30 
REVIEWS. 
as merely writing for those who, with very limited means at their disposal, 
are desirous of procuring a microscope to aid their researches. We wish 
to give some idea of what would be a good way of procuring a good, plain 
instrument for use , and at a moderate cost. Microscopes, as is well 
known, are divided into simple and compound —terms sufficiently well un¬ 
derstood to need no definition; the former may be divided into those used 
in the hand, and those provided with a stand or apparatus for supporting 
the object to be viewed. In choosing the latter, the principal points to be 
attended to are, “ to see that the stage is of sufficient size and strength, 
and that the arrangements for holding the lenses, and moving them in 
different directions, are convenient.” 
Microscopes of this kind used for dissecting are furnished by all the best 
makers. Of those we have used we prefer that furnished by Mr. Ross. 
In this instrument the arm at the top, which carries the lens-holder, has 
a forward motion, by rack and pinion, and a traversing motion, on a pivot, 
by which means the lens can be carried in any direction over the stage. 
It is usually furnished with lenses of one inch, half an inch, quarter of an 
inch, and one-tenth of an inch focal lengths, and sometimes with a Wollas¬ 
ton’s doublet. For a figure of this instrument, accompanying the above 
description, we must refer to the pages of Schacht’s valuable manual on 
“The Microscope, and its application to Vegetable Anatomy and Physiology.” 
For those who may not be disposed to purchase so expensive a form 
of simple microscope, we can recommend the very portable one, called 
“ Quekett’s Dissecting Microscope,” lately produced by Mr. Highley. 
Of this microscope the accompanying 
figures will give some idea. Fig. 1 
shows the instrument folded up, with 
an Indian-rubber band round it, in 
a manner which admits of its being car¬ 
ried in the pocket. The two wedge- 
shaped pieces of wood unfold, and form 
the legs (see figs. 2 and 3). Fig. 2 
shows the internal arrangement and the 
manner in which the mirror, lenses, and lens-holder are packed away. The 
straight flat bar, on the right in fig. 2, serves to keep the legs from closing 
together, and also as a support for the mirror, which slides into a piece of 
brass tubing, attached to the flat bar. The circular hole at the lower end 
of fig. 2, is another piece of brass tubing, into which the lens-holder 
slides. The instrument is furnished with three lenses, and is to be had at 
a moderate price. 
