It was inevitable that such radical changes would modify the course of industrial progress. Because of the importance of slavery as the underlying cause of the war, there has been a natural tendency to regard its abolition as the most striking and significant net result of the great conflict, but it is to be doubted whether the emancipation of the negro had as great an effect on subsequent economic development as the other innovations, which were so obscured by the turmoil of the war that they received but little attention and were regarded as being of much less significance. The complete transformation in the tariff policy of the nation permitted the growth of manufacturing to an extent that would have been impossible had the war not occurred; the construction of the transcontinental railroads had an immeasurable effect on the development of the great region west of the Missouri river; the concentration of capital provided the means by which industrial enterprises could be carried out on a gigantic scale; the establishment of a uniform currency and a better banking system accelerated the growth of industry and trade. It is in these changes that one finds the key to much of the economic history of the United States since the Civil War. The period from 1860 to 1900 was one of development and exploitation. The years prior to the Civil War had been marked by the advance of the political dominion of the United States to the Pacific Ocean, and at the same time the nation had enjoyed an era of notable agricultural, industrial and commercial prosperity, especially in the states east of the Mississippi River. However, the tremendous possibilities of the country were only beginning to be realized in 1860, and remarkable as was development before that year, it was completely eclipsed by the amazing progress made during the latter part of the century. An abundance of unoccupied land, of rich and varied natural resources, favorable climatic conditions, a complete absence of checks on individual initiative and enterprise and of restrictions on internal communication and trade, and the encouragement afforded to industry by the liberal policies of the federal government all combined to create economic opportunities of boundless scope. Labor, capital and transportation facilities alone were needed and as these increased the wealth production of the United States multiplied with astonishing rapidity. The extension of the railway system permitted the constant growth of agriculture and rendered accessible the mineral and forest products in which the land abounded; cheap and plentiful raw materials from field, mine and forest, made possible a phenomenal increase of manufacturing. Multitudes of European immigrants, eager to share in the wealth of the new world, poured in and recruited the labor force necessary for the industrial conquest; and the invention and application of labor-saving machinery of every description increased