F. W. Clarke on Atomic volumes of Liquids. 183 
ume of the acid is 174. This, then, is also the atomic volume 
of triethyl boron, and, subtracting from it the atomic volume of 
C,H, ,, we have left for that of boron the number 25°5, closely 
agreeing with the result obtained from the bromid. But we do 
The chlorids of these three elements have respectively the 
vapor volumes 257, 262, and 252. The bromids of boron an 
phosphorus have respectively 239 and 241. Triethyl boron, 
ttethyl phosphine, and triethyl arsine have the vapor volumes 
157, 154, and 159, and triethyl phosphate and triethyl arsenate 
have 132 and 130. ; 
Kopp, from the chlorids, found the atomic volumes of phos- 
phorus and arsenic to be probably equal. e comparison of 
these vapor volumes confirms this view, and adds boron as also 
possessing the same atomic volume as phosphorus and arsenic. 
-_ To make this still more certain I have calculated the atomic 
} Volumes of these elements from the vapor volumes of their com- 
pounds, in the manner already described. 
Por boron I have made calculations from eleven compounds, 
Ton in its liquid compounds, the numbers 30°9, 25°8, 25°5, 
os 26-1, 19°7, 25:3, 31-9, 24:1, and 19:9. The average 
Although there are yery great variations between these 
: different numbers, it will be seen hereafter that the averages 
_— obtained by this method agree closely with the numbers foun 
by ac experiment. : 
_ _, The atomic volume of phosphorus I have calculated in a 
: manner in eleven of its liquid compounds, exclusive of 
} =the chlorid and bromid. I include Kopp’s numbers for these 
4 last, however, for the sake of completeness in making up the 
Mle acid, triethyl phosphate, tetreth 1 pyrop! osphate, and 
& Ens all atts chlorophosphites. fi these, giving 
