No less important is the price of wheat, or rather of the principal article of food of the people, for the time being, with which the price of inland raw material—in so far as it can be produced from the same soil alternately with wheat—and, in the long run, also the wages of labor, are so essentially connected.(783) The same indispensable necessity of wheat which causes its price to fluctuate so largely from year to year, and from month to month, promotes the uniformity of its average price,(784) when many years are taken into the account.(785)(786) (_Malthus._) If, by reason of great progress made in the art of agriculture, the cost of the production of wheat should fall to one-half of what it was, a large increase of population would certainly not be delayed long. And so, on the other hand, there would be a decrease of population if, by the destruction of artificial means of irrigation, or other steps in the direction of a retrogressive civilization, the cost of the production of wheat were to be permanently increased. But even the average price of wheat, during a long series of years, is not entirely invariable. The increasing consumption compels the nation, as a whole, to provide for its requirement of wheat from less fertile sources, which increases its price generally. It is true that the progress of the science of agriculture and of the corn-trade counteract this tendency, retard the advance of the price of wheat, and may, for a time, produce an opposite tendency. It is true, also, that the people are induced by their most general and vital interests to take advantage of this possibility. But spite of the frequency of exceptions to it, the rule remains.(787) If, therefore, we wished to so fix a perpetual annuity that it should always be worth as much money as a certain quantity of wheat had cost, on an average, during the three preceding decades, the thing-value of this annuity would, on the whole, rise with an advance in civilization.(788) To obtain something that would remain the same, it would be necessary to combine wheat with at least one chief commodity, the intrinsic basis of the price of which had a development independent of the price of grain; but the whole to be made payable in money. The precious metals are, in many respects, so diametrically opposed in properties to wheat, in their dispensableness, transportable character and durability, for instance, that these two classes of commodities are best adapted to act as counter-balances to each other.(789) Section CXXX. History Of The Prices Of The Chief Wants Of Life.