S. Haughton on the Reflection of Polarized Light, etc. 109 
drawing of the aluminum spectrum is given, with zinc and cadmium 
r com sar eabe 
The author has also described and figured the mode of absorption of 
the invisible, rays “4 Pa aT of various alkaloids and glucosides. Bodies 
of these classes, inds, are usually intensely opaque, acting on the 
invisible spectrum with an Sater comparable to that with which col- 
ering matters act on the visible. This intensity of action causes the 
ect of minute impurities to disappear, and thereby increases the value 
of the characters observed. It very often happens that, at some pe or 
other of the oe spectrum, a band of absorption, or maximum o city, 
occurs; and the position of this ae, haces a highly distinctive 3 
ter of the substance which produc 
Among natural igo Masia ‘i previously known yellow uranite, 
the author found that in adularia, and feldspar ge ggte, a strong fluo- 
rescence is produced ath the action of the rays of high refrangibility, 
referable not to impurities, but to the essential constituents of the crystal, 
particular variety of fluor-spar shows also an interesting feature, though 
in this case referable to an impurity, exhibiting a well-marked reddish 
fluorescence under the exclusive influence of rays of be. very highest 
refrangibility. This property renders such a crystal a useful instrument 
research. 
With some metals broad, slightly convex electrodes were found to have 
@ great advantage over — exhibiting the invisible lines far more 
strongly, while with some metals the difference was not 
he blue negative light rane when the jar is removed and the 
ectrodes are close together, was found to be ch in invisible 
rays, especially — rays of moderate refrangibility. These exhibited 
lines independent of the electrodes, and therefore referable to the air. 
This blue light ‘i a very sas jaca and is formed by what 
the — calls an are dise 
r concludes with some speculations as to the cause of the 
superiority of broad electrodes, and of the heating of the negative 
a 
On the Reflexion of Polarized Light on Polished Surfaces ; by the 
Rev. Samvet Haveston.—When a plane-polarized beam of light is in- 
“cg on a polished surface at a certain angle of incidence, and polarized 
certain azimuth, the reflected beam of light is circularly polarized. 
“The ween of this angle of incidence is called by the author the 
Coefficient of Refraction, and upon it appears to depend the brilliancy 
ofa olschod surface, 
seg of the azimuth of incident polarization is called the 
Coefficient of Reflexion, and upon it appears to depend the rich dustre, 
strikingly exhibited in polished copper an 
The per contains an account of the experiments made to a 
with precision, these constants for the following substances :— 
A. Transparent Bodies. 
oo ee pe ass gee 
Munich glass . Glass o timony. 
3. Pari (°). 6. Quartz crystal. : 
