Theodolite
By Communications and Publishing
1900 (approx.)
Detailed Description
Personal communication from Clay Martin, Field Records Collection, on June 26, 2018, "surveying instrument known as a theodolite, used for measuring vertical and horizontal angles. It was made by Young & Sons of Philadelphia and looks like it's from around the turn of the 20th century. I am guessing it was used by USGS map surveyors from around that time."
Sources/Usage
Public Domain.
Photo by USGS.