J. P. Cooke—Atomic Weight of Antumony. 123 
on our guard, and in the following determinations very great 
pains were taken to add just the requisite amount of the silver 
salt, and the argentic chloride was subsequently examined for 
traces of any such occlusion. But, excepting this close atten- 
tion to well-known precautions, the determinations were made 
in the same way as before. 
ANALYsIS OF ANTIMONIOUS CHLORIDE. 
No. Wt. of SbOl,. Wt. of AgCl. % of Chlorine. 
Ey 22220 4°1682 46°407 
2; 1°9458 3°6512 46°420 
Mean value She 46438 
calculating what would be the composition of a preparation of 
antimonious chloride in which ;,'%, of a per cent. of oxygen 
had replaced an equivalent amount of chlorine, assuming, of - 
course, Sb = 120 an = 35°5,—-we obtain the following very 
striking accordance :— 
Analysis. Sb = 120, Gl = 35°5 
Ghlotine: «ce. dc ke 46°413 
4ygen a Rs 213 
Antimony eRe ee ig ee | 53°369 
100°000 * 1007000 
The general conclusions, then, which we deduce as the 
results of this investigation, are— 
First, that the value of the atomic weight of antimony found 
by Schneider in 1856—Sb=120 3—must be accurate within a 
few tenths of a unit, but that the most probable value of this 
.-. as deduced from our experiments, is Sb=120, when 
Secondly, that the apparent disagreement with this result, 
presented by the partial analyses of antimonious chlori e, is 
probably due to the constant presence of oxichloride in the 
preparations of this compound. 
The investigation from the first: has been a study of constant 
