The Harvard Model Microscope non-inclining, c. 1888
The microscope is signed on stage: Bausch & Lomb Optical Co. and is marked on the limb with the 1876 and 1885 patent dates. The serial number is stamped on the wood case, 5508. It is an example of the Bausch & Lomb "Harvard" model microscope.
The body of the microscope is constructed in lacquered brass, while the base has a bronzed lacquered brass finish. The height of the tube can be extended by means of a drawtube. The drawtube has a Society Screw on the lower end to accommodate very low power objectives and other accessories. The coarse focusing is by push-tube and the fine focus utilizes a micrometer screw, which operates the patented B&L mechanism. The substage consists of a Wale type iris diaphragm. The mirror is adjustable on its swinging arm and is double sided with plane and concave glasses; it can be positioned above the stage to illuminate opaque objects. The microscope is supplied with two B&L eyepieces, two B&L objectives (marked 1/4 and 3/4) with their brass canisters.
This model was supplied in several versions. This particular example is the most simple version have push-tube coarse focusing and no inclination. Other versions allowed for inclination of the microscope and /or rack and pinion main focusing