The third edition of Malthus’ essay, which appeared in 1806, is now before us: and consists of two volumes of about one thousand pages in all, of large type, full of the most interesting accounts ever given of the manners and customs of the different nations of ancient and modern times. The first volume is divided into two books. In Book I. there are fourteen chapters, the first of which states the Law of Population, or the _tendency_ which population has to increase more rapidly than the means of subsistence. The second chapter treats of the general checks to population, and the way in which these operate. Then come three most interesting chapters on the checks to population among savage nations, followed by one on those obtaining among the ancient inhabitants of Northern Europe. Chapter seven gives an account of the checks existing among modern pastoral nations; and this is followed by an account of the checks in Africa, and Northern and Southern Siberia. Then follows a most interesting account of the brutal checks to population in Turkey, and the lamentable starvation checks of Hindostan and China. Book I. ends with chapters on the checks to population among the ancient Greeks and Romans. In Book II. there is a most important account given by Mr. Malthus of the results of his extensive travels in Europe, in 1799 and after years, with details of the checks to population existing in Norway, Sweden, Russia, Germany, Switzerland, France, England, Scotland, and Ireland. If those persons who at present think that the Malthusian law of human increase has been found by subsequent investigation to be erroneous, could only be induced to read Mr. Malthus’ essay in the original, they would soon find that all these objections have been anticipated in that celebrated work, and perhaps acknowledge, with Mr. J. S. Mill and other economists, that the truth is “axiomatic,” or no longer requiring discussion. In the last pamphlet, indeed, which we have seen, dedicated to one of the most deservedly popular of modern British authors, Thomas Carlyle, the writer, like Mr. Carlyle himself, speaks as if the law of Malthus _had_ been refuted; but, as usual in such cases, it is clear that the writer has not the least idea of what the celebrated Essay on Population was written to prove. In his first chapter, Malthus observes that Euler, a great mathematician, had calculated that, on the supposition of such a moderate amount of mortality as one in 36 (which is considerably higher than our present mortality of one in 42 in England), and with the further supposition of the births being to the deaths as three to one (a ratio which seems nearly to hold good, at present, in New Zealand), the period of doubling a population would be only 12⅘ years; and Sir William Petty, in his work on _Political Arithmetic_, supposed a doubling to be possible in some ten years.