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SCIOPTICON MANUAL.
It consists of an ordinary microscopic glass slip, of greater
thickness and size than usual, with a spherical cavity about
three quarters of an inch across, and one-sixteenth of an
inch deep, ground and polished in the middle of one face.
This, when in use, is closed by a thin glass cover, which is
kept in place by adhesion and atmospheric pressure, the
cavity beneath it being filled with water containing the insect
or other object.
If it is desired to use high powers, we must be contented
with a limited selection of objects, choosing such as are
strongly defined and well colored. Diatoms, blood-disks,
or other objects which are delicately tinted or colorless are
quite unfit for such use. A strongly colored eye of a fly,
sting of a wasp, or other part of an insect, such as a claw
of a spider, answer well.
In this case I have obtained the best results with Zent-
mayer’s ts objective, using an extra condenser, consisting
of a plano-convex lens of about three inches focus, and an
inch and a half in diameter, placed about an inch back of
the object.
This greatly increases the illumination of the field.
In using the gas microscope, much depends upon the
efficiency and convenience of the support for lenses and the
stage, or what is known commonly as the “ gas microscope
attachment.”
The microscope attachment for the Sciopticon is repre¬
sented by the following wood cut.
The microscope body, to which the
objective is attached by a sliding tube,
is fitted to the grooved arm, and moved
by rack and pinion for accurate focus¬
ing, similar to our best table micros¬
copes. This curved arm is fastened to
the stage plate, which is attached to
Ji'ig. 54.