Chemistry and Physics. 59 



SCIENTIFIC INTELLIGENCE. 



I. Chemistry and Physics. 



1. Chemical Reactions Produced by Radium. — Ber'thelot 

 lias made a series of experiments upon the chemical action of the 

 rays emitted from a small sample of radium chloride (about O'lg.), 

 which had been obtained from M. Curie. The active salt was 

 contained in a small hermetically sealed glass tube, and for the 

 purposes of experiment this tube was enclosed in a second tube, 

 so that the rays were obliged to traverse two glass walls where 

 the substance to be experimented upon was in contact with the 

 outer tube, while three layers of glass were interposed when the 

 radium acted from without a vessel containing the substance. 

 It is possible, if radium rays vary as light rays do, that a part 

 of the active rays may have been intercepted by the glass. 

 The experiments were performed in the dark, with the use of 

 parallel experiments without radium for comparison. It was 

 found that solid iodine pentoxide was decomposed by the radium 

 rays, as by light, into iodine and oxygen, while concentrated 

 nitric acid, in the same manner, became yellow. These two 

 reactions are endothermic, hence it is shown that the rays supply 

 chemical energy. On the other hand, it was shown that several 

 exothermic reactions were not produced by the rays. The 

 conversion of rhombic sulphur in carbon disulphide solution into 

 insoluble sulphur, which is caused by the action of light and 

 is slightly exothermic, was not produced by the radium rays. 

 The exothermic polymerization of acetylene gas, which is in- 

 duced by electric effluvia, but not by light, was not effected bjr 

 the radium. Oxalic acid, which is oxidized by atmospheric 

 ox} T gen even in diffused light, did not undergo this oxidation 

 under the influence of the radium rays. It was found further, 

 as had been previously noticed, that the glass in which the 

 sample was contained was blackened, evidently from the reduc- 

 tion of lQad, while near the blackened regions a violet tint, prob- 

 ably due to the oxidation of manganese, was observed. — Comptes 

 Rendus, cxxxiii, 659. 



Soon after the appearance of Berthelot's article, which has 

 been noticed above, Becquerel published a note upon the same 

 subject. Attention is there called to the fact that salts of 

 barium containing radium are spontaneously phosphorescent, so 

 that in making experiments with them the phosporescent light 

 should be cut off by the use of black paper or a thin sheet 

 of aluminum foil. He observes that the production of ozone 

 by radium rays, which has been noticed by M. and Mme. Curie, 

 is an endothermic action analogous to those observed by Berthe- 

 lot. The chemical action of the rays in their photographic behavior 

 is recalled, as well as their strong coloring action on glass, porce- 

 lain, paper, rock-salt and sylvine, their alteration of barium 



