472 
POPULAR SCIENCE REVIEW. 
for its reception, termed a cell, or in what is called a l ice-boy, 
or animalcule cage, more particularly if tlie objects be swimming- 
in water. For larger objects, sucli as zoophytes, or for showing 
the circulation in plants, a glass trough is necessary, which may 
be filled with water, laid upon the stage, and the object 
examined with a low power. For ordinai-y objects (not living), 
such as vegetable structures, parts of insects, &c., it is sufficient 
to lay them upon a flat piece of glass (or slide), and to place over 
them a round or square piece of very thin glass (made and sold 
for this purpose) ; and thus to examine them, either dry, or having 
first moistened them with a drop of clean water, which assists 
their transparency — care being taken to avoid air-bubbles 
between the two pieces of glass as much as possible, and 
to keep the upper part of the thin glass cover dry. 
It now only remains to refer the student to some form of 
microscope which, not being too costly, will probably be within 
his means, but which at the same time shall be of guaranteed 
-excellence, that he may not be tempted to waste his money upon 
inferior productions. In doing this it is manifestly invidious to 
single out any one name from a number of excellent makers, or 
to say which is the best of such manufacturers as Smith and 
Beck, Ross, Powell and Lealand, and others, when all are of such 
acknowledged merit. If we particularly allude to the first of 
these, it is because, besides the well-known excellence of then- 
instruments, their less expensive microscopes appear to us to 
be adapted for the purpose we have in view. 'Their Educational 
Microscope is a portable, compact, and complete instrument, 
consisting of stand, mirror, spring-stage, condenser, dia- 
phragm, two eye-pieces, and two objectives, viz., an inch, and 
-a quarter inch, magnifying respectively, 55, 100, 200, and 350, 
linear. The price of this instrument is ten pounds ; and for 
an additional five pounds, all the apparatus necessary may be 
"Secured, consisting of a Lieberkiihn, parabolic reflector, polar- 
izing- apparatus, camera luc-ida (for drawing- the magnified 
object), micrometer, live-box, and glass trough. This 
additional apparatus may be purchased at any future time. 
If the student is more ambitious, he may purchase the Student’s 
Microscope with § and A objectives (reaching- a linear magnify- 
ing power of 430), and apparatus complete, for £20. But for 
those whose means are more limited than either of these would 
imply, there is still an instrument, which may be within their 
reach, viz., Field’s Compound Microscope, called the Society 
of Arts Microscope. This marvel of cheapness ai-ose from 
a competition for an award offered by a committee of the 
Society of Arts, in 1854, for a low-priced compound microscope 
which should combine cheapness with the greatest degree 
of excellence. The award was made to Mr. G. Field, optician. 
