6 



10 grains of metallic salt, which does not crystallize, but first 

 assumes the consistence of wax ; and then dries, transparent, 

 of the colour before mentioned. 



In order to determine the state of oxydation in which Iron 

 dissolves most easily in the acid of Vinegar, 



Ten grains of the following substances, viz. Carbonate of 

 Iron, Pharm. Dub. (A)*, Oxydum ferri rubrum, Pharm. Dub. 

 (B), Iron filings (C), scales of Iron (D), were digested with a 

 heat varying from 90 to 150 degrees for four days, each in 

 two drachms measure of acetic acid, spec, gravity 106.5, pro- 

 cured by distillation of acetate of Copper. The solutions 

 {designated by the letter annexed to the substance used in the 

 experiment) presented the following appearances: 



A. Deep claret colour, somewhat viscid — no residuum. 



B. Light red — residuum weighed Grs. 8| 



C. Reddish amber colour — residuum 6| 



D. Light amber tinge — residuum • • 9i 



All the residua were washed with distilled water, and dried 

 before weighing, with a heat of about 150. 



Hence it appears, that the carbonate of Iron is perfectly 

 soluble in acetic acid, whilst but a small portion of the red 

 oxyd dissolves. Accordingly I have found that the sulphat of 

 Iron exposed to such a degree of heat as converted it in part 

 into red oxyd was less fit for the preparation of the Tinctura 



acetatis 



* This is obtained by decomposing sulphat of Iron by carbonate of Soda. 



