The following was extracted from the 1879 Miller Brothers catalog:
Stand 12 Inches in Height, and Draw Tube
Heavy Base and Arm of green japanned cast iron, Body and all other parts of well finished brass. The body can be inclined to any angle. Coarse addjustment by spiral motion, fine adjustment by a new construction, which is efficient with high powers. Plane and concave mirrors adjustable for oblique light. Revolving diaphragm inlayed even with the stage. The stage is of glass, with perfectly smooth motions in all directions. One Eyepiece, 2 objectives 2/3 inches and 1/4 inches focus of our own make. This instrument having been designed under advise of our most eminent Physicians, Professors, and Amateurs in microscopes is cheerfully recommended by them especially for Medical purposes. The whole packed in an upright Black Walnut wood case with drawer.
Price....$50.00
While unsigned the microscope appears to be identical to the instrument described in the 1879 Miller Brothers catalog. Evidently, this firm made and/or sold this model. The microscope employs a coarse adjustment by spiral tube motion. There is a grove cut into the surface of the inner tube. This meshes with a small protrusion inside the outer tube. As a consequence of this, the microscope focuses smoothly just by twisting the inner tube within the outer. The fine focus adjustment on this instrument is a knob located under the stage that tilts the spring loaded upper stage plate up and down. A similar coarse adjustment by spiral tube motion and fine adjustment by stage tilt is found in a small Grunow microscope in this collection.
