Examination of a few American Minerals. 1 23 



5. 3fag?iesite, Hoboken, 1ST. J. 



I obtained this specimen from a vein in the serpentine. It 

 was absolutely white and free from impurities, and found to be 

 nearly pure carbonate of magnesia. 



Mr. H. B. Cornwall analysed it with great care, and reported 

 the following results : 



Magnesia, . 

 Lime, . 

 Protox. iron, 

 Water, 



Carbonic acid, 

 Silica, 



46*71 • Carbonate of magnesia, 98*45 

 trace Carbonate of iron, . 0*90 



0-56 



0-30 . . . ... 0-30 



50-00 



0-23 0-23 



97-80 99-88 



6. Anthophyllite, New York City. 



There are numerous boulders of this mineral found on the- 

 Island of New York, and it also occurs in situ near the corner 

 of 59tji st. and 10th avenue. I found the specimen, which I 

 gave to Mr. Cornwall for analysis, on 49th st., near Columbia 

 College. 



A fragment was taken from the interior of the boulder and 

 carefully pulverized. 0'443 grms. heated to whiteness lost 

 0-038 grms. = 8-577 per cent. 



0-336 grms. were fused with a mixture of carbonates of soda 

 and potassa, and the mass dissolved in hydrochloric acid, 

 obtained silica 0*150 grms. = 46'428 per cent. 



The acid solution was nearly neutralized with carbonate of 

 soda, and boiled with excess of acetate of soda, and the pre- 

 cipitated acetate of iron converted into sesquioxide by ignition, 

 found 0*035 grms. = 9*375 per cent, protoxide. 



The lime was precipitated by oxalate of ammonia, and con- 

 verted into carbonate by ignition ; found - 0l7 grms. = 5*059 



MAT, 1865. 10 Ann. Ltc. Nat. Hist. Vol VlII. 



