Scope and ContentManual: K+E Log Log Duplex Trig No. N4080 Manual. Published by Keuffel & Esser Co., New York & Hoboken. Copyright 1943,1948. Issued in box with K&E slide rule model N4080, objects 2009.006.0137, made circa 1955-1957. Softcover, 5-1/4" x 7-1/4" high, pp. [iv], 123 plus covers. Authors were Lyman M. Kells, Willis F. Kern and James R. Bland, all at the United States Naval Academy. Keuffel & Esser main office and factories were in Hoboken in this period.