\ 



NATIVE CINNABAH. 245 



quantity to ascertain what species of sugar it might most 

 nearly resemble ; we take it to be manna. 



We may therefore consider it as decided that besides Conclusion. 

 the principles discorerod in the jui6e of asparagus by 

 Mr. Robiquet, there e^^ists in it a principle which is crys- 

 tallizablc like the salts, but is neither acid nor neutral, 

 and of which the solution in water is not aft'ected by any 

 of the reagents usually employed to ascertain (he presence 

 and nature of the salts dissolved in water; and also 

 another principle which appears to resemble manna. 



XIII. 



A Chemical Examination of Native Cinnabar. Bt/ 



M. Kl.APROTII. 



I. The Cinnabar of Japan, 



HE cinnabar of Japan is brought to Europe in the External cha- 



form of single grains, more or less large and crystalline, racters of thq 

 w , . ^ , , , f , . 1 cjnnabar of la- 



Its colour is of a deep cochineal red, approaching the pan. 



grey colour of steel in the places which arenot damaged; 



in others it is of a scarlet red, inclining to a brick-dust 



colour. The grains are fragments of ilattened hexahe- 



dral prisms ; externally smooth and of a metallic lustre ; 



internally very bright and of a semi-metallic lustre. 



Their fracture crosswise is conchoidal, but longitudinally, 



it is obscurely lamellated. This mineral is tender, its 



scrapings of a scarlet red, and its specific gravity=7.710. 



Its fragments sometimes include specks of pyrites, and in 



other instances they adhere to a quartzose gangue. In 



order to distribute these heterogeneous parts uniformly 



through the mass of grains subjected to analysis, they were 



mixed and pounded together. 



J. One thousand grains of this powder were sublimed impurities sc- 

 in a small glass retort with a receiver adapted thereto, and parated from 

 filled w ith water. The water of the receiver acquired a he^t^ 

 turbid yellowish appearance from the particles of sulphur, 

 which were volatilized. It had a faint smell of sulphura- 

 ted hidrogen, and a slight taste of sulphureous acid. The 

 matter remaining in the retort weighed 38 grains. It was 



Vol. XV.—Nov. 1806. H k digeste(\ 



