BotaenPs Analym of Calcareous Tungsten ^c. 



119 



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i 



-brittle — is scratched by a kuifc — infusible before the 

 blow^pipe. The specific gravity of a pure piece was 5.98. 

 It occurs in a gangue of quartz, associated with the ferru- 

 ginous oxide of Tungsten.* 



Analysis. 



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A. Distilled water digested upon the niineral in powder, 

 dissolved nothing. It was then treated with ammonia, but 

 no portion of it was dissolved. Fifty grains exposed for 

 one hour to a high red heat in a platina cruciblej lost noth- 

 ing perceptible of their weight. 



B. One hundred grains of the mineral reduced to a fine 

 powder were mixed with three times their weight of pure 

 caustic potash and exposed for one hour to a moderate red 

 heat in a crucible of pure silver. The contents of the cru- 

 cible when removed from the fire, were of a blue colour 

 resembling smalt. The mass after having been digested 

 with water was thrown on a filter and the insoluble powder 

 repeatedly washed with distilled water. Upon this pow- 

 der when collected, diluted muriatic acid was poured when 

 it was entirely dissolved, with eflfervescence excepting .5 

 grains of silex. 



C. The muriatic solution was then evaporated to dry* 

 ness, and the mass treated with distilled water, when there 

 remained undissolved, one grain of a powder having a dark 

 brown colour. Nitric acid when digested upon it, dissol- 

 ved it in part and left .25 grain silex. The nitric solution 

 was precipitated by ammonia ; the precipitate when wash- 

 ed and dried, weighed .74 grain. It was then treated with 

 muriate of ammonia, to which a small quantity of sugar 

 was added in order to separate the oxide of manganese.! 

 The oxide of iron remaining undissolved amounted to ,55 

 grains ; we have then by difference, oxide of manganese 

 equal to. 19 grain. 



D. The solution of the muriate in water was tested for 

 iron, but none could be discovered. It was then decora- 

 posed by carbonate of soda at a boiling heat; the precipi- 



* It is also accompanied by native bismuth, native silver, galena, sulphate 

 of lead, and magnetic, and common pyrites. 



t This method of separating iron from manganese is recommended by Mr. 

 Faraday, Jour. Royal luilitutioa. VI 357. 



