ACTION OF CATHODE RAYS.

Waikato Argus, Volume IV, Issue 275, 16 April 1898, Page 2 (Supplement)

ACTION OF CATHODE RAYS.

Goldstein was the first to dicover that common salt is coloured brown and potassium cMoride violot by the action of tho cathode rays, says the Engineering and Mining Journal. Tho discoverer attributed this phenomenon to somo physical change undergone by the salts. Wiedemann aud Schmidt attributed it to their partial conversion into snbchloride, and Giesel actually succeeded in preparing similar coloured subcblorides in a chemical way. But the chemical hypothesis is now invalidated by tho researches of 11. Abegg. He obtained the salts in question in a pure and finely powdered state, so as to bo able to colour them all through. His first experiments showed that the colour* ing does not spoil the vacuum in the tube, as it would if chlorine wero evolved. The salts were rendered colourless again by high exhaustion producing rays with a strong heating effect. The substances could be coloured and uncoloured any number of times in succession. "When the coloured salt was dissolved it produced no reducing or alkaline reaction. When undissolved in a saturated solution it retained its colour. All this tells against a chemical change. Moreover, an easily reduced chlorine is not reduced by the cathode rays. It is well to remember that the colouration of these alkaline salts is a phenomenon not produced by light. On the othor hand, cuprous chlorine is blackened by light, but not acted upon by the cathode rays.