388 Miscellaneous Intelligence. 



This was left for twenty-four hours, and was then entirely so- 

 luble in water, with the exception of an amylacious matter, 

 weighing, when dry, 2.5 grammes (38.6 gr.). It was a portion 

 of the cloth not perfectly altered by the acid. The diluted acid 

 mucilage was saturated with chalk, and filtered through cloth, 

 it was then clear, and of a slight amber colour. After wash- 

 ing the filter well, and pressing strongly the sulphate of 

 lime, all the liquors were united, and evaporated to a syrup, 

 which was less coloured than that of capillaire. A small quan- 

 tity of sulphate of lime separated on cooling. The evaporation 

 being continued to dryness, a slightly coloured transparent gum 

 was obtained ; it weighed 26.2 grammes (404.6 gr.), and was pro- 

 duced from 21.5 grammes (332 gr.) of cloth, abstracting the one 

 gramme of water, and the 2.5 grammes (38.6 gr.) of amylacious 

 ligneous matter. The sulphate of lime also retained a portion of 

 vegetable matter, for it blackened, Sfc. on being heated. To as- 

 certain whether this increase of weight was due to the fixation of 

 the elements of water, or sulphuric acid, five grammes (77.2 gr.) 

 of the gum were dissolved in water and oxalic acid added to them. 

 The precipitate collected, and strongly heated, gave ,28 grammes 

 (4.3 gr.) of lime. The solution then evaporated to dryness 

 was treated with boiling nitric acid, and diluted with water; 

 nitrate of barytes then gave a precipitate, which, heated red, gave 

 1.6 grammes (24.7 gr.), equivalent to ,54 grammes (8.34 gr.) 

 of sulphuric acid. As no aeriform matter was disengaged dur- 

 ing the action of the acid on the cloth, the 26.2 grammes 

 (404.6 gr.) of gum may be supposed to be thus constituted. 



Ligneous matter 21.5 



Elements of sulphuric acid fixed in an un- 

 known manner 2.83 



Elements of water fixed in an unknown 



manner -4 



Combined lime 1.47 



26.2 gr. 



Hence it appears probable, that the heat evolved during the ac- 

 tion of sulphuric acid on vegetable substances is occasioned by 

 the fixation of the elements of the acid and of water. 



