To recur now to Bastiat’s illustration. It is evident that if there is any reason why William at the end of the year should return to James more than an equally good plane, it does not spring, as Bastiat has it, from the increased power which the tool gives to labor, for that, as I have shown, is not an element; but it springs from the element of time—the difference of a year between the lending and return of the plane. Now, if the view is confined to the illustration, there is nothing to suggest how this element should operate, for a plane at the end of the year has no greater value than a plane at the beginning. But if we substitute for the plane a calf, it is clearly to be seen that to put James in as good a position as if he had not lent, William at the end of the year must return, not a calf, but a cow. Or, if we suppose that the ten days’ labor had been devoted to planting corn, it is evident that James would not have been fully recompensed if at the end of the year he had received simply so much planted corn, for during the year the planted corn would have germinated and grown and multiplied; and so if the plane had been devoted to exchange, it might during the year have been turned over several times, each exchange yielding an increase to James. Now, therefore, as James’ labor might have been applied in any of those ways—or what amounts to the same thing, some of the labor devoted to making planes might have been thus transferred—he will not make a plane for William to use for the year unless he gets back more than a plane. And William can afford to give back more than a plane, because the same general average of the advantages of labor applied in different modes will enable him to obtain from his labor an advantage from the element of time. It is this general averaging, or as we may say, “pooling” of advantages, which necessarily takes place where the exigencies of society require the simultaneous carrying on of the different modes of production, which gives to the possession of wealth incapable in itself of increase an advantage similar to that which attaches to wealth used in such a way as to gain from the element of time. And, in the last analysis, the advantage which is given by the lapse of time springs from the generative force of nature and the varying powers of nature and of man.