ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
G95 
For low powers tlie condensing system on the hank is sufficient. 
For projection work apochromatics are not essential. Low and medium 
systems can be used direct without eye-piece. With high powers the 
image of the source of light should be thrown upon the preparation ; 
with low powers, on the objective, so that 
the preparation is illuminated by a con- p IG< 102 . 
verge at pencil. An important point is the 
exclusion of all extraneous light. This is 
effected by the use of paper covers over 
the optical bank, &c. 
Pringle’s Vertical Photomicrographic 
Apparatus. — Mr. Andrew Pringle’s vertical 
photomicrographic apparatus (fig. 102) con- 
sists of a 1/4-plate bellows-body camera, 
18 in. long, sliding between two metal up- 
rights which are fixed to a heavy iron 
base upon which the Microscope stands. 
The camera can be turned aside, if wished, 
while the Microscope is being adjusted, 
and clamped at any part of the uprights. 
The usual ground- and plane-glass focus- 
ing- screens are supplied with the appa- 
ratus. 
Practical Photomicrography, * — Afte 1 ' 
stating that his photomicrography was o^ 
a peculiarly utilitarian nature, his object 
being, not to perform a difficult feat for the 
sake of overcoming difficulties, but rather 
to produce a lasting record of appearances 
presented by some special microscopical 
preparation, Mr. A. F. Stanley Kent went 
on to remark that, one of the first essen- 
tials to good microscopic work is a stand 
of first-class workmanship ; for, while it 
is quite true that work with low powers 
may be done with low-priced instruments, 
it is, nevertheless, a fact that for really good work, and more especially 
for work with the higher powers, the very best of everything in the 
way of apparatus is absolutely essential. 
So far as the stage is concerned, Mr. Kent thinks that individual 
tastes play a large part in the selection, the simple stage being held to 
be amply sufficient by some workers, while others regard a mechanical 
arrangement as almost a sine qua non. Personally, he is inclined to 
recommend that, in a case of a Microscope to be entirely devoted to 
photography, and more especially if any considerable amount of high- 
power work be contemplated, a mechanical stage of the best con- 
struction should be selected. 
The length of the Microscope-tube is an important matter, and one 
about which there has been much discussion ; but, inasmuch as several 
* Anthony’s Photographic Bulletin, xxiii. (1892) pp. 621-4, 660-3. 
