THE RONTGEN RAY AND ITS RELATION TO PHYSICS 581 



from the sun. Sometimes they have seen a sun spot and noted a deflec- 

 tion of the magnetic needle on the earth. Very likely that is true. I 

 don't know that they have discovered any electrostatic effect. But we 

 know that electrostatic effects will be carried on through as perfect a 

 vacuum as you can get. Then we have gravitation action too. Now, 

 you have got all those things electromagnetic action, light which 

 would be an electromagnetic phenomenon, and then we have gravitation, 

 and we have got to load the ether with all those things. Then we have 

 got to put matter in the ether and have got to get some connection 

 between the matter and the ether. By that time one's mind is in a 

 whirl, and we give it up. 



Now we have got something worse yet we have got Rontgen rays on 

 top of all that. Here is something that goes through the ether, and it 

 not only goes through the ether but shoots in a straight line right 

 through a body. Now, what sort of earthly thing can that be? A body 

 will stop light or do something to it as it goes through; but what on 

 earth can it be that goes through matter in a straight line? Why, our 

 imagination doesn't give us any chance to do anything with that pro- 

 blem. It is a most wonderful phenomenon. Now, we can suppose that 

 they are ultra violet light. Indeed, we can get a limit to the wave- 

 length to some extent. Nobody, however, has ever proved that the Ront- 

 gen rays are waves. But we can get a limit of the wave-length if they are 

 waves, because when I have a tube that gives me a shadow which is only 

 a thousandth of an inch broad, or rather from the greatest intensity 

 out to clear glass a thousandth of an inch broad, I can calculate the 

 wave-length of the thing that would produce such a shadow. It has 

 got to be very small indeed; one knows that right away, because any 

 ordinary light would make a few waves at the edge of the shadow, and 

 by measuring those waves you could get the wave-lengths of the light. 

 But there was no appearance whatever on any of my photographs of any 

 such phenomenon as that. I did not have any of these waves at the 

 edge of the shadow whatever. It went directly from blackness to light. 

 But putting it under the microscope and measuring from almost imag- 

 inary points, from lightness to darkness, I could get a limit to the wave- 

 length. Now, as to that limit, I published it in one of the journals 

 six months ago, or more, and it came at about one-seventh, I think, 

 that of yellow light. Others have determined the wave-length and got 

 even below one-seventh that of yellow light. Some have got one- 

 thirtieth that of yellow light, and so on. Some of them I am rather 

 doubtful about, because they say they have bands. If they have bands 



