Chemical Science. 397 



26. PREPARATION OP SALICENE. 



The following is the process recommended for this purpose by 

 M. Peschier. The bark of the willow is to be dried, crushed, boiled 

 for one or two hours in water, and the liquid separated by a cloth, 

 and powerful pressure. Subacetate of lead is to be added as long as 

 precipitation occurs ; the whole filtered ; the clear liquor boiled with 

 enough carbonate of lime to decompose the excess of acetate of 

 lead, saturate the acetic acid, and remove the colour. Being left to 

 settle, the clear liquor is to be decanted, the deposit washed twice or 

 thrice, the washing liquor added to the former, and the whole evapo- 

 rated to the consistence of an extract. This extract, whilst hot, is 

 to be put into bibulous paper, and pressed for some hours ; after 

 which it is to be digested in alcohol of s. g. 0.847, the fluid filtered 

 and concentrated, when it will yield crystallized salicene, very white 

 and pure. 



Salicene thus obtained, when administered in doses, of from 15 to 

 18 grains, in the intervals of intermitting fevers, was found perfectly 

 effectual in stopping their progress*. 



27. NEW KIND OF INDIGO. 



The Registro Mercantil of Manilla describes a new kind of indigo 

 lately discovered in that island. This plant has been long known to 

 the natives, especially in the provinces of Caramini and D'Albay ; 

 they gave it the name of payanguit or avanguit, and obtain a 

 superb blue colour from it. In 1827 it attracted the attention of 

 Pere Mata, one of the members of the Economical Society of 

 Samar. He made many experiments upon it, formed it into cakes, 

 and dyed cotton, linen, and silk goods with it. The colour he ob- 

 tained was so rich, and so equal to that of indigo, that he sent some 

 of the cakes and the dyed fabrics to the Society, who directed other 

 members residing in the same province to repeat Pere Mata's expe- 

 riments. All obtained most satisfactory results, and they sent many 

 of the cakes, the leaves, and even the living plants, to Manilla. A 

 committee of merchants and chemists was appointed to ascertain, by 

 every kind of trial, whether the colouring matter was identical with 

 that of indigo, and might be introduced as such into the market at 

 the same price. The committee reported in the affirmative on these 

 points, declaring that the payanguit had all the valuable properties 

 of the plant to which it had been comparedf. 



28. CHARRING OF WOOD AT Low TEMPERATURES. 



Mr. Phillips has described the following case of the slow decom- 

 position of wood at low temperatures : 



Mr. Charles May, chemist, of Ampthill, has sent me some speci- 

 mens of wood, converted into nearly perfect charcoal at a very low 



* Ana. de Chim, xliv. p. 418. f Bib, Univ. 1830, p. 223. 



VOL. I. FEB. 1831. 2 D 



