from heoied phosphorus compounds. 331 



passing in both directions. The light at the anode never showed 

 the fine bright pencils so characteristic of the anode rays, and 

 the spectrum proved that if any anode rays were produced they 

 were due to the silver chloride, and not to the aluminium 

 phosphate. 



Other methods of making the aluminium phosphate into a 

 solid mass, capable of being used as an anode, without mixing 

 with an}' substance likely to produce anode rays, were tried, but 

 without success. It was therefore decided to use some more 

 fusible phosphate, and a mixture of sodium and lithium pyro- 

 phosphates with a little graphite was heated in the quartz tube 

 until it fu.sed. This tube was then fitted up as the anode in a 

 bulb similar to that described above. On evacuating and passing 

 a discharge this tube behaved in a curious way. When the 

 pressure was not too low, there was a torch of light surrounding 

 the anode, in front of this a dark space, and then at about the 

 centre of the bulb a little ball of luminosity, which probably 

 corresponded to a striation in the pjositive column. On putting 

 on a magnetic field transverse to the direction of the rays from 

 the anode, the torch seemed to jump out nearer to the glowing 

 ball, at the same time spreading out symmetrically about the axis 

 of the anode, and curling round towards the cathode ring. The 

 appearance was as though a stream of rays were suddenly brought 

 up against a barrier. The effect produced seemed to be inde- 

 pendent of the direction of the magnetic field, so long as the lines 

 were at right angles to the direction of the discharge. That 

 sodium was shot off' from the anode could be seen by the gradual 

 appearance of the yellow sodium light upon the cathode — appear- 

 ing at first on the side nearer to the anode and gradually spreading 

 all over it. The spectrum of the light at the anode showed the 

 lines of sodium and lithium brilliantly, also the brightest mercury 

 lines, including the tliree new lines in the orange the wave- 

 lengths of which are given by the author in a previous paper* 

 as 6232, 6121, 6070. 



In a more perfect vacuum the gas luminosity in the bulb 

 disappeared, but the glow at the anode remained. There was 

 however no sign of the fine pencils of light, with the accompany- 

 ing phosphorescence of the bulb, which is so characteristic of the 

 anode rays. In a magnetic field the glow at the anode was mostly 

 deflected in the positive direction, but there was some which 

 behaved as though it were negatively charged. In order to decide 

 whether the rays deflected in the positive direction were really 

 positively charged, or whether they were negatively charged rays 

 travelling towards the anode, their behaviour in an electrostatic 



* Proc. Camb. Fhil. Hoc. Vol. xiv. Pt 5. 



22—2 



