ANTIQUE SEXTANT
FORD * LONDON
 
 
 BACK SIGHT EQUIPPED 
Ca 1870
 

 
PRESENTED is a 19th Century “Ford of London”
mariner’s sextant with ebony frame. ivory graduated arc and vernier, and bronze fittings. The arc measures from – 5 to
plus 110 degrees. This, all original, and very nicely made instrument has a brass index arm
measuring a 11 3/4 inches with an early form ivory vernier scale, reading from right to left from 0 to
20 arc minutes, dual peep sights, three sun shades. and a third mirror and second peep sight which was used for
taking back sights. The shades on this instrument are designed to be moved from the upper position to the lower position depending
on which horizon is being used, i.e. in front of or behind the observer.

 
Back sight equipped instruments are normally found
on octants and it is very unusual to see a sextant of this later period fitted with the extra machinery.
 
HISTORICALLY IMPORTANT notations of Local Apparent Noon celestial observations are
handwritten throughout the inside of the case’s sides, top and bottom. They are a record that the most simple form of
sights were being used by the navigator which allowed him to determine his latitude without using a lot of math or needing
tables. The only information required was the declination of the sun at the time of the sight, and its
observed altitude. Simple addition and subtraction solved the
problem.Here the height
observed of 34 d 45 minutes is deducted from 89 d 59m leaving a remainder of 55 d 15 m to which the sun’s declination of 14
d 06 m has been deducted. The result is 40 d 09 m. In this case the navigator made a 10 m error. We` also do not know if he
is North or South of the equator because he did not label declination as North or South. If the declination was South, he
would have been in North Latitude.
 
PROVENANCE: The sextant was made by one
of the Ford’s or a descendant who are known to have been instrument makers in London.
Gloria Clifton’s Directory of British Scientific Instrument Makers 1550-1851 (London, 1995), p. 103,
mentions a John Ford (fl. 1851-1855) at 177 Shadwell High Street (London), who is known to have sold an octant.
An earlier member of the Ford family, William Ford (perhaps the father of John Ford), resided in Cannon Street
(London) in 1764 and was registered as an optician. Webster’s Registry of Instrument Makers shows a George Ford who moved
from England to the United States, but this is not relevant.

Recent ownership was by a  Connecticut yachtsman who had it in his
collection for many, many years.

                   Maker Ford
* London   
                            Old
Style Vernier    Back
                        Shades
in upper position
                 Shades
in lower position

CONDITION: The instrument, its ivory name,
graduated arc, and its hardware are in good condition, with a nice patina and verdigris of age. All
three bronze legs are present. All the machinery is present and in working order except that the mirrors are degraded
by age. The instrument has that nice antique look that comes with over 130 years of age. The original keystone case is
good condition, missing only its key and a piece of cork. There is an old chip on its right front.

All in all, a nice example from a little
known English instrument maker.

DIMENSIONS: 

  • Arc reads – 5 to +110 degrees
  • Length of index arm 11 3/4″
  • Width of frame at arc   9 3/4″
  • Index mirror         42 x 32
    mm
  • Horizon mirror      24 x 20 mm
  • Back sight mirror  24 x 20 mm
  • Three index movable shade glasses
  • Two peep sights
  • Weight    2 Lbs  8 oz

OUR UNCONDITIONAL GUARANTEE: If not
completely satisfied with your purchase it may be returned, if without damage, within three days of receipt in its original
condition and packaging. Returns must be insured for their full value. All that is required is a prior email authorization
by us for the return. Unfortunately, no refund can be made for the cost of shipping, packaging and handling.

International buyers
welcome,
but inquire first.  We have satisfied customers in Argentina, Australia, Austria, Belgium, Bermuda,
British Virgin Islands, Canada, Chile, China, Czech Republic, Democratic Republic of Congo, Denmark, England, France,
Germany, Greece, Holland, Hong Kong, Iceland, Ireland, Israel, Italy, Japan, Kuwait, Martinique, Mexico, New Zealand,
Norway, Nova Scotia, Panama, Poland, Portugal, Puerto Rico, Romania, Saudi Arabia, Scotland, Singapore, Spain, Sweden,
Switzerland, Thailand, Turkey, United Arab Emirates, USVI and the Eastern Caribbean.