Francis A. Walker; Henry George 44i scientific basis. He became the first president of the American Economic Association. His chief works, each marked by vigour and independence of thought, are The Wages Question (1876), Money (1878), Land and its Rent (1881), Political Econ- omy (1883), International Bimetallism (1896), and Discussions in Economics and Statistics (1899). Walker helped to give the coup de grdce to the wages fund doctrine, and his theory of distribution has come to be known as the residual theory. Not only did he exert a great influence on economic thought but his contributions to statistics as Superintendent of the Ninth and Tenth Census were scarcely less pronounced. Another important milestone in the progress of economic science is marked by Henry George (1839-97). George, living in California at a time when everything seemed to point to the rapid growth of bonanza farms, came to the conclusion that the solution of the modern social problem lay in the nationalization of land, through the medium of the single tax. Beginning with Our Land and Land Policy (1871), he elaborated his general theory in Progress and Poverty (1879), which ran through count- less editions. The same ideas with further applications were repeated in Social Problems (1884), Protection or Free Trade (1891), A Perplexed Philosopher (1892), and The Science of Political Economy (1898). In all other respects an extreme individualist, Henry George carried to its logical extreme John Stuart Mill's theory of the unearned increment. One-sided as his doctrine has come to be considered, he contributed two important points to the progress of economic thought in the United States. The one was his theory of privilege— even though he was extreme in limiting this to land ; the other was the theory that wages are fixed by the product of rentless land, which started the thinking of Professor Clark. The real beginning of the modern science of economics is to be found in that group of younger men, all of them, with one exception, still living, who founded at Saratoga in i883^ ^the American Economic Association. This has now become one of the most influential scientific organizations in the country. The underlying principles of this group of younger thinkers, almost all of whom had studied in Germany, appeared in 1886 in a volume entitled Science oj Economic Discussion. The most eminent of the group is John Bates Clark (1847- ), whose
