110 Proceedings of Learned Societies. 
B. Pure Metals. 
1, Silver. 4. Zine. 
2. Gold. 8, Lead. 
3. Mercury. 9. saa 
- Platinum, 10. 
5. Palladium. 11. ves and steel, 
6. Copper. uminum. 
C. Alloys. 
1. Copper om tin (speculum ones he Copper and zine CC 
2. Copper an 10 (2Cu+-Za). 
3. (9Cu-+ Zn). i . (Cu-+Zn), 
—<— = ze «(Cu Zn ). i - + (cua 
ee ee “ (7Cu+Zn). ._. - “i (oa 
Ss “ (6Cu-+ Zn). ry ee « (Cu44Zn), 
eae: . eg 16; 3° “ (Cu+5Zn), 
8 ' “ (4Cu-+-Zn). 
The determination of the optical constants of these substances leads 
to many interesting conclusions; among which the following may be — 
stated :— 
1. That Transparent bodies, as well as metals, possess a coefficient of 
reflexion, which is  aleamag very sensible, although there are bodies in 
= it is very sm oy 
at Silver is ie only substance which possesses the qualities of 
brillia Shiieg and lustre, represeni> ted by the coefficients of refraction and 
sega rar in a high de, 
. Of the metals wei have high “soe and little Zustre may be 
a Mercury, Palladium, Zine, and 
4, Of the metals which have high Ietied and little brilliancy there are 
only two, Gold and C 
5. Results of the highest interest appear from an examination of the 
optical constants of the alloys of copper and zinc, which cannot be “a 
in an a 
6. In the details of the several experiments, the author calls a 
to several remarkable laws, or indications of laws, which appear to oy 
to — some notice from theorists Z 
the azimuth of the incident beam is less than the eireulat 
Hat, the axis major of the reflected ellipse, at the principal incid 
lies in the plane of incidence; but when the azimuth is greater than ts 
circular limit, it is perpendicular to the plane of incidence, and as the 
incidence varies, the axis major twice approaches to a minimum distance 
from lan 
prane. . 
b. There appears to the author to be some indication in the expat 
ments on metals, that the quantity known to theorists as (;) is not 
function of the ——s only; a conclusion which, i Laeger 
— the intervention of a nt Ailey e suppressed, or 
eeeuice® ion, to account for 
