64 Scientific Intelligence. 
New Erecting Prism; by Josereu ZentTMayer.—Mr 
Joseph Zentmayer exhibited ae described a single prism, which 
erects the i image completely, and in such a way oe the incident 
and emerging rays are parallel, which, as far as we cnow, was 
never accomplished before. In connection with tne microscope, 
s it was shown, it interfered very little with the definition, and, 
although the light i is twice refracted and reflected, the loss of ight 
is much less than one would expect. With the microscope, the 
prism is placed right above the objec sai e, and the instrument may 
be used in any inclined position. r of such prisms might be 
used also for an erecting binocular microscope of which the two 
bodies have the same inclination to the s tage. 
Fig. 1 shows the front and profile of the prism. The projection 
of the front is a square, that of the profile an isosceles triangle. 
The angles at the base of the triangle are 27° 19’ for crown glass 
of a refracting index of 1°53, in ae ss obtain the greatest aper- 
ture combined with the smallest pri 
Fig. 2 is a view from above. The peer of A, B, and C of figs. 
1 and 2 are the identical ones, their dotted parts are the ays 
‘isee of the rays inside of the glass, and their course may be reat 
