326 PROFESSOR LETTS ON PHOSPHORUS-BETAINES. 
the numerous and carefully conducted experiments he had made on the action 
of the two bodies, that under certain conditions none of the true hydrobromate 
is obtained. 
In the experiment just described both the bromacetic acid and the triethyl- 
phosphine were diluted with a large quantity of ether, and the temperature 
was not allowed to rise; whereas in previous experiments no ether was 
employed as a rule, and the two bodies were allowed to react on each other 
in the pure state. Much heat was developed, and as before stated the product 
of action was frequently heated to 100° C. to cause it to solidify. 
Now it has been shown that the hydrobromate (and other salts) of triethyl- 
phosphorus betaine are decomposed when heated in such a manner that 
carbonic acid escapes, and a salt of triethyl-methyl-phosphonium remains. 
Xx x 
(CH) ,PK = (CH) PC +CO,. 
CH,COOH CH, 
Whereas the product of action of bromacetic acid on triethyl-phosphine 
yields on heating only a small quantity of carbonic acid, but a large quantity of 
a solid volatile body (see p. 328). It is obvious then that the action of heat is a 
ready method for estimating the amount of hydrobromate of triethyl-phos- 
phorus-betaine present in any specimen of the product of action of bromacetic 
acid on triethyl-phosphine. 
2°9 germs. of the product just described, and which had been proved to con- 
tain hydrobromate of triethyl-phosphorus-betaine, were heated in an apparatus 
so arranged that any permanently gaseous products could be caught. 
It began to effervesce at 200° C. At 215° C. the effervescence was very 
brisk, and at 230° it suddenly solidified to a pure white product. 192 ce. of 
gas were evolved. 
The solid residue was heated over the naked flame, it fused, boiled, and a 
considerable quantity of a pure white substance passed over at 303° C., which 
solidified in the condenser. Were then is conclusive evidence that the product 
did not consist entirely of the hydrobromate of triethyl-phosphorus-betaine ; had 
it done so no volatile body would have been formed, and 373 cc. of carbonic 
acid would have been produced. In round numbers, only half that quantity of 
gas was evolved, so that at least one-half of the substance consisted of a 
different body from the betaine compound. 
Another experiment was made as follows :—12 grms. of triethyl-phosphine 
were added rapidly to 14 grms. of bromacetic acid. The mixture was allowed 
to grow very hot, and was cooled only when the phosphine boiled. As soon 
as all action was over, the viscous dark-brown product was divided roughly 
into two parts, one of which was heated in a distilling flask provided with the 
arrangement already described for catching liquid and gaseous products. The 
