18 CHASING A STEAM ENGINE. LOCOMOTIVES: THEIR PROGRESS. 1. THE application of steam to the purposes of locomotion had been suggested by many ingenious speculators; by Savery, Robison, and Watt, in England; by Oliver Evans, in the United States; by Cugnot, in France. But the first definite attempt to realise the idea was undoubtedly that of William Murdock, Watt's assistant, in 1784. His model was constructed on the high-pressure principle, and ran upon three wheels. The boiler was heated by a spirit lamp, and the dimensions of the whole may be inferred from the fact that it was not above thirteen or fourteen inches high. Yet it attained, or even excelled, the speed of an ordinary runner. One night, when the inventor was returning from his labours in the mine at Redruth, in Cornwall, he resolved to test the powers of his machine, and selected for the purpose a pathway leading to the church, about a mile distant from the town. It was narrow, and bordered by high hedges on either hand. Lighting the lamp, Murdock soon had the satisfaction of getting the boiler heated, but the moment a sufficient quantity of steam was generated, away sped the tiny locomotive, and away, at full speed, started the inventor after it! Soon his ears were assailed by cries of alarm, and when he overtook his runaway machine, he found they proceeded from the rector of the parish, who, meeting the hissing and flaming pigmy on his road, concluded it could be nothing else but a device of the Evil One! Though so far successful, Murdock, for unexplained reasons, made no further effort to develope his invention. 2. The idea, however, fell upon fruitful soil. A friend and pupil of Murdock's was careless Richard Trevithick, one of the captains' in a Cornish tin-mine, who, influenced probably by Murdock's experiments, resolved upon constructing a steam carriage for use upon ordinary roads. Obtaining pecuniary help from his cousin, Andrew Vivian, he took out a patent in the year 1802, and a locomotive A TERRIFIED TOLLMAN. 19 soon issued-a Minerva in full armour-from Trevithick's fertile brain. In appearance it resembled the ordinary four-wheeled stage-coach-the engine, which consisted of one cylinder, with a boiler and furnace-box, being placed in the rear of the hind axle. The movement of the piston was transmitted to a separate crank-axle, and the latter, by means of certain mechanical contrivances, also set in operation the axle of the driving-wheel, which, by the way, was mounted with a fly-wheel. The same crank-axle worked the steam-cocks and the force-pump, as well as the bellows which quickened the combustion of the fire. 3. This successful machine having exhausted the curiosity of half Cornwall, Trevithick and Vivian decided upon exhibiting it in London, that it might receive the stamp of metropolitan approval; they accordingly' steamed' as far as Plymouth, whence it was to be forwarded to London by sea. An amusing incident occurred on the road:-While rolling along in full force, to the terror of every gaping yokel they met with, Vivian caught sight of a tollgate ahead, and called out to Trevithick, who drove the engine, to slacken speed. Trevithick obeyed the injunction, but the machine had acquired so great an impetus from the rapid rate at which it had been proceeding, that it was with difficulty stopped just as the bar was reached. The tollman flung wide his gate with trembling obsequiousness. 'What have us got to pay here?' cried Vivian. 'Na, na, na,' stuttered the terrified tollman. What have us got to pay, I ask you?' again shouted Vivian. 'Nonoth-nothing to pay! My de-dear Mr. Devil, do drive on as fast as you can! There's no-nothing to pay !' 4. Some experiments on the Wandsworth and Croydon tramway, where horses were employed to drag to and fro the coal-wains, suggested to Trevithick's active imagination the possibility of adapting his steam engine to the iron road, and thus was shadowed forth the future railway locomotive, which was to accomplish so much for the diffusion of intelligence and the annihilation of local prejudices. His tramway engine was completed in 1804, and its merits first tested upon the Merthyr Tydvil Railway, in 20 AN IMAGINARY DIFFICULTY. South Wales. The trial was, to a certain extent, a success. The engine dragged after it, at the rate of five miles an hour, several wagons loaded with ten tons of bar iron; but it was found unfitted for regular working. In like manner had Watt's first steam engine failed. But Trevithick lacked Watt's stability of resolve and steadiness of purpose. Instead of concentrating all his powers upon the successful development of his invention, he abandoned it for fresh fields and pastures new,' and lost the opportunity of securing a renown only second to that of Watt's. The Cornish miner was a man of remarkable ability, but he wanted in perseverance. He flew from scheme to scheme with childish eagerness, and consequently met with failure upon failure. Then he lost heart, and vented his disappointment in jeremiads against fortune. The world always went wrong with him,' he said. Alas! this is the continual complaint of the man who is always going wrong with himself, and frets through a profitless life without - a Steady Aim! 5. An imaginary difficulty at first beset the minds of the ingenious men who laboured upon the locomotive. They fancied that the smooth wheels of the engine (if any considerable burden rolled behind) would not bite or grip the equally smooth rails of the tramroad, but would fly round and round without making any real progress. To obviate this supposed result, Mr. Blenkinsop, of Leeds, in 1811, obtained a patent for a racked or tooth-rail to be laid along one side of the tramroad, into which the enginewheels worked as pinions fit into a rack. This cumbrous contrivance restricted the speed of the engine to about 34 miles per hour. 6. William Hedley, a 'viewer' in Mr. Blackett's colliery, near Wylam, constructed, about 1813, a locomotive engine upon improved principles, and 'Puffing Billy,' as it was called, continued in use for several years. It is now preserved in the Patent Museum at South Kensington, and is well worth the examination of the scientific enquirer. But, without seeking to detract from the merits of Hedley or his predecessors, it must fairly be owned that the real father of |