The pumping stations are substantial structures of brick, roofed with iron. The boiler house is removed some distance from the engine house for greater safety from fire; the building, about 40 by 50 feet, contains from six to seven tubular boilers, each 5 by 14 feet, and containing 80 three-inch tubes. The pump house is a similar brick structure about 40 by 60 feet, and contains the battery of pumping engines to be described later. At each station are two iron tanks, 90 feet in diameter and 30 feet high; into these tanks the oil is delivered from the preceding station, and from them the oil is pumped into the tanks at the next station beyond. The pipe-system at each station is simple, and by means of the "loop-lines" before mentioned the oil can be pumped directly around any station if occasion would require it. The pumps used on all these lines are the Worthington compound, condensing, pressure pumping engines. The general characteristics of these pumps are, independent plungers with exterior packing, valve-boxes subdivided into separate small chambers capable of resisting very heavy strains, and leather-faced metallic valves with low lift and large surfaces. These engines vary in power from 200 to 800 horse-power, according to duty required. They are in continuous use, day and night, and are required to deliver about 15,000 barrels of crude oil per 24 hours, under a pressure equivalent to an elevation of 3,500 feet. We have lately examined the latest pumping engine plant, and the largest yet built for this service, by the firm of H.R. Worthington; it is to be used at the Osborne Hollow Pumping Station. As patents are yet pending on certain new features in this engine, we must defer a full description of it for a later issue of our journal. The Pennsylvania line has a single 6-inch pipe 280 miles long, with six pumping stations as shown in the map, and groups of shorter lines, with a loop extending from the main line to Milton, Pa., a shipping point for loading on cars. At Millway, Pa., a 5-inch pipe leaves the Pennsylvania line and runs to Baltimore, a distance of 70 miles, and is operated from the first named station alone, there being no intermediate pumping station.[1] The Cleveland pipe, 100 miles long, is 5 inches in diameter, and has upon it four pumping stations; it carries oil to the very extensive refineries of the company at the terminal on Lake Erie. The Buffalo line is 4 inches in diameter and 70 miles long; it has a pumping station at Four-Mile and at Ashford (omitted on the map). The Pittsburg line is 4 inches in diameter and 60 miles long; it has pumping stations at Carbon Center and at Freeport. [Footnote 1: Millway is about 400 feet above tide-water at Baltimore, but the line passes over a very undulating country in its passage to the last named point. We regret that we have no profile on this 70 mile line operated by a single pumping plant.--_Ed. Engineering News_.]