EXPERIMENTS AND OBSERVAIIONS ON CINCHONA. 227 



(c) The precipitate when dwed, weighed fourteen grains 

 and a half. It had a brownifh yellow colour, was tranfparent, 

 and had a refinous appearance and fra6lure. It was alfo hard 

 and brittle, and adhered ftrongly to the filter. In every par- 

 ticular it refembled the precipitate produced in the former ex- 

 periment (Exp. I. €.) by gelatine, after the infuiion of galls 

 was completely faturated by cinchona. 



(d) In the filtred liquor {Exp. 11. b) infufion of cinchona Infufion of cin* 



produced no change. <^'^°"^ g^^e '^•> 



° farther preci- 



. pitate. 



Experiment 111. 



To an ounce and a half of the fame infuiion of cinchona, Infufion of c'n- 

 half an ounce of the folution of gelatine was added. It pro- ^^?"^ ^'%^^T^ 

 duced only a flight degree of turbidnefs, and changed the co- fignsoi" tannin.' 

 lour of the infufion from a pale greenifli to a reddith yellow co- 

 lour. When filtred, it pafled perfeftly tranfparent, and the 

 bottom of the filter was covered with a red varnifli ; but it 

 had gained only one grain in weight. In other experiments 

 with larger quantities and fironger infuiion of cinchona, the 

 prefence of tannin was more ftrongly indicated. 



Experhnent IV. 

 Infufion of galls was not afFe£ted by redlified fpirits of wine, Infufion of galis 

 Fn which ifinglafs had been long infufed. "f^ngSf-''^ 



lolved in al- 



Experiment V. ci.ho]. 



(«) A tin6ture of cinchona was prepared by infufing it in Tinaure of 

 the fame reftified fpirits. After it was filtred forae refin was pi^.trbVwai' 

 feparated by precipitation with water and filtration. ter, 



(6) With infufion of galls this tindure gave a copious pre- and by infufuns 

 cipitate, exactly refembling that produced by the fame re- °^sal's» 

 agent and infufion of cinchona. [Exp. I. c.) 



Experiment VI. 

 With tinaure of galls the fame tin6ture of cinchona gave Tlndlure of 



. . galls and of 



no precipitate. cinchona gave 



no precipitate. 



Experiment VII. 



In the mixed tindure {Exp. VI.) a copious precipitate was tllldilutedby 

 water. ^ 



Q 2 Experiment 



produced by diluting it with water. 



