DESCRIPTION: This is a medium size microscope, a modification of the Tolles Student Model, that has a Y-shaped foot and arises from two upright flat plates to a trunnion joint. It is only slightly heavier than the Tolles student, and only slightly larger than the Tolles Student. Its proportions and design are not anywhere near those of the Tolles B stand. The Lister limb has the typical Boston Optical Works rounded triangular profile. Coarse focusing is by straight rack and pinion, fine is by short lever to the nose. There is a nickel-plated graduated drawtube.

The stage is round with two stage clips and a fitting to accomodate things like a stage forceps.

The substage is attached to a disk in back of the stage so that it can rotate around the Y-axis of the stage.

The substage focuses via a knob(a) which controls the rack and pinion focusing. From the substage, a post(b) protrudes forward to the substage support ring. Half way, a rod(e) which carries the mirror is attached to this post is held in place by a knob(c). At the front end of the post, the condenser support ring is held in place by a second knob(d), which when loosened allows the support to be removed.

ACCESSORIES:

This microscope is equipped with a 1 inch and a 2 inch eyepiece, two objectives, a stage diaphragm, a substage condenser, a Tolles-type camera lucida, and a support stand meant to hold a mirror for overhead illumination for opaque objects(not shown). Curiously, the mirror assembly for this microscope does not seem to fit this support stand(not shown). The objectives include an unsigned Tolles Student 1/4 inch objective, and a divisible 3 inch / 2 inch objective signed by Tolles. The divisible objective apparently has its date of manufacture, 83x7x17 etched near its threads and this likely refers to 1883-July 17. That would be just four months prior to Tolles' death. Although other divisible objectives are listed in the Tolles 1872 catalog, this particular objective is not listed in either the 1872 or the 1883 Tolles catalogs.

HISTORY OF THIS DALTON MICROSCOPE:
As noted this stand is most appropriately classified as a modification of the Tolles Student Model. For a review of all the known BOW stands, please see the page about the history of Tolles and Dalton's Microscopes.