Keuffel & Esser Company
1867 - 1987
The Keuffel & Esser Company was founded by William J. D. Keuffel and Herman Esser in New York in 1867. The company started by selling drawing materials and drafting supplies. Later the company expanded to offering surveying instruments some the work of John Paoli. In 1920s they began manufacturing slide rules.
"Keuffel & Esser," Smithsonian Nation Museum of American History, http://amhistory.si.edu/surveying/maker.cfm?makerid=17 (accessed 02/04/2015)