THE K RAYS OF M. BLONDLOT. 211 



prism jippears to be anomalousl}' refracting; in other words, its indices 

 of refraction increase rather than decrease with increasing wave length 

 of the rays. M. Blondlot suggests that the augmentation of brilliancy 

 observed in a small luminous source under the action of the N rays 

 may be attributed to a transformation of these radiations into lumi- 

 nous ones in conformity to the law of Stokes. 



STOKING UP OF THE N RAYS. 



M. Blondlot finds that man}- substances are able to store up the 

 N rays and emit them for some time after having been subjected to 

 the influence of a source. This property, it will be seen, is similar to 

 the phenomenon of phosphorescence which is observed with ordinar}^ 

 light. Among the substances which appear to store up the N rays 

 are quartz, Iceland spar, fluorspar, glass, and many others. Alumi- 

 num, wood, paper, and ])araffin, on the other hand, do not appear to 

 possess this property of storing up N rays to any very appreciable 

 extent. The phenomenon is so general that a large portion of the 

 bodies upon which the sun's ra3'S fall are said b}- M. Blondlot to 

 become saturated with the raj's and to give them out undiminished in 

 some cases as long as four days after they have been removed from 

 the influence of the sun. 



N RAYS PRODUCED BY MECHANICAL PROCESSES. 



It appeared that compression and other distortions of metals, wood, 

 glass, ru))ber, etc., caused these substances to emit N rays while under 

 such mechanical constraint. Crystalline substances, tempered steel, 

 and some other bodies possessing special internal structure, are stated 

 to be spontaneous and permanent sources of N ravs. As an illustra- 

 tion of the permanence with which this property remains associated 

 with such substances, M. Blondlot mentions that a sword found in an 

 ancient sepulcher dating from the Merovingian epoch, was found to 

 give out the N rays strongly. It thus appears that the emission of the 

 N rays ])y tempered blades of steel may continue for centuries with- 

 out becoming enfeebled, and as regards continuous emission, therefore, 

 the N raj's may be compared with the radiation of uranium, radium, 

 polonium, and other sources of Becquerel rays, although, of course, in 

 other respects the two kinds of radiations are entirely dift'erent. 



EMISSION OF N RAYS BY THE HUMAN BODY. 



M. Charpentier, while repeating in his laboratory many of the 

 experiments of M. Blondlot on the i)roduction and observation of 

 N rays, noted that the luminosity of phosphorescent substances used 

 to defect the presence of the rays appeared to increase when tlie 

 observer approached these phosphorescent su})stances. Continuing 



