ADIE BACK SIGHT OCTANT by <br>
Spencer, Browning & Rust
This Fine Instrument Has Been Sold!
Strictly Elegant Condition!
Spencer, Browning & Rust Engraving
is an elegant back sight
octant which could have been made as early as the first quarter of the
19th Century. It carries the name of Adie & Son, Edinburgh on the
ivory cross bar of the frame. This company is known to have made
various types of instruments such as stick barometers, surveying
compasses, theodolites, telescopes, and mining compasses, but never a
ADIE'S BRIEF HISTORY: They were active during the
period, 1835-1857, as an optician, meteorological &
mathematical instrument maker, located in Edinburgh, Scotland. The firm
was founded by Alexander James Adie (1775-1858),
an optician and instrument maker, in partnership between Alexander Adie
(w.1823-1834) & his son. Adie & Son were appointed by King
William IV, and manufactured domestic cistern barometers and marine
This mariner's octant was made during the last half of the 18th Century
and is likely the work of Spencer.Browning & Rust
under private label for Adie. It has two horizon mirrors and
two peep sights. The lower assemblage is for taking “back sights“ and
the upper is for traditional observations. The mark, SBR,
Spencer, Browning & Rust, appears on the arc between 45°; and
50°. SBR is known to be one of England's foremost instrument makers. The
sharpness of the arc's numerals shows
that this instrument was made to the highest level of then
existing technology by a company that stood at the top of its trade. Some time
ago, it was polished and lacquered making it suitable for
presentation as an important gift.
The back shows
the complex machined parts of the
Adie & Son is listed
in Webster's Database of Instrument makers for various
instruments, but no sextants or octants.
The instrument is 14 inches on the vertical
which is oversize for octants, but smaller than the typical Hadley style
octant of 17“. Hadley that invented the "double reflecting"
principal introducing it to the Royal Society in London in 1731.
& Son, Edinburgh n the crossbar
initials between 45 and 50 degrees on
MARKINGS: You can clearly see the mark of SBR
between 45 and 50 degree position on the arc. Adie's & Son name
is on the cross piece of the arc. Inside the cover of the case on the
right side, in pencil, is inscribed D 36 over 9/4 and at the bottom a
Vernier reads from right to left 0 to
20 arc minutes
step case with
INSTRUMENT: The ivory arc measures from - 5 to plus 95 degrees on
a Ebony frame which is in excellent condition. It is known
that Mahogany went out of use in favor of Ebony some time after 1750. The
octant has a flat brass index arm without a stiffening
brace that measures 14 inches from its
top to the bottom of the index arm. Tangent screws
began replacing finger clamps in the last quarter of the 18th
Century. There are two horizon mirrors, each
mounted on an adjustable turntable where the base can be rotated
by loosening a screw which locks the mirror's position.
There is a single set of three shades which may be moved from
the upper to lower position. The ivory vernier scale reads from
right to left from 20 to 0 arc minutes. There are two peep
sights. The adjustable tangent screw followed the use
of the index arm clamp which ended around the last quarter if the
these features date the instrument after 1750 and before 1800.
See Peter Ifland's
comprehensive sextant work, "Taking the Stars". particularly
figure 64, page 57.
Index mirror and movable shade
CONDITION: The instrument is
in outstanding condition, except that there is a
hairline age crack across the 30 degree mark. The graduated arc
and all its hardware are original
and exceptional. All three bronze legs are
present. It has the original ivory pencil on the
cross bar which are usually
missing from most instruments of this age. All three mirrors have
most of their silvering, and
are in excellent condition for their age. The
machinery is all present and the shades are
The Case is the early
style “stair step“, keystone design of this period.
Both the top and bottom are free of cracks.
Two corks hold the instrument secure. There are
no labels. It is strong and sturdy, and the
octant fits as it should. There is a lock,
but no no key. The hook is present but its arm is
in case. A few pencil notations on the right
All in all, a rare,
desirable, and special example of an early Hadley
style octant .
Arc reads - 5 to +95
of index arm 14" long
Width of frame at arc
11 1/4 " wide
Index mirror 50 x
Horizon mirror - 30
x 22 mm
Back sight mirror - 30
x 22 mm
Three movable shade
Weight octant 2
Lbs 9 oz
OUR 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 also a retired Master
Upon Oceans, and held a U.S. Navy "D" Qualification as
a Senior Skipper - Oceans. From 1995 through 2000, he
served as a Varsity Offshore Sailing Team coach at the
U.S. Naval Academy.
Ground to the 48 contiguous
OUR UNCONDITIONAL NO NONSENSE
GUARANTEE: If not completely satisfied with
your purchase it may be returned within five days of
receipt in its original packaging if without damage.
Return items must be insured for their full value.
Only a prior email authorization from us for the
return is required. Shipping charges are included in
this offer within the continental United States if an
error is due to our fault.
welcome, but inquire first. We have satisfied
customers in Argentina,
Australia, Austria, Belgium, Bermuda, British Virgin
Islands, Canada, Chile, Republic of China, Czech
Republic, Democratic Republic of Congo, Denmark,
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Hong Kong, Hungary, Iceland, Indonesia, Ireland,
Israel, Italy, Japan, Kuwait, Latvia, Luxembourg,
Malaysia, Martinique, Mexico, New Zealand, Nigeria,
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Portugal, Puerto Rico, Romania, Russia, Saudi Arabia,
Scotland, Singapore, South Africa, Spain, St. Maarten,
Sweden, Switzerland, Thailand, Turkey, United Arab
Emirates, USVI and the Eastern
FORMS OF PAYMENT are Bank wire transfer,
cashier's check, or personal check in which case the
item will be held until cleared. Our prices are
quoted net to seller, but credit cards may be
accepted through PayPal for verified members by
This superior octant
is for someone who will appreciate its elegant condition!
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Sea Collection™, All Rights Reserved
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