ACTION OF PHOSPHIDE OF SODIUM ON HALOID ETHERS. 199 
proportion of water as we employed in our two previous experiments. The 
two were then boiled until the sulphate had dissolved, and a boiling and con- 
centrated solution of caustic baryta was added in excess. The distilling flask 
was then connected with a condenser, and its contents heated. ‘An oily liquid 
passed over with the water, which had the odour of toluol, and a boiling point 
of 112°—exactly that of toluol. Moreover, its weight amounted to 1:0 grm., 
whereas the quantity we ought to have obtained was 1:2 grm. 
There can be no doubt then that the base very easily decomposes into 
toluol and tribenzyl-phosphine oxide. 
That this decomposition is effected by the temperature we must doubt, as 
we concentrated the solution of the base by boiling, and it suffered no change. 
But, on the other hand, there can be no doubt that if weak solutions of the 
acid sulphate and baryta are employed, the base is almost—if not altogether 
the sole product—whilst with strong solutions only the oxide is formed. 
Action of Carbonate of Barium on the Acid Sulphate.-—Carbonate of barium, 
when added to a solution of the acid sulphate, at once effervesces, and sulphate 
of barium is formed, whilst the base remains in solution, from which it is easily 
obtained by evaporation and subsequent cooling. 
The reaction occurs according to the equation, 
(C,H,),PHSO, + BaCO, =CO, + BaSO,+ (C;H,),P(OH). 
We have not observed the production of any oxide of tribenzyl-phosphine 
in this reaction, even when a very concentrated solution of the acid sulphate is 
employed, and we therefore recommend it as the simplest and most certain 
method for obtaining the base, for the acid sulphate is very easily formed from 
the chloride. 
_ This reaction also shows that no carbonate of tetrabenzyl-phosphonium can 
exist ; nor ought we to be surprised at this, considering that the alkaline power 
of aromatic phosphines, like that of corresponding amines, is very markedly 
less than it is in the case of ethyl or methyl phosphines or amines. 
Hydrate of Tetrabenzyl-Phosphonium.—this body is one of the most beauti- 
ful of all the compounds of tetrabenzyl-phosphonium. It is very soluble even 
in cold water, and crystallises in very beautiful rhombohedral plates, which 
we have on one occasion obtained nearly $ an inch long and 4 inch broad. 
_ The crystals have a very striking refractive power, so that they resemble in 
appearance the large crystals of phosphonium iodide, which may be formed by 
slow sublimation. 
