78 Proceedings of Royal Society of Edinhurgh. [dec. 19 , 
been obtained, as no free bydrobromic acid was observed, but tbis 
supposition seemed to be negatived by tbe fact that tbe above 
analyses indicate that for every molecule of tbe pbospbine only one 
atom of bromine bad been added. Tbis fact appeared to indicate 
that a substitution product bad really been formed, but as we shall 
sbow presently tbe reactions of tbe brominated body do not support 
sucb a view of its constitution. 
Tbe subjoined numbers sbow that only a very slight difference 
would exist in tbe composition of these two bodies, and that the 
analytical results obtained by us would agree almost equally well 
with either. 
Obtained Calculated for 
Mean Eesults. 
Bz 2 HP.Br 
BzgBrP. 
Carbon, 
. 56-5 
57T 
57-3 
Hydrogen, 
. . 5-3 
5T 
4-8 
Bromine, . 
. 26-5 
27-2 
27-3 
We therefore turned to tbe^ reactions of tbe brominated body for 
some clue to its constitution. 
Tbe compound, when warmed with an alcoholic solution of potash 
or soda, was at once decolorised and a colourless body resulted, 
which crystallised from alcohol in colourless needles. A specimen 
of this crystalline body, after several crystallisations from alcohol, 
gave the following numbers : — 
Carbon, . . . . 76’5 
Hydrogen, . . .6*7 
When boiled with spirit it was also decolorised, a volatile body 
smelling like bromide of benzyl being disengaged, whilst colourless 
crystals separated from the solution. These after recrystallisation 
gave an analysis : — 
Carbon, . . . .76*8 
Hydrogen, . . . 6’6 
These two determinations proved that the brominated body decom- 
posed when treated either with an alkali or with alcohol, and we 
suspected, from the'appearance and properties of the crystalline body 
formed, that dibenzyl phosphine had been reproduced. The above 
numbers, however, do not agree with those required for dibenzyl 
phosphine, and we thought it possible that the brominated body 
had not been submitted for a sufficient length of time to the action 
of the decomposing agent. 
