ANALYSIS OF JADE. I OP 



the same results, though from different specunens, I sought 



to discover an alkali in the amulets, by employing nitrate Examined for 



of barytes to decompose them according to Klaproth's me- '^ 



thod. 



A hundred parts of nephritic jade were mixed with five Heated with 

 times their weight of nitrate of barytes. This mixture Irytes.'^" 

 divided into four parts ; and after having exposed the first to 

 the action of the fire in a platina crucible till it ceased to 

 swell up, I added to it the second, and so on with the rest. 

 The whole, after having been exposed to a red heat for at 

 least half an hour, exhibited a spongy mass of the colour of 

 goose-dung. This was pulverized, and diluted with a large Water affus(«i, 

 quantify of cold water. The mixture assumed a lilac red '^"^^ adXd '^ 

 colour, which disappeared by a boiling heat, but returned 

 on adding a few drops of muriatic acid, and again disap- 

 peared on adding a farther quantity of the acid, which gave 

 the liquor a yellow colour. It contained a white insoluble 

 powder, weighing 43 parts. This powder was exposed to 

 the fire with four times its weight of barytes ; and the spongy 

 white substance thus produced dissolved completely in water 

 and in muriatic acid, without exhibiting the colours men- 

 tioned above. 



The muriatic solutions having been mixed together, sul- The solution 

 phuric acid was added in excess, which separated the ba- P'^^^'P'^^ted by 



, 1 . p 1 -1 sulphuric acid. 



rytes, and part ot the silex. 



The liquor was filtered, and evaporated, till all the mu- The muriatic 

 riatic acid was distilled ofi. The residuum moderately dry f ""^ ^''^^'^'^ '^^ 



"' •'by heat. 



was digested in distilled water, which dit^^solved the whole, „ . , 



° , . . ' Residuum dis- 



except the last portions of silex, and a little sulphate of solved in water 



lime. 



The solution being filtered, ammonia was added, which ^"^ precipita- 

 precipitated the alumine and metallic oxides. j^^^^ ^ animo- 



These substances having been separated, the liquor re- The liquor 

 maining after filtration was evaporated, and the residuum ^^''^por^^ed, 

 heated to redness. This, which was of a whitish colour, and earthy sul- 

 weighed 56 parts. Being diluted with cold water, l6 parts ^d. ' ^' 

 of calcined sulphate of lime were separated by filtration. 

 The alkaline sulphate therefore weighed after calcination 40 



The 



