Signedon knife: B. & L. OPT. CO. / U.S.A.
Primary SourcesBausch & Lomb Optical Company, Microscopes & Accessories (Rochester, NY: Bausch and Lomb Optical Co., 1929), 163, 172.
Bausch & Lomb Optical Co., Catalog D-111: Scientific Instruments (Rochester, NY: Bausch & Lomb Optical Co., 1940), 128.