Purification of Gum Resins, 6fc. 
49 
The phosphate of soda may be replaced by an arseniate of 
the same base. 
Borate of cobalt may also be prepared as follows ; pour an 
excess of borate of soda into a solution of a salt of cobalt, 
and add a solution of sub-carbonate of potash or soda as long 
as there is any precipitation. Wash, filter, and calcine 
slightly. 
Another Blue. Take twelve parts of slightly calcined phos- 
phate of cobalt, twelve parts of melted phosphate of soda, 
two parts of melted borax, four parts of calcined alumine, 
and three parts of calcined subcarbonate of soda. Rub the 
whole well together in a wedgewood mortar, and afterwards 
heat it to redness in a crucible. 
If instead of cobalt, copper be used, I am of opinion that 
beautiful green colours will be the result. 
Jour, de Pharm. 
ART. XV.— ON THE PURIFICATION OF GUM RESINS &c. 
By E. Mouchong, Jr., of Lyons. 
Although the gum resins in general are not now of the 
same importance as they were during the reign of polypharma- 
cy, still they demand our attention to a certain degree, and 
hence I have been led to make some remarks on the modes 
of purifying them. 
To decide with any certainty on this subject, I subjected 
some of those gum resins most generally used to different 
comparative treatments, with water, vinegar and alcohol. 
Although all the gum resins which come to us in impure 
masses, require to be purified, I confined myself to those 
which are most frequently subjected to this operation, namely, 
ammoniac, galbanum and sagapenum, and it should be no- 
ticed that a great analogy exists between the relative pro- 
Vol. 1. — No. I. 7 
