land 
1895. ] NEW YORK ACADEMY OF SCIENCES. 179 
be deficient in red light, while the other image was abnor- 
mally red. 
If we assume the phenomenon to be due to reflection and re- 
fraction, this appearance is readly explained by a referenee to 
Quincke’s values for the angles of maximum polarization for 
the different Fraunhofer lines. 
This angle for the line C, Quincke gives as 78° 28’, and for 
the line G his value is 73° 39’. 
Now if @ is the amplitude of vibration in the reflected ray 
when the incident beam is polarized in the plane of incidence, 
and a’ the amplitude when the plane of polarization of the in- 
cident beam is perpendicular to the plane of incidence the angle 
2-_ qg/2 . 2 
of maximum polarization will be reached when aa is a maxi- 
* Wie mite 
mum, 7. e., when — is a minimum. 
The experiments of Jamin show that this angle coincides, at 
least very nearly, with the angle for which a’ isa minimum; a 
‘es 
+ al 
intensé 
conclusion which one would expect without the aid of experi- 
ment. Hence the angle 78° 28’ is that angle for which the com- 
ponent of the reflected vibration parallel to the plane of inci- 
dence is a minimum for the case of red light, and the component 
of the emitted vibration in the same plane isa maximum. On 
the other hand the angle of maximum emission of violet light in 
this plane occurred at 73° 39’. Accordingly it is evident that 
red light predominates in the beam emitted at the angle 78° 28’, 
and violet in the beam emitted at 73° 39’. The approximate 
———s ee 
