118 J. P. Cooke—Atomic Weight of Antimony. 
our preparations of chloride of antimony by distilling a weighed 
amount from a platinum nacelle at as low a temperature as pos- 
sible in a current of dry carbonic acid, and heating the residue 
to a temperature of about 275°. We thus obtained the follow- 
ing results :-— 
No. Wt. of SbCl,. Residue. % of residue Sb,0,Cly. 
t, 6°7286 0°0212 0°315 
Zs 4°5150 0°0151 0°334 
3. 7°9320 0°0258 0°325 
In order to yield 0°146 per cent of oxygen, which would 
reduce the per cent of chlorine in the preparation from 47-020 
to 46-608, as in the scheme on page 116, there would be required 
1:155 per cent of Sb,O,Cl,. 
Although the results of the above determinations accord 
within a few per cent of the quantity estimated, yet it was per-~ 
fectly clear during the course of theexperiments that they did not 
at all represent the total quantity of the oxichloride present in 
the preparation examined. Not only was the composition of 
the preparation not materially altered by the slow distillation, 
—a fact shown by the determinations marked e in the table on 
page 47, and by which we were misled at the outset,— but also 
the product from our distillation yielded when distilled again 
apparently as much residue as before. In a word, we foun 
the same phenomena repeated in these distillations at a low tem- 
rature which had been so noticeable when the chloride was 
danger, and we had taken unusual precautions on both these 
points, the explanations suggested did not seem to us sufficient ; 
and we came to the conclusion that the oxichloride must distil 
over with the chloride of antimony to a certain limited extent, 
and that it was only an excess above this definite amount which 
was left behind as residue. Of course, SbOCI not only is not 
volatile, but is at once decomposed by heat; and we do not 
suppose that this compound by the tension of its own vapor is 
arried over in distillation. It isa very dilute solution, as it 
were, of SbOCl] in SbCl, which thus distils; and the distilla- 
tion of the oxichloride may resemble the carrying over © 
