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at right angles; but it will be obvious that this arrangement was not calculated to produce any result in the way of a steam-blast in the chimney. In fact, the waste steam seems to have been turned into the chimney in order to get rid of the nuisance caused by throwing the jet directly into the air. Trevithick was here hovering on the verge of a great discovery; but that he was not aware of the action of the blast in contributing to increase the draught, and thus quicken combustion, is clear, from the fact that he employed bellows for this special purpose; and at a much later date in (1815) he took out a patent which included a method of urging the fire by means of fanners. Although the locomotive tried upon the Merthyr Tydvil Railway succeeded in drawing a considerable weight, and travelled at a fair speed, it nevertheless proved, like the first steam-carriage, a practical failure. It was never employed to do regular work, but was abandoned after a few experiments. Its jolting motion champed up the cast-iron road, which was little calculated to bear so heavy a weight, — though it was very light as compared with modern engines, -and it was consequently dismounted from its wheels, and the engine was subsequently fixed and used to pump one of the largest pumps on the mine, for which work it was found well adapted. Trevithick was satisfied with merely making a few experiments with his steam-carriage and engine; and being a volatile genius, fond of new projects, he seems to have thought no more of the locomotive, but left it to take care of itself. Yet his machine, although unfitted for actual work, was a highly meritorious production, and its invention may be said to constitute an important link in the history of the mechanism of the steam-engine. Trevithick having abandoned the locomotive for more promising schemes, no further progress was made with it for

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some years. An imaginary difficulty seems to have tended, amongst other obstacles, to prevent its adoption and improvement. This was the supposition that, if any heavy weight were placed behind the engine, the “grip " or “bite ” of the smooth wheels of the locomotive upon the equally smooth iron rail, must necessarily be so slight that the wheels would slip round upon the rail, and, consequently, that the machine would not make any progress. Hence Trevithick, in his patent, recommended that the periphery of the driving-wheels should be made rough by the projection of bolts or crossgrooves, so that the adhesion of the wheels to the road might be secured. This plan was adopted in Trevithick's engine tried on the Merthyr Tydvil Railway, and its progress must therefore necessarily have been a succession of jolts, very trying to the cast-iron plates of the colliery tram-road. Following up the presumed necessity for a more effectual adhesion between the wheels and the rails than that presented by their mere smooth contact, Mr. Blenkinsop, of Leeds, in 1811, took out a patent for a racked or tooth-rail laid along one side of the road, into which the toothedwheel of his locomotive worked as pinions work into a rack. The boiler of his engine was supported by a carriage with four wheels without teeth, and rested immediately upon the axles. These wheels were entirely independent of the working parts of the engine, and therefore merely supported its weight on the rails, the progress being effected by means of the cogged wheel working into the cogged-rail. The engine had two cylinders instead of one, as in Trevithick's engine. The invention of the double cylinder was due to Matthew Murray, of Leeds, one of the best mechanical engineers of his time, Mr. Blenkinsop, who was not himself a mechanic, having consulted him as to all the practical arrangements of his locomotive. The connecting-rods gave the motion to two pinions by cranks at right angles to each other; these pinions communicating the motion to the wheel which worked into the toothed-rail. Mr. Blenkinsop's engines began running on the railway extending from the Middleton collieries to the town of Leeds, a distance of about three miles and a half, on the 12th of August, 1812.* They continued for many years to be one of the principal curiosities of the neighbourhood, and were visited by strangers from all parts. In the year 1816, the Grand Duke Nicholas (afterwards Emperor) of Russia observed the working of Blenkinsop's locomotive with curious interest and expressions of no slight admiration. An engine dragged behind it as many as thirty coal-waggons at a speed of about three miles and a quarter per hour. These engines continued for many years to be thus employed in the haulage of coal, and furnished the first instance of the regular employment of locomotive power for commercial purposes. The Messrs. Chapman, of Newcastle, in 1812, endeavoured to overcome the same fictitious difficulty of the want of adhesion between the wheel and the rail, by patenting a locomotive to work along the road by means of a chain stretched from one end of it to the other. This chain was passed once round a grooved barrel-wheel under the centre of the engine: so that, when the wheel turned, the locomotive, as it were, dragged itself along the railway. An engine, constructed after this plan, was tried on the Heaton Railway, near Newcastle; but it was so clumsy in its action, there was so great a loss of power by friction, and it was found to be so expensive and difficult to keep in repair that it was very soon abandoned. Another remarkable expedient was adopted by Mr. Brunton, of the Butterly Works, Derbyshire, who, in 1813, patented his Mechanical Traveller to go upon legs,

* Annals of Leeds, vol. ii. p. 222.

chap. viii.] THIE WYL AM WAGGON-WAY. 77

working alternately like those of a horse!" But the engine never got beyond the experimental state, for, in one of its trials, it unhappily blew up and killed several of the bystanders. These, and other similar contrivances with the same object, projected about the same time, show that invention was actively at work, and that many minds were now anxiously labouring to solve the important problem of locomotive traction upon railways. But the difficulties contended with by these early inventors, and the step-by-step progress which they made, will probably be best illustrated by the experiments conducted by Mr. Blackett, of Wylam, whose persevering efforts in some measure paved the way for the labours of George Stephenson, who, shortly after him, took up the question of steam locomotion, and brought it to a successful issue. The Wylam waggon-way is one of the oldest in the north of England. Down to the year 1807 it was formed of wooden spars or rails, laid down between the colliery at Wylam— where old Robert Stephenson had worked—and the village of Lemington, some four miles down the Tyne, where the coals were loaded in keels or barges, and floated down the river past Newcastle, thence to be shipped for the London market. Each chaldron waggon was originally drawn by one horse, with a man to each horse and waggon. The rate at which the journey was performed was so slow that only two journeys were performed by each man and horse in one day, and three on the day following, the driver being allowed 7d. for each journey. This primitive waggon-way passed, as before stated, close in front of the cottage in which George Stephenson was born; and one of the earliest sights which met his infant eyes was this wooden tram-road worked by horses. Mr. Blackett was the first colliery owner in the North who took an interest in the locomotive engine. He went so far as to order one direct from Trevithick to work his waggonway, about the year 1811. The engine came down to Newcastle; but for some reason or other, perhaps because of the imperfect construction of the waggon-way as compared with the weight of the engine, it was never put upon the road. Mr. Blackett eventually sold it to a Mr. Winfield, of Gateshead, by whom it was employed for many years in blowing the cupola of his iron-foundry. Mr. Blackett had taken up the wooden road in 1808, and laid down a “plate-way ” of cast-iron—a single line, with sidings. The waggons continued to be drawn by horses; but the new iron road proved so much smoother than the former wooden one, that one horse instead of drawing one chaldron waggon, was now enabled to draw two. Still determined to make the experiment of working his plate-way by locomotive power, Mr. Blackett, in 1812, ordered another engine, after Trevithick's patent, which had yet two years to run. He also resolved to employ the rack-rail and toothed drivingwheel, like Blenkinsop's, and he had the road altered accordingly. The locomotive was constructed by Thomas Waters, of Gateshead, who executed the work for Trevithick on commission. This engine was of the most awkward construction imaginable. It had a single cylinder six inches in diameter, with a fly-wheel working at one side to carry the cranks over the dead points. The boiler was of cast-iron. Jonathan Foster, the Wylam engine-wright, who superintended its construction, described the machine to the writer as having “lots of pumps, cog-wheels, and plugs, requiring constant attention while at work.” The weight of the whole was about six tons. When completed, it was conveyed to Wylam

* A description of Mr. Brunton's locomotive is given by Dr. Lardner in his work on “The Steam Engine,” 7th edition, p. 338.

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