Chemical Experiments on Qiiaktcum. lOf) 



trated liquor yielded yellow flocculent precipitates with the 

 alkalis, and on examination was found to hold nitrate of 

 lime in solution. 



The undissolved portion was of a deep chocolate brown co- 

 lour. A similar substance may also be obtained by evapo- 

 rating the recent nitric solution to dryness, taking care not 

 to apply too much heat towards the end of the process. 



The substance obtained by either of these means possesses 

 the properties of a resin in greater perfection than guaiacum ; 

 it is equally soluble in alcohol and sulphuric ether, insoluble 

 in water, &c; but when burned it emits a peculiar smell, 

 more resembling animal than vegetable bodies. If, how- 

 ever, fresh portions of nitric acid be added three or four 

 times successively, or if a large quantity be employed to 

 form the solution, the. product obtained by evaporation is 

 then of a very different nature; for it has lost all the cha-, 

 racteristic properties of a resin, having become equally so- 

 luble in water and alcohol ; the solution of it in this state 

 having an astringent bitter taste*. 



7. Guaiacum is copiously soluble in the pure and carbon- 

 ated alkalis, forming greenish brown liquids. 



Two ounces of a saturated solution of caustic potash took 

 up rather more than Gh grains of the resin ; the same quan- 

 tity of liquid ammouia dissolved only 25 grains. 



Nitric acid formed in these solutions a deep brown preci- 

 pitate, the shades of which varied according to the quantity 

 of acid which had been employed. 



This precipitate was found, on examination, to possess the 

 properties of that formed by nitric acid in the solution of 

 guaiacum (?. E.) in alcohol. 



Dilute sulphuric acid, when poured into any of the above 

 alkaline solutions, formed a flesh-coloured curdy precipitate. 

 Muriatic acid produced the same effect. 



The two last-mentioned precipitates differ from guaiacum, 

 in being less acted upon by sulphuric ether and more soluble 



• Vvlt Mr. Hatehett's two papers on an artificial Substance which possesses 

 the principal c.'.-'uc'.cri.tic PfOMrtiei of Tannin. Phil. Trans. 1805, p. 811 



in 



