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Presented is an ebony frame, ivory arc, antique
sextant made by the well known maker Spencer, Browning & Co. of London, Ca 1860. It is in outstanding original condition
and has the well known instrument seller’s label of John Kehew of 69 North Water St., New Bedford which is
in excellent original condition. It has the added feature of being fitted with a brass focusing telescope which make it very
rare for this period. The likelihood is that it was used on a whaling ship through there is no record of that.
The arc measures from – 5 to plus 105 degrees. The ivory plate on a
cross bar between the two limbs is engraved “Spencer Browning & Co. London”, Additionally, in the center of the ivory
degree’s scale between 50 and 55 degrees is inscribed in script “SBR” identifying the ivory was engraved by Spencer,
Browning & Rust, of London.

SBR was in business in London from 1784 to 1840, specializing in instruments for navigational use. It’s business continued
under the name of Spencer, Browning & Co. which ceased business in 1870.
They had an early dividing machine and inscribed arcs for others.
This beautifully made instrument has a ribbed
brass index arm measures 12 inches long on the index arm. The horizon mirror is on an adjustable turntable and can
be rotated by an arbor. Note the thumb screw, ivory vernier scale, reading from right to left from 0 to 20 arc minutes, a
movable peep sight with threaded rising piece that accepts a telescope, and two sets of sun shades all of which help
date the instrument. There is no provision for a handle on this sextant which marks it as a transitional piece between
an octant and a sextant.

Some time after 1780, the addition of a tangent screw, as fitted
to this instrument, allowed for fine adjustment and represents one of the two major changes in the basic operation of
the octants and sextants for the next 150 years! The second was the fitting of telescopes. As was the practice with octant’s
of larger size, this sextant was not fitted with a handle which indicates it is one of the earliest of that type made by Spencer
Browning making it a noteworthy instrument by this maker.

  Period Notation of Provenance
INSTRUMENT CONDITION: The sextant appears in its last
used condition having been maintained properly. The mirrors are in much better condition than might be expected though
they do show their age. The horizon mirror has two cracks. The ivory is in perfect condition, except that the vernier
has two age cracks.The engraving is sharp and distinct.  Missing is a small ivory plate on the back, and a lead pencil
cap. The index arm clamp has one small piece of clamp missing. The shade glasses are complete and in good working order. The
ebony frame shows as near new. The instrument has its original machinery, a two hole peep sight, and brass telescope.
Everything is original and in good working order.

THE CASE: The stepped “keystone” solid Oak case
is in excellent condition, very clean inside, and has some age cracks top and bottom and shrinking on
its bottom panel. It has a cross piece added for strength, and has been refinished. There is a 3/8″ chip missing in its
lower right corner. There is a lock, but no key. A label on the inside, in excellent condition, reads John
Kehew of 69 North Water St., New Bedford. 
               “SBR” imprint
at 55 degrees
The machinery
        Early style stepped keystone case
     Makers name
All in all,
a highly desirable and worthwhile example from one of the better known English instrument makers.
Length of frame 12″
Width of frame at arc   9 3/4″
Index mirror 50 x 30 mm
Horizon mirror 24 x 20 mm
Weight    2 Lbs 2 oz
QUALIFICATIONS: We are one of the few company’s still selling navigation
instruments that know anything about them. For purposes of judging whether Joel’s opinion counts, he was the editor
of the chapter on sextants of the 1977 Edition of “Bowditch”, The American Practical Navigator, NAVPUB 9; a member of the
U.S. Naval Academy Navigation Symposium Board, 1975 -1978; the author of a book on marine sextants, Cornell Maritime Press,1975,
and the founding president of Nautech Maritime Corporation which partnered with Tamaya of Japan in the introduction of the
MS 733 Spica, the MS 833, Jupiter, MS 933 Venus sextants and the famous NC-2 navigation computer, in the U.S. market. Joel
is a retired Master Mariner, and held a U.S. Navy “D” Qualification as a Senior Skipper – Oceans.
six years he was a Varsity Offshore Coach at the U.S. Naval Academy.
Rarely do you find an instrument that
is that is 147 years old in this original condition with a perfect historic label. A superior addition to any collection.