JAMIN ON METALLIC REFLEXION. 101 



and, if they are easier, they are not the less important. There 

 must be sought, for each metal, the values of the constants, and 

 the manner in which they vary with the circumstances which 

 modify the polish, density, and molecular state of the body, 

 must be determined : further, the different simple colours of 

 the spectrum should be employed, and the laws of the in- 

 equality of action produced in them by metals, investigated. 



Conclusions. 



The memoir which I present has for its object to determine, — 



1st. The intensity of the light reflected from polished metals, 

 when the incident ray is polarized in the azimuths of 0° and 90°. 



2nd. The ratio of these intensities, by a different process. 



3rd. The difference of phase of these rays, after reflexion. 



4th. To show that the results of experiment are perfectly re- 

 presented by the mathematical formulae of M. Cauchy. 



5th. To investigate, after reflexion from a metallic mirror, the 

 direction of the axes of the ellipse in which the molecules of 

 aether vibrate, when the incident ray has been polarized in any 

 azimuth whatever. 



6th. To determine, by calculation and experiment, the inci- 

 dences for which the polarization becomes again rectilinear after 

 a certain number of reflexions from parallel plates. 



7th. To find the azimuths of restored polarization under all 

 incidences. 



8th. To investigate the value of the angles of restored polari- 

 zation when the two planes of incidence are inclined to each 

 other, and the incidences on the two mirrors are unequal. 



