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260, turning, carries the engines about with it. It is an ingenious and curious device.

49. "To Oliver Evans," says Dr. Ernest Alban, the learned German engineer, "was it reserved to show the true value of a long-known principle, and to establish thereon a new and more simple method of applying the power of steam—a method that will remain an eternal memorial to its introducers." Dr. Alban here refers to the earliest successful introduction of the non-condensing high-pressure steam-engine.

Oliver Evans, one of the most ingenious mechanics that America has ever produced, was born at Newport, Delaware, in 1755 or 1756, the son of people in very humble circumstances.

He was, in his youth, apprenticed to a wheelwright, and soon exhibited great mechanical talent and a strong desire to acquire knowledge.

His attention was at an early period drawn to this possible application of the power of steam to useful purposes by a boyish prank. Placing a small quantity of water in a gun-barrel, and ramming down a tight wad, he put the barrel in the fire of a blacksmith's forge. The loud report which accompanied the expulsion of the wad was an evidence to young Evans of the great, and, as he supposed, previously undiscovered power of steam.

Subsequently, meeting with a description of a Newcomen engine, he at once noticed that the elastic force of confined steam was not there utilized.



He then designed the non-condensing engine, in which the power was derived exclusively from the tension of high-pressure steam, and proposed its application to the propulsion of carriages.

50. About the year 1780 Evans joined his brothers, who were millers by occupation, and at once employed his inventive talent in