3. Nautical Instruments

3.94 IMPORTANT SEXTANT.   Second quarter 1800’s navigational instrument made by one of England’s most respected firms of the era, “Troughton & Simms, London” as hand-engraved on the large arc.   This complex “pillar frame” sextant is of the highest quality ever made.  The amazing inlaid sterling silver scale is calibrated from -5 to 155 degrees subdivided by 10 arc minute increments, effectively making it a “quintant.”  Above the maker’s name on the arc is the engraved word indicating “Silver.”  The matching vernier scale in the index arm allows for a reading down to an accuracy of 6 arc seconds!   The reading is set by the index arm stop and tangential fine adjust knobs.  A pivoting magnifier with built-in light diffuser aids in taking the reading.  This instrument is actually 2 sextants in one, having a “double frame” consisting of two sheets of thick brass held together by numerous posts or “pillars,” hence the name.  The index arm is braced for additional support.  This instrument is complete with both index and horizon mirrors and its full set of 4 index and 3 horizon filters.  The height-adjustable sight holder is controlled by a large knurled knob on the reverse.  Also on reverse is the lovely sculpted rosewood handle for holding and 3 brass “feet” for support in the box.  The box itself is noteworthy, being the early keystone type made of rich mahogany with hand-dovetailed construction.  It is complete with brass hinges, functional skeleton lock with key and hook and eye closures.  Remarkably, it is complete with all accessories, including long and short telescopes, cross hair scope, both eyepiece filters and mirror box adjusting tool.  The instrument measures 10 inches high by 11 ½ inches wide.  The box is 11 inches high, 14 inches wide and 5 ¼ inches thick.  Excellent original condition throughout.  The instrument itself is unmodified, fully functional and exhibits traces of the original orange lacquer finish.  The box is in remarkably fine original condition, extremely sound, with no cracks or losses so common in wooden objects of this vintage.   Approximately 170 years old.  No finer sextant was ever made!   We are pleased to  be able to offer it here.  Price Request

Edward Troughton introduced his innovative pillar frame design in 1788.  Functioning much like the trusses of a bridge, it provided rigidity for greater accuracy and lighter weight for ease of use.  The design was immediately embraced by mariners and Troughton’s contemporaries at the time when such instruments were transitioning from wood to brass.  Brass had evolved as the material of choice because of its stability in a marine environment.  Troughton’s design was copied by a number of nautical instrument makers in the early 1800’s.  However its complexity and high cost finally led to its extinction by the middle of the century.

Provenence:   Inlaid into the lid of the box is a brass plate engraved “LIEUT. J. R. LE HUNT WARD RN.”  Some in depth research certainly could reveal much more interesting history.  The British Naval Registry documents the service of the officers in HM Navy.

3.92  RARE HISTORIC MINIATURE SEXTANT.   Truly extraordinary, mid-1800s presentation sextant made by one of England’s most elite makers!  This delightful little instrument is signed on the large arc in perfect hand-engraved script, “Troughton & Simms, London.”  Of all brass construction with a V-shaped frame, the sextant has an inlaid silver arc reading from -5 to 160 degrees, effectively making it a quintant.  Incredibly, these divisions along with the vernier scale on the index arm, allow this sextant to match the accuracy of it larger cousins, down to 20 arc seconds!  A pivoting magnifier is provided for taking the reading.  The index arm has a miniaturized version of a thumb screw stop and tangential fine adjust.  The sextant is complete with its 2 horizon filters and 2 index filters in perfect condition.  The index mirror and horizon mirror are in beautiful condition.  The whole presentation is totally complete in its shaped rich mahogany box.  The octagonal ebony handle screws into the frame with a secure fit.  There are two optics, a peep and a telescope which fit into the height-adjustable sight holder.  Rounding out the accessories, there are both sight tube filters, mirror adjustment tool, and the functional skeleton key for the brass lock.  Of monumental importance for its value and appeal is the beautifully-hand-engraved  presentation on sterling silver inlaid into the top of the box.  It reads, “Presented at the Public Examination on the 13th of June 1851 to Gentleman Cadet, Henry Goodwyn by the Honble Court of Directors of the East India Company, as a mark of the Courts approbation of his attainments in Mathematics while at the Military Seminary.”  The overall presentation is nothing short of phenomenal for an instrument 166 years old!  Totally complete and virtually in the same condition when it was made.   All surfaces are in their original bright brass lacquer finish.  This is a nautical gem of the highest order, if ever there was one!  Most certainly worthy of the finest world class collection and/or museum.  5350

The East India Company, also known as the Honourable East India Company or the British East India Company was formed to pursue trade with the "East Indies" (present-day Southeast Asia), but ended up trading mainly with Qing China and controling the Indian subcontinent.

Originally chartered as the "Governor and Company of Merchants of London trading into the East Indies", the Company accounted for half of the world's trade  in basic commodities such as cotton, silk, indigo dye, salt, saltpeter (for gun powder), tea, and opium. The Company was also instrumental in the founding of the British Empire in India.

The Company received a Royal Charter from Queen Elizabeth I on December 31, 1600, making it the oldest among several similarly formed European East India Companies. Wealthy merchants and aristocrats owned the Company's shares, but the government owned no shares and had only indirect control.

During its first century of its operation, the Company's focus was on trade, not the building an empire in India. But early in the 18th century when the Mughal Empire began to decline, Company interests turned from trade to territory as the East India Company competed with its counterpart, the French East India Company.
By 1803, at the height of its rule in India, the Company had a private army of about 260,000, twice the size of the British Army! The Company eventually came to rule large areas of India with its private armies, exercising military power and assuming administrative functions.  Company rule in India effectively began in 1757 and lasted until 1858. But following the Indian Rebellion of 1857, the resulting Government of India Act 1858 led the British Crown to assume direct control of the Indian subcontinent in the form of the new British Raj.

Despite frequent governmental intervention, the Company's on-going financial problems finally led to its dissolution in 1874.

3.48  INCLINOMETER.   Most unusual early 1900’s ship’s pilothouse inclinometer marked, “STRUMENTI NAUTICAL E. CHANZ, TRIESESTE,” engraved on the pendulum bob.  This Italian-made ship’s instrument is unique in our experience, having a glazed brass body mounted to a sculpted hardwood backboard.   As configured it is exceptional in that it is both functional and beautiful.  It has a jet black background engraved with degrees of list in single degree increments from 0 to 51 port and starboard, marked by 10’s.  The heavy, solid brass pendulum bob has a center line engraved on the tip of the pointer to precisely indicate the heel or list within a half degree of accuracy!   The pivot at the apex is steel secured within a blackened brass fitting.   It provides a very smooth, uninterrupted action.   The instrument is housed in its sheet brass enclosure with triangular glass window, all of which is mounted to the one piece hardwood backboard in natural finish.  In use this inclinometer was hung on the athwartships bulkhead in the pilot house in a prominent place.  Insuring its secure attachment are three thick brass tabs.   The one at the top is fixed, whereas the two at the bottom are slotted, cleverly allowing the instrument to be “trued up” if necessary.  11 inches tall by 12 ¾ inches wide overall.  2 ¼ inches thick.  Excellent, fully restored condition.  695 Back to Top

The quaint seaport town of Trieste is located on the extreme northeastern border of Italy, at the head of the Gulf of Trieste on the Adriatic Sea.  Throughout history it has been influenced by its location at the crossroads of the Latin, Slavic and Germanic cultures.  Trieste was one of the oldest cities in the Habsburg Empire and in the 19th century it was the most important port of that member of the “Great Powers.”  As a prosperous seaport in the Mediterranean, Trieste became the fourth largest city of the Austro-Hungarian Empire (after Vienna, Budapest and Prague).  It underwent an economic revival during the 1930s and played a key role in the struggle between the Eastern and Western blocs after World War II.  Today Trieste is one of Italy’s richest regions, serving as a center for shipping, shipbuilding and finance.

3.88  GERMAN SEXTANT.   Very unusual and very innovative, turn-of-the-last century mariner’s sextant made by the noted instrument maker “Carl Bamberg, Berlin, D.R.G.M. No. 631761/3” as engraved on the index arm.  Obviously Bamberg did not produce over 600,000 sextants!   But the /3 may be a clue that this instrument was produced in 1903, or was the third of its kind ever made.  It certainly is unique, having many features not seen on instruments made in other countries at that time.  Its simple brass block lattice frame supports a very narrow silver scale calibrated in degrees from 0-150 (effectively making it a quintant), subdivided to 20 arc minutes and marked by 10’s.  The reading is made by means of a pivoting vernier magnifier with light diffuser over the left reading 0-20 vernier scale with an accuracy of one arc minute.  The index arm stop is an unconventional knurled knob located parallel to the scale.  The fine adjust tangent screw is spring-loaded.  The index and horizon mirrors are unique.  The horizon mirror does not have a split image as in most sextants.  That aspect is embodied in the very different prismatic sighting scope which magnifies.  The scope has a calibrated reticule which provides a view of the mirror as well as the horizon.  Rather than having the typical filter array of index and horizon mirrors, this sextant has only two pivoting filters mounted directly on the objective!  This simple but elegant system is a vast departure from almost every other sextant produced during that era.  The back of the instrument has 3 extremely large “feet” to accommodate the equally large sculpted hardwood handle.  The instrument measures 10 ½ inches wide on the large arc and the overall height 9 ¾ inches.  With its huge feet it is an amazing 6 ¾ inches thick overall.  Condition is virtually perfect.  We have not encountered a stranger, yet more impeccable example in our 35+ years.  A real rarity!  SOLD

3.84  EARLY MARINER’s  QUADRANT with MUSEUM PROVENANCE.   Particularly well-preserved navigational instrument dating from the late 1700’s, ex. museum collection.  This large octant, otherwise known as a “Hadley quadrant,” has limbs of mahogany, ivory scales and brass furniture.  It is of the double reflecting type, introduced by John Hadley to the Royal Society in 1735, after which such instruments saw acceptance and production in very nearly this same form for the next 100 years!  This example has distinctive characteristics which date it to circa 1790.  They include the existence of a backsight, mahogany vs. ebony construction, interchangeable filters, ivory pencil and large flat index arm with simple stop and left reading 0-20 vernier scale.  (See our customer help feature “History of the Sextant”).  This instrument is of classic form with an engraved ivory scale reading from -2 to 99 degrees signed with the “SBR” monogram indicating it was made by the prestigious firm of Spencer, Browning & Rust using their recent version of Jesse Ramsden’s dividing engine invented in the early 1780’s.  The ivory index arm vernier scale is calibrated from 0 to 20 minutes, providing an accuracy of one arc minute.  The frame is of mahogany (vs. ebony) indicating it is of earlier manufacture.   It is complete with its very rarely-found pencil for noting readings and small inland trapezoidal ivory notepad inlaid on the reverse.   The reverse also bears all of the brass fittings for adjusting the mirror boxes and all three brass “feet.”  This handsome instrument measures 16 inches long by 13 inches wide on the long arc.  The original case is constructed of hand-dove-tailed pinewood in its very desirable early deep blue paint.  Interestingly a number of the mariner’s original observations are penciled in the lid, making it a great, first hand, real time, intimate window into shipboard history!  The museum accession numbers “T266” are finely painted in red on both the instrument and its box.  The box measures 17 ½ inches long by 15 ¼ inches wide and 3 ¾ inches thick.  Aside from their already acknowledged rarity, such instruments hardly ever come to the market with their original boxes, and virtually NEVER in such fine, pristine, original condition!  This quadrant is well over 200 years old!!  Price Request

The venerable firm of Spencer, Browning and Rust was a prolific manufacturer of navigational instruments since the partnership was established in 1780.  The name appeared in the London Directories between 1780 and 1784 as being at 327 High Street, Wapping, London.   In 1798 the firm moved to 66 High Street and remained there into the 1840’s when the firm name became Spencer, Browning & Co. 

3.41  MARINER’s QUADRANT.   Very rare, museum-quality navigating instrument from the age of sail.  This 18th century quadrant, otherwise known as an “octant” is signed on the flat brass index arm in engraved script, “GILBERT & GILKERSON  ~ Tower Hill London.”  This early astronomical angle measuring device has limbs of mahogany with inset ivory scales and brass furniture.  The index arm is 16 inches long overall and terminates in an engraved vernier scale on ivory which sweeps over the large ivory scale divided from -1 degree to 99 degrees divided by 20 arc minutes.  The vernier, divided from 0 – 20 allows a reading down to one arc minute.  The single thumbscrew stop on the index arm (without the later form tangential fine adjustment) belies this instrument’s 18th century origins.  The fact that the large scale effectively describes an arc of 90 degrees is the reason such instruments were known as “quadrants.”  This example has a double peephole foresight and a single antiquated “back sight.  All three mirror boxes are present as is the full set of 3 interchangeable sun filters.  A blank ivory nameplate is inset into the cross brace and the rarely-found ivory pencil is still in place.  The brass index arm stop is present on the right limb.  On the reverse, this instrument retains all three brass “feet,” trapezoidal ivory note pad for recording readings with the pencil, and a complicated set of adjustments for the two horizon mirrors.  In short this rare surviving relic is totally complete and in an outstanding state of original preservation.  Complete in its old original keystone pinewood box.  Interestingly, several notations from actual readings are scribed on the interior in pencil and in chalk.  The instrument itself measures 13 inches wide on the arc.  The box measures 18 inches long by 15 inches wide and is 4 inches thick.  The box is surprisingly sound and in great condition.  SOLD 

The partnership of William Gilbert and James Gilkerson was begun in 1793 as mathematical instrument makers and opticians at 8 Postern Row, Tower Hill, London.  They were succeeded by Gilkerson & Co, in 1809.  The partnership was known to have made and sold sextants, rules, globes and ring dials.  William Gilbert was heir to a long line of mathematical and scientific instrument makers beginning with his grandfather, John Gilbert (I) in 1719 and his father, John Gilbert (II) in 1751.

(Gloria Clifton, “Dictionary of British Scientific Instrument makers 1550 -1851,” 1995, Zwemmer, Philip Wilson Publishers, London).

3.81  MARINER’s QUADRANT.  Very rare, highly desirable 18th century navigational device known as a quadrant, or alternatively “octant.”  This early example is patterned after John Hadley’s double reflecting quadrant first introduced in 1731.  It is an extraordinary instrument which has limbs of mahogany with brass furniture and a finely engraved boxwood scale inlaid into the large arc.  The scale is divided from 0 to 90 degrees, or one quarter of a circle, hence the designation “quad”rant.  The degrees are marked by 5’s.  Each degree is sub-divided into 20 arc minute segments, with diagonal lines cutting across 10 concentric circles.  With this arrangement the index arm and its ivory “line of faith” can provide a reading to an accuracy of 2 arc minutes, interpolated to 1 arc minute.  Below the diagonal scale is a second linear scale divided into single degrees and subdivided to 20 arc minutes.  These precise divisions are quite remarkable considering they were hand-done, before the advent of the mechanical dividing engine!  To attain such accuracy the instrument was necessarily large.  The index arm is slightly over 18 1/2 inches in length and the scale is 15 inches wide.  The quadrant is equipped with an index mirror and horizon mirror, a set of three pivoting filters, and a peep sight with pivoting shade.  It has a blank ivory nameplate in the cross brace.  On the reverse are three brass “feet” and the horizon mirror box adjusting assembly.  The index arm stop is a single brass thumb screw.  There is no fine adjustment feature on these early instruments.  Condition is remarkably excellent for a working device which saw sea service over 240 years ago!  A true museum piece! Price Request

The search for “The longitude” in early 18th century England was encouraged by the Board of Longitude which offered a massive prize of £30,000 for the solution.  It spurred much innovative interest in celestial navigation.  In May 1731 John Hadley, an English mathematician, presented a paper to his fellow members of the Royal Society in London describing the use of a double reflecting quadrant or "octant."  His quadrant was based on the principle of light reflection and angles of incidence that were described by Robert Hooke, Isaac Newton, and Edmund Halley in the previous century.  The principle is that when the angle of a celestial object and the horizon is seen through a double reflection, that angle is condensed in half between the two reflecting surfaces.  Thus Hadley's quadrant, reading to 90°, had an arc of only 45°, or one eighth of a circle, making it an "octant."  Basically the instrument consisted of a triangular wooden frame with a swinging index arm pivoted at the apex.  A mirror was fixed at that point which would move with the arm.  A second mirror, half of which was transparent so that the user could view the horizon, was fixed to one limb and a sight was attached to the opposite limb.  A precise scale, calibrated in degrees, was scribed on the arc of the bottom limb of the triangle, across which the index arm moved.  This continued to be the basic form of angle measuring navigational instruments for the next 250 years, and still remains, even with the advent of GPS!

Quite independently of Hadley, Thomas Godfrey, a Philadelphia glazier and acquaintance of Benjamin Franklin, devised an improved altitude measuring device based on the same principle over a year earlier.  The instrument had been tested in the sloop TRUEMAN on voyages to Jamaica and Newfoundland from 1730-1731.  The Royal Society recognized the equal contributions of both men and awarded them a prize of £200 each.  Godfrey also received a prize from the Board of Longitude (of chronometer fame) for his work.  However it was Hadley who ultimately received the most credit for the invention.

The improvements in navigation of the Hadley quadrant or "octant” as it came to be known, over previous instruments was immense.  Not only was it more accurate, it provided simplicity of operation, and the ability to "capture" the object being sighted for rapid, multiple sightings.  The merits of the quadrant were immediately noticed by the British Admiralty and its commercial production was begun.  Even so, the instrument did not find popular acceptance and general use amongst traditionally minded mariners until after 1750.

The earliest Hadley quadrants, like backstaves, were constructed of walnut or other indigenous woods, with the scales being engraved on boxwood (although examples on brass do exist).   With the discovery and growing importation of exotic woods such as ebony, rosewood and African mahogany beginning in the 1750's, the use of mahogany was quickly implemented, gradually giving way to the exclusive use of ebony, then ultimately brass by the mid-1800's.

From the article “Evolution of the Sextant” by Rod Cardoza
http://westsea.com/captains-log/evolutionofthesextant.html

3.80  PRESENTATION SEXTANT.  Truly exceptional first half of the 19th century British pocket sextant also known as a “box sextant.”  This fabulous example of the early scientific instrument maker’s art is all brass, housed in its original mahogany case.  This maker of this precision instrument is identified with the hand-engraved signature “T. Dunn, Edinburgh.”  It is inlaid with a scale of sterling silver calibrated in half degrees of arc from -5 to 140 marked by tens.  The fine silver vernier scale on the index arm provides an accuracy down to a single arc minute.  To facilitate the minute reading a pivoted magnifier is provided.  What is truly exceptional about this instrument, placing it far above most others of its type, is that it actually has a fine adjustment tangent screw, typically only seen in much larger sextants of the era.  Cleverly, it also has two pivoting sun filers within the body, actuated by levers on the periphery of the case.  A removable sight is also provided, which rests in the case when not in use.   The instrument is encased in a knurled brass cover which hermetically seals it when not in use, and acts as a handle when screwed onto the other side.  Adding more value and desirability it is beautifully engraved with the presentation “TO James Peddie FROM Geo.& Jas.s Gunn JUNE 1842.”  The quality of the engraving is the finest we have ever seen!  The instrument itself measures 3 inches in diameter and 1 ¾ inches thick.  The mahogany box of splined construction with original brass hook and eye closure and inlaid brass plaque measures 4 by 4 inches and 2 1/4 inches thick.  Remarkably pristine original condition after 174 years!  Certainly the finest box sextant we have ever had the pleasure of offering.  
Price Request 

Gloria Clifton, author of “Directory of British Scientific Instrument Makers 1550 – 1851,” 1995, The National Maritime Museum, lists Thomas Dunn on page 90 as a Mathematical, Philosophical instrument maker and Optician, working first in 1843 at 50 Hanover Street in Edinburgh, Scotland then at 106 George Street through 1867.  Thomas began his business with his brother, John Dunn II in 1841, who at the time was working in Glasgow.  It is interesting to note that the presentation date of 1842 predates Thomas’s move to Edinburgh, apparently still in the employ of his brother.

3.77  SEXTANT & OCTANT PARTS.  We now offer for sale a large variety of original old parts for 19th and early 20th century sextants, including filters, mirror boxes, mirrors, telescopes, peep tubes, sights, mounting feet, telescope holders, vernier magnifiers, individual glass sun filters, screw-on eyepiece sun filers, etc. etc.  The large diversity of this unmarked material is not identifiable by specific make and model.  However we can provide “look alikes” and “nearly the same” replacements for your instrument lacking same.  Prices are very reasonable for these authentic antique components compared to the cost of a newly fabricated replacement.  VARIOUS