of its power. The solution lay in joining the cities to each other and to the Atlantic world markets by iron rails running east and west. This railroad expansion is what makes the last decade before the Civil War such a remarkable series of years in the West. In the half decade, 1850-55, the Baltimore and Ohio and Pennsylvania railways reached the Ohio River; the links of the present Lake Shore system between Buffalo and Chicago by way of Cleveland and Toledo were constructed; and the Pennsylvania line was put through from Pittsburgh to Chicago. The place of the lake country on the continental alignment and the imperial situation of Chicago, and later of Omaha, came to be realized. The new view transformed men's conceptions of every port on the Great Lakes in the chain from Buffalo to Chicago. At a dozen southern ports on Ontario, Erie, Huron, and Michigan, commerce now touched the swiftest and most economical means of transcontinental traffic. This development culminated in the miracle we call Chicago. In 1847 not a line of rail entered the town; its population then numbered about twenty-five thousand and its property valuation approximated seven millions. Ten years later four thousand miles of railway connected with all four points of the compass a city of nearly one hundred thousand people, and property valuation had increased five hundred per cent. The growth of Buffalo, Cleveland, and Detroit during this period was also phenomenal. When the crisis of 1861 came, the service performed by the Walk-in-the-Water and her successors was seen in its true light. The Great Lakes as avenues of migration had played a providential part in filling a northern empire with a proud and loyal race; from farm and factory regiment on regiment marched forth to fight for unity; from fields without number produce to sustain a nation on trial poured forth in abundance; enormous quantities of iron were at hand for the casting of cannon and cannon balls; and, finally, pathways of water and steel were in readiness in the nick of time to carry these resources where they would count tremendously in the four long years of conflict. CHAPTER XI The Steamboat And The West Two great fields of service lay open before those who were to achieve by steam the mastery of the inland waterways. On the one hand the cotton kingdom of the South, now demanding great stores of manufactured goods, produce, and machinery, was waiting to be linked to the valleys and industrial cities of the Middle West; and, on the other hand, along those great eastward and westward rivers, the Ohio and Missouri, lay the commerce of the prairies and the Great Plains. But before the steamboat could serve the inland commerce of the West, it had to be constructed on new lines. The craft brought from the seaboard were of too deep draft to navigate shallow streams which ran through this more level country.