46 J. P. Cooke—Atomic Weight of Antimony. 
repeated, and so on indefinitely as long as the material lasts. 
In this way, from several ‘kilograms of the commercial 
chloride we obtained the few grams of beautifully clear and 
perfect crystals used in our analyses. In the fifth preparation, 
the crystals were obtained not by fusion, but by cooling a 
saturated solution of the previously distilled chloride in purified 
sulphide of carbon. Such a solution, saturated at the boiling 
point of sulphide of carbon, deposits the larger part of the 
chloride, when cooled to the ordinary temperature. Naturally, 
every precaution was taken during the course of these prepara- 
tions to protect this exceedingly hygroscopic substance from 
contact with moist air, and all the transfers were made in a 
portable photographic developing chamber, the air of which 
was kept dry by dishes of sulphuric acid. The portions for 
analysis were transferred, in this chamber, to tightly fitting 
weighing tubes; and, after the weight was taken, they were 
dissolved in a concentrated aqueous solution of tartaric acid, 
using about five grams of tartaric acid to each gram of chloride 
of antimony. Thesolutions were then diluted 
in an air bath at temperatures varying from 110° to 120°. 
They were weighed with the small dis k of paper used in this 
H. ay and, ‘the excess of this reagent having Beene ved by 
warming the filtrate with a small eae: of ferric aie: the 
bea abies tallized chloride of Veron and Fontaine, Paris, which was 
Purified in the manner described above, 
6 Was made from a erystallized chloride marked Rousseau Fréres, Paris, purified 
as before. 
c Was tasters again distilled and crystallized. 
d, The same c, after ten additional distillations. 
u 
