182 
THE MICROSCOPE. 
[Nature and Art, June 1, 1867. 
and quarter-inch powers. The cut shows its general 
form ; J is the body, B a draw-tube to increase its 
length, D is the eye-piece, and C is a little animal- 
rig. 
cule cage. Mr. Highley has also constructed an 
instrument which lie lias termed the “ complete 
microscope ” (fig. 6). This is a piece of neat work- 
manship, and has certain intrinsic merits. It packs 
into a box 8 inches by 61,-, and 4 inches deep, and 
is provided with a condenser on the Webster plan, 
and with a polariscope. The application of the 
latter is ingenious. The ray of light is polarized 
by reflection, the place of the ordinary flat 
mirror being taken by what is termed a 
“ polarizing bundle.” The analyzer is situate 
in the body of the microscope. 
Of compound microscopes the above are 
the chief forms lately introduced to the public. 
In the class of simple microscopes we know 
of only one novelty. This is the instrument 
known as “ Dr. Lawson’s Binocular Dissecting 
Microscope” (fig. 7). It is intended for the use 
of naturalists and anatomists, and is somewhat 
peculiar. Its stage is in the shape of a trough, 
and is made of gutta-percha. To this the animal 
or structure intended for dissection is pinned 
down under water. Beneath the stage is a plane 
mirror, which reflects light to the object under 
notice through a small glass plate inserted in the 
bottom of the trough. The sides of the case draw 
out and form arm-rests, and the lenses are placed 
on a sliding horizontal bar, which in its turn is 
attached to a vertical rod, which has a telescope 
movement. The top and sides “ let ” down, and 
contain the knives, needles, forceps, scissors, &c., 
requisite for dissection. The lenses are not simply 
convex lenses, but are portions of the periphery 
of a large lens, thus preventing all distortion. 
When a small object — say a worm or the eye of 
an animal, is dissected under water, all the parts 
are seen with the aid of this instrument standing 
out in relief, and magnified so that the operator 
has no difficulty in recognizing the several tissues, 
&c. Readers are aware that in the older forms 
of dissecting microscopes the absence of the bino- 
cular arrangement, giving a rather flat picture of 
the object, renders the difficulty of dissection often 
very great. 
Having disposed of the microscopes themselves, 
we come now to the second portion of our subject, 
the new methods of illuminating microscopic 
objects ; and in the first place we may speak of the 
Fig. 7. 
Fig. 8, 
