Boicenh Analysis of a variety of J\^ephrite. 347 



arated in this manner, when washed and calcined, weighed 



44.688 grains. 



C. The solution (B), was neutralized with ammonia and 

 j treated with the hydrosulphate of ammonia. — The precip- 

 itate when ignited and calcined with nitric acid weighed 

 2.313grains. When fused with caustic potash, it imparted 

 to it a tinge of green, giving indications of a trace of man- 

 ganese. The oxide of iron remaining after the action of 

 caustic potash, amounted to 1.747 grains- We have then 

 by difference alumine equal to 0.562 grains. 



D. The lime was precipitated from the liquor (C), by 

 j the addition of oxalate of potash; when calcined it weighed 



4.250 grains. 



E. To the remaining solutiouj (D), after the separation 

 of the lime, caustic potash was added in excess, and the 

 fluid boiled. The magnesia separated by this treatment, 

 when washed and calcined, weighed 34.631 grains. 



F. 250 grains of the mineral were introduced into a small 

 porcelain retort which was connected with the mercurial ap- 

 paratus, and kept at a red heat during one hour. A portion 

 of water distilled over, but no carbonic acid was obtained. 



The composition of this mineral is therefore, 





Per ] 00 Parts. 



A. Water 



13.417 conta 



B, Silica 



44.688 



C. Alumine 



00.562 



C. Oxide of Iron 



01.747 



D. Lime 



04.250 



f*. Magnesia 



34.631 



C. Oxide of Mangs 



inese a trace 





99.295 



^ 



100.000 





000.705 Loss. 



22.47 



01.09 

 13.40 



On comparing the results of the preceding experiments 

 IJpon this substance, with the analyses of Nephrite which 

 have been hitherto published, we find a considerable differ- 

 ence in chemical composuion; the Sraithfield mineral cpn- 

 tajns a much greater proportion of water, and only a very 

 small quantity of alumine. It differs from Nephrite also in 



4 



