542 SCIENCE PROGRESS 



the publication of the chemical properties of the new element, 

 which should settle this point. Meanwhile Scott, at a recent 

 meeting of the Chemical Society, has communicated the dis- 

 covery of a new oxide from a ferruginous sand from New 

 Zealand. It is an extremely refractive substance, and not 

 readily attacked by concentrated sulphuric acid or fused 

 caustic soda. It is slowly attacked by bisulphate of potash, 

 giving an orange melt. Heated with hydrofluoric acid and 

 the requisite quantity of potassium carbonate, it gives a 

 double fluoride, analogous to potassium fluortitanate. The 

 equivalent was determined by conversion of the double fluoride 

 into oxide by ignition with sulphuric acid, and subsequent 

 extraction with water. The mean of two results gave an 

 approximate atomic weight of 175. The chemical behaviour 

 of the element made it perfectly clear that it is not a member 

 of the rare earth group, and that it is a homologue of titanium 

 and zirconium. 



The Photochemistry of Hydrogen-Chlorine Gas Alixtures. — 

 A number of papers have appeared recently on this still unsolved 

 photochemical problem. In one of these, Wendt, Landauer, 

 and Ewing {J.A.C.S., 1922, 44, 2377-82) have directed their 

 attention to an observation of Draper that the induction period 

 in this reaction can be eliminated by a preliminary exposure 

 of the chlorine to ultra-violet light. That the activation of 

 the chlorine can be brought about in this manner has been 

 confirmed by these authors, who have also shown that the 

 chlorine gas retains a portion of its activity even after twenty- 

 four hours. This active form of chlorine cannot consist of the 

 free atoms, since from evidence of the behaviour of other gases 

 in the monatomic state, it would be expected that free chlorine 

 atoms would recombine in a short time. If CI3 were the active 

 form, the reaction should occur on mixing active chlorine 

 with hydrogen in the dark. The authors find that even with 

 intense pre-illumination no hydrochloric acid is produced. 

 The possibility of the active form being CI3 is thus eliminated. 

 Wendt ascribes the activation rather to the destruction of 

 negative catalysts than to any activation of the chlorine 

 itself. 



Weigert (Z. Elektrochem., 1922, 28, 456-8) has studied 

 another aspect of the problem. Draper observed that immedi- 

 ately after exposure of a mixture of hydrogen and chlorine to 

 light, an increase in volume occurred which was due either to 

 an increase in the number of molecules by dissociation, or to 

 the liberation of heat. Weigert shows that the phenomenon is 

 a photochemical after-effect. On illumination of a gas mixture 

 by the light from an electric spark, a wave of expansion spread 

 out from the illuminated region which synchronised with a 



