martial salt. Thus, as in the case of the more rapid decom- 

 position of sulphat of Mercury, nitrate of Bismuth, and mu- 

 riate of Antinion}', the acid by its superior affinity for water 

 may deposit a considerable part of the oxyd it formerly held 

 in solution. This opinion appears confirmed by the fol- 

 lou'ing experiments: 



1st. The Tinctura Acetatis ferri cum Alcohol, Pharm. 

 Dub. which does not aftect the colour of Litmus paper, if it 

 be diluted with water immediately reddens it.* The experi- 

 ment succeeds uniformly if the moistened paper, in both in- 

 stances, be immediately dried. If the paper dipped in the 

 undiluted Alcohol tincture be exposed some minutes to air, 

 a very slight tinge of red is perceptible, probably in conse- 

 quence of the extended surface of the Alcohol attracting 

 moisture from the atmosphere. 



2d. If the Alcohol tincture be evaporated to an extract and 

 this be dissolved in water, the solution reddens Litmus paper, 

 and after some time deposits an oxyd. It must be however 

 remarked, that the Alcohol tincture remains clear for several 

 days when exposed to air in an open glass, and that even 

 when it is diluted with water so as to redden Litmus, it re- 

 tains its transparency. 



Sfl. The tincture with rectified spirit, which has grown tur- 

 bid in close vessels reddens Litmus. The deposited oxyd is 

 so minutely divided, that it is extremely difficult to obtain 

 the liquor clear by filtration. 



4th. If 



* This happens when 3 parts by measure of water are added to 20 of tincture, 

 and more strikingly when equal parts of tincture and water are mixed. 



