330 PROFESSOR LETTS ON PHOSPHORUS-BETAINES. 
I. II. 19 E IV. Calculated for C,H,,PO,Br 
Carbon, 36:5 37°0 376 36:3 374 
Hydrogen, . 78 Si 8:2 81 7:0 
——— 
Bromine, . 31-7 31:2 31:4 309 31:0 31:1 
but the percentage of hydrogen is too high. 
As the bromine was readily precipitated by nitrate of silver, it was con- 
sidered that the body could scarcely be the bromacetate of triethyl-phosphine 
H , 
((C,H,)y P< 600—CH,Br) and as the hydrobromate of triethyl-phosphorus- 
betaine (CHP Et, coon) had been shown to give abundance of 
carbonic acid, and to yield a different substance when heated, the new body 
could not be identical with it. 
There remains the isomer of the two preceding bodies (GH).PK GO C_cH 
3 
the aceto-bromide of triethyl-phosphine. It is quite conceivable that it would 
be volatile without decomposition, and it is probable, if not certain, that its 
bromine would be precipitated by nitrate of silver. The evidence appeared to 
be in favour of the identity of this substance with the volatile product in 
question, although the high percentage of hydrogen which the latter contained 
was against this view of its composition. 
The product was very deliquescent, and soluble in alcohol and chloroform, 
but not in ether. It yielded no sparingly soluble compound with chloride of 
platinum neither when alcoholic solutions of the two were mixed nor when it 
was converted into chloride (by action of oxide of silver and hydrochloric acid). 
Attempts were made to determine its vapour density by Vicror MEYER’s 
method (using vapour of mercury as the source of heat), but without success, 
as it charred. 
It was considered probable that, by acting on it with oxide of silver, its 
nature could be determined. For if its constitution were expressed by the 
formula (C:H;);P Bante CH, oxide of silver should give either a correspond- 
ing hydrate, or oxide of triethyl-phosphine and acetate of silver. 
Br 
(HPC “- +2AgOH = (C,H;),PO+ AgBr+CH;COOAg+H,0. 
3 
Several experiments were tried on the action of oxide of silver on the 
product. The first of these showed that oxide of triethyl-phosphine is formed. 
The oxide was collected in the pure state; its boiling-poiut determined, as well 
as other of its characteristic properties. The bromide of silver produced at the 
same time was identified, but no acetate or other soluble salt of silver could be 
