384 J. W. Gibbs — Vapor- Densities. 
of PC],, PCl,, and Cl,, which is the barometric pressure cor- 
rected for the small quantity of air remaining in the flask; the 
the temperature and volume. The numbers of these five 2 
Taste [X.—PrRcHLoripe anp ProrocHiorRIpE OF PHosPHoRvs. | 
Experiments on the mixed vapors by WuRTz. 
4 
4 
Excess of 
No. of P Dp 
Be bine ch Oibibanhchsed cabs? [ots] Sad ee an 
z 
XIT | 17329 | 756-1 | 423 668 | 3924 | 7255 | 7607 | —46 
748°4 | 413 6°80 390°1 | 7255 | 747 5 
VII | 17624) 7510} 411 6°88 392° | 739-7 | TI31 | —22°1 
VIII} 169°35 | 724-1 394 716 391°8 | 721-9 | 750° | —26-4 
Vv 75°26 | 743-3 343 7-03 3349 | 735-2 64 2171 
Ir 64:9 58:5 338 7-38 346°4 766-9 782°9 | —24°4 
XI | 175°75 | 7600 | 318 7-00 309°2 | 751-2 | 776°8 168 
IV 176°26 | 766-3 27Tt 7-06 265-7 751-0 "710°9 | —14°6 | 
Ix 160-47 | 753-5 214 44, 221°1 760-6 166°8 | —13°3 
I 165-4 760°0 94 7-25 195-3 | 761°3 | 768 — 85 
VI | 17034 | 751-2 174 8-30 200°6 | 777-8 | 7876 | —364 
Tit | 17428 | 742-4 168 4 180°6 | 755°3 | 7665 | —23°8 
columns are taken from the memoir cited, except that the cor 
rection of the barometric pressures has been applied by the 
present writer in accordance with the data furnished in that 
: 
memoir. The two next columns contain the values of P, and 
P,. These would naturally be calculated from M, and M, by 
M, 
n given explicitly, those of P, and P, have been calculated 
from the recorded values of z and 8, Since the weight of the 
pL fae 
possible perchloride is 9-99 My we have 
Pst? Beka | 
222un = 2 sig 
Moreover, 
PprazeP or. 
since both members of the equation express the pressure due 
to the excess of the protochloride. The values of P, and Ps 
were obtained by these equations, 
_ The eighth column of the table gives the values of p caleu- 
_ lated from the preceding values of f,, P,, and P,, by equation 
(16); and the last column, the difference of the observed _ 
 Salculated values of p. The ave difference is 18"™, OF 
little more than two per cent, ae observed pressure being 
