The great trade is the home trade, and the greater the tendency to the performance of trade at home the more rapid will be the increase of prosperity, and the greater the power to effect exchanges abroad. The reason of this is to be found in the fact that the power of production increases with the power of combined exertion, and all combination is an exchange of labour for labour, the exchange being made at home. The more exchanges are thus effected the smaller is the number of the men, wagons, ships, or sailors employed in making them, and the greater the number of persons employed in the work of production, with increase in the quantity of commodities produced, and the _power_ to exchange grows with the power to produce, while the power to produce diminishes with every increase in the _necessity_ for exchange. Again, when the work of exchange is performed at home, the power of combination facilitates the disposal of a vast amount of labour that would otherwise be wasted, and an infinite number of things that would otherwise have no value whatever, but which, combined with the labour that is saved, are quite sufficient to make one community rich by comparison with another in which such savings cannot be effected. Virginia wastes more labour and more commodities that would have value in New England, than would pay five times over for all the cloth and iron she consumes. Again, the quantity of capital required for effecting exchanges tends to diminish as commerce comes nearer home. The ship that goes to China performs no more exchanges in a year than the canal-boat that trades from city to city performs in a month; and the little and inexpensive railroad car passing from village to village may perform almost twice as many as the fine packet-ship that has cost ninety or a hundred thousand dollars. With the extension of the home trade, labour and capital become, therefore, more productive of commodities required for the support and comfort of man, and the wages of the labourer and the profits of the capitalist tend to increase, and commerce tends still further to increase. On the other hand, with the diminution of the power to effect exchanges at home, labour and capital become less productive of commodities; the wages of the labourer and the profits of the capitalist tend to decrease, and trade tends still further to diminish. All this will be found fully exemplified among ourselves on a comparison of the years 1835-36 with 1841-42, while the contrary and upward tendency is exemplified by the years 1845-6 and 7, as compared with 1841-2.