THE RONTGEN RAY AND ITS RELATION TO PHYSICS 585 



If other people got them in other ways, why, there is something else 

 coming in. I don't know what it is. 



PROF. THOMSON: I should like to say just there, Professor, if you 

 would allow me, that I used exactly that arrangement first, and got 

 rays with the concave cathode. The anode at this end and the inter- 

 posed plate of platinum between, with that wire extending outward, 

 is the standard form of Crookes' tube the first tube, in fact, that I 

 used. I got not only sharp effects but rays. 



THE CHAIRMAN: Was the platinum red? 



PROF. THOMSON: The platinum was red yes, of course, and it was 

 a vigorous source of rays. I got rays with the same tube that Professor 

 Rowland does not get them. 



PROF. ROWLAND: Well, that has nothing to do with the point. The 

 point that I raise is this, that there was certainly no doubt that I did 

 not get any, and the cathode rays were falling from the object. That 

 is the thing. Now, one thing that I wish to remark is that most people 

 draw a tube like that. They don't say where the wires go. Mine 

 generally went out, so that they were very far away from this object. 

 By curving wires around in different ways I can get an inductive action. 

 I don't doubt that I could fix up a tube so that I could get lots of rays 

 out of any part. However, the time is passing, and I will just say one 

 word with regard to the point Prof. Thomson raised with regard to 

 the fluorescence over the surface of the glass. He thought something 

 was stopped by the glass. I must say that Lenard, when he first experi- 

 mented upon this subject and I regard his experiments as quite as 

 valuable as Rontgen's, probably , he got several kinds of rays coming 

 out through an aluminium window. He got rays which were deflected 

 by the magnet, as well as others. He had not separated them, how- 

 ever. When the Lenard paper came to the laboratory I remarked to 

 my students: " That is the best discovery that has been made in many 

 a day." I immediately set somebody to work experimenting. He tried 

 to get some results and would probably have discovered the Rontgen 

 rays at that time if it had not been that the University of Chicago 

 called him off, and Johns Hopkins University was very poor and could 

 not call him back, and he had to stop in the midst of his work. They 

 always say in Baltimore that no man in that city should die without 

 leaving something to Johns Hopkins. Now, Dr. Pupin mentioned a 

 means of showing whether the rays were reflected a little reflector in 

 which he had them brought to a focus, as I recollect it. I have read an 

 account in which an experimenter did find the rays were brought to a 



