[Illustration: Richard Trevithick.] [Illustration: FIG. 50.--Trevithick's Locomotive, 1804.] RICHARD TREVITHICK was the first engineer to apply steam-power to the haulage of loads on the railroad. Trevithick was a Cornishman by birth, a native of Redruth. He was naturally a skillful mechanic, and was placed by his father with Watt's assistant, Murdoch, who was superintending the erection of pumping-engines in Cornwall; and from that ingenious and accomplished engineer young Trevithick probably acquired both the skill and the knowledge which, with his native talent, enterprise, and industry, enabled him to accomplish the work which has made him famous. He was soon intrusted with the erection and management of large pumping-engines, and subsequently went into the business of constructing steam-engines with another engineer, Edward Bull, who took an active part, with the Hornblowers and others, in opposing the Boulton & Watt patents. The termination of the suits which established the validity of Watt's patent put an end to their business, and Trevithick looked about for other work, and, not long after, entered into partnership with a relative, Andrew Vivian, who was also a skillful mechanic; they together designed and patented the steam-carriage already referred to. Its success was sufficiently satisfactory to awaken strong confidence of a perfect success on the now common tram-roads; and Trevithick, in February, 1804, had completed a "locomotive" engine to work on the Welsh Pen-y-darran road. This engine (Fig. 50) had a cylindrical flue-boiler, _A_, like that designed by Oliver Evans, and a single steam-cylinder, _B_, set vertically into the steam-space of the boiler, and driving the outside cranks, _L_, on the rear axle of the engine by very long connecting-rods, _D_, attached to its cross-head at _E_. The guide-bars, _I_, were stayed by braces leading to the opposite end of the boiler. No attempt was made to condense the exhaust-steam, which was discharged into the smoke-pipe. The pressure of steam adopted was 40 pounds per square inch; but Trevithick had already made a number of non-condensing engines on which he carried from 50 to 145 pounds pressure.