Taking again land No. 1, which yields corn at 10s. a bushel, let us imagine that there is an increased demand for wheat. Instead of breaking up land No. 2 an attempt might be made to increase the yield on No. 1, but nothing will be gained by it because the new bushel produced on No. 1 will cost 15s., which is just what it would cost if raised on second-class land. Furthermore, the price will now rise to 15s., and the two bushels will be disposed of for 30s., thus giving the proprietor a rent of 5s., because they have only cost 25s. to produce.[331] There is still another possibility, however. Resort might be had to emigration and colonists might be encouraged to cultivate the best soils of distant lands, soils equal in fertility to those in the first class. The products of such lands would be got in exchange for the manufactured goods of the home country, to which the law of diminishing returns does not apply. But some account of the cost of transport, which increases the cost of production, must be taken, and this leads to the same result, namely, a rent for those nearest the market, because of the advantages of a superior situation. Distance and sterility, as J. B. Say remarks, are the same thing. If land in America yields corn at 10s. a bushel and freightage equals 5s., it is clear that corn imported into England must sell for 15s.—exactly the same condition of things as if land of the second order had been cultivated, and English landlords of the first class will still draw a rent of 5s. This third possibility was scarcely mentioned by Ricardo, and he could hardly have foreseen the wonderful developments in transportation that took place during the next fifty years, which resulted in a reversal of the law of diminishing returns and the confuting of the prophets.[332] The great Ricardian theory, _prima facie_ self-evident, is in reality based upon a number of postulates to which we must pay more attention. Some of them must be regarded as economic axioms, but the validity of others is somewhat more doubtful. In the first place there is the assumption that the produce of lands unequally fertile and representing unequal amounts of labour will always sell at the same price, or, in other words, will always possess the same exchange value. Is this proposition demonstrably sound? It is true when the product in question—for example, corn—is of uniform quality and kind. When the goods offered on the same market are so much alike that it is a matter of indifference to the buyer whether he takes the one or the other, then it is true that he will not pay a higher price for the one than he will for the other. This is what Jevons called the “law of indifference.”[333] In the second place it is implied that this exchange value, uniform for all identical products, is determined by the maximum amount of labour required for its production, or, in other words, by the amount of labour necessary for the production of the more costly portion.