‘ 
68 On a Binocular Microscope. 
Art. X.—WNotice of a Binocular Microscope; by J. L. Rippett. 
I pevisEp last year, and have lately constructed and used, a 
combination of glass prisms, to. render both eyes simultaneously 
serviceable in microscopic observation. 
Behind the objective, and as near thereto as econ epcy “ 
light is equally divided, and bent at right angles, and m 
travel in opposite directions, by means of two rectangular mien 
which are in contact by their edges somewhat ground away. 
reflected rays are received at a proper distance for binocular vision, 
upon two other rectangular prisms, and again bent at right angles; 
being thus either completely inverted, for an inverted microscope} 
or restored to their first direction, for the direct microscope. 
outer prisms may be cemented to the inner, by Canada balsam; 
or left free, to admit of adjustment to suit different observers. 
Prisms of other form, with due arrangement, may be substituted. 
I find the method is applicable with equal advantage, to every 
grade of good lens, from Spencer’s best sixteenth, to a common 
three inch magnifier; with or without oculars or erecting eye 
died 
Ereniith and depth, whatever power hemay employ. Objects ate 
seen holding their true relative positions, and Wearing their 
shapes. A curious exception must be made. In viewing opake 
solid bodies, with one eye-piece to each eye, depression appears 
as elevation, and elevation as depression, forming a singular illu- 
ion. For instance, a metal spherule appears as a glass 
silvered on the under side ; anda crystal of galena, like an empty 
box. By the additional use of erecting eye-pieces, the images 
become normal and natural. Match “drawings of any solid ob- 
ject, made from each eye-piece, by the aid of the camera Jucida, 
when properly placed in the common stereoscope, appear to stand 
out in natural relief. hese, if engraved and printed in the propet 
position with respect to each other, might find an appropriate 
place in books on the arts and sciences. 
In constructing binocular eye-glasses, I use, for lightness and 
economy, four pieces of common looking-glass, instead of prisms: 
With these instraments, the microscopic: dissecting knife cat 
be exactly guided. The watch-maker and artist can work undef 
the binocular eye-glass, with certainty and satisfaction. In look- 
jutervening spaces, the thickness of which can be correctly est 
mated. Blood corpuscles, usually seei as flat disks, loom out a8 
oblate spheroids. In brief, the whole microscopic world, as thus 
displayed, ss a tenfold greater interest, in every phase eX 
hibiting, in a new light, beauty — symmetry indescribable. 
University of La, New Orleans, Oct, 1, 185 
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