180 TRANSACTIONS OF THE | [apr. 1, 
ratio between the two colors for any angle is shown in the dia- 
gram. It is evident that light emitted at any angle larger than 
75° will be predominantly red At the same time the shape of 
the curves accounts for the lack of any noticeable predominance 
of violet in the neighborhood of 73° 39’, 
The figure shows the curves of intensities of the reflected 
components of vibration parallel to the plane of incidence as 
roughly plotted from the values given above. The lines mM Dp, 
M, D,, etc., represent the intensities of the emitted red vibrations 
in this plane for various angles; while the lines nN D, N, D,, etc., 
represent the intensities of the emitted violet vibrations for the 
same incidences. The lines N M,N, M,, etc., are the measure of 
predominance of red over violet, or vice versa. The steepness. 
of the curves at points corresponding to angles greater than 
the angle of maximum polarization and the lack of steepness 
at points corresponding to angles less than the angle of maxi- 
mum polarization are evidently the cause of the marked predom- 
inance of red at large angles and the lack of noticeable predom- 
inance of violet at any angles. This characteristic of the curves 
follows from the fact that the points of maximum polarization 
correspond to very large angles. 
XIV. 
EXPERIMENTS UPON SILVER. 
Owing to the great kindness of Mr. Herbert G. Torrey, As- 
sayer of the U. S. Assay Office, I was next able to make @ 
series of observations upon molten silver. These experiments 
were the most satisfactory of any which were made in the course 
of the research. All of the sources of error which had existed 
in preceding cases were here eliminated. The surface was per- 
fectly defined, it was accurately horizontal, and there were no 
variations in intensity from point to point. The results of 
the experiments are given in full. 
30° SDS 40° 45° 
Left. Right. Left. Right. Left. Right. Left. Right. 
46.0 36.0 44.5 33.4 ayaa Soll 42.0 30.5 
47.2 36.0 45.0. 733.7 AO Sle) By) 42.0 31.0 
46.5 35.0 44.5 34.0 AS 3) ost) Al clk 
AGrotonlO 4510" = 134.0 ASD oe. 42.5 30.5 
46.5 35.5 
46.5) 35.p 44.75 33.8 43.72 32.05 41.9 30.8 
———— — So — —— 
Yi 43249 2 w = 78.55° 2 w = 75.27° 2) od 
pD— aos p—.189 == 254 p= .2070 
