The manner in which increasing population advances rent, as explained and illustrated in current treatises, is that the increased demand for subsistence forces production to inferior soil or to inferior productive points. Thus, if, with a given population, the margin of cultivation is at 30, all lands of productive power over 30 will pay rent. If the population be doubled, an additional supply is required, which cannot be obtained without an extension of cultivation that will cause lands to yield rent that before yielded none. If the extension be to 20, then all the land between 20 and 30 will yield rent and have a value, and all land over 30 will yield increased rent and have increased value. It is here that the Malthusian doctrine receives from the current elucidations of the theory of rent the support of which I spoke when enumerating the causes that have combined to give that doctrine an almost undisputed sway in current thought. According to the Malthusian theory, the pressure of population against subsistence becomes progressively harder as population increases, and although two hands come into the world with every new mouth, it becomes, to use the language of John Stuart Mill, harder and harder for the new hands to supply the new mouths. According to Ricardo’s theory of rent, rent arises from the difference in productiveness of the lands in use, and as explained by Ricardo and the economists who have followed him, the advance in rents which, experience shows, accompanies increasing population, is caused by the inability of procuring more food except at a greater cost, which thus forces the margin of population to lower and lower points of production, commensurately increasing rent. Thus the two theories, as I have before explained, are made to harmonize and blend, the law of rent becoming but a special application of the more general law propounded by Malthus, and the advance of rents with increasing population a demonstration of its resistless operation. I refer to this incidentally, because it now lies in our way to see the misapprehension which has enlisted the doctrine of rent in the support of a theory to which it in reality gives no countenance. The Malthusian theory has been already disposed of, and the cumulative disproof which will prevent the recurrence of a lingering doubt will be given when it is shown, further on, that the phenomena attributed to the pressure of population against subsistence would, under existing conditions, manifest themselves were population to remain stationary.