If in any country which actually produces nourishment for its inhabitants, according to the progression above-mentioned, (p. 27.) a plan is set on foot for the extension of agriculture; the augmentation must be made to bear a due proportion to the progress of industry and wants of the people, or else an outlet must be provided for disposing of the superfluity. And if, at setting out, a foreign consumption cannot be procured for the produce of husbandry, the greatest caution must be had to keep the improvement of the soil within proper bounds: for, without this, the plan intended for an improvement will, by over-doing, turn out to the detriment of agriculture. This will be the case, if the fruits of the earth be made to increase faster than the numbers and the industry of those who are to consume them. For if the whole be not consumed, the regorging plenty will discourage the industry of the farmer. But if, together with an encouragement to agriculture, a proper outlet be found for the superfluity, until the numbers and industry of the people, by increasing, shall augment the home-consumption, which again by degrees will diminish the quantity of exportation, then the spring will easily overcome the resistance; it will dilate; that is, numbers will continue to increase. From this may be derived another principle: _That agriculture, when encouraged for the sake of multiplying inhabitants, must keep pace with the progress of industry; or an out-let must be provided for all superfluity_. In the foregoing example, I have supposed no exportation, the more to simplify the supposition: I was, therefore, obliged to throw in a circumstance, in order to supply the want of it; to wit, an augmentation of inland demand from the suspension of hunting; and I have supposed those who formerly supported themselves by this, to consume the superfluous food of the farmers for the price of their labour. This may do well enough as a supposition, and has been made use of only to explain principles; but the manners of a people are not so easily changed; and therefore I have anticipated a little the supposition of trade, only to shew how it must concur with industry, in the advancement of agriculture and multiplication. Let me next consider the consequences of an augmentation of agriculture in a country where the inhabitants are lazy; or where they live in such simplicity of manners, as to have few wants which labour and industry can supply. In this case, I say, the scheme of agriculture will not succeed; and, if set on foot, part of the grounds will soon become uncultivated again.