2O On Radiant Matter. 



revolves a light mica fly (6 b). The fly consists of four 

 square vanes of thin clear mica, supported on light 

 aluminium arms, and in the centre is a small glass 

 cap which rests on the needle-point. The vanes are in- 

 clined at an angle of 45 to the horizontal plane. Below 

 the fly is a ring of fine platinum wire (c c), the ends of which 

 pass through the glass at d d. An aluminium terminal (e) is 

 sealed in at the top of the tube, and the whole is exhausted 

 to a very high point. 



By means of the electric lantern I project an image of 

 the vanes on the screen. Wires from the induction-coil are 

 attached, so that the platinum ring is made the negative 

 pole, the aluminium wire (e) being positive. Instantly, 

 owing to the projection of Radiant Matter from the plati- 

 num ring, the vanes rotate with extreme velocity. Thus 

 far the apparatus has shown nothing more than the pre- 

 vious experiments have prepared us to expect ; but observe 

 what now happens. I disconnect the induction-coil alto- 

 gether, and connect the two ends of the platinum wire with 

 a small galvanic battery ; this makes the ring c c red-hot, and 

 under this influence you see that the vanes spin as fast as 

 they did when the induction-coil was at work. 



Here, then, is another most important fact. Radiant 

 Matter in these high vacua is not only excited by the nega- 

 tive pole of an induction-coil, but a hot wire will set it in 

 motion with force sufficient to drive round the sloping vanes. 



Radiant Matter is deflected by a Magnet. 



I now pass to another property of Radiant Matter. 

 This long glass tube (Fig. 14), is very highly exhausted ; 



FIG. 14. 



it has a negative pole at one end (a) and a long phosphor- 

 escent screen (b, c) down the centre of the tube. In 

 front of the negative pole is a plate of mica (b, d) with 



