Action of Hypochlorous Acid on Organic Bodies, 539 



the materials be chemically pure. The arsenic is placed in a 

 Hessian crucible, and above it the zinc ; heat is gradually applied 

 up to the melting-point of the zinc, and the crucible is then kept 

 for a quarter of an hour at the temperature of the wind- furnace. 

 The crucible is then withdrawn, and its contents poured into 

 cold water. 



When this substance is treated with hydrochloric acid, a 

 violent disengagement of hydrogen and arseniuretted hydrogen 

 ensues, the liquid becomes yellow-coloured, which, passing 

 through brick-red, changes into dark brown; and finally a reddish- 

 brown powder is left, which is the body in question. From 

 about 300 grms. of alloy, 1 grm. of pure hydride of arsenic was 

 obtained. 



The substance was analysed by heating a weighed quantity in 

 a suitable apparatus, and collecting and measuring with all 

 suitable precautions the hydrogen disengaged. From 1 grm., 

 0*00484 grm. of hydrogen were obtained. The formula As 2 H 

 requires 0*00688 grm., and the formula As H 2 requires 0*025 

 grm. Solid hydride of arsenic, As 2 H, is a light voluminous 

 reddish-brown powder, in appearance resembling binoxide of 

 lead. It is insoluble in the ordinary reagents; it decomposes 

 at 200° C. into pure hydrogen and arsenic. It burns in the air 

 with a yellow flame, forming arsenious acid, metallic arsenic, 

 and a small quantity of a black substance which is probably a 

 new oxide of arsenic. Dilute acids are without action upon it, 

 with the exception of nitric acid, which oxidizes it to arsenious 

 and arsenic acids. It is gradually decomposed by the alkalies, 

 forming metallic arseniate. It burns in chlorine, forming chlo- 

 ride of arsenic; in bromine, forming bromide of arsenic and 

 bromide of hydrogen ; and in iodine in a similar manner. Wieder- 

 hold has not succeeded in combining it with other bodies. 



Carius* has found that ethylene and its homologous and ana- 

 logous hydrocarbons can directly combine with hydrate of hypo- 

 chlorous acid and with peroxide of hydrogen, while he describes 

 the reactions as being sharp and well defined. 



The combination is best effected by means of the solution of 

 hypochlorous acid, which must not be too strong, for otherwise 

 it gives off free chlorine, which produces secondary actions. 

 This solution is prepared by adding to stoppered vessels of a 

 litre capacity filled with chlorine 15 grammes of precipitated 

 oxide of mercury which has been heated to 300°, diffused in a 

 little water. The whole is well shaken, and the operation per- 

 formed in a dark place. By using larger quantities than these, 

 or oxide which has not been heated to 300°, the experiment fails, 



* Liebig's Annalen, vol. cxxiv. p. 265 ; and Mav 1863. 

 2N2 



