120 J. P. Cooke—Atomic Weight of Antimony. 
acts in this way, as we found out in more than one instance to 
our cost 
Detaits oF AnTIMONY DETERMINATION. 
The antimonious chloride was first transferred to a very care- 
fully dried weighing tube, and thence to the large flask in 
which it was dissolved. ‘he transfer to the weighing tube was 
made in a dry atmosphere, and only required two or three sec- 
onds. It is evident, however, that a slight absorption of mois- 
ture at this point is not important; for, even if it increased the 
apparent weight of the assay by several milligrams, it would 
only reduce to a barely perceptible extent the percentages of 
all the constituents leaving the relative values wholly un- 
changed. It is only when, on boiling the chloride, after such 
an absorption, the chlorine is driven off, that the essential 
change of composition results. 
Weight of tube and antimonious chloride --20°9609 grams. 
* “ after transfer to flask - - -- -- 16°3920 
“+ @hloride analysed. 220520221005. -. 45689 “ 
The weight of the tube and chloride while on the balance 
pan remained invariable for a sufficient length of time to give 
positive assurance of the constancy of the weights. The chlo- 
ride was dissolved in a saturated solution of tartaric acid con- 
taining about 15 grams of the pure acid, and then diluted with 
carbonic acid and water and precipitated as before described. » 
The precipitate, having been washed and collected as before, 
was dried in an air bath, at about 110°. ; 
Weight of small filter................ 0°0434 grams. 
- porcelain crucible —s0Laiee 
101-2566“ 
2, crucible and precipitate.....104°6762 
“ red sulphide of antimony.-.. 34196 “ 
A portion of the dried precipitate dissolved in hydrochloric 
aeid gave no residue. The rest was then transferred to a pla- 
