By 1880, Keuffel & Esser was offering a "Y Level, Telescope 18-20 inch long, magnifying power 22 times, best make, guaranteed, in mahogany case, with Tripod complete" for $140. Since Keuffel & Esser did not begin manufacturing surveying instrument until 1885, these early K&E instruments were probably made by others. The serial number suggests that this example dates from around 1885.
Keuffel & Esser, Catalogue & Price List (New
York, 1880), p. 102.
Ref: Keuffel & Esser, Catalogue of Transits, Levels, Etc. (New York, 1885).
