Images(3)

octant

Date1860-1880

Inventory Number5247

ClassificationOctant

Subject

Maker Thomas L. Ainsley fl. 1858 - 1886

Repaired by Newton Brothers fl. 1870 - 1910

Cultural Region

Place of Origin

Dimensions28 x 23 x 26 cm (11 x 9 1/16 x 10 1/4 in.)
box: 8 x 28 x 30 cm (3 1/8 x 11 x 11 13/16 in.)
From tip to tip / cord of: 23 cm (9 1/16 in.)
Index arm to Vernier scale: 26 cm (10 1/4 in.)
top of instrument to bottom of instrument: 28 cm (11 in.)

Material

Accessoriesbox

DescriptionThis octant has a T-form, ebony frame and a curved crossbow with an inlaid ivory name plate. There is a reinforced brass index arm with an ivory vernier scale. The limb has an ivory scale divided -4° - 108° every 20', with the vernier divided 0-20' every 1'.

It has an adjustable index mirror with three square shades, as well as an adjustable horizon glass operated by a tangential rack and pinion thumb screw which moves a small plate. The front sight is a plain pinhole with a cover; the back sight has two pinholes and a cover. There is a slow-motion tangent screw and clamp on the index arm. The instrument has feet.

With keystone case.

Signedstamped on ivory nameplate: T. L. AINSLEY / South Shields on tradecard in case: NEWTON BROTHERS / .../ II, Prince's Dock Walls, Hull.

ProvenanceDavid Wheatland purchased from Roux-Devillas Paris, July 27, 1964 (lot 2/568). Donated to CHSI April 1977.