great rapidity and great certainty in bringing commodities to market. A deal table may be made in a few hours, a piece of cloth in a few weeks, and a moderate-sized house in a month or little more. Tables, cloth, and houses may be produced with certainty in any quantity required. It results from this that it is scarcely possible that, under ordinary circumstances, the selling price of a product of manufacture should for any long time much exceed its normal price. (2.) The nature of manufactures is, in general, such as to fit them admirably for distant transport. Any considerable elevation of price, therefore, is pretty certain to attract supplies from remote sources. (3.) Further, considered in their relation to human needs, I think it may be said of manufactured goods, that either the need for them is not very urgent, or, where it happens to be so, substitutes ... may easily be found. From all these circumstances it results that an advance in the price ... either attracts supplies, or deters purchasers, ... preventing any great departure from the usual terms of the market.
“Turning now to the products of agricultural, pastoral, or, more generally, ‘extractive’ industry, we find the circumstances under which this class of goods is brought to market in all respects extremely different from those which we have just examined, and such as to permit a much wider margin of deviation for the market from the normal price. Here the period of production is longer, the result of the process much more uncertain, the commodity at once more perishable and less portable, and human requirements in relation to it are mostly of a more urgent kind: (1.) The shortest period within which additions can be made to the supply of food and raw material of the vegetable kind is in general a year,