American expansion westward, as elsewhere suggested, was favored more by the Ohio River than by any and all others: it ran the right way. Throughout the earlier decades of the pioneer era the greater portion of traffic was down stream. Even in the later days of steamboating the downstream traffic was ever heaviest. In 1835 the total tonnage received and entered at the port of Pittsburg was 63,221 tons; of this, 41,533 tons was export. In 1837 the total number of boats arriving at Pittsburg from February 10 to July 1 was five hundred and ninety-three; the total number departing was five hundred and eighty-two.[48] If the upstream trade did not equal the downstream trade in the days of steamboats, it can be readily imagined how great was the difference in the days of rowed and pushed craft. Upstream traffic began to thrive with the founding of Pittsburg and other cities in the upper Ohio Valley. A market was then created, and the product of the lower valley began to ascend. Thus dawned the era of the famous keel-boat, the first craft of burden that plied to and fro on western waters. True, the name was applied to craft that came earlier. Colonel Burd, the English officer who led one of the marauding expeditions from Detroit into Kentucky in the Revolutionary War, came from the lakes and ascended the Licking in keel-boats. It is given on good authority that Tarascon, Berthoud and Company of Pittsburg introduced the use of keel-boats on the Ohio in 1792.[49] The keel-boat heralded a new era in internal development, an era of internal communication never known before in the Central West. As a craft it is almost forgotten today. Our oldest citizens can barely remember the last years of its reign; but the cry of the steersman to "lift" and "set" that once rang in our river valleys, is still one of the undying memories of their childhood days. It was a long, narrow craft perhaps averaging twelve to fifteen feet by fifty, and pointed at both prow and stern. On either side were provided what were known as "running boards," extending from end to end. The space between, the body of the boat, was enclosed and roofed over with boards or shingles. A keel-boat would carry from twenty to forty tons of freight well protected from the weather; it required from six to ten men, in addition to the captain, who was usually the steersman, to propel it upstream. Each man was provided with a pole to which was affixed a heavy socket, The crew, being divided equally on each side of the boat, "set" their poles at the head of the boat; then bringing the end of the pole to the shoulder, with bodies bent, they walked slowly along the running boards to the stern--returning quickly, at the command of the captain, to the head for a new "set." "In ascending rapids, the greatest effort of the whole crew was required, so that only one at a time could 'shift' his pole. This ascending of rapids was attended with great danger, especially if the channel was rocky.