranged to focus on the
"horizon vane," thus approaching the idea of the reflected sun in
the Hadley quadrant and the sextant. A most interesting instrument,
half-way between a cross-staff and the Davis quadrant, is illustrated
in Seller's book on navigation published in 1676. He calls it a
"Plough." Above, it has the small arc of the Davis quadrant with the
sliding rod of the cross-staff below. These were, of course, imperfect
instruments, but still a great advance over previous devices to obtain
time and latitude.

[Illustration: SECT. III.

The Description and Use of the Plough.

_The Description of the Plough._

This Instrument was antiently in use amonght Mariners, although at this
day it is not so commonly used as formerly; it consists of a Staff
having a small Arch, and three Vanes.

_The Figure of the Plough._

The Staff is about two foot and a half long, or three foot at the most;
at the Center-end of which is erected a small Arch, that is divided
into 85 degrees; on the side of the Staff are set off the Graduations
proper to the Plough, beginning at five or six degrees, and encreasing
to ten degrees towards the Arch, every degree being divided into single

The Vanes are a _Horizon-Vane_, as A, and _Shadow-Vane_, as B, (to be
used as in the Quadrant) and a _Sight-Vane_ moving upon the Staff, as
at C.


[Illustration: DAVIS QUADRANT

"Made by William Williams in King St. Boston." An ivory plate has
"Malachi Allen 1769." Mahogany, 24 inches long, convex glass in the
shade vane; fine example of cabinet work. In Peabody Museum, Salem.]

The Davis quadrants are usually made of ebony, rosewood, or other
dark woods, with boxwood scale arcs and could be made by expert
wood-workers. The numerous examples preserved attest the skill of the
old cabinet-makers, for they are never warped or twisted while their
jointing is a Chinese puzzle. Probably the _Mayflower_ carried a Davis
quadrant and quite likely an astrolabe, and of course, a compass, for
the compass had been in use for two centuries.

Whether the compass was independently invented in Europe or was
borrowed from the Chinese is uncertain. The old marine compasses
were set in gimbals. The magnet was a thin bar attached, usually
with sealing wax, to the under side of the compass card, the whole
mounted in a thin bowl of turned wood. These were the compasses
of the eighteenth century. There is one in the Salem collection
inscribed,--"Benjamin King Salem in New England", with the date
"1770" cut in the box; another has the mark of Benjamin King, 1790.
A surveyor's compass, wooden throughout, including wooden sights, is
inscribed,--"Made by James Halsey near ye draw bridge Boston." The
liquid compass first suggested by Francis Crow in 1813 and improved by
E. S. Ritchie of Boston, has largely displaced the older devices.

The "nocturnal", used at night, as its name signifies, appeared at
an early date, exactly when it does not seem possible to say. One in
the Salem collection is marked,--"Nathaniel Viall 1724". By adjusting
the movable discs to the date on the scale for the day of the month,
sighting the north star through the hole in the center and then
bringing the arm against the "guard stars", the hour was indicated with
reasonable accuracy. Good pictures and descriptions of the nocturnal
may be found in old books on navigation.

In 1730, John Hadley in England and Thomas Godfrey in Philadelphia,
independently invented the octant, known for nearly two hundred
years as Hadley's quadrant. Both Hadley and Godfrey received awards
for their devices. Although called quadrant in this country it is
generally known elsewhere as octant, which is the better name, for the
instrument represents but one eighth of the circle. By the principle
of reflection, however, it covers ninety degrees and the scale is so
marked. The Davis quadrant with its two arcs does represent one fourth
of the circle and for that instrument the name is correct.

The Hadley was a great improvement over the Davis quadrant and other
older devices for finding latitude. By moving the arm the sun is
reflected by the mirror at the apex and "brought down" to the horizon
line and the eye is protected by colored glasses of various degrees
of density through which the sun's rays shine. Catching the sun the
instant it is on the meridian (noon), the scale indicates the altitude
by which the latitude was figured with the Bowditch Navigator, used for
more than one hundred years by American seamen, or Moore's before that
and numerous others back to the early eighteenth century. The Hadley
quadrant is still used in its modern form with telescopic eye-pieces
although the sextant--one-sixth of the circle and by reflection
one-third--is a more accurate instrument and also may be used to make
lunar observations to obtain longitude, a complicated and difficult
matter, so difficult that the authors of the older works did not even
take trouble to explain the process, for only the most expert could
make this observation, nor were the results satisfactory.

The sextant was devised about 1757 and as now made is framed wholly of
metal. To prevent corrosion, the scale, which is minutely divided, and
has a "vernier" with a magnifying glass to show divisions of minutes,
is made of gold or platinum in the best instruments. A half-circle
has been devised and is exceedingly rare. An example in the Salem
collection was made before 1818. A curious double-jointed dividers
accompanied it and the entry in the museum catalog reads,--"used
to correct a lunar observation for longitude." A full "circle of
reflection" is also sometimes used, more often on land than at sea.
This is a beautiful instrument and is not often met with in collections
or in use. All of these instruments are similar in character and may be
traced, as previously stated, to the ancestral astrolabe.

[Illustration: NOCTURNAL

"Nath'll Viall 1724." Boxwood, arm seven inches from centre to tip. In
Peabody Museum, Salem.]

The early Hadley quadrants were huge affairs made of wood with an
arm twenty-four inches in length. Today they are more generally of
metal with arms from ten to twelve inches. Using the sextent or Hadley
quadrant the observer stands facing the sun, but old Hadley quadrants
were made with a "back sight" so that they could be used like the Davis
quadrant, thus making two independent observations the average of which
would ensure greater accuracy.


1. "Made by John Dupee 1755 for Patrick Montgomerie." All wood, ebony,
arm 22 inches long.

2. "Made by Ino. Gilbert on Tower Hill London for Hector Orr Augt. 6,
1768." Ebony, arm 20 inches long.

3. "Norie & Co. London." Ebony and brass, _ca._ 1840. Arm 11-3/4
inches, telescopic eyepieces, used by Capt. John Hodges.

4. "Spencer Browning and Rust London." Ebony frame, brass arm 17
inches, ivory scale, pencil inserted in cross piece, _ca._ 1800, used
by Capt. Henry King.

5. "J: Urings London." All brass, arm 20 inches, back sight broken off,
_ca._ 1780, rare.]

To obtain the ship's latitude with comparatively good results was an
easy matter with the quadrant and its fore-runners, but the great
problem for centuries was how to find the longitude, now universally
and quickly obtained by the chronometer and simple observations in
the morning or at noon. Spring clocks and watches appeared about 1530
but they were unreliable and of no use on long voyages. Sand glasses
like those of the old Colonial churches were used on ships and so
conservative is the British mind that some were in use on British naval
vessels as late as 1828 and one authority states as late as 1839.
Greenwich Observatory was established in 1675 and a Royal Commission
was soon appointed with authority to award prizes for important
inventions in aid of navigation. A prize of £20,000 was finally
offered for a time-keeper that should meet certain requirements which
practically meant absolute accuracy. In 1767, John Harrison produced
the chronometer, based on the principle of an invention of 1735, and
eventually he received the reward. Chronometers were so expensive and
so hard to obtain that few New England ships had them until more than a
half a century later. Other devices were tried to obtain longitude by
lunar observations and by Jupiter's satellites, but these observations
were too difficult to be of practical use. Today, fine watches serve
for short trips and chronometers are carried by nearly all vessels
making long voyages.

That so important an instrument as a telescope or spy-glass is rarely
mentioned in books on navigation or in sea journals seems strange. It
is exceedingly difficult to obtain information of any being taken to
sea, although one would think a spy-glass would be about the first
aid on ship-board especially when skirting the coast. Telescopes did
not become of practical use, even if the principle had been known,
until they were made in Holland in 1608. It is at least certain
that Columbus did not have one and probably there was none on the
_Mayflower_, although its passengers had recently come from Holland
where telescopes were invented a few years before. So far no references
to them have been found in a rather casual examination of old log-books.

In the Marine Room Collection of the Peabody Museum at Salem, is a
spy-glass four feet long, octagonal in form, two and one-half inches in
diameter, with a short focusing tube. It was taken from a British prize
vessel off the coast of Ireland, in 1779, by Capt. James Barr in his
Salem privateer. Another glass of similar form, but longer and with a
mahogany case, was used on a United States naval vessel about 1815. The
spy-glass, familiar to everyone, in two or three sections, was used at
sea through the first half of the nineteenth century and is often seen
tucked under the left arm, in the portraits of ship-masters brought
home from foreign ports. Many of these were excellent instruments,
especially those from Dollond of London. There is also in the Salem
collection a rude telescope or spy-glass five and one-half feet long
with a copper case about three inches in diameter looking precisely
like a section from a house water-conductor. It focuses by a small
upper sliding section, fitted like a stove funnel. This glass was
brought from Nagasaki, Japan, by a Salem ship-master about 1865. It had
been used there to observe vessels coming into the harbor. It may be
Dutch and it is evidently very old.


1. "Bradford London." Brass frame and silver scale arm 14 inches long,
_ca._ 1815, used by Capt. George Bailey before 1840.

2. "L. Bleuler, London." Ebony frame, ivory scale, brass arm 14 inches
long, _ca._ 1820, came from Plymouth, Mass.

3. "G. Gowland 76 Castle St. Liverpool." Used by David Livingstone in
his African explorations and after his death sold at Zanzibar by order
of the Royal Geographical Society and bought by Capt. William Beadle,
of Salem, and used on some of his voyages.]

The speed of a vessel was first obtained by throwing overboard a
floating subject at the bow and noting the time elapsed when it passed
an observer at the stern. From this the log line with "knots" was
derived, with the fourteen and twenty-eight seconds sand glasses to
record speed. A "knot" indicates a geographical or sea mile which has
been standardized at 6080 feet; the land or statute mile is 5280 feet,
therefore, if a vessel is said to be sailing at the rate of thirteen
knots, a railroad train going at the same speed would be running at
the rate of fifteen miles an hour. The term "knot" is used solely
to indicate rate of speed; the distance covered is always stated in
nautical or sea miles. "Heaving the log" meant throwing out from the
stern of a vessel a small float attached to a line running from a reel
held clear of the rail, the float remaining stationary in the water.
At the instant the log is "heaved" a sand glass is turned. On the line
are knots (hence the term), pieces of marline or rags tied through the
strands and spaced the same fraction of a mile apart,--above forty-six
feet and six inches,--which twenty-eight seconds is the fraction of
an hour,--about one one-hundred and twenty-eighth. Therefore, using a
twenty-eight seconds glass and checking the line the instant the sand
runs out, the number of knots and fractions paid out on the line will
at once indicate the number of sea miles per hour which the vessel is
going. This, of course, is doubled if the fourteen-seconds glass is
used, which is done when the vessel is going very fast.

The old log lines have been superseded by many forms of the "patent
log" and the museum is indeed fortunate which possesses an original
log line, reel and float in perfect condition. There is an excellent
example in the museum collections of the Marblehead Historical Society.
Once discarded, the lines were soon used to tie up packages and the
reels and floats were thrown away. The patent log with its revolving
blades, now universal, was devised by Humfray Cole in 1578; it was
improved by various persons from time to time but, strange to say,
did not come into general use for nearly three centuries. The rotating
blades in the water record the rate on an indicator on the vessel which
may be read at any time. So far, the earliest reference to the use of
a device of this sort among our New England navigators is the "Gould's
patent log" used by Captain George Crowninshield on his famous yacht
_Cleopatra's Barge_ during the voyage to the Mediterranean in 1817.

Charts were made in very ancient times but they were crude and almost
useless. The first nautical maps appeared in Italy at the end of the
thirteenth century, and it is said that Bartholomew Columbus brought
the first one to England in 1489. The close of the sixteenth century
saw many map makers at work, including Gerard Mercator whose name is
perpetuated in the familiar scale charts in our geographies known as
"Mercator's projection" which were the sea charts in general use.
Globes were carried on ships in preference to charts in the early
days and what is known as "great circle" sailing was evolved from
them. Davis describes it in 1594 and it is possible that Cabot knew of
the theory a century before. Such a simple instrument as a parallel
ruler was not invented until late in the sixteenth century and tables
of logarithms and Gunter's scale by which navigators make all their
calculations were not known until the year the _Mayflower_ sailed.

During the first century following the settlement of New England it is
probable that the small coasting and fishing vessels were navigated by
dead reckoning and not venturing far beyond the sight of land a compass
was the only instrument carried. But the larger vessels sailing from
Boston, Salem, Portsmouth, Newport and other ports on voyages to the
West Indies, England and Spain, it would seem should have carried
instruments with which observations could be made to obtain their
approximate position. Mr. George Francis Dow has searched the early
probate records of Essex County coast towns between 1634 and 1680, a
period of nearly fifty years, and finds but thirteen references to
nautical instruments in inventories and wills. Sometimes they are
listed as "marriners instruments" and in one case a quadrant is valued
at £1. Robert Gray of Salem, who died in 1661, possessed a "quadrant, a
fore-staffe (cross-staff), a gunter's scale, and a pair of Compasses."
John Bradstreet, who died at Marblehead the previous year, owned "3
small sea books" valued at £1. 6s. The inventory of the estate of
Jonathan Browne of Salem, who died in 1667, discloses a "fore-staff,"
and that of the estate of John Silsby of Salem, taken in 1676, lists
"marriners instruments and callender, 14s."

In a very detailed inventory made in Salem before a notary publick on
Nov. 4, 1702, of the equipment of the ship _Province Galley_, 90 tons,
owned by Roger Derby, the only instruments for navigation that appear
are "Two Compasses, two ha[lf] ho[ur] glasses, a ha[lf] Watchglass, a
ha[lf] minute glass ... a hand lead line, a deep sea lead line."

The _Boston News-Letter_, July 16, 1716, has the following
advertisement: "A Parcel of Mathematical Instruments, viz: Quadrants,
Meridian Compasses, all sorts of Rules, black lead Pencils, and brass
Ring Dials, etc. To be sold by Publick Vendue at the Crown Coffee
House in King's Street, Boston, on Thursday next." The same issue has
the advertisement of "William Walker in Merchants Row, near the Swing
Bridge," who had quadrants for sale.

In looking back and noting the slow process of perfecting all nautical
instruments, the wonder is how the old ships were navigated through
distant seas without greater loss of life and vessels. The dangers
were real during our commercial-marine activities following the period
of the Revolution and the early nineteenth century, as attested by
reference to old newspapers and letters, and to such records as the
Diary of Rev. William Bentley of Salem, where nearly every Sunday some
of his parishioners asked for prayers for friends at sea or for the
loss of husband, son or brother. The shipmasters of Salem, Boston,
Providence, New York and Baltimore, undertaking distant voyages, had
few good charts--none for the new regions they visited--they had no
chronometers, few had sextants, and their compasses were frequently
unreliable. And yet these men--most of them were scarcely past their
majority in years--with the courage and enthusiasm of youth, in ships
filled with valuable cargoes, entrusted to their care by wealthy
owners, sailed into uncharted seas, visited unknown lands, and, all the
while rarely reported, finally came safely back, to their everlasting
credit and the enrichment of the country.

We do not know exactly what instruments the old shipmasters carried
with them on these voyages, but we do know that they were comparatively
few and very inferior to those in use today. An idea of the paucity in
some instances may be obtained from the story of the ship _Hannah_,
condemned at Christiansand in 1810, in the protest of American
shipmasters which is now preserved in the New Haven Historical Society
collections. It reads: "We, the undersigned masters of American vessels
now in the port of Christiansand, having heard with astonishment that
one of the principal charges against the American brig _Hannah_, from
Boston, bound direct to Riga, and condemned at the prize court at this
place, is as follows,--that the said court have pronounced it absolutely
impossible to cross the Atlantic without a chart or sextant. We
therefore feel fully authorized to assert that we have frequently made
voyages from America without the above articles, and we are fully
persuaded that every seaman with common nautical knowledge can do the

No doubt many valuable data lie hidden in old log-books and sea
journals, early newspaper files, shipping records of old business
houses and elsewhere. To anyone with time and the inclination for
research a fascinating field is open where material of historical and
scientific value may be found. The writer is not aware that any such
investigations have been made or accounts of any published.

Accurate knowledge of the instruments carried by Colonial shipmasters
on their voyages to the West Indies or along our coast and across the
Atlantic would be of much interest, and still more to know what were
supplied by owners or carried as their personal property by masters
and supercargoes for the longer voyages to Russia, the Mediterranean,
Africa, India, China, and the South Seas. It would be interesting to
know, besides this, what had been their experiences with them: the
accuracy of observations, how the compass behaved, etc. The early
nineteenth century shipmasters were close observers, and in his works
on navigation Lieut. M. F. Maury pays them high compliment for the
valuable assistance rendered in furnishing notes and observations on
currents, shoals, coast lines, compass variations and winds, for the
charts and sailing directions which he compiled.

With these things in mind this paper has been prepared, hoping that
someone may be encouraged to take up the work systematically. It is a
subject which seems to have been neglected, and the results certainly
will repay much time devoted to its investigation.


Coming out of St. Eustatia, Nov. 16, 1765]

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