ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
679 
apparatus by which it is possible to draw microscopic preparations 
quickly, and without the need of any complicated mechanism. The 
principle of the apparatus depends on the fact that most microscopic 
preparations are transparent, and that a bright white drawing paper can 
serve as source of light with low 
magnifications. 
On a simple stand, an eye-piece 
diaphragm a (fig. 101) and an object- 
stage b can be adjusted in height one 
above the other. Under this, on the 
table, is the drawing paper. The 
effect of the fine opening in the eye- 
piece diaphragm is that object and 
drawing appear to the eye always ex- 
actly in the same position above one 
another. In this diaphragm a lens 
can be placed. Lenses (c) as well 
as diaphragms ( d ) can also be in- 
serted in the object-stage. As lenses, 
the author has used spectacle 
glasses +5, + 10, —5, —10, — 20 D, 
&c. 
Without lenses and with the dis- 
tance between a and the drawing 
paper (e.g. 30 cm.) double the dis- 
tance between a and b, a double mag- 
nification of the drawing is obtained. 
For higher magnification, the object- 
stage must be brought nearer to the 
eye-piece, or the drawing paper re- 
moved further. Both can be effected 
by the use of lenses ; the apparent 
separation of the drawing plane is 
produced by placing concave lenses 
in the object-stage, while the object 
itself can be magnified and brought 
nearer to the eye by placing convex 
lenses in the eye-piece diaphragm. 
In the latter case, a concave lens in 
the object-stage, at least double as 
strong as the convex lens in the eye- 
piece, is indispensable. 
New Form of Dissecting-Stand 
and Lens-Carrier. — Lt.-Col. H.G. F. 
Siddons, at the October meeting of 
the Society, exhibited and described 
a portable dissecting-stand and lens- 
carrier. V/hen opened out, a bent 
metal plate with large aperture bridged the space between the (folding) 
hand-rests, and upon this, either a transparent or a blackened plate 
could be clamped by four spring clips, while a mirror was erected below, 
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