But man’s power of invention increases, and in the higher stage of industrial evolution the facilities for labour are enormous. We have but to think of steam and of electricity with all their tremendous developments of power. Finally the discovery of the unity of force leads men to look upon Nature as a storehouse of energy and to devise means by which natural forces may be guided, one form of energy converted into another and transferred from place to place; and thus man becomes almost all-powerful. He is not able to create, it is true, but he may at least mould and shape to his desire that which Nature has already formed. Thus the discovery how to direct the forces of Nature enables us again, according to the principle already cited, to escape the disabilities of human differentiation with its attendant incongruities. [Sidenote: Boundless Growth of Commerce] As already stated, division of labour leads to exchange; exchange leads to commerce. Commerce is exchange on a large scale, organised into a system with special regard to the production of a store, or supply. The latter requires a certain knowledge of trade; the centres of demand must be sought out, and the goods transported to these centres. In this way a fruitful reciprocal action develops; and as production influences trade, so may trade influence production, governing it according to the fluctuations of demand, and leading to the creation of stores of commodities for which a future market is to be expected. Thus commerce presupposes special knowledge and special skill; it develops a special technique through which it is enabled to execute its complicated tasks. Men who live by trade become distinct from craftsmen; and the mercantile class results. Merchants are men whose task is to effect an organised exchange of natural and manufactured products. Commerce always displays an impulse to extend itself beyond the borders of single nations--not to remain inland only, but to become a foreign trade also; for the products of foreign countries and climates, however valuable they may be, would be inaccessible except for commerce. Thus trade becomes both import and export. The first step is for the tradesman or his representative to travel about peddling goods, or for an owner of wares or money to offer capital to an itinerant merchant with the object that the latter may divide the profits with him later on. This leads to the sending of merchandise to a middleman, who places it on the market in a distant region--commission business. The establishment of a branch or agency in a foreign country, in order to trade there while in immediate connection with the main business house, follows; and, finally, merchants deal directly with foreign houses without the intervention of middlemen, thus entering into direct export trade. This, of course, presupposes a great familiarity with foreign affairs and confidence in their soundness; consequently it is possible