28 



[Feb. 21, 



Mr. Carbutt : Do I understand j^ou to say that no positive results have 

 been obtained yet at the bell of the receiver of the exhaust pumps? 



A. I say that I understand that no sensitive plate has yet been obtained, 

 ■which, placed in the Crookes tube, will have any aclinic effect produced 

 on it by the cathode rays. "When they pass outside the tube they are no 

 longer cathode rays. 



Q. But if placed on the bell of the receiver of an exhaust pump? 



A. I have not tried that. 



Q. Just to-day I made the experiment of exposing a pair of steel 

 scissors ; and in five minutes obtained a strong negative effect, getting my 

 rays from the negative pole. 



Q. Then they went through the glass of your receiver ? 



A. No, sir ; they struck right on the metal scissors. 



Q. Where had you your photographic plate? 



A. On a bell receiver. I used no Crookes tube, nothing but just the 

 rays as they came down from the negative pole. The plate w^as lying on 

 a little table as connected with the positive pole and the rays were seen 

 traveling down on the plate on which were laid tiie scissors. 



A. I think you had an effect very mucli like the electric discharge 

 effects shown on the screen to-night. I believe that a great many state- 

 ments made concerning the ability of other sources of light to produce 

 Rontgen rays are due either to heat effects, or to electric effects. 



Dr. J. Cheston Morris asked if Edison was experimenting with celluloid 

 plates. Prof. Houston said he did not know. 



Eemarks by Mr. Julius F. Saclise were as follows : 



So far as the photographic properties of the new X rays of Rontgen are 

 concerned, it is yet a question whether they will ever be of any practical 

 value or use for photographic purposes, as the term is usually understood. 



The fact that these rays can neither be refracted, condensed nor dis- 

 persed, is a fatal objection to their application to photograpliy. 



It will be noticed that all of the registered or permanent results obtained 

 and shown here this evening are by no means photographs in the ordinary 

 sense of the word; they are merely fixed shadows or "sciographs" 

 obtained by the interposition of a sensitive gelatine plate. 



I do not wish to be understood as depreciating this new factor in 

 physics, nor to appear skeptical as to any practical results that may be 

 forthcoming in the future. It is now certain that a great discovery has been 

 made by Prof. Rontgen, notwithstanding the fact that these identical 

 rays have been produced thousands of times, in nearly every physical 

 laboratory in the world, and that it only needed the neighborhood of a 

 luminous film to reveal them, and to do this was Prof. Riiutgen's oppor- 

 tunity. The step to substitute a sensitive plate to register the shadow 

 was a short one, and we have here to-night a practical demoDstration of 

 the results. 



