The corporation known as the Ohio Company, with a great purchase of land from Congress in 1787, by keen advertising, and the methods of the modern real-estate boomer, started the tide of emigration and the fleet of boats down the Ohio. The first craft sent out by this corporation was named, appropriately enough, the "Mayflower." She drifted from Pittsburg to a spot near the mouth of the Muskingum river. Soon the immigrants began to follow by scores, and then by thousands. Mr. McMaster has collected some contemporary evidence of their numbers. One man at Fort Pitt saw fifty flatboats set forth between the first of March and the middle of April, 1787. Between October, 1786, and May, 1787--the frozen season when boats were necessarily infrequent--the adjutant at Fort Harmer counted one hundred and seventy-seven flat-boats, and estimated they carried twenty-seven hundred settlers. A shabby and clumsy fleet it was, indeed, with only enough seamanship involved to push off a sand-bar, but it was a great factor in the upbuilding of the nation. And a curious fact is that the voyagers on one of these river craft hit upon the principle of the screw-propeller, and put it to effective use. The story is told in the diary of Manasseh Cutler, a member of the Ohio Company, who writes: "Assisted by a number of people, we went to work and constructed a machine in the form of a screw, with short blades, and placed it in the stern of the boat, which we turned with a crank. It succeeded to perfection, and I think it a very useful discovery." But the discovery was forgotten for nearly three-quarters of a century, until John Ericsson rediscovered and utilized it. Once across the divide, the early stream of immigration took its way down the Ohio River to the Mississippi. There it met the outposts of French power, for the French burst open that great river, following their missionaries, Marquette and Joliet, down from its headwaters in Wisconsin, or pressing up from their early settlements at New Orleans. Doubtless, if it had not been that the Mississippi afforded the most practicable, and the most useful highway from north to south, the young American people would have had a French State to the westward of them until they had gone much further on the path toward national manhood. But the navigation of the Mississippi and its tributaries was so rich a prize, that it stimulated alike considerations of individual self-interest and national ambition. From the day when the first flatboat made its way from the falls of the Ohio to New Orleans, it was the fixed determination of all people living by the great river, or using it as a highway for commerce, that from its headwaters to its mouth it should be a purely American stream. It was in this way that the Mississippi and its tributaries proved to be, as I have said, a great influence in developing the spirit of coherent nationality among the people of the young nation.