This essential difference which the Physiocrats sought to establish between agricultural and industrial production was at bottom theological. The fruits of the earth are given by God, while the products of the arts are wrought by man, who is powerless to create.[36] The reply is obvious. God would still be creator if He decreed to give us our clothes instead of our daily bread. And, although man cannot create matter, but simply transform it, it is important to remember that the cultivation of the soil, like the fashioning of iron or wood, is merely a process of transformation. They failed to grasp the truth which Lavoisier was to demonstrate so clearly, namely, that in nature nothing is ever created and nothing lost. A grain of corn sown in a field obtains the materials for the ear from the soil and atmosphere, transmuting them to suit its own purpose, just as the baker, out of that same corn, combined with water, salt, and yeast, will make bread. But they were sufficiently clear-sighted to see that all natural products, including even corn, were influenced by the varying condition of the markets, and that if prices fell very low the net product disappeared altogether. In view of such facts can it still be said that the earth produces real value or that its produce differs in any essential respects from the products of industry? The Physiocrats possibly thought that the _bon prix_—_i.e._ the price which yielded a surplus over and above cost of production—was a normal effect of the “natural order.” Whenever the price fell to the level of the cost of production it was a sure sign that the “order” had been destroyed. Under these circumstances there was nothing remarkable in the disappearance of the net product. This is doubtless the significance of Quesnay’s enigmatic saying: “Abundance and cheapness are not wealth, scarcity and dearness are misery, abundance and dearness are opulence.”[37] But if the _bon prix_ simply measures the difference between the value of the product and its cost of production, then it is not more common in agriculture than in other modes of production. Nor does it extend over a longer period in the one case than in the other, provided competition be operative in both cases; on the contrary, it will become manifest in the one case as easily as in the other, especially if there be any scarcity. It remains to be seen then whether monopoly values are more prevalent in agricultural production than in industrial. In a very general way, seeing that there is only a limited quantity of land, we may answer in the affirmative, and admit a certain degree of validity in the Physiocratic theory. But the establishment of protective rights and the occurrence of agricultural crises clearly prove that competition also has some influence upon the amount of that revenue.