“With few exceptions, the works produced in the United States have been prepared as text-books(89) by authors engaged in college instruction, and therefore chiefly interested in bringing principles previously worked out by others within the easy comprehension of undergraduate students.”(90) Of these exceptions, Alexander H. Everett’s “New Ideas on Population”(91) (1822), forms a valuable part in the discussion which followed the appearance of Malthus’s “Essay.” The writer, however, who has drawn most attention, at home and abroad, for a vigorous attack on the doctrines of Ricardo is Henry Charles Carey.(92) Beginning with “The Rate of Wages” (1835), he developed a new theory of value (see “Principles of Political Economy,” 1837-1840), “which he defined as a measure of the resistance to be overcome in obtaining things required for use, or the measure of the power of nature over man. In simpler terms, value is measured by the cost of reproduction. The value of every article thus declines as the arts advance, while the general command of commodities constantly increases. This causes a constant fall in the value of accumulated capital as compared with the results of present labor, from which is inferred a tendency toward harmony rather than divergence of interests between capitalist and laborer.” This theory of value(93) he applied to land, and even to man, in his desire to give it universality. He next claimed to have discovered a law of increasing production from land in his “Past, Present, and Future” (1848), which was diametrically opposed to Ricardo’s law of diminishing returns. His proof was an historical one, that in fact the poorer, not the richer lands, were first taken into cultivation. This, however, did not explain the fact that different grades of land are simultaneously under cultivation, on which Ricardo’s doctrine of rent is based. The constantly increasing production of land naturally led Carey to believe in the indefinite increase of population. He, however, was logically brought to accept the supposed law of an ultimate limit to numbers suggested by Herbert Spencer, based on a diminution of human fertility. He tried to identify physical and social laws, and fused his political economy in a system of “Social Science” (1853), and his “Unity of Law” (1872). From about 1845 he became a protectionist, and his writings were vigorously controversial. In his doctrines on money he is distinctly a mercantilist;(94) but, by his earnest attacks on all that has been gained in the science up to his day, he has done a great service in stimulating inquiry and causing a better statement of results. While undoubtedly the best known of American writers, yet, because of a prolix style and an illogical habit of mind, he has had no extended influence on his countrymen.(95)