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On a New Alkali Hornblende. 81 



allowing the mass to solidify, a portion of the powder was 

 found to have collected at the top of the mass, while the 

 rest was at the bottom, the intervening part being quite 

 free from mineral grains. The solid mass was then cut in 

 two and the salts dissolved by treatment with water. 

 After three successive separations the hornblende was 

 obtained quite free from grains of garnet — the only 

 impurities present being some composite grains consisting 

 of garnet and nepheline. This powder was then placed 

 under a lens and all the composite grains picked out 

 by means of a fine needle. In this way a quantity of pure 

 hornblende sufficient for purposes of analysis was 

 obtained, while the garnet was obtained directly in a 

 state of purity without the necessity of a final separation 

 by hand. 



Both minerals were found to be quite fresh and bright 

 and quite unacted upon by the fused salts. 



The hornblende^ was then analyzed by Dr. Harrington 

 with the followino; results : — 



Silica 34-184 



Titanium dioxide 1 • 527 



Alumina 11 -517 



Ferric oxide 12-621 



Ferrous oxide 21-979 



Manganous oxide • 629 



Lime 9-867 



Magnesia 1 - 353 



Potash 2-286 



Soda 3-290 



Water2 . ... -348 



99-601 

 Specific gravity 3 • 433 



1 We would suggest Hastingsite as a varietal name for tliis hornblende, connecting 

 it with the region where it occurs. 



2 Loss after igniting for about fifteen minutes. On furtlier ignition the powder 

 gained in weight owing to oxidation of the ferrous oxide. 



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