Herman Pfister (1847-1911) was born in Switzerland and, by 1870, he was manufacturing surveying and engineering instruments in Cincinnati, Ohio. Louis M. Prince (1850-1918) opened a store in Cincinnati in 1873, selling a wide variety of optical and mathematical instruments. In this instrument the horizontal and vertical circles are silvered, graduated every 30 minutes of arc,
and read by vernier to single minutes. There are stadia wires in the telescope, and a clamp and tangent to the telescope axis.
Ref: Charles Smart, The Makers of Surveying Instruments in America Since 1700 (Troy, N.Y.,
1962), p. 131; and vol. 2 (1967), p. 234.