1896.] 



31 



made by a number of members present, among whom may be named Dr. 

 Paul Beck Goddard, Joseph Saxton, Prof. Henry and Prof. James 

 Rodgers, all names that are still held in high esteem in the scientific 

 world. 



While upon the subject of Moser's theory, I will state that therfe have of 

 late come to my notice several cases which seem to confirm his theory of 

 latent light, or invisible photographic rays. The most marked instance 

 was where a number of platinum prints were packed away and laid un- 

 disturbed in the dark for several months, and in several cases had repro- 

 duced themselves or formed a reverse positive picture upon the surface of 

 the white plate paper mount which laid immediately over the print I 

 merely mention tliis matter at this time so as to place it upon record, as I 

 expect to bring it before the Society in a more formal way in the near 

 future. As a fitting close to this paper I will quote the language of 

 Robert Hunt, used in connection with Moser's theory and read here half 

 a century ago, as it will apply with equal force to the theory of the un- 

 known waves known as the X rays of Roatgen : " As a subject of pure 

 scientific interest this discovery promises to develop some of those secret 

 influences which operate in the mysterious arrangements of the atomic 

 constituents of matter, to show us the road into the hidden recesses of 

 nature's works, and enable us to pierce the mists which at present envelope 

 some of its most striking phenomena. It has placed us at the entrance of 

 a great river flowing into a mighty sea, which mirrors in its glowing 

 waters some of the most brilliant stars which beam through the atmos- 

 phere of truth." 



Referring to the paper read by Mr. Julius F. Sachse, Mr. 

 Joseph Wharton asked: 



Q. Will the gentleman please explain more fully what is the action of 

 the X rays upon the more sensitive gelatine film as contrasted with their 

 action upon the collodion ? 



A. I have not had the time to verify it by experiment ; but as the case 

 stands at present I cannot explain it except that the rays pass through the 

 collodion film : they fail to arrest. That is the only explanation I can 

 give at the present moment. 



Q. That seems to be somewhat at variance with many of the observa- 

 tions that we have had set before us to night : namely, that a number of 

 so-called colloid bodies seem to be pervious to the ray ; while a number 

 of the crystalloid bodies seem to be impervious. Here are pitch, gum, 

 leather and several other bodies which are pervious to the ray (all col- 

 loids) ; while quartz, rock salt and other crystals (the speaker naming 

 several) all appear opaque to the ray. It may be worth while to bear in 

 mind, in future investigations, the question whether there may be a line 

 drawn between colloids and crystalloids in transparency for the new ray, 

 and if so to search for the reason of that distinction. 



