But though land is not the produce of industry, most of its valuable qualities are so. Labor is not only requisite for using, but almost equally so for fashioning, the instrument. Considerable labor is often required at the commencement, to clear the land for cultivation. In many cases, even when cleared, its productiveness is wholly the effect of labor and art. One of the barrenest soils in the world, composed of the material of the Goodwin Sands, the Pays de Waes in Flanders, has been so fertilized by industry as to have become one of the most productive in Europe. Cultivation also requires buildings and fences, which are wholly the produce of labor. The fruits of this industry can not be reaped in a short period. The labor and outlay are immediate, the benefit is spread over many years, perhaps over all future time. A holder will not incur this labor and outlay when strangers and not himself will be benefited by it. If he undertakes such improvements, he must have a sufficient period before him in which to profit by them; and he is in no way so sure of having always a sufficient period as when his tenure is perpetual. These are the reasons which form the justification, in an economical point of view, of property in land. It is seen that they are only valid in so far as the proprietor of land is its improver. Whenever, in any country, the proprietor, generally speaking, ceases to be the improver, political economy has nothing to say in defense of landed property, as there established.