NOTES. 639 
parallel to the silvered surface, is refracted, on entering the prism, 
' meets the silvered surface at an angle of 72° and is, after reflec- 
tion, refracted on leaving the prism into a course parallel to that 
at which it entered. Some of the curious effects produced are 
mentioned in the Transactions of the Royal Microscopical Society. 
A Douste Erecrine Brnocutar.— In the Report of the Croy- 
don Microscopical Club, it is stated that at its last annual meeting 
there was exhibited an erecting binocular on Mr. Stephenson’s 
plan, made double so that two persons could examine the object 
at the same time. 
ANGULAR APERTURE or THE Eyr.—It having been carelessly 
assumed that in order to obtain a perfectly natural effect, the 
lenses of a photographic camera must be reduced to a linear aper- 
ture 2, in., the average diameter of the pupil of the human eye, 
and that a large aperture gives objects differently from ordinary 
vision, Mr. G. S. Cundell observes, in the “ Monthly Microscop- 
ical Journal,” that the ocular focus is only about s in., an 
therefore only four times its linear aperture. A corresponding 
size of camera lens having 12 inch focus would be 3 inches, not 
inch. Such a lens, so far as aperture is concerned, would be as 
free from aberrations and “ distortion” as the human eye. For the 
sake of stereoscopic effect he would use a lens of 2} inches diam- 
eter, that corresponding with the average distance apart of the 
human eyes, and reproducing the object, a head for instance, as 
We see it in nature, without the hard, cutting lines of monocular 
Vision, which all painters deprecate and avoid. 
NOTES. 
We take pleasure in calling the attention of our readers to the 
publication, in another portion of this number, of the several 
memorials made to the Commissioners of the Central Park in New 
York, relative to Dr. Hawkins, and the restoration of his work so 
wantonly destroyed by order of Mr. Hilton, who, we understand, 
is no longer in charge of the works of art and nature which he 
evidently did not have the education fully to appreciate. As these 
memorials are the expression of the most cultivated and influential 
class of citizens of New York, and can but meet with a warm 
response throughout the country, we trust that the present Board 
Of Commissioners will fully realize the importance of restoring 
