GEORGE STEPHENSON 287 than it was to lift the coal out. The steam-engine was then in a very incomplete condition, and both pumping- and lifting-engines were crude and clumsy affairs. To be sure Watt, the mathematical instrument-maker, had invented the double- acting steam-engine, but few had been manufactured, and those in common use were "atmospheric" engines, known as "Newcomen's" engines. A pumping- engine had a long, vertical cylinder, with arrangements for admitting steam at the top. The weight of the piston, piston-rod, and pump-rod, which ran down a shaft to the lowest point in the mine, being balanced by a counter-weight on a sort of weU-svveep, the steam, admitted by hand, forced the piston to the bottom of the cylinder. The steam was then shut off, and a spray of water was turned on within the cylinder. This water condensed the steam and reduced the press- ure within to almost nothing, so that the air pressure on the exterior face of the piston (which amounted to over a ton for every square foot of surface) drove the piston to the top of the cylinder, and lifted the full length of the stroke a large quantity of water. It is evident that the office of engineer was not an easy one. It was all he could do to take care of the steam end of the pump ; another man was needed to look after the lower end, where the pump-valve worked in another vertical cylinder. The water entered this cylinder through holes in the sides, some higher, some lower, according to the stage of water in the mine. The pumps did not run continuously, but they lowered the water to the bottom as often as it was necessary. As the level of the water in the mine fell, it was necessary to plug the upper holes in the pump cylinder ; the man who watched the lower end and plugged those holes was known as the " plugman." It is difficult to con- ceive of a less inspiring occupation than that to which George Stephenson was promoted at the age of seventeen. Alone in the dark, chilled by the damp air, and wet by the black water, he was forced, by lack of other occupation, to note every mechanical detail of the machinery, and to study methods of improv- ing it. At the age of eighteen he heard of some wonderful engines made by Watt & Boulton, at their new factory, and was told that the engines were fully described and illustrated in books. So he determined to learn to read. . He was encour- aged in this resolve by stories that a French soldier, by the name of Napoleon Bonaparte, was sweeping everything before him on the continent of Europe, and that he was planning the subjugation of Great Britain. Information about Na- poleon could be gained from printed newspapers if one could only read. But where should he learn ? There was no public school in Wylam ; none of our hero's companions went to school ; none of the people he associated with could read or write. However, he found a teacher in a young man by the name of Robert Cowens, of whom he took three lessons per week in the evening. He earned money for books and instruction by mending shoes and repairing clocks. He was handy with tools, and quick at seeing the relations of things. As soon as he could read and write he learned to cipher, taking a slateful of " sums," set by his teacher, to his work in the morning, to be " done " during
