134 Royal Society : — 



spending terms of the nitrogeu-series. The deportment of the phos- 

 phorus-bodies in their relation to other compounds has as yet been 

 scarcely investigated. For several months I have been engaged in 

 this study, which promises a rich harvest of results. INIost of the 

 experiments were made with triethylphosphine, a substance which, 

 in consequence of its convenient position in the system of organic 

 compounds, in consequence of the variety of its attachments, the 

 energy and precision of its action, and, lastly, the well-defined cha- 

 racter of its compounds, \\ill probably become an agent of predilec- 

 tion in the hands of the chemist. 



It is my intention to trace the history of this remarkable body in its 

 several directions ; and for this purpose, in fact, a considerable amount 

 of material has been already accumulated. But since necessarily some 

 time must elapse before such an inquiry, which from the peculiar 

 character of the compound is often obstructed by unusual difficulties, 

 can be completed, I beg leave to present my results in the same 

 measure as the inquiry advances, hoping that at a later period I 

 may be allowed to collect the scattered observations, and to lay them 

 in a more elaborated and digested form before the Societj^ 



Among the numerous reactions of triethylphosphine, my attention 

 has been chiefly directed to the compounds which this body furnishes 

 when submitted to the action of organic chlorides, bromides, and 

 iodides. 



I. Action of Bibromide of Ethylene upon Triethylphosphine. 



In the anhydrous condition the two bodies act even at the common 

 temperature with considerable power upon each other, a white cry- 

 stalline substance being immediately precipitated. If the reaction be 

 allowed to go on in the presence of a large volume of anhydrous 

 ether, the deposition of the crystalline body is considerably retarded, 

 unless the mixture, in an appropriate apparatus, be exposed to the 

 temperature of boiling water. After a short digestion, on distilling 

 off the ether and the excess of bibromide, a crystalline cake is left in 

 the retort, consisting of several bromides, the nature and the relative 

 proportions of which appear in a great measure to depend upon the 

 rapidity of the reaction. I have found it most convenient to work 

 with ethereal solutions at the common temperature. 



The determination of the bromine in the crystalline body revealed 

 at once the compound character of this substance, for it steadily 

 diminished by dissolving the bromide in absolute alcohol, and repre- 

 cipitating it partially by ether. By repeating this process four or 

 five times, a body of constant composition was obtained. 



The compound thus prepared is a crystalline mass, without odour, 

 extremely soluble in water, and even in absolute alcohol, but inso- 

 luble in anhydrous ether. It exhibited a rather unexpected compo- 

 sition, for on analysis it was found to contain 



C,„H,,PBr„ 



and consequently to have been formed by the simple union of I equiv. 



