[A] Franz Oppenheimer, _Theorie der Reinen und Politischen Œkonomie_. Berlin, 1912.--_Translator._
We can determine with approximate accuracy the amount of land of average fertility in the temperate zone, and also what amount is sufficient to enable a family of peasants to exist comfortably, or how much such a family can work with its own forces, without engaging outside help or permanent farm servants. At the time of the migration of the barbarians (350 to 750 A. D.), the lot of each able-bodied man was about thirty morgen (equal to twenty acres) on average lands, on very good ground only ten to fifteen morgen (equal to seven or ten acres), four morgen being equal to one hectare. Of this land, at least a third, and sometimes a half, was left uncultivated each year. The remainder of the fifteen to twenty morgen sufficed to feed and fatten into giants the immense families of these child-producing Germans, and this in spite of the primitive technique, whereby at least half the productive capacity of a day was lost. Let us assume that, in these modern times, thirty morgen (equal to twenty acres) for the average peasant suffices to support a family. We have then assumed a block of land sufficiently large to meet any objection. Modern Germany, populated as it is, contains an agricultural area of thirty-four million hectares (equal to eighty-four million, fifteen thousand, four hundred and eighty acres). The agricultural population, including farm laborers and their families, amounts to seventeen million; so that, assuming five persons to a family and an equal division of the farm lands, each family would have ten hectares (equal to twenty-five acres). In other words, not even in the Germany of our own day would the point have been reached where, according to the theories of the adherents of natural law, differentiation into classes would begin.
Apply the same process to countries less densely settled, such, for example, as the Danube States, Turkey, Hungary and Russia, and still more astounding results will appear. As a matter of fact, there are still on the earth’s surface, seventy-three billion, two hundred million hectares (equal to one hundred eighty billion, eight hundred eighty million and four hundred sixteen thousand acres); dividing into the first amount the number of human beings of all professions whatever, viz., one billion, eight hundred million, every family of five persons could possess about thirty morgen (equal to eighteen and a half acres), _and still leave about two-thirds of the planet unoccupied_.