218 
ON CITRATE OF MAGNESIA. 
copper with sulphuretted hydrogen ; but it is not dissolved 
so easily by cyanide of potassium or sulphuret of ammo- 
nium ; but it dissolves readily in ammonia when air is al- 
lowed access,forming ammoniacal oxide of copper anddepo- 
siting sulphur. The authors have not yet made any ana- 
lysis of this compound, but it is very probable that its com- 
position is identical with that of blue copper. It is more 
difficult to answer the question whether it has the same com- 
position as the bluish sulphur compound prepared by Win- 
kelblech. The samples made by the authors, according to 
the method described by Winkelblech, did not possess the 
beautiful blue colour of the compound described. — lb. 
ART. LXTII. — ON CITRATE OF MAGNESIA, AND A 
PURGATIVE WATER MADE WITH THIS SALT. 
By M. Roge Delabarre. 
On making some experiments with the salts of magnesia, 
I had occasion to observe that the citrate of magnesia is de- 
void of the bitter and disagreeable taste which characterize 
the other soluble salts of this base. 
This result, which at first surprised me, appeared less ex- 
traordinary on considering that of all the soluble salts of 
iron, the citrate is almost the only one which is free from 
the particular taste that distinguishes the ferruginous salts. 
Experiments founded on these observations, led to the 
conclusion that these facts, so far from being exceptions, 
may be taken as illustrations of a law which may be thus 
generalized : — That, of all the salts of any base, the citrate 
