PURIFICATION OF COBALT FROM ZAFFRE. 
37 
found to correspond with the high character given to it, the 
seeds might be obtained and plantations formed in Trinidad 
and others of our islands, which would in process of time 
add much to the diversity and importance of their exports, 
and contribute somewhat likewise to the strength of the 
artillery which the medical practitioner employs to repel 
the assaults of mortality. — Pharm. Jour. 
ART. X.— ON THE PURIFICATION OF CO BALT FROM ZA FFRE. 
By Mr. B. H. Paul, 
Assistant in the Laboratory of the Pharmaceutical Society. 
Having found that the process for obtaining a salt of 
cobalt from zaffre, by the use of oxalic acid, was attended 
with considerable inconvenience, and did not yield a pure 
product, I have endeavoured to ascertain whether some 
other more advantageous process might not be employed ; 
and among uthers it occurred to me that the process adopt- 
ed by Mr. Phillips for the quantitative separation of this 
metal from nickel, if somewhat modified, would answer for 
for the purification of zalfre. This process is founded upon 
the property possessed by nickel of being precipitated by 
potash from an ammoniacal solution of the two oxides, 
while cobalt is unacted upon. 
The zaffre of commerce consists essentially of impure 
oxide of cobalt, obtained by roasting the sulpho-arseniuret 
of cobalt, or cobalt ore, and mixing the product with a quan- 
tity of sand; it contains, besides cobalt, iron, copper, bismuth, 
and nickel. 
This is treated with hydrochloric acid, which dissolves al 
but the sand, and the liquid evaporated to free it from excess 
of acid; on the addition of water, a white substance remains 
VOL. XIII.--NO. i. 4 
