324 Proceedings of the British Association. 



On the radical of the Kakodyle Series, by Prof. Bnnsen.— 

 The easiest method of procuring pure kakodyle is the following. 

 Chloride of kakodyle, carefully freed from the oxide by treatment 

 with strong hydrochloric acid, is allowed to stand some time over 

 chloride of calcium and quick lime, to remove the water and all 

 excess of acid. It is then introduced into a distillatory apparatus 

 carefully filled with carbonic acid, and containing some slips of 

 clean sheet zinc. Any of the metals which decompose water 

 will answer, but zinc is the best. It is probable that hydrogen 

 or carbon would produce a similar decomposition with suitable 

 modifications of the apparatus. The vessel is then hermetically 

 sealed, and the mixture of zinc with the chloride, is exposed for 

 some hours in a water bath to a temperature of 212° F. When 

 the decomposition is complete, a white saline mass is formed, 

 which melts into an oily liquid between 240° and 248° F. ; while 

 the tube is still hot, the point of the tube leading into the con- 

 denser is dipped below the surface of boiled distilled water : as 

 the apparatus cools, the water rises into it. The tube is hermet- 

 ically sealed : the water dissolves chloride of lime, leaving the 

 excess of zinc and the kakodyle, which falls as an oily liquid to 

 the bottom. This is rectified twice or three times, filled with 

 carbonic acid as before ; the water being afterwards removed by 

 chloride of calcium in the usual way. Thus obtained, it is a 

 colorless liquid, transparent and of a high refractive power, in 

 appearance and odor much resembling the oxide of kakodyle, 

 and ignites instantly on being brought in contact with air, giving 

 off water, and carbonic and arsenious acids. 



Abstract of a letter from Prof. Liehig to Dr. Play fair. — This 

 letter announces the discovery of a white crystalline substance, 

 in large quantities, obtained by M. Schunk from the lichens 

 which are employed in preparing archil, [Lecanora tartarea, &c.) 

 by extraction with ether. It differs from erythrine, and the com- 

 pounds described by Dr. Kane, in its insolubility in water. It 

 dissolves readily in alkaline solutions, and is capable of being 

 again precipitated by acids, if the solution be recently made ; but 

 if kept standing for some hours, acids produce no precipitates : it 

 has been decomposed, and is converted into carbonic acid, and 

 orceine. If the substance be dissolved in baryta water, and the 

 clear solution boiled, a large precipitate of carbonate of baryta 

 occurs, and the filtered solution gives, on evaporation, large quan- 



