Fine early-20th Century universal theodolite by British scientific instrument manufacturers, Troughton & Simms, established in 1826 by Edward Troughton and William Simms.

This theodolite has been constructed in lacquered and oxidised brass the main tube with rack-and pinion focussing to objective, mounted to a circular protractor with double bubble level twin verniers and oil lamp transit illumination, secured to A-frame over swivelling platform signed as per title with further vernier scale and bubble levels to tri-form base with adjustable feet -- 15in. (38cm.) high overall; together with a modern period-style electric transit lamp secured to Perspex display base.