In treating of the productions of the earth, in consequence of agriculture, I have all along distinguished them from those which spontaneously proceed from the force of nature: these are the immediate gift of God, those are the return of the labour of his creatures. Every one knows that the labour of mankind is not in proportion to their numbers, but to their industry. The produce therefore of agriculture must be estimated, not according to the quantity of fruits only, but also according to the labour employed to produce them. These things premised, the question here proposed to be examined arises, viz. Which species of agriculture is the most advantageous to a modern society, that which produces the greatest quantity of fruits _absolutely_ taken, or that which produces the greatest quantity _relatively_ taken, I mean to the labour employed? This question might easily be resolved, in general, by the application of principles already deduced; although it cannot admit of a direct answer, in the manner I have put it. One, therefore, may say indeterminately, that species is the best which produces a surplus the best proportioned to the industry, and to the demands of all the free hands of the state. But as this solution would not lead me to the object I have in view, I have thrown in an alternative in order to gain attention to the principles which I am going to examine, and which influence and determine the establishment of the one or the other species of agriculture. The principal difficulty I find in the examination of this question, is to distinguish the effects of agriculture from those of the spontaneous production of the earth. The returns from pasture, for example, relatively taken, are, as we have observed, both from reason and from experience, far greater than those of corn fields, (vid. supra, chap. 8.) though I little doubt but that, absolutely taken, the case is quite otherwise; that is to say, that an acre of the finest corn land will produce more nourishment for man, than an equal portion of the finest pasture: but here we are following the proportion of space and produce, not of labour; for if the produce of both acres be considered relatively to the _labour_ necessary for the cultivation, as well as to the extent; the produce of pasture will be found far greater: this however I ascribe to the spontaneous operation of nature, and not to the superior utility of this kind of agriculture. Since therefore it is impossible, rightly to separate the effects of nature from those of art and industry, in this species of improvement, let us confine our speculations to those only which have for their object the turning up the surface, and the sowing or cultivating annual vegetables. For the better conveying our ideas, let us take an example, and reason from a supposition.