RONTGEN RAYS. 
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aluminium disc ; on causing the discharge to pass through the tube 
from a coil, the electric waves from the cathode are thrown on to the 
anode, which, being at an angle, reflects or focuses the discharge in cone 
form to a sort of bombardment on bottom of globe inside ; this seems 
to cause other rays to be repelled from the outside surface of the globe 
and produces the form of ray which has the properties I have mentioned. 
This tube is practically the same as the Geissler, and only differs in 
form, it being simply a question of the vacuum. I believe this one 
carries only two millionths of an atmosphere, therefore you may say it 
is almost a vacuum. An absolutely perfect vacuum is impossible, but 
you can get very near it. (The lecturer experimented in the dark). 
That is all you have for seeing the invisible. I will now place a 
black cloth in front of this tube and cover it up ; now you see there 
are no visible rays through that cloth, but you will observe how the 
chemical screen is lighted up with the rays that pass through the cloth. 
We might have the light quite out and see whether I can show you the 
bones of my hand and arm. I do not know whether all present will be 
able to see them. Can you see the bones in my hand and arm ? (Loud 
applause). Those who wish can view them afterwards, also their legs, 
arms, ribs, and anything else they like ; but it is somewhat difficult to 
see the trunk of body unless the room contains a dry atmosphere. 
Owing to the presence of so much moisture, due to gas and evaporation 
from our bodies and respiratory organs, the current leaks. The tube 
requires heating with a spirit lamp in this way for good results ; and in 
such an atmosphere the damp will most likely so attract the internal 
discharge of the tube that perforation of glass may result. (One tube 
perforated after the lecture while exhibiting ribs and liver). 
There is evidence of an electric discharge with these rays from surface 
of tube. I have simply shown you that these rays have no light; you 
saw the black cloth over them, and you saw the peculiar action they 
had upon this potassium platino-cyanide screen. It was, I believe, in 
experimenting with some similar chemical that Professor Rontgen (I 
understand he is coming to England to tell us all about it one of these 
days) first noticed this peculiar phosphorescence. Then, I believe (I am 
only speaking now in a popular way from newspaper information, 
which, as you know, we must always accept with a good deal of reserve, 
especially special telegrams), it was to a certain extent accidental that 
some objects were placed in a box containing photographic plates, which 
photographic plates, so the story goes, were used for some other purpose, 
and the professor noticed that there were some bodies photographed on 
those plates which were foreign to the subject that he had been experi¬ 
menting with. He immediately thought of these rays, tried some object 
on the plate which was enclosed in the box, and there was the discovery ! 
It is these simple things which very often lead to such great results, and 
I believe that this particular application of electricity is certainly going 
to be of the very greatest use to surgery in the future. Of course all the 
stories that you hear of these wonderful so-called discoveries, that you 
can see whether you have a diseased heart and all that sort of thing, are 
not accurate and are exaggerated ; but most certainly you can see the 
heart as a shadow with the screen—the tube being in proper electrical 
condition. You can also see the liver rising and falling in a most 
beautiful way ; you can see the ribs, you can see the skull, jaws, and 
teeth ; you can, of course, see the bones of the body indiscriminately 
just as you like and please to look at them—always provided you have 
