Chemistry and Physics. 85 



of mica : this gave elliptic polarization. But the facts stated 

 proved the existence of double refraction and made a fortiori 

 simple refraction highly probable. I proved then further that 

 the radiations which I had studied were really deviated by a 

 quartz prism and could be concentrated by a lens; it was also 

 shown that they were reflected by a plate of smooth glass and 

 diffused by an unpolished glass surface. 



The facts stated indicate that the rays under examination were 

 not Roentgen rays or X-rays, which suffer neither reflection nor 

 refraction, but a new kind of rays traversing aluminium, wood, 

 black paper, etc., polarized rectilineally on emission, susceptible of 

 rotatory and elliptical polarization, and reflected or diffused, but 

 producing neither fluorescence nor photographic action. To this 

 kind of radiation I gave the name of JV-rays. It is to the N-rays, 

 in fact, that the phenomena of polarization pertain which I had 

 observed and at first attributed to X-rays. If we analyze by a 

 quartz prism the complex of rays emitted by a Crookes' tube, it 

 is found that the X-rays are not deviated while the N-rays are 

 deflected toward the base of the prism. It is easy then to prove 

 that the N-rays alone act on a small spark while the X-rays seem 

 to have no action on it. I have thus established the polarization 

 of the N-rays and not that of the X-rays; also the velocity of 

 propagation, which I have measured by a method published in 

 these Archives, belongs not to the X-rays but to the N-rays. 

 The confusion was unavoidable until the existence of the new 

 radiations was recognized. 



A further study of the N-rays has enabled me to prove that 

 any source of light of very small intensity may be employed to 

 show their existence, as a small gas flame, a platinum wire at a 

 red heat, a phosphorescent screen. All of these sources of light 

 have their brilliancy increased by the action of N-rays. A 

 Crookes' tube is not the only source of N-rays; they are emitted 

 also by an electric arc, a Nernst lamp, an Aner burner, and most 

 of all by the sun. 



The reflection and refraction of the N-rays follow the same 

 laws as those of light ; in particular the law of Descarlis has 

 been verified with a high degree of precision in the experiments 

 made with prisms and lens (of aluminium). In the emission 

 from a Nernst lamp I have proved the existence of a large num- 

 ber of radiations of different indices comprised between the 

 values 1*04 and 1*85. I have isolated the different pencils by the 

 aid of an aluminium prism, I have measured their wave-length 

 by the aid of reseaux traced on glass by the classic method, and 

 the method, based upon the use of Newton's rings, has given 

 results agreeing with the preceding. The wave-lengths are com- 

 prised between 0^*0081 for the index 1*04 and 0^*0176 for the 

 index 1-85. 



It follows from what has preceded that the N-rays are com- 

 pletely analogous to light, from which they differ only in the 

 lengths of the waves, which are much shorter. Now light, ultra- 



