These words came true in a miraculously short space of time. Previous to the adoption of the steamboat navigation, say in 1817, the whole commerce from New Orleans to the upper country was carried in about twenty barges, averaging one hundred tons each, and making but one trip a year. The number of keel-boats employed on the Upper Ohio could not have exceeded one hundred and fifty, carrying thirty tons each, and making one trip from Pittsburg to Louisville and back in two months, or about three voyages in the season. The tonnage of all the boats ascending the Ohio and Lower Mississippi was then about sixty-five hundred. In 1811 the first steamboat was constructed at Brownsville, Pennsylvania, on the Monongahela. Several others were built soon after, but it was probably fifteen years before steamboats came into such general use as to cause any diminution in the flat-and keel-boat navigation. These first boats were built after models of ships, with deep holds. They also were constructed with low pressure engines and heavy machinery. Hence they were useless in low water, very hard to propel against the current, and their carrying capacity was greatly reduced. In order to attain greater speed, the builders soon made the boats long and narrow but it was not until they came to the decision that boats would run faster on the water than in it, and began making them flat and broad, that they finally got a boat capable of carrying a thousand tons, when drawing only four feet, and when empty only two and one-half feet. Then with a high pressure engine at each wheel they could make unprecedented speed; and these boats afforded traveling and freight accommodations equal to any. Although the prices of passages did not exceed hotel rates, yet more bountifully filled tables were not to be found on land and the boats were marvels of splendor in their appointments. The chief improvement made in the river steamboats was placing one large wheel at the stern of the boat entirely behind the hulk and with long paddles the full length of the beam, operated by double engines and quartering cranks. This had the advantage of allowing the wheel to fly in the eddy water of the boat, while it cleared the boat of the afterdraft. With these improvements rapid currents and shallow waters could be conquered.