260 
POPULAR SCIENCE REVIEW. 
practical result being, that the enlarged image has the appearance of being 
seen by both eyes at the same time, and at a sufficient distance to make 
them both useful. 
In Mr. Wenham’s former instrument, the bisected rays diverged 'when 
they passed the prism, so that the right-hand half of the rays reached the 
right eye, and the left-hand, the left. Applying, however, the fact known 
to stereoscopists, that the remedy for a transposition of the projecting and 
depressed part of the picture, when viewed through the instrument, was a 
transposition of the two stereoscopic pictures, Mr. Wenham transposed 
the images of his microscope, by so constructing the lens that the divided 
pencil of rays converged, instead of diverging, crossing each other imme- 
diately above the objective, and thus passing, the right - hand half to the left 
eye, and vice versa, the result being orthoscopic ,* * * § instead of pseudoscopic,\ 
as before. 
The two eye-pieces are placed sufficiently near to suit those whose eyes 
are naturally near together, but by means of draw-tubes attached to 
them they may be made to diverge half an inch further, thus suiting all 
eyes. The chief advantage which this instrument possesses over that 
of M. Nachet, is that only a single refracting prism is used instead of 
a double system, as in the latter instrument, the definition under high 
powers being of course much more perfect the fewer deflections the rays 
have to undergo. 
No one can fail to be struck with the beautiful appearance of objects 
viewed undertlie binocular microscope. Itschief application is to such objects 
as require low powers, and can be seen by reflected light, when the 
wonderful relief and solidity of the bodies under observation astonish 
and delight even the adept. Foraminifera,J always beautiful, have their 
beauties increased tenfold, vegetable structures, pollen, and a thousand 
other things are seen in their true light, and even Diatoms, § we may 
predict, will receive elucidation as to the vexed questions of the convexity 
or concavity of their infinitely' minute markings, so that both the scientific 
and dilettante microscopist may find work for the ey'es, or food for the ima- 
gination. A very important and valuable scientific fact must not be over- 
looked ; namely, the application of the binocular to anatomical investigation. 
Prepared microscopic injections exhibit under the ordinary microscope 
a mass of interlacing vessels, whose relation, being all on the same plane, 
it is not easy to make out with any degree of satisfaction ; but placed under 
the binocular they' at once assume their relative position. Instead of a flat- 
band of vessels, we now' see layer above layer of tissue ; deeper vessels 
anastomosing with those more sujierficial ; the larger vessels sending 
branches, some forward and some backward, and the whole injection 
assumes its natural appearance, instead of being only like a picture. 
* From two Greek words, signifying “straight,” or true vision, 
t From two Greek words, signifying “false vision.” 
J Foraminifera are lowly organisms belonging to the Rhizopoda, the 
lowest type of animals. They resemble “ Amoeba,” (see article “Lowest 
Forms of Life ”), but are protected by calcareous shells. 
§ Objects of which the true nature, animal or vegetable, is not yet defined. 
