RECENT WORK ON THE X RAYS. 109 



reflected. The result arrived at, wliich Prof. Rood says is only to 

 be regarded as a first approximation, was that platinum foil re- 

 flects the one two-hundred-and-sixtieth part of the X rays inci- 

 dent on it at an angle of forty-five degrees. Prof. G. Yicentini 

 and Dr. G. Pacher, in a paper read before the Reale Istituto 

 Veneto di Scienze, report having found distinct evidence of an 

 irregular refraction from a parabolic brass mirror. 



Regarding the value of these rays in surgery there are at pres- 

 ent hardly sufiicient data to warrant a positive conclusion. How- 

 ever, a most thorough and profusely illustrated article appeared 

 in the American Journal of the Medical Sciences for March, 1896, 

 entitled The Clinical Application of the Rontgen Rays. It is much 

 the best exposition which this branch of the subject has yet re- 

 ceived, and if one can depend on the pictures, the new agent 

 promises to be, if nothing more, at least a great aid to diagnosis. 



An interesting commercial application of the rays is an- 

 nounced by Bugnet and Goscard in the Comptes Rendus. " The 

 proofs which we have the honor to submit to the Academy show 

 in juxtaposition silhouettes of genuine diamonds and of imita- 

 tions, both loose and set. Prolonged exposure soon succeeds in 

 causing the silhouettes of genuine diamonds to disappear, while 

 false diamonds continue to behave like opaque substances. The 

 same procedure has also enabled us to distinguish natural jet 

 from its mineral imitation." 



At a meeting of the Royal Society, on February 13th papers 

 on the Rontgen rays were read by Lord Kelvin and Prof. J. J. 

 Thompson. A discussion followed, the general tone of which 

 showed that, although many interesting points have been cleared 

 up, there is still considerable difference of opinion among the au- 

 thorities regarding fundamentals, and, while extremely valuable 

 experimental work has been done, we are yet far from a final ex- 

 planation of the origin and properties of this new (?) form of 

 energy. 



The following, from an unbeliever, may perhaps be of interest : 

 Ch. V. Zenger says, in speaking of some pictures obtained by 

 Domalip, Professor of Electrotechnics at the Polytechnicum of 

 Prague: "The interesting point is that Domalip has obtained 

 electric images on a plate by means of plates of copper, brass, 

 zinc, lead, and steel. This is, in my opinion, the proof that there 

 is here merely a phenomenon of electric induction producing 

 phosphorescence of the gelatin, and at the same time an electric 

 discharge in the gelatin, and, lastly, the fluorescence of the am- 

 bient air, and as in case of the dark discharge of electricity. In 

 my opinion, these are the three agents which determine the de- 

 composition of the silver salts in the sensitive layer. There are 

 no special radiations, no X rays, and no dark light.^' 



