208 0N VARIOUS SPLCIES OF CINCHONA. 



. large quantity of alcohol assisted by heat, little is left to hv 

 done by the acids. The matter taken from the bark by acids 

 is acccording t*> all appearance the same, as that which dis- 

 solves in alcohol, as I shall show farther on. 

 Nitric acuK Nitric acid acquires from it a red, inclining to rose-colour, 



and sometimes to a deep orange [nacarat] : but these tints 

 vary greatly in their intensity according to the strength of the 

 acid; the stronger this is, the more they incline to yellow. 

 The nitric acid Jose$,much of its acidity by this combination, 

 at least as far as we can judge from the taste: it is true it 

 dissolves at the same time ft certain quantity of lime, which is 

 detected by oxalate of ammonia, and this contributes to its 

 neutralization. 

 Action of car- If saturated carbonate of potash be p'oured into this nitric 

 soluaon° n the sollltion » a flnc mJ precipitate is formed : but if the common 

 carbonate be employed, and added in excess, the colour of 

 the precipitate becomes violet, purple, or blue. Thus alkalis 

 have the property of blueing that colour of these barks, which 

 is naturally red. 

 and of solu- Metallic solutions likewise form in it precipitates of various 



ttons of metals, colours, and more or less abundant, according as the nitric 

 acid contains more or less vegetable matter: but, if the ex- 

 cess of acid be saturated, the metallic salts then produce in it 

 ver) copious precipitates, and the liquor is deprived of colour. 

 • 1. Solution of muriate of tin produces in it a rose-coloured 

 or carnation precipitate. 



2. That of sulphate of iron, a grayish precipitate. 



3. That of copper a chesnut brown. 



4. Sulphate of titanium, assisted with a little carbonate of 

 soda, formed with the nitric solution of cinchona an orange 

 red precipitate, pretty analogous in colour to that produced 

 by solutions of this metal with galls. 



5. Alum occasioned no change in the acid solution of cin- 

 chona : but aided by a little alkali it carries down with it the 

 colouring part, and the liquor is rendered colourless. 



Might be em- In the countries where these cinchonas grow, a very fine 



ployed as a anc j permanent chesnut red for wool and cotton might be ob- 

 dye. r ° 



tained from their bark. Soap turns it to a rose colour. 



Sulphuric and The sulphuric and muriatic acids, diluted with water, and 

 muriatic acids. . p 0UIC{ ] 



