249 



Preliminary experiments Avere made several years ago with some of 

 the simpler acid chlorides, but the very imperfect absorption of the phos- 

 phine, and the formation of solid hydrogen phosphide seemed to make the 

 attempts unpromising, and the subject was dropped for a time. 



A year ago. with Charles E. Yanderkleed, the subject was taken up' 

 again, and dichlor-acetyl chloride selected as the acid chloride to experi- 

 ment with tirst, since the reaction had been shown to take place with the^ 

 chlorides of mono- and t)"i-chlor-acetic acids. The reaction proceeded 

 satisfactorily, though slowly, and the originally liquid chloride gradually 

 thickened to a Tliick. yellow. Transparent mass, from which by solution in 

 alcohol and precipitation bj' ether a tine crystalline powder was obtained, 

 giving on analysis ligures for phosphorus and chlorine corresponding to 

 the ])hosphide expected. CHCl, COPH,. 



This substance is extremely solulile in alcohol, insoluble in ether, chlo- 

 roform, and petroleum ether, insoluble in but soon decomposed by water, 

 especially on warming, witli the formation of hydrogen phosphide (PH,) 

 and dichlor-acetic acid, judging by the odor. It is quite stable in dry air 

 and chars without melting at aiiout 200° centigrade. Its behavior is what 

 miglit 1)0 expected, from a comparison with the amides, especially its 

 greater tendency to decompose with water, on account of the more weakly 

 basic character of phosphine compared with ammonia. 



Experiments are being now made by Miss Frances M. DeFrees on the 

 preparation and properties of benzoyl phosphide. C^ H5 COPHo, and a crys- 

 talline compound has been obtained, charring without melting, and show- 

 ing similar solubilities and decompositions to those of the dichlor-acetji 

 phosphide. 



Adsorption of Dissolved Substances. 

 P. N. Evans. 



The term "adsorption" is used for the attraction exerted by a solid 

 surface on gases or dissolved substances. With regard to gases, the effects 

 are familiar in the action of porous solids, such as charcoal, which seem 

 to condense gases within the pores as if under considerable pressure: the 

 action is a selective one, however, for in the case of charcoal some gases, 

 ammonia for instance, are very much more affected than others. The 

 numerous chemical reactions taking place in the presence of such porous 



