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Brass framed quintant.

1880-1890

Experimental brass framed quintant.

1885-1895

Ebony and brass quintant.

1782-1785

Surveyor's quintant invented by George Beck and made by M. Dawson, Plymouth, about 1780. Polished brass frame, a detached wooden handle. Signed on the index arm: M,, Dawson fecit | Plymo Dock No 6. Marked on the index arm: G. Beck Invt. Polished brass scale from -10° to 205° every 30', measuring to 193°. Brass vernier to 1', zero at the centre. The double-ended tangent screw and the clamping screw are on the back of the index arm. No shades. Two index glasses, adjustment by screws; adjustment of the horizon glass by two levers and a milled clamping screw. A partly silvered sight vane with a peephole is fixed next to the index glass; a second sight vane on a swivelling arm is fitted on the centre strut. In a shaped mahogany box.

Brass framed surveyor's quintant with case.

1775-1785

Quintant made by (William) Cary, London, about 1890. Anodized brass straight-bar pattern frame; polished limb, a wooden handle with a brass-lined hole for placing it on a stand. Signed on the limb: Cary, London. Marked on the limb: Platina. Marked on the centre strut: HO [broad anchor] 12. Inlaid platinum scale from -5° to 160° every 10', measuring to 148°. Gold vernier to 10", zero at the right. The tangent screw and clamping screw are on the back of the index arm. Four shades (all grey/green); three horizon shades (all grey/green). Index-glass adjustment by capped screw; adjustment of the horizon glass by a capped screw and a capped thumb screw. Magnifier on a 80 mm swivelling arm. Threaded telescope bracket in two parts, fitted for correcting collimation error; perpendicular adjustment by rising-piece and a milled knob. Telescope (171 mm) inverted image, four cross-wires. An anodized brass column on a tripod stand with three milled levelling screws, for mounting the quintant. The counterbalanced swinging mount can be locked into the desired position by milled screws. Wth wooden carrying case.

Brass framed quintant, with carrying case.

1885-1891

Quintant made by John Dennett Potter, London, about 1885. Anodized brass diamond-pattern frame, wooden handle. Signed on the limb: J.D. Potter; Poultry & Tower Hill London. Marked at the bottom of the index arm: H O [broad arrow] 10. Inlaid silver scale from -5° to 163° every 10', measuring to 138°. Silver vernier to 10". The tangent screw and clamping screw are on the back of the index arm. Four shades (three grey, one green); three horizon shades (two grey, one green). Index-glass adjustment by screw; adjustment of the horizon glass by capstan screws and a square-headed screw and a detached key. Magnifier on a 90 mm swivelling arm, a frosted glass shade. Threaded telescope bracket in two parts, fitted for correcting collimation error; perpendicular adjustment by rising-piece and a milled knob. Telescope (82 mm) erect image; telescope (184 mm) inverted image, two parallel cross-wires; telescope (155 mm) star finder; extra draw tube (80 mm) inverted image, four cross-wires. Sight-tube (80 mm); three shaded eyepieces (all green); detached threaded telescope bracket for the star finder; adjusting key; adjusting pin. Mahogany keystone box, containing in the lid three certificates of examination of the National Physical Laboratory, for 1885, [illegible, stuck over] and for 1910. The lid also contains a trade label for Cary, Porter Ltd, and a Notice by them explaining how the star finder should be attached to the framed; it was an addition, made by Cary in April 1889. Formerly the property of the Hydrographic Office of the British Admiralty.

Diamond- pattern frame quintant with case.

1860-1889

Quintant with 3-inch radius limb, anodized brass frame and silver inlaid scale marked -5° to 165° (144° range), 20 arc-min. divisions' with silver vernier scales to 30 arc-sec. and hinged wooden handle, without box, by (William) Cary, London, 1850-1860. Fitted with tangent and clamping screws at back of the index arm; two shades (both green); two horizon shades (both green); index-glass and horizon glass with screw adjustment; Magnifier (single lens) on 45 mm swivelling arm and Threaded telescope bracket with two telescopes, (70 mm) erect image, (105 mm) inverted image and sight tube (69 mm).

Brass framed quintant.

1850-1860