ABSTRACT
Stones consisting entirely or in a great part of carbonate of lime, calcium carbonate are known as limestones, and are quarried chiefly in the form of chalk, which is a soft white rock of almost pure calcium carbonate, limestones, and marbles. Some of the fossiliferous limestones through which the Christiania granite rises have been changed into marble, which is a crystalline solid, but their original corals and shells have not been wholly effaced. Sandstones should not after twenty-four hours' immersion absorb more than 10 per cent, of their volume of water; limestones not more than 17 per cent.; granites not more than 1 per cent. Generally speaking, the smaller the amount of carbon steel contains, the nearer will its properties resemble those of wrought iron; the greater the quantity it possesses tends to make its characteristics similar to cast iron.
