Sextant by Henry Hughes in Mahogany keystone box
Early 7 inch sextant by Henry Hughes, London (1830 â€“ 1840+) housed in it's original mahogany keystone box. The sextant has a black anodised brass curved-pattern frame with an ebony-wood handle. The reinforced index arm includes an eyepiece magnifier on a 75 mm swivelling arm. |
The radius, from the index arm pivot to bottom edge of vernier scale, is 7 inches (178 mm).
The limb is natural brass with an inlaid silver scale for sightings of -5 to 145 degrees. Fine graduations are marked every of 10 minutes of arc, minor graduations every 1 degree and major, marked graduations every 10 degrees (starting at zero). The silver vernier scale has fine graduations of 1 minute of arc and minor marked graduations every 2 minutes of arc. The tangent screw, working against a spring load, and the clamping screw are on the back of the index arm.
There are four colour tinted glass shades for the sun sight (three red and one green) and three shades for the horizon sight (two red and one green).
The telescope mounting is in two parts and its perpendicular height is adjustable by a rising post controlled by a milled knob.
The index mirror has a single crack extending from top-centre to the bottom-left corner.
One telescope - and a matching red filter eyepiece lens - are fitted in the box, however this does not screw into the (larger) telescope mounting.
Marked on the limb are the maker's name, "H. Hughes, London", and the serial number "2051".
The name of the original owner (John H. Wishham) is engraved on the middle arc of the anodised frame.
The sextant sits in it's original mahogany keystone box on three black anodised brass supports. Inside the lid is a slightly damaged label of "H.Hughes, Optical, Nautical & Mathematical Instrument Maker, ... London".
Henry Hughes was one of the 19th Centuryâ€™s great instrument makers. After his son joined the business in the mid to late 1800â€™s, the company became H. Hughes & Son. The business was then passed on to the grandson, and towards the end of the century it became a Limited company (Henry Hughes & Son Ltd.). In 1947 it merged with another company and became Kelvin & Hughes Ltd., which is still in business today.
Henry Hughes Sextant Image-sold