NEW SOURCES OF RADIATIONS 23 



most easily observed. The experiment is an 

 easy one to set up and to repeat. This property 

 of " N " rays is analogous to that of the red 

 and infra-red rays discovered by Edmond 

 Becquerel. It is also analogous to the action 

 of heat on phosphorescence. Nevertheless, I 

 have not noticed as yet an increased rate of 

 exhaustion of the phosphorescent capacity under 

 the action of " N " rays (see p. 74). 



The kinship of " N " rays with known radia- 

 tions of large wave-length seems a certain 

 fact. As, on the other hand, the property 

 possessed by these rays of traversing metals 

 differentiates them from all known radiations, 

 it is very probable that they are comprised in 

 the five octaves of the series of radiations, 

 hitherto unexplored, between the Rubens rays 

 and electro-magnetic oscillations of very small 

 wave-length. This is what I propose to verify 

 (note 8). 



