cross-head of one piston, at the dead point of the turn of the crank; f, that at the full leverage; gg, the piston cross-head guides; hh, the connecting-rods; ii, the driving-wheels, running on the fish-bellied edge-rail, one of the improvements in railways included in the patent; k, the toothed wheel and endless chain; m m, the cylinders and pistons for acting on the axles as already described.

Engines on this plan were introduced by Stephenson on the Killingworth and on the Hetton Colliery Railway; and although every exertion was made by him to render them efficient and economical, and to get them into use on the different railways which began at that time to be formed, it is the opinion of competent authorities that they did not possess "those advantages which the inventor had anticipated."

On the 27th of September, 1825, the Stockton and Darlington line of railway, twenty-five miles long, was opened for public traffic. Twenty miles of this was worked by locomotives and horses, the powers of each being put thus in close competition. At this early period of the history of a line of railway, the first ever laid down on the improved principles as introduced by Stephenson, and which formed the nucleus of the railway system, the locomotives employed on it were five in number, four having been manufactured by Messrs. Stephenson at their factory at Newcastle, and one by Mr. Wilson of the same town. Such, however, was their inefficient working condition, that the power of steam was about to be abandoned, and the railway conducted by horses. Timothy Hackworth, to whom we have before alluded, and who, through the intervention of George Stephenson, had been appointed manager of the working department of the railway, stepped forward at this critical juncture, and proposed to construct an engine capable of working the line to the extent already mentioned. His offer was accepted, and he forthwith began his operations. The boiler of the engine made by Wilson, already alluded to, was taken as the boiler of the new machine. "This boiler was a plain cylinder," says the account from which we quote, in the Practical Mechanic's Journal, "thirteen feet in length, and four feet five inches diameter. The heating surface was obtained from a double tube of malleable iron in the form of the letter W, traversing the whole length of the boiler. One side of this tube was made available for the fire-grate, and the heated vapour being passed through it was returned by the opposite one to the chimney, which was actually a vertical continuation of this end. With this contrivance the engine had a heating surface double that of any other engine of its time. She was carried on six four-feet wheels, four of them being springmounted, and was the earliest of the six-wheel coupled class. The cylinders, eleven inches in diameter and twenty inches stroke, were placed vertically at what is now the smoke-box end of the engine, and worked directly upon the first pair of wheels. At the same end was attached a malleable iron cistern, into which the water passed from the tank previous to being introduced into the boiler, the driver having the power of regulating the supply; and a pipe from the steam-exhaust was led into the cistern for the purpose of admitting steam at pleasure to heat the water. Another pipe was provided for the purpose of leading off a steam-jet from the exhaust-pipe at the chimney end for discharge beneath the grate; the intention being to facilitate the combustion. In addition to its being the original of a class of engines now so universal, this engine was the first

which had a blast-pipe fitted to it, the whole of the exhaust steam, excepting only such a portion as was required for the purposes before alluded to, being conveyed into the centre of the chimney, and then thrown out in a jet from a conical pipe." Trevethick led his waste steam to the chimney by a a pipe, no conical or blast-pipe being used to send it up the chimney in the form of a jet. Although Trevethick, before a committee of the House of Commons, claimed the use of the waste steam passing into the chimney as a means of quickening the draught, one writer on locomotive engineering states, that he had "no intention or expectation of improving the draught of the chimney thereby." How this holds with the fact it is now difficult to determine; but to return. The engine thus constructed by Hackworth was named the "Royal George," and commenced running in October 1827. The following statement affords an evidence of its power as compared with that of horses, with which it competed. The cost of the engine was 4257.; in one year (1828) she conveyed over twenty miles 22,442 tons, at a cost of, including all repairs, and maintenance, and interest on such capital at 10 per cent, one farthing per mile: "an economy in working which is rarely exceeded at the present day." The cost of the same work performed by the horses was 9981.; thus showing a difference of 5321. in favour of the engine over the animal power. "The points in the improvement," says the same writer, "in the Royal George' which conduced to this important result, evidencing not only her great superiority over her compeers, but the vast resources of the imperfectly developed locomotive system, were simply these: the increased evaporative surface of the boiler; the perfect command over heavy loads in all states of the weather, by reason of the superior tractive adhesion derived from the six-coupled wheels; and the introduction of the blast-pipe, an invention which alone will carry down the name of Hackworth to future ages in connexion with early locomotive history. Up to the period of which we write, no really efficient locomotive was in use, as the steam pressure invariably fell, in spite of the best efforts of the driver; and the superiority of the 'Royal George' in this respect alone at once elevated it far above its contemporaries, for it was capable of maintaining a speed of nine miles per hour throughout its run of twenty miles." Hackworth introduced other improvements in this engine, as the short-stroke force-pump, and the substitution of the adjustible springs to act on the safety-valves instead of weights.

We now approach that period in the history of steam locomotion at which the great impetus was given to the perfection of the engine. We allude to the opening of the Liverpool and Manchester Railway in 1830. In considering the means to be used for working the line, the choice of the directors lay between the employment of stationary steam-engines and locomotives. It is unnecessary here to enter into detail as to the investigations which the company deemed requisite to be instituted in order to ascertain the most efficient and economical method of working the line; suffice it to state that, in opposition to the Report of the engineers appointed to investigate the matter, Messrs. Rastrick and Walker, who recommended stationary engines, the directors ultimately resolved to adopt locomotive power; and offered for the best engine a prize of 550l., to be decided by a public competition. It is generally understood that the opinion of Robert Stephenson in favour of locomotives induced the directors to adopt this power; and it is nothing derogatory to the great fame of Robert

Stephenson to state that it appears he was much indebted to Timothy Hackworth for a variety of sound practical information; indeed, Hackworth was the only person at this period who had any thing like a practical knowledge of the whole bearings of the case.

In offering the above reward for the best locomotive, the directors made the following stipulations: "the engine was to consume its own smoke; to be capable of drawing after it three times its own weight at ten miles an hour, and have not exceeding 50 lbs. pressure upon the square inch on the boiler; two safety-valves, one locked up; engine and boiler to be supported on springs, and rest on six wheels if it should exceed four and a half tons; height to top of chimney not more than fifteen feet; weight, including water in boiler, not to exceed six tons, but preferred if of less weight; boiler, &c. proved to bear three times its working pressure, and pressure-gauge provided; cost of machine to be not more than 550l." The following is a description of the public trial of the competing engines: The "Rocket," constructed by George Stephenson, and of which we give a representation in fig. 141, weighed 4 tons 5 cwt., and the tender, with water

fig. 141.

and coke, 3 tons 4 cwt. 2 lbs.; it had two loaded carriages attached, weighing 9 tons 10 cwt. 3 qrs. 20 lbs., thus making the whole weight to be moved equal to 17 tons. The velocity attained by this engine was 14 miles an hour, with an evaporation of 114 gallons per hour, and consumption of coke equal to 217 lbs. per hour. The greatest velocity attained was at the rate of 24 miles per hour. The "Sanspareil," by Timothy Hackworth, and of which we give a representation in fig. 142, was the next engine tried, although from its not having been made in strict accordance with the specified rules, it was scarcely competent to enter the lists of competition. The weight of the engine was 4 tons 15 cwt. 2 qrs.; the tender and water and fuel being 3 tons 6 cwt. 3 qrs.; the loaded carriages, three in number, attached to it being equal to 10 tons 19 cwt. 3 qrs.; the whole weight to be moved being equal to 19 tons 2 cwt. The engine in her eighth trip became disabled through the feed-pump becoming disordered in its action, the level of the water in the boiler got low

therefore, and the leaden plug, which was used as a safety-valve, getting melted, an end was thus put to the experiment. Her rate of speed was however satisfactory, being equal to conveying 19 tons at fifteen miles per

hour. The greatest velocity attained was 22 miles per hour. The consumption of fuel was very great in this engine, being equal to 692 lbs. per hour; this was in consequence of the great draught induced by the steamblast in the chimney.

fig. 143.

The third engine, the "Novelty," by Messrs. Braithewaite and Erricson, and of which we gave a representation in fig. 143, carried its own water and fuel, and weighed 3 tons 1 cwt. The weight of the tank, water, and fuel, being 16 cwt. 14 lbs.; the two loaded carriages being 6 tons 17 cwt.; the total weight being 10 tons 14 cwt. 14 lbs. In consequence of successive accidents in the working arrangements of this engine, it was withdrawn from competition; its performances, however, were very satisfactory so far as they went.

Another engine, named the "Perseverance," constructed by Mr. Burstall, was also entered for competition; but being unsuited to the railway, was at once withdrawn. The judges on this interesting occasion were Mr. Nicholas Wood, Mr. Rastrick, and Mr. Kennedy. The prize was awarded to Mr. Stephenson for his engine the "Rocket."

The "Rocket" undoubtedly owed its efficiency, at least in an economical point of view, from the construction of the boiler, and the large amount of surface which was presented to the action of the heated air. This was obtained by introducing twenty-five copper tubes, three inches diameter, into the interior of the boiler, at its lowest diameter; these tubes opened at one end into the space below the chimney, and at the other into what is now termed the fire-box; by this arrangement, the flame and heated air passed through the tubes, which were surrounded by the water in the boiler. The furnace or fire-place was an external box, about three feet deep and two wide; the furnace was provided with an external casing; into the space thus formed the water from the boiler passed: a large additional amount of heating-surface was also thus obtained. The boiler or fluetubes" which has since proved to be the main-stay of the modern locomotive”—was the invention of Mr. Henry Booth, the secretary of the railway; a gentleman "to whom railways are indebted for much of their practical efficiency." From the invention not having been patented, Mr. Booth did not receive the great pecuniary advantages which might otherwise have resulted from this highly valuable improvement. We understand, however, that he received a pecuniary reward from the directors of the railway on account of it. As will be seen on inspection of the diagram, the cylinders were placed outside the boiler, near the fire-box, and inclined at an angle; and the piston-rod of which is connected with the drivingwheel by means of a connecting-rod.

In the "Sanspareil" of Hackworth, the cylinders were inverted and placed vertically; the piston-rod cross-head worked between parallel guides; and to the cross-head was attached the connecting-rod which communicated motion to the hind wheels; the fore and hind wheels were coupled by a connecting-rod. The boiler was cylindrical, with the flue returned to the front, where it entered the chimney; the flue was of course entirely surrounded with water.

The "Novelty" possessed some arrangements of considerable merit, the most distinguished feature being the construction of the boiler and fire-place. This will be seen by an inspection of the diagram in fig 144: 7 is the furnace placed inside the boiler, and surrounded with water; fuel is supplied to the fire-place c by the tube or funnel e, passing through the dome of the boiler, and covered with a lid or cap. Air is forced into the fire, to maintain combustion, by a small pair of fanners worked by the engine, through the pipe b communicating with the ash-pit c. The heated air is forced along the series of pipes fg to the chimney h, the steam space being at ii. By this arrangement a large amount of heated surface is obtained; the fireplace not only being surrounded with water, but the long range of pipes fg. The peculiar arrangements of the engine will be seen by the diagram in fig. 143. Mr. Stephenson not only obtained the prize, but the appointment of engine-manufacturer to the company. The attention of the firm was now devoted to the perfecting of the mechanism of the locomotive. "Each engine that issued