182 PROFESSOR LETTS AND N. COLLIE ON THE 
altheugh it is the only one analogous to any of those employed for preparing 
amines ; and we shall give a short sketch of the other methods by which, from 
time to time, the phosphines have been prepared. 
Paut THENARD was the discoverer of the first organic phosphorus com- 
pounds.* In the year 1843 he investigated the action of chloride of methyl on 
phosphide of calcium ; and in 1847 he communicated to the Academy further 
results as to the nature of the bodies obtained in the reaction. The investiga- 
tion was attended with great difficulties, owing to the labour involved in 
separating the different products, and in obtaining them in the pure state ; also, 
on account of their explosive and inflammable nature, and their poisonous 
properties. 
In spite, however, of these difficulties, THENARD appears to have isolated 
trimethyl-phosphine; a substance analogous to kakodyle, P,(CH;),; and 
a substance analogous to solid phosphide of hydrogen, P,(CH;).. The 
last he describes as an inert solid body; but the second, as a spontane- 
ously inflammable liquid boiling at 250° C.—very explosive, poisonous, and 
unstable. 
THENARD recognised the relations existing between trimethyl-phosphine 
and ammonia, and predicted the existence of the then undiscovered organic 
compounds of nitrogen, arsenic, and antimony. In the meantime, Wirtz and 
HornmaNnNn had verified THENARD’s predictions, having discovered the compound 
ammonias ; and Lorwie and ScHWEITZER had obtained stib-ethyl. 
HorMann and Canourst turned their attention in 1855 to the study of the 
phosphines, and repeated THENARD’S experiments, with this difference, however, 
that they substituted phosphide of sodium for phosphide of calcium. They 
obtained trimethyl-phosphine, THENARD’s phosphorus kakodyle and iodide of 
tetramethyl-phosphonium—but only after great difficulty. Speaking of the action 
of phosphide of sodium on iodide of methyl, they say,—‘“ The action is very 
energetic when the two are heated together (@ chaud). Moreover, inflammable 
and detonating substances are formed, so that this method of preparation is 
not without danger, and exposes the fruit of one’s labour to loss ...... It 
is unreliable (trop pew sir), and furnishes mixtures, of which the separation 
presents enormous difficulties.” For these reasons, they sought for a simpler 
and more certain process. This they found in the action of zinc ethers 
on terchloride of phosphorus, which gives a compound of chloride of zine 
and the tertiary phosphine, from which potash separates the latter in a state 
of purity. 
By means of this reaction, HorMANN and Canours prepared the tertiary 
phosphines of methyl, ethyl, and amyl. They determined some of their most 
* Comptes Rendus, vols. xxi. and xxv. 
+ Comptes Rendus, xli. 
