"Gambey à Paris"
height 12.5 inches; horizontal circle 10 inches diameter; telescope 17.25 inches long
This was used by the mapping branch of the United States Army Engineers--a tag on the box reads "U.S. Topographical Bureau, Theodolite No. 6"--and was probably made in the 1840s. The horizontal circle is silvered, graduated to 5 minutes, and read by four verniers and two magnifiers.