Fig. 46.—Evans’s Non-condensing Engine, 1800.
This engine, which he called the “Columbian Engine,” was of a peculiar form, as seen in [Fig. 46]. The beam is supported at one end by a rocking column; at the other, it is attached directly to the piston-rod, while the crank lies beneath the beam, the connecting-rod, 1, being attached to the latter at the extreme end. The head of the piston-rod is compelled to rise and fall in a vertical line by the “Evans’s parallelogram”—a kind of parallel-motion very similar to one of those designed by Watt. In the sketch ([Fig. 46]), 2 is the crank, 3 the valve-motion, 4 the steam-pipe from the boiler, E, 5 6 7 the feed-pipe leading from the pump, F. A is the boiler. The flame from the fire on the grate, H, passes under the boiler between brick walls, and back through a central flue to the chimney, I.
Subsequently, Evans continued to extend the applications of his engine and to perfect its details; and, others following in his track, the non-condensing engine is to-day fulfilling the predictions which he made 70 years ago, when he said:
“I have no doubt that my engines will propel boats against the current of the Mississippi, and wagons on turnpike roads, with great profit....”
“The time will come when people will travel in stages moved by steam-engines from one city to another, almost as fast as birds can fly, 15 or 20 miles an hour.... A carriage will start from Washington in the morning, the passengers will breakfast at Baltimore, dine at Philadelphia, and sup in New York the same day....
“Engines will drive boats 10 or 12 miles an hour, and there will be hundreds of steamers running on the Mississippi, as predicted years ago.”[45]
