SCIENTIFIC MEMOIRS. 



VOL. IL— PART VI. 



Article IV. 



Memoir on the Polarization of Heat ; by Macedoine 

 Melloni. Second Part*. 



[From the Annales de Chimie et de Physique, vol. Ixv., May, 1837.] 



In the first part of this Memoh- it was shown, that calorific rays, 

 transmitted by a pair of tourmalines which completely polarize 

 light, undergo every degree of polarization. Certain species of 

 heat, in sensibly equal quantities, traverse the two plates, what- 

 ever be the position, parallel or perpendicular, of their axes of 

 crystaUization : others pass, in different proportions, in these two 

 directions of the axes ; and, lastly, others only traverse the system 

 when the axes of crystallization are parallel. 



In the examination of the method according to which the 

 polarization of light becomes sensible by means of tourmahnes. 

 It was shown that, notwithstanding the great differences of effect 

 presented by the various species of heat, it was not necessary to 

 suppose the existence of a different aptitude for polarization in 

 each ; but, on the contrary, that all might undergo an equal and 

 complete polarization in the interior of the tourmalines, and yet 

 appear more or less polarized at their emergence. These effects 

 are sufficiently accounted for by supposing that the tourmahnes 

 refract doubly every sort of radiant heat, and that, in each par- 

 ticular case, one of the two pencils of rays proceeding from this 

 double refraction is more or less absorbed during its passage. 

 The two refracted pencils being of the same intensity, polarized 



vol i p^'32t] ^'''' "^ '^'' ^'""''''' ""'" ^' ''"""'^ '" Scientific Memoiws. 

 VOL. IT. PART VI. K 



