TOLLES'S STUDENT'S MICROSCOPE

15 inches high, weight 6 pounds

This instrument, designed under the advice of several of the Professors of the Medical School of Harvard College and other well-known Microscopists, is of the pattern and size most approved by experts. The base, uprights, and curved arm are of iron, handsomely japanned; on a trunnion joint, made on a new plan to wear well, by which the instrument can be placed in any position, from vertical to horizontal, with a stop to prevent movement in either direction beyond these points. It is furnished with a l-inch Eye-Piece, two second-quality Objectives, of about 1 inch and 1/4 inch power, giving about 80 and 350 diameters, a plain Stage with spring clips for holding the object slides, revolving Diaphragm, concave Mirror, with movement to give oblique light; for illumination of opaque objects, the mirror is removed to an upright stand; course adjustment for focus is effected by sliding the compound body which is held in its place by a spring, fine adjustment by a movable plate and screw on the stage, which is efficient with high powers. The stand is made with all the care bestowed on his first-class instruments, and proves satisfactory for the use of amateurs, students, and the ordinary work of the medical profession. The workmanship is superior to that of any instruments of the class made in Europe. The form is the Jackson pattern recommended by Dr. W. B. Carpenter as the one least liable to tremor, and is the one most approved by all American microscopists. Price, in an upright Black Walnut case, $50. Stand and Case alone $28.

Variations and Additions. - Extra Eye-Pieces, 2 in. 1 1/2 und 3/4. $4 each; a superior Camera Lucida $5; Sub-Stage for Accessory apparatus, $5; a Sliding Stage, giving vertical and horizontal motions by the hand, and adapted for the use of Mathwood Finder, $15. Fine adjustment by lever and micrometer screw, $16. Rack and Pinion for coarse adjustment, $12, drawtube, $4. Plain Mirror, $3. Thin glass stage to rotate on the optical axis, $10. The stand in all brass, $10. Any of TolIes’s first quality Objectives may be used on this instrument, and can be added to order at list prices. Packing Boxes for transportation, $1.