From this time, the number of pipe-lines have multiplied, until to-day there are thousands of them scattered throughout every oil-producing field of America. The first long main transportation line for oil was laid in 1880 from Butler County to Cleveland, a distance of over 100 miles, and immediately after its completion, trunk lines were commenced from the Bradford oil region to the Atlantic seaboard. The popularity of this new method of oil transportation may be judged from the fact that within three years from the completion of these first propositions, the National Transit Company possessed over 3,000 miles of oil pipe-lines, and had iron tank storage for 35,000,000 barrels of crude oil. Then a few master minds came to the front, and loyally supported by Mr. John D. Rockefeller, of Standard Oil fame, they undertook the herculean task of practically girdling the States with a system of oil pipe-lines that has no parallel anywhere. They eliminated the jaded horses, oil-boats, wooden tankage, and slow freights, tedious methods, and questionable practices of handling petroleum, and substituted therefor the stem pump, the iron conduit, the steel tank storage, and systematic and businesslike methods which soon commanded the confidence and respect of all oil-producers. They extended their pipe-lines to practically every producing well and established a transportation system which serves the industry to-day as no other on earth is served. The advantages of the modern pipe-line to the oil-producer are obvious. A pipe-line connection to a producer’s tank ensures prompt service and a cash market for his product at all times. The small line connected with his tank conveys the crude oil therefrom, either by gravity or by means of a pump, into a receiving tank of the gathering or field lines of the pipe-line system, from which it is pumped into the main trunk pipe-lines to the refineries. [Illustration: OIL PIPE-LINE CONNECTIONS IN THE AMERICAN FIELDS] The system by which the producer can have payment for his oil at any time, for he is credited with its value when it once enters the pipe-line, is the perfection of simplicity, accuracy, and efficiency. The pipe-line of which the gathering or field lines are composed varies in diameter from 2 to 8 inches, the joints of which are screw threaded. The main trunk lines are from 6 to 10 inches in diameter, and pumping stations, supplied with powerful plant driven by steam or internal combustion engines of the Diesel type, are located at suitable points of the line. According to the nature of the crude oils to be passed through the pipe-line must the erection of pumping houses be governed: for instance, in handling the heavy Californian or Mexican crudes, the pumping stations have to be much nearer each other than when a lighter crude oil is transported. Some of the heavier oils have, in fact, to be heated before they enter the pipes at all.