Base-Dia. 8" (20.3cm) graduated to 360 degs by 30' with two vernier scales, one 30-0, the other 100-0-100. On upper surface of base "to 100th of the radius ". Fitted with two milled screws, one to turn the instrument in azimuth, the other (modern) to lock it. Two spirit levels 4.5" long one mounted N-S, the other E-W.
Compass-Dia. 4.4" (11.2cm) mounted at centre of base. Fitted with an edge bar needle triangular in section 3.6" (9.2cm) long, with a jewelled pivot cap at centre. A needle lifting mechanism is fitted and is operated by a knob at side of compass. Graduated to 8 points (with reversed E & W points), quadrantally in degrees, and anti-clockwise to 360 degs.
Vertical arc-Dia. 8" (20.3cm) attached to centre of base. Has rack teeth on outer edge. Graduated 90-0-90 by 30', 30-0-30, and 100-0-100. Vernier scale graduated 15-0-15 and inscribed "Diff of Hypo & Base " "Perp in 100th of base", " Diff in Hypo & Base is carried on telescope mounting bracket which is pivoted at base of vertical arc.
Telescope-Length 11.75" (29.9cm). Erect with cross wires and O.G. shutter. A spirit level 5.5" (14cm) long is attached to the underside. Attached to mounting bracket by two "Y" mounts.
In fitted wooden box 13 x 9.5 x 9.75" (33 x 24.1 x 24.8 cm).