g06 °N VARIOUS SPECIES OF CINCHONA. 



chaly beates, 5. The muriate of iron, or any other ferruginous salt, pro- 

 duces in it a deep green colour, and soon after a precipitate 

 of the same tint. 



emetic tartar, fj. The antimoniated tartrite of potash occasions no preci- 

 pitation in it. This substance therefore is not the same as 

 that, which in the infusions of certain species of cinchona 

 precipitates this metallic salt. 



and litmus. 7. Lastly it very perceptibly reddens infusion of litmus. 



Scarcely solu- The acidity of this substance, and the precipitation occa- 



ble in water sionocl by alkalis in its concentrated solution, led me to sus- 



freed from J . . 7 



ackrj ' pect, that its solubility was in part owing to the presence of 



the free acid that accompanies it: and this appeared to me to 

 be confirmed by the circumstance, that, when once separated 

 by an alkali, washed, and dried, it was no longer soluble in 

 water but in an infinitely small proportion, 

 unless an acid To acquire.a greater degree of certainty upon this subject, 

 theVater* * P ut some * nt0 water acidulated with various acids; and I 

 found in fact, that it dissolved in them readily, and that its 

 solutions resumed a bitter taste, similar to that it had before 

 it was precipitated by an alkali. 

 Seems to retain I remarked, that this substance, when precipitated, re- 

 some of the al- ta j nec i a part f ( ne alkali employed to throw it down: at 

 kah that threw r . r . . . 



it down. least the following experiment seemed to prove this. After 



its solution had been precipitated by ammonia, and washed in 

 a large quantity of water, I mixed with it caustic potash, 

 which immediately produced a very evident smell of ammo- 

 nia; and this was not, the case, before it had been precipitated 

 by that alkali. 



It is evident therefore, that this substance combines with a 

 portion of the ammonia, which is employed to precipitate it 

 from its solution; unless the acid, which naturally accompa- 

 nies it, forms with this alkali an insoluble salt, tnat mixes 

 with the resinous mutter, a circumstance that appears not 

 very probable. 

 Neutralizes I* seems from these properties, that this substance acts the 



both acids and p ar t sometimes ot an acid, at others of an alkali, since it 

 combines with both these, and in part neutralizes their pro- 

 perties. 

 Soluble in ex- If, after having precipitated this matter by alkalis, an excess 

 cess of alkali. f 



