SPARRY IRONSTONE. 275 there is a whole hill composed of this species of iron stone, which has been worked for several hundred years. It is there accompanied with red ironstone, which lenders the smelting very advantageous. Asia.—In the mines of Catharinenburg. America.—West Greenland ; and Mexico. Uses. It affords an iron which is excellently suited for steel taking. The black variety is said to afford the best hind of iron. Observations. 1. It is nearly allied to brown ironstone, and brown- s par, and there is a transition from calcareous-spar through brown-spar, sparry ironstone to brown iron- stone. 2. Cast-iron obtained from this species, or from brown h'onstone, presents a whitish colour and radiated frac- tnre; whereas that obtained from red ironstone, and se- Vcr al other ores of iron, has a dark grey colour, and a S r anular fracture. vFurther, the cast-iron obtained iiom this species can be converted into steel; but a great por tion of that obtained from red ironstone, &c. passes to the stf *te of malleable iron, long before the mass in the fur nace has become steel. The steel obtained from this ore is said to contain a small portion of manganese, which is opposed to be the cause of its durability in the fire, and "’hat renders it less liable to become soft and irony. 5. It generally occurs more or less weathered. B) cx ~ posure to the air, it experiences a gradual decomposition, "’hich has a great effect on its external aspect This de- c °mposition at lirst affects only the external coloui, ex- g 2 ternal