34S Boiven^s Analysis of the Kephrite. 



fessor Silliman, atone of the marble quarries, near New- 

 Haven, and his opinion was that this mineral coincided ex- 

 actly with the Swedish Sahlite or Malacholite- 



I 



r 



Akt. XVIL — Analysis^ of a variety of J\*epJirite, from 

 Smilhfitld^ ii. /. By George T. Bo wen, of Providence. 



■ 



This beautiful mineral occurs at Smithfield, imber'ded in 

 large nodules in while primitive Hmestone. Its color is bright 

 apple green — sometimes tinged with blue; the colour of 

 its powder is white — its hardness is equal to that of felspar 

 its fracture dull and splintery — it is highly translucent, and 

 very difficult to break on account of its great tenacity — be- 

 fore the blowpipe it is Infusible- Its specific gravity varies 

 from 2,594 to 2.787. — Its powder when boiled with sul- 

 phuric or nitromuriatic acid, is entirely decomposed, the 

 obtained solution yielding an abundant precipitate with 

 Phosphate of soda and ammonia. 



Analysis. 



A, Fifty grains of the mineral in the powder were ex- 

 posed, during thirty minutes, to a red heat in a platina cru- 

 cible ; the colour of the powder was not altered. The 

 weight after calcination was 43.250 grains; the moisture 

 dissipated amounted therefore to 6.750 grains in 50 grains, 

 Of 13.500 per 100. A piece of the mineral weighing 10^ 

 grains was then heated during thirty minutes, witliout having 

 been reduced to powder. Its green colour disappeared; it 

 lost its translucency, and became of a pure white ; its hard- 

 ness was also much increased as it now scratched glass uith 

 facility. The loss of weight amounted to 13.625 grains. 

 The mean of three experiments gave as the loss by calci- 

 lations 13.41 7-grain3 per 100. 



B. One hundred grains of the mineral in powder were 

 fused with 300 grains of caustic potash, in a silver crucibl 

 and kept at a red heat during one hour. The contents of 



^» 



the crucible, when removed from the fire, were of a Hgl^^ 

 green colour. — Muriatic acid was added in excess, and the 

 fluid evaporated to dryness. — The dry mass was then treat- 

 ed with water acidulated with muriatic acid ; the silex sep- 



* Done in the Laboratory of Yale College. 



