22 On Radiant Matter. 



throw in a trace more gas. Instantly the stream of Radiant 

 Matter responds. Its velocity is impeded, the magnetism 

 has longer time on which to act on the individual molecules, 

 the trajectory gets more and more curved, until, instead of 

 shooting nearly to the end of the tube, my molecular bullets 

 fall to the bottom before they have got more than half-way. 

 It is of great interest to ascertain whether the law 

 governing the magnetic deflection of the trajectory of 

 Radiant Matter is the same as has been found to 

 hold good at a lower vacuum. The experiments I have 

 just shown you were with a very high vacuum. Here 

 is a tube with a low vacuum (Fig. 16). When I turn on 



FIG. 16. 



the induction spark, it passes as a narrow line ot 

 violet light joining the two poles. Underneath I have 

 a powerful electro-magnet. I make contact with the 

 magnet, and the line of light dips in the centre towards 

 the magnet. I reverse the poles, and the line is driven 

 up to the top of the tube. Notice the difference be- 

 tween the two phenomena. Here the action is temporary. 

 The dip takes place under the magnetic influence ; the 

 line of discharge then rises and pursues its path to the 

 positive pole. In the high exhaustion, however, after the 

 stream of Radiant Matter had dipped to the magnet it 

 did not recover itself, but continued its path in the altered 

 direction. 



By means of this little wheel, skilfully constructed by 

 Mr. Gimingham, I am able to show the magnetic deflection 

 in the electric lantern. The apparatus is shown in this dia- 

 gram (Fig. 17). The negative pole (a, b) is in the form of a 

 very shallow cup. In front of the cup is a mica screen (c, d), 

 wide enough to intercept the Radiant Matter coming from 

 the negative pole. Behind this screen is a mica wheel 

 (e, f) with a series of vanes, making a sort of paddle-wheel. 

 So arranged, the molecular rays from the pole a b will be 

 cut off from the wheel, and will not produce any movement. 



