Science has also proved itself to be a great source of employment, as well as wealth. By developing new processes it has given employment to whole armies of workmen in numerous arts, manufactures, and occupations. Some of those employments necessitating scientific training. About 300,000 persons are employed on railways alone in Great {37} Britain, besides those who were engaged in their construction; and in the postal department alone of the telegraph service of this country more than fifteen thousand operatives are employed. Chemical works also find employment for twenty-six thousand, and gasworks for ten thousand work people. The telegraphs of the United States of America alone, provide employment for about 7,000 persons; and the railways of the world employ about 1,900,000 men. It may be objected that the extension of science in this country, instead of increasing employment for workmen has produced an opposite effect, by so increasing the production of goods by machinery, and by physical and chemical processes, that we have glutted the markets of the world in years gone by, and are now suffering the results of over-production. This is a very limited view of the case; over-production is only true of particular manufactures, and is a result of ill-directed commercial energy, to which manufacturing skill is only a servant. The objection also contains its own reply;--that it is certainly much greater to our advantage to have supplied other nations with manufactured commodities, than that other nations should have supplied us, as they would have done had they the manufacturing skill. At present, however, continental nations are gradually supplanting us in manufactures; and gradually supplying us with the goods which we {38} formerly supplied them, and our fear is that this is largely a result of our neglect of science. In many cases instead of superseding labour, science has changed its kind, or its mode of distribution;--in the case of steam-ships, instead of navigation being conducted entirely by nautical ability, it is partly effected by the skill of the engineer; conveyance of goods by road and canal has not been entirely supplanted, but partly supplemented by conveyance by railways. The diminution of labour which sometimes occurs in consequence of the progress of science is extremely small compared with its increase. The number of waggoners and horses now employed, merely to collect and deliver all the goods for railways, is actually much greater than the whole of those employed for conveying all the goods of the country before railways were constructed.