[Illustration: Scotch carpet-loom.] Let us see what mechanical ingenuity can effect in producing the most useful and ornamental articles of domestic life from the common earth which may be had for digging. Without chemical and mechanical skill we should neither have Glass nor Pottery; and without these articles, how much lowered beneath his present station, in point of comfort and convenience, would be the humblest peasant in the land! The cost of glass is almost wholly the wages of labour, as the materials are very abundant, and may be said to cost almost nothing; and glass is much more easily worked than any other substance. Hard and brittle as it is, it has only to be heated, and any form that the workman pleases may be given to it. It melts; but when so hot as to be more susceptible of form than wax or clay, or anything else that we are acquainted with, it still, retains a degree of toughness and capability of extension superior to that of many solids, and of every liquid; when it has become red-hot all its brittleness is gone, and a man may do with it as he pleases. He may press it into a mould; he may take a lump of it upon the end of an iron tube, and, by blowing into the tube with his mouth (keeping the glass hot all the time), he may swell it out into a hollow ball. He may mould that ball into a bottle; he may draw it out lengthways into a pipe; he may cut it open into a cup; he may open it with shears, whirl it round with the edge in the fire, and thus make it into a circular plate. He may also roll it out into sheets, and spin it into threads as fine as a cobweb. In short, so that he keeps it hot, and away from substances by which it may be destroyed, he can do with it just as he pleases. All this, too, may be done, and is done with large quantities every day, in less time than any one would take to give an account of it. In the time that the readiest speaker and clearest describer were telling how one quart bottle is made, an ordinary set of workmen would make some dozens of bottles. But though the materials of glass are among the cheapest of all materials, and the substance the most obedient to the hand of the workman, there is a great deal of knowledge necessary before glass can be made. It can be made profitably only at large manufactories, and those manufactories must be kept constantly at work night and day.