THE NEW RADIATIONS— CATHODE RAYS AND RONTGEN 



RAYS.*^ 



Bv A. Dastre. 



It i.s g-encrall}' agreed that one of Jihe characteristic features of our 

 age is the enormous development of the applications of science. This 

 is a commonplace truth. We are completely surrounded on all sides 

 b}^ these applications; they are intimately mingled with all the condi- 

 tions of everyday life; they take part in our housing, our clothing, 

 oui- lighting, our transportation in man}' ways; they assist us in com- 

 nuuiicating with our friends, far and near; thev produce our portraits, 

 or they simply amuse us, so that they can not be ignored. But this 

 utilitarian aspect of modern science should not obscure its educational 

 and philosophic value. Referring, for instance, to contemporary 

 phvsics only, the march of ideas has not been less remarkable than the 

 progress of discoA^er}". Theory and practice have advanced side by 

 side. Boldness of speculation has attained the same height as skill in 

 experimentation. It may be said in this connection that the evolution 

 of theories compares favorably with the marvelous development of 

 facts, and the philosophy of science with science itself. This we have 

 previously attempted to show to our readers in our essays on osmose, 

 on cryoscop}', and on tonometry; here we wish to examine from the 

 same point of view ideas that have accumulated in recent 3'ears con- 

 cerning cathode rays, Rontgen rays, and on the radio-activity of 

 matter. 



I. 



The term "cathode rays" was suggested in 18S3 b}- the well-known 

 physicist, Wiedemann, who had been engaged in studying them, but 

 the object to which the name was applied was not entirely new. 

 Cathode rays had several years before occasioned celebrated experi- 

 ments in the hands of an English scientist, W. Crookes, long well 

 known through other original investigations. The beautiful experi- 

 ments of Crookes, disseminated by their author throughout Europe, 

 had attracted the attention not merely of the majority of physicists, 



''Translated from the Revue des Deux Mondea, Dec. 1, 1901. 



271 



