EXPERIMENTS ON GUM KINO. ^33 



Kino is little foluble in cold water, but much more in hot, Its folution ia 

 though a portion of it is infoluble. The folution is flightly '''^"^'''"^"'°"'* 

 acid: alcohol does not precipitate it, but feparates fome red- 

 diQi flocks; when made with boiling water it grows turbid on 

 cooling, and depofits a brown red precipitate. 



A faturated folution is precipitated by mild alkalis, but Pf^'picated by 

 water in fufficient quantity re-ditfolves the precipitate. S'kalles"'^ ""^^"^ 



Cauftic alkalis likewife precipitate it, but if added iu excefs 

 re-diflblve the precipitate. 



Glue diffolved in water forms a very confiderable rofe- and coagulated 

 coloured coagulum with the folution of kino; and if the quan- ^^^ s'ue* 

 tities be fuch, that both fubftances are faturated, the fuperna- 

 tant fluid will be nearly colourlefs. 



Though thefe appearances indicate the prefence of tannin Its tannin prc- 

 in kino, it does not precipitate ferruginous falts black, but of g^^^^^" """^ 

 a beautiful deep green, fcarcely alterable by expofure to the 

 air. This property it has in common with the infufions of cin- Contains a prin- 

 chona and rhubarb ; wlience it is probable, that thefe three fub- P'P'f ^n^inon to 

 Itances contam a principle or Iimilar nature. rhubarb. 



This principle, whatever it be, is very deflru6tible: for, if This principle 

 a little oxigenated muriatic acid be poured on the precipitate ^.^^ deftiuc. 

 it forms with iron, this lofes its colour, and does not re-appear 

 on the addition of an alkaline carbonate, which produces only 

 a red oxide of iron. 



The folution of kino copioufly precipitates acetite of lead of Precipitates 

 a yellowifli grey; nitrate of filverof a reddifli yellow, and tar- 1°'"^. m^talhc 



T - . ^ , folutions. 



trite of antimony of a yellowifli white, but much more copi- 

 oufly than the infufion of tan or of cinchona; which feems to ufeful as anan- 

 indicate, that it would be a better antidote in cafes of perfons tidote. 

 pjoifoned by this metallic fait. 



Wool and cotton being boiled in a folution of kino, and then Dyes wool and 

 dipped in a bath of fulphate of iron, appeared on immerfion |^^"^" ^ '''*'^''- 

 of a bottle-green ; but being walhed and dried, the colour be- 

 came a blackifli brown. It was very durable. 



Hot alcohol diffolves kino very well, all but a fmall portion. Diflblves in hot 

 Water renders the folution a little turbid, but precipitates ^'*^"^°'' . 

 nothing. 



The portion infoluble in alcohol, nearly a fourth of the whole. Contains a por- 

 bas neither the bitternefs nor aftringent tafte of kino; but, on '^'°" °^ 2"'"- 

 ibe contrary, is rather mucous and fwcet. It eafily diflblves 



in 



