As the petroleum is ordinarily mixed with more or less water when brought to the surface, it is thrown first into a tank, and the superior gravity of the water causing it to sink to the bottom, it is drawn off from beneath, and the petroleum placed in barrels. These tanks are of all sizes, ranking from thirty to two thousand barrels each.
For the present, wells that were formerly pumped at a profit are biding their time; for at present prices of oil operations upon them would be ruinous. This renders the computation of the weekly yield of the Oil Creek region comparatively easy. There are at the present time not far from one hundred flowing wells along the valley of the creek, producing probably on an average about forty thousand barrels per week. A portion of this is refined in the county, but by far the largest part is shipped to a distance, either by the Alleghany River by way of Pittsburg, or by the Philadelphia and Erie or Atlantic and Great Western Railroads to the Eastern markets.
The necessities of the trade have given rise to many ingenious inventions in getting the oil to market. The wells extend along Oil Creek for a distance of about fourteen miles from its mouth. The ground is not favorable for land carriage, as the valley is narrow and the stream tortuous. The creek itself is too small for navigation under ordinary circumstances, and a railroad with steam power would be in the highest degree dangerous. To compensate for all these difficulties, a system of artificial navigation has been adopted. Throughout the whole distance, at intervals of perhaps a mile, dams have been constructed across the creek, with draws in the centre, that can be easily opened at the proper time. In this way 'pond freshets' are arranged one or two days in a week. By the appointed time, all persons having oil to run out of the creek have their boats ready, and as the water from the upper dam raises the creek below, the fleet of boats sets out. Each successive dam raises the water to a higher level, and as the fleet proceeds, small at first, it increases until, as it approaches the river, it often numbers two hundred boats, bearing with them not less than ten thousand barrels of petroleum.