43« 



NA TURE 



{Sept. 4. 1879 



to ascenaii if the itrtani of rafliant matter fro. n the ne>;ative 

 pole al^o carries a current. Here (Fig. 18) is an apparatus which 

 will decide the question at once. The tube contains two negative 

 terminals [a, b) close together at one end, and one positive 

 terminal (c) at the other. This enables me to send two streams 

 of radiant matter side by side along the phosphorescent screen — 

 or by disconnecting one negative pole, only one stream. 



If the streams of radiant matter carry an electric current they 

 will act like two parallel conducting wires and attract one 



parallel streams of radiant matter exert mutual repulsion, acting 

 not lilie current carriers, but merely as similarly electrified 

 bodies. 



another ; but if they are simply built up of negatively electrified 

 molecules they will repel each other. 



I will first connect the upper negative pole (a) v/ith the coil, 

 and you see the ray shooting along the line d,f. I now bring 

 the lower negative pole {b) into play, and another line (e, h) darts 

 along the screen. But notice the way the fir.'-t line behaves ; it 

 jumps up from its first position, df, to d g, showing that it is 

 repelled, and if time permitted I could show you that the lower 

 ray is also deflected from its normal direction : therefore the two 



Fia. .9. 



Radiant Matter produces Heat when its Motion is arrested 



During these experiments another property of radiant matter 

 has made itself evident, although I have not yet drawn attentiore 



to it. Tlie glass gets very warm where the green phosphore? cence 

 is strongest. The molecular focus on the tube, which we saw 

 earlier in the evening (Fig. 8) is intensely hot, and I have 

 p-epared an apparatus by which this heat at the focus can be 

 rendered apparent to all present. 



I have here a small tube (Fig. 19, a) with a cup-shaped 

 negative pole. This cup projects the rays to a focus in the 



middle of the tube. At the side of the tube is a small electro- 

 magnet, which 1 can set in action by touching a key, and the 

 focus is then drawn to the side of the glass tube (f*ig. 19, b). 

 To show the first action of the heat 1 have coated the tube with 

 wax. I will put the apparatus in front of the electric lantern 

 (Fig. 20, d), and throw a magnified image of the tube on the 

 screen. The coil is now at work, and the focus of molecular 



