12 "JV RAYS 



no longer produces any fluorescence, and is 

 itself absolutely invisible in the dark. They 

 are fainter, however, in this case. They can 

 also be produced continuously by means of 

 an electric machine giving a spark a few 

 millimetres in length. 



At first I had attributed to Rontgen rays 

 the polarization which in reality belongs to the 

 new rays, a confusion which it was impossible 

 to avoid before having observed the refraction, 

 and it was only after making this observation 

 that I could with certainty conclude that I was 

 not dealing with Rontgen rays, but with a new 

 species of light. 



It is interesting to collate these remarks 

 with the view expressed by M. Henri Becquerel, 

 that in certain of his experiments ''manifesta- 

 tions identical with those giving refraction and 

 total reflection of light may have been pro- 

 duced by luminous rays which had traversed 

 aluminium " (see Comptes Rendus, t. xxxii., 

 March 25, 1901, p. 739). 



