Page:Popular Science Monthly Volume 12.djvu/283

Rh Four engines competed, and the "Rocket," built by Stephenson, received the prize.

63. This engine (Fig. 33) weighed four and one-fourth tons, with its supply of water. Its boiler was of the fire-tubular form, a form

that had grown into shape in the hands of several inventors, and was three feet in diameter, six feet long, with twenty-five three inch tubes, extending from end to end of the boiler. The steam-blast was carefully adjusted by experiment, to give the best effect. Steam-pressure was carried at fifty pounds per square inch.

The average speed of the Rocket on its trial was fifteen miles per hour, and its maximum was nearly double that, twenty-nine miles an hour; and afterward, running alone, it reached a speed of thirty-five miles.

The shares of the company immediately rose ten per cent, in value. Thus the combination of the non-condensing engine with a steam-blast and the multitubular boiler, designed by the clear head and constructed under the watchful eye of an accomplished engineer and mechanic, made steam-locomotion so evident and decided a success that thenceforward its progress has been uninterrupted and wonderfully rapid.