This alidade belonged to the University of Pittsburgh. There is a level mounted below the telescope. The vertical circle is graduated on the rim to 30 minutes and read by vernier to single minutes. The base is skeletal. It come with a compass (serial number 6870), wooden plumbing arm, and clamps for holding the paper. It was made after the establishment of the Eugene Dietgen Co. in Chicago in 1893.
Ref: Eugene Dietzgen Co., Catalogue & Price List (Chicago, 1921), pp. 318-319.