126 NATURAL HISTORY MISCELLANY. 
one side and then toward the other, so that each picture shall rep- 
resent the view actually taken of the object by each side of the 
objective. The latter method of the three, is doubtless the one 
most generally applicable in practice. ; 
Pictures formed in this manner, and mounted upon cards ready 
for use in the ordinary stereoscopes, would greatly excel in ele- 
gance and definiteness any present means of disseminating results 
in many branches of microscopical study. As a means both of 
popularizing the familiar facts of microscopy, and of interchang- 
ing among microscopists the knowledge of novel results of inves- 
tigation, they would be invaluable. Few objects, for instance, 
would be more interesting to persons of general, if not scientific 
culture, than excellent stereoscopic views of the structure of plants, 
insects, and other familiar natural objects; and almost any micro- 
scopist would be glad to possess similar views representing the 
latest researches into the structure and relations of tissues, the 
micro-chemistry of poisons and adulterations, or the anatomy of 
typical species in any family of microscopic organisms. Such pic- 
tures might be usefully prepared by any public institution, and 
distributed to scientific institutions and societies ; or, preferably, 
prepared by some scientific, not sensational, private source, and 
furnished to buyers, like Dancer’s micro-photographs, through the 
ordinary channels of trade. 
In order to photograph, without delay, any field of view which a 
working microscopist deems worthy of preservation, he should 
have a camera mounted on a plank which is blocked at one end 
for the feet of the stand used as a “ working instrument.” Then, 
whenever desired, the eye-piece is removed, the instrument lev- 
elled into a horizontal position and placed accurately on the plank, 
and the magnified image instantly thrown upon the focussing plate 
of the camera. Finding the usual band, passing around pulleys 
and over the fine-adjustment wheel, to be a slight annoyance in 
carrying out this plan with the stand I ordinarily use (a large 
stand of the “ Jackson ” model), I make the fine adjustment by 4 
somewhat soft cylinder of India-rubber lying upon the wheel. 
This cylinder is rather more than three inches long, is an inch and 
a half in diameter, and weighs about four ounces. It is open 
through its centre, like a tube with thick walls and small bore, 
and is mounted upon one end of a straight, light, wooden rod, the 
other end of which is supported on or near the top of the camera. 
Sy en- 
eet 
