Bausch & Lomb Optical Co., Rochester N.Y. U.S.A.
Serial number 170740, c. 1923
The No. 40 Model Pocket Microscope
The microscope is constructed entirely of brass with the main body having a black enameled surface finish. Depending on the setting of the draw-tube and the lenses used with the objective, this microscope gives magnifications in the range 60-250. With the draw-tube fully extended the microscope measures about 23 cm in the inclined position. The main focus is by push tube. The fine focus is accomplished by turning the knurled ring of the outer tube. The mirror is single sided with a concave glass; it can be mounted on an adjustable arm under the stage for conventional use or above the stage for use with opaque objects. The instrument collapses to a small size by pushing in the tubes and folding the legs. There is a plush lined fabric-covered case bearing the B&L logo on the cover.