Theodolite

Invented in 1720 by Jonathan Sisson, the theodolite is the basic instrument for measuring horizontal and vertical angles. It consists of a sighting tube in the form of a telescope, and a vernier for measuring the angles. This theodolite was manufactured by Cooke, Troughton & Simms of York, England. The telescoping, or adjustable tripod can be raised or lowered to keep the survey instruments at eye level.