separated by a space of 12 inches to permit the enclosed pipe to be screwed home. The sleeve is then pushed over the 12inch gap, and the whole space between the pipes is filled with lead poured in melted. The line is held in place on the bottom of the river by two sets of heavy chains parallel with the pipe and about twenty-five feet from it, one on each side. Every 300 feet a guide chain connects the pipe with these lateral chains, and beyond each one of these connections an anchor, weighing over a ton, keeps the whole in place. The line crossing the salt marshes approaching the river is laid in a rectangular wooden box, filled with hydraulic cement to withstand corrosion.

The pumping stations are located at central points in the valleys. These stations consist of permanent buildings, a boiler house and a pump house, which contain the necessary steam power, and a steam and oil pump combined in one. The pumps employed for this service are magnificent machines. Most of them have been built by the Worthington Company. Fig. 59 shows a pumping station of the "Transit Oil Company" with the Worthington system. The Worthington pumps have been described by the Engineering News and the Scientific American somewhat as follows:

"Each pump has four steam cylinders-two high and two low pressure-steam jacketed, each set working tandem, direct acting. Each pair of cylinders actuates two single-stroke rams of the exterior packed type. The engineer thus has the only possible source of plunger leakage always before him. The steam, going from the high to the low pressure cylinder, passes through a receiver, where it is heated. The valve boxes are subdivided into small chambers, with leather-lined metallic valves with low lift and large surfaces. The general dimensions

Average duty, 105,000,000 foot pounds per 100 pounds of coal.

Rated capacity, 1,500,000 gallons against a pressure equal to 2,000 feet head of water."

The disproportion of diameter between the steam pistons and pump plungers shows the nature of the service the pumps are designed to perform. To maintain an even pressure on the line, a pair of compensating cylinders and plungers at the outer end of the rams take the place of the usual air chamber or fly wheel. These are two vertical cylinders, each mounted on trunnions near its centre. "A heavy pressure is maintained by the accumulator and fluid on the rear of the plungers, tending to thrust them out. As the rams of the main pump move outward from the centre position the compensating cylinders swing on their trunnions and take increasingly oblique positions as the pump gets nearer the end of its stroke. The compensating rams are forced out during this period and re-enforce the action of the steam, whose pressure is getting lower owing to expansion. On the return stroke the compensating rams are pushed back against the accumulator pressure, their cylinders swinging back to the perpendicular position. In this period, therefore, the action of the steam at a high pressure in the steam cylinder is resisted by the rams. As the stroke returns from the center in the other direction the compensating rams act as in the other half stroke. By thus opposing the action of the unexpanded and resisting the action of the expanded steam, an almost even action is preserved at all periods of the stroke, and a nearly constant pressure is exerted on the liquid pumped." By this means the column of oil is kept continually in motion without any violent concussion on the line, as is generally the case with a direct-acting pump. During the last few years the National Transit Company have been building their own pumps, constructing for trunk line service enormous triple expansion crank and fly-wheel engines, which are superseding other makes of pumps on their lines. At each station there is generally one of these high-duty engines and a lowduty one for relief or emergency service. Most of the pumping is done by the machine just described, the other being employed when the main pump is being repaired or adjusted.

A station equipped with a high-service pump has also seven

or eight horizontal tubular boilers, 80 to 100 horse power each. Six of the boilers are fired at once. They are placed in a boiler-house 40 feet square, built of brick and covered with a corrugated iron roof. The pumps are in a separate brick building, being separated for greater safety from fire. The stations are lighted by electricity, as the pump never stops moving the oil forward every day and night in the year. The stations are connected with one another and with the main offices of the pipe lines by independent telegraph wires. When a producer's tank is measured and accepted by a gauger and the oil passed into the pipe line, a report is telegraphed to the central station of that section of the field. A complete record of the capacity of each tank in the field is here kept, by which the feet and inches of the oil indicated by the despatch are at once converted into barrels and placed to the credit of the producer on the books of the pipe line. By this means, at the end of each day, an accurate return can be made of the oil received; which, checked by an equally accurate report of the oil delivered, enables the pipe line to know their stocks at all times.

At each station there are two or more receiving or storage tanks built of light boiler iron; the usual size being about 90 feet in diameter, and 30 feet high. These tanks have conical roofs of wood covered with No. 20 iron. Each tank holds about 30,000 barrels of oil. A general idea of the plan of construction of storage tanks can be learned from the following specifications under which the tanks of many of the pipe lines are built: