To sum up the whole of this first branch of the argument,—“taking into consideration the actual rate of increase which appears from the best documents to have taken place over a very large extent of country in the United States of America, very variously circumstanced as to healthiness and rapidity of progress,—considering further the rate of increase which has taken place in New Spain and also in many countries of Europe, where the means of supporting a family, and other circumstances favourable to increase, bear no comparison with those of the United States,—and adverting particularly to the actual increase of population which has taken place in this country during the last twenty years[132] under the formidable obstacles which must press themselves upon the attention of the most careless observer, it must appear that the assumption of a rate of increase such as would double the population in twenty-five years, as representing the natural progress of population when not checked by the difficulty of procuring the means of subsistence or other peculiar causes of premature mortality, must be decidedly within the truth. It may be safely asserted, therefore, that population when unchecked increases in a geometrical ratio of such a nature as to double itself every twenty-five years.”[133] The problem is only half stated; it is still to be shown what is the rate of the increase of Food. The case does not admit the same kind of proof. We can suppose an unchecked increase of men going on without any change in human nature; we have only to suppose for the future the same encouragement to marriage and the same habits of life, together with the same law of mortality. But with the increase of food the causes do not remain the same. If good land could be got in abundance, the increase of food from it would be in a geometrical ratio far greater than that of the men; that of wheat, for example, would be sixfold, as we have seen. But good lands are comparatively few; they will in the nature of things soon be occupied; and then the increase of the food will be a laborious process at a rate rather resembling a decreasing than an increasing geometrical ratio. “The yearly increment of food, at least, would have a constant tendency to diminish;” and the amount of the increase in each successive ten years would probably be less and less. In practice, the inequalities of distribution may check the increase of food with precisely the same efficacy as an actual arrival at the physical limits to the getting of the food. “A man who is locked up in a room may fairly be said to be confined by the walls of it, though he may never touch them.”[134] But the main point is, that, inequalities or no inequalities, there is a tendency to diminished productiveness. Under either condition the quantity yielded this year will not be doubled or trebled for an indefinite period with the same ease as it was yielded this year. In a tolerably well-peopled country such as England or