56 Mr. George on Fustic and its 



Having ascertained the chemical composition of this wood 

 by some preliminary experiments upon 200 grains of fustic 

 reduced to a fine powder and dried at 212° Fahr., poured 16 

 ounces of boiling water, left to digest till cool, decanted off 

 the clear infusion, and repeated the digestions in 16 ounces of 

 boiling water three times, poured the whole together and fil- 

 tered, washed the filter with 16 ounces of water at 150° Fahr. 

 added the washings to the filtered liquid, and evaporated the 

 whole to dryness at a temperature not exceeding 160° Fahr. 

 The dry mass weighed 30*10 grains. The insoluble part re- 

 maining upon the filter weighed 168'75 grains. 



Upon the residual 168*75 grains after the action of water 

 poured 6 ounces of boihng alcohol, and digested 24 hours; di- 

 gested a second time in 6 ounces of alcohol, filtered, washed 

 the filter with 2 ounces of alcohol, evaporated the alcoholic so- 

 lutions (which were of a dark orange colour) to dryness, the re- 

 sidue, weighing 18 grains, had a shining resinous appearance, 

 its colour black when seen in mass, and of a deep orange when 

 finely divided: at a temperature of 300° Fahr. it melted. 



Upon 100 grains of fustic in powder, and dried at 212° Fahr. 

 were boiled 6 ounces of alcohol in a covered vessel one hour, 

 poured off the solution which was of a dai'k orange colour, and 

 again digested in 4 ounces of boiling alcohol halt" an hour, fil- 

 tered both solutions and washed the filter with alcohol, evapo- 

 rated the solution to dryness; the dry mass weighed 24 grains; 

 digested the part remaining upon the filter in boiling water and 

 evaporated the clear solution to dryness: a substance agreeing 

 in all its characters with gum remained, it weighed 2 grains. 



The residual woody fibre after the action of alcohol and 

 water, weighed when dried at 212° Fahr. 74 grains. 



To estimate the amount of tannin in the aqueous solutions, 

 I first made some experiments to ascertain the proportions in 

 which the peculiar tannin of fustic and gelatine combined. 

 Having made a clear infusion of fustic containing 52 grains of 

 aqueous extract, solution of isinglass was added gradually, as 

 long as any precipitate fell down, the tannate was precipitated in 

 large brown coloured flakes; found that 11 grains isinglass 

 were required to throw down the whole, and that the tannate 

 of gelatine formed weighed 25*30 grains ; hence, it is composed 

 of tannin 14*30, gelatine 11; or in 100, — tannin 56*53, ge- 

 latine 43*47. 



To ascertain the amount of tannin, made an aqueous ex- 

 tract of the soluble matter contained in 200 grains of fustic, 

 added solution of isinglass as long as any precipitate fell down. 

 After being dried at 212° the tannate formed weighed 14 

 grains, containing 7*91 grains of tannin, or 3*95 per cent on 



the 



