DE. JACKSON'S ANALYSES. 549 



" III. Chemical analysis of the magnesite veins in Roxbury Vt., Verd-antique. These 

 veins are probably like those analyzed by Dr. Hayes. They yielded per cent, 



Magnesia, 38.88 



Carbonic acid, 37.12 



Protoxyd of iron, .... 9.00 

 Undecomposed serpentine, . . . 15.00 



100.00 

 "The protoxyd of iron was originally in combination with carbonic acid in the stone, 



forming carbonate of iron, an isomorph with carbonate of magnesia. 



" IV. Chemical analysis of the dolomite spar veins in Roxbury Vt., serpentine. A 



cleavage crystal, with angles of 106, 15, was analyzed, and yielded, 



Carbonic acid, 46.50 



Lime, 30.52 



Magnesia, 18.47 



Protoxyd of iron, 4.25 



Silica, . 0.05 



99.79 



" In this mineral the carbonic acid is combined with the lime, magnesia, and protoxyd 

 of iron. 



"V. Chemical analysis of the serpentine of the Verd-antique of Europe. It was picked 

 out clean as possible, reduced to small grains, and washed with very dilute muriatic acid 

 to cleanse it from adhering carbonate of lime. The attack was made by means of carbon- 

 ate of soda, in the usual manner of rendering insoluble silicates soluble in acids. The 

 results obtained were 



Silica, ., . . 42.40 



Magnesia, 31.20 



Protoxyd of iron, .... 13.90 

 Water, . . . . . . . 12.50 



100.00 



" The Roxbury, Vt. serpentine, analyzed in the same manner, yielded 

 Silica, . . . . . . . 42.60 



Magnesia, . . . . . 35.50 



Protoxyd of iron and oxyd of chromium, 8.30 

 Carbonate of Lime, .... 0.60 



Water, 13.00 



100.00 



T. S. Hunt, Esq., of Montreal, analyzed the white veins from the serpentine of Roxbury, 

 and " obtained from 100 parts, 2.76 of talc, and 1.82 of silica, besides 2.40 of peroxyd of 

 iron, corresponding to 3.48 of carbonate of iron, the rest being carbonic acid and mag- 

 nesia, with a little manganese." His account of these veins and the serpentine is as 

 follows : " The greater portion of the iron exists here [in the veins] as carbonate, as is 

 evident from the fact that it is dissolved by a boiling solution of nitrate of ammonia ; but 



