OF CENTRAL CANADA PART II. 133 



with a drop of nitrate of cobalt and again ignited. Yields a large 

 amount of water in the bulb-tube. Normal composition : sulphuric 

 acid 32.52, magnesia 16.26, water 51.22. Occurs in Canada, as an 

 efflorescence or incrustation, on exposed surfaces, and on the edges of 

 the planes of bedding, of shales and other strata, where it is formed 

 apparently by the action of percolating water containing soluble 

 matters derived from the decomposition of pyrites. It occurs thus 

 in some of the slaty talcose layers associated with the iron ores of 

 Marmora, and also on the weathered shales of the Utica series, noar 

 Montreal, Quebec, and Collingwood ; and still more abundantly 011 

 some of the dolomitic beds of the Clinton and Niagara Formation, as 

 near Dimdas and elsewhere. Sulphate of magnesia occurs also in 

 solution in the Tuscarora water, and in some other mineral springs. 



101. Iron Vitriol (Green Vitriol, Copperas, Melanterite, &c.) : 

 Pale-green, greenish -white ; brownish-yellow by partial decomposition. 

 Monoclinic in crystallization, but occurring mostly in efflorescent 

 crusts and minute hair-like indistinct crystals. Soluble : taste, inky 

 and metallic. H = 2.0, or less. BB, blackens and becomes mag- 

 netic. In the bulb-tube yields a large amount of water, and gives 

 off sulphurous acid. The aqueous solution gives a deep-blue pre- 

 cipitate with " red prussiate of potash ;" and in general also with 

 the yellow prussiate, from the presence of more or less sesquioxide 

 of iron. Normal composition : sulphuric acid 28.8, protoxide of 

 iron 25.9, water 45.3. Occurs on decomposing pyrites and marcasite, 

 and on the exposed surfaces of rocks in which these minerals are 

 present. It is thus found, in small quantities, on many of the ores 

 from the mineral veins of Lake Superior, Lake Huron, the Hastings 

 region, and other parts of Canada. A specimen of iron pyrites from 

 the Galway Lead Mine in the northern part of the county of Peter- 

 borough, became covered in the course of a few weeks with delicate 

 tufts of minute acicular crystals of this mineral. 



102. Nickel F^rioZ(Moreiiosite): Pale-green, greenish- white. In 

 efflorescent tufts of minute crystals on nickel ores. Soluble : taste, 

 strongly metallic. BB, evolves sulphurous acid, swells up, and forms 

 a dark grey mass. With borax, gives reactions of nickel oxide (see 

 Part I.). In the bulb-tube yields a large amount of water. If free 

 from iron, the aqueous solution does not yield a blue precipitate with 

 red or yellow " prussiate of potash." Normal composition : sulphuric 



