Maker's Name: 
Troughton and Simms, London
Where made: 
13 × 13 × 37 cm

Brass 5 inch theodolite with 4 screw base and table stand. Telescope eyepiece carries crosshairs for alignment and three bubble levels allow levelling. Vernier scales are etched on vertical circle and on opposite ends of diameter on base. Standard vernier theodolite which uses cross hairs aligned along telescope optical axis to measure horizontal and vertical angles. Vertical angles from 0-45° and horizontal angles from 0-180° can be measured. Both scales can be clamped and then finely adjusted with tangent screws. An attached microscope allows accurate reading of the scales. The construction also permits a plumb bob to be suspended from the centre of the vertical scale.