10 
REroRT—1854. 
tides being highly, though still imperfectly transparent, and permitting the inferior 
layers to be seen through them. This effect we see produced when many watch- 
glasses are laid in a heap, or when a plate of transparent mica or talc being heated 
red-hot is thus separatedinto multitudes of thin layers, each of which, of inconceivable 
thinness, is found to bo highly transparent, while the entire plate assumes the lusnc 
of a plate of silver. This explanation receives a very striking confirmation from the 
stereoscopic phenomena which he now drew attention to. He then presented to 
the Section and described a very simple and portable modification of file stereoscope, 
consisting of two lenticular prisms mounted inn frame like a double eye-glass. L|«m 
examining with this two diagrams, drawn one for the right, the other for the Iclt nr. 
with lines suited to give 1.1m idea when viewed together of a pyramid, cube, cone, of 
other mathematical solid, but the lines on one drawn on a white ground, the other 
on a dark or coloured ground, on viewing them together the solid appeared withth* 
metallic lustre. The author termed it " Glance.” This, he conceived, demonstrated 
his original idea to be correct. 
On a Method of measuring the Absorption of Polarized Light in doubly n 
feuding Crystals. By M. Dove, Berlin 
deli* 
is sufficient to combine with the crystal a plate of glass, or a pile of p»* * . u 
inclined until it exactly compensates the polarizing power of the cm a. ^ 
known by the complete disappearance of the figures in the unannealea g 
angle of inclination affords data for the determination of the ratio sought. 
M. Duboscq then presented to the Section philosophic apparatus fo h p hor 
projection on a screen to a large auditory all the phenomena ol . meeting 
was requested to permit Prof. Stokes to exhibit and explain at the eveu b 
the apparatus, and to show with it the leading phenomena of Pe® • 
On Photographs of the Moon and of the Sun. 
By the llev. J. B. It bade, M.A., F.B ^- ^ (o 
The author recounts in the first place the prominent results °*'® e .' C V> 9 su cct‘i 
obtain photographic pictures of celestial bodies, previous to i r. oWn nb- 
m 1851, and then proceeds to plueuomeua which have fallen 
servation. ( „ b j c h illustraW 
“ The two daguerreotypes of the moon, an original and a com 1 , - . ter pjctu* 
this paper, will be examined with some interest by the Section. j n Am frl1 * 
produced by the moon herself, in the focus of Bond's refractor, was u ^ ^ 5CBrt rlv 
It possesses a very remarkable, but latent sharpness, which, nowc 8 sn>"-- 
visffile to the eye, that to ascribe to it this character mav aimos B c f it » 
1 he proof of its having such a property is furnished by’the ben “ obtain' 1 J 
the same size, which mv friend, the Royal Astronomer for jj^clf, 
throwing strong sunlight upon the moon’s daguerreotype P‘ cl thfl c0 nju£^ 1 '' 
obtaining a reverse solar impression of it in a common camera, ^ ^ ®oo ■ 
being equal. The tones of grey and yellow which mark the acre ^ 
become, when handled by the sun, fine'contrasts of black and though 
chain round the portion of the Marc Imbriurn, is finely g' ven P details in 
lost requires a stretch of the mind's eye to discover some ot ^ cf j»trt - 
al. I he well-known ray of light from Menelaus passing tur 6 iftU n% 
dare Seremtatis, is another point of striking contrast in said tha £ ‘ , 
as the outline of the shadows in several of the craters. “ “ ; gmVtb. ^ ’ 
llosse was much interested with this happy experiment by P rof JSthe 
tended to solve a question which had often occurred to him in th* 9 1* 
bcnehcial use of penetrating sunlight under such circumstances; “ 
almost 
ginal 
the Mare 
well as the 
