wheels, working into a toothed-rack, a contrivance which is liable to many objections. About the year 1813, Mr. Blackett, of Wylam, who had previously received one of Trevithic's engines, erected another similar to it on his railway, about five miles west from Newcastle; and what was of still greater importance, made some accurate experiments on the power of the adhesion of the wheels, which set this question completely at rest,—this engine moving and drawing a very considerable load after it, without any other auxiliary. The Wylam railway, however, was of an extremely imperfect description, and but ill adapted for displaying the power of the engine to any advantage. Still it continued to do its work with effect, and to afford daily demonstration of the practicability of the plan. Hence it gave rise to other attempts of a similar kind in different quarters, and always with increasing success; as the defects of former plans came to be avoided, the nature and operation of the machinery to be better understood, and successive improvements to be suggested, by constant experience in the making of engines. It was on the Killingworth railway that these trials and improvements were chiefly made. The engines were constructed by Mr. George Stephenson, now the engineer of the Liverpool and Manchester railway, from whose manufactory most of the engines since employed have been produced. It was on the 25th July, 1814, that the first engine was tried on the Killingworth railway. It drew after it, according to Mr. Wood, in the excellent work named at the head of this paper, eight loaded carriages, weighing in all about twenty tons, and moved at the rate of four miles an hour, and this upon a slight ascent; so that on a perfect level it would have drawn forty tons. The great improvement in this machine was the introduction of two steam-cylinders, instead of one, which, acting at different parts of the wheels, produced a much more regular motion than formerly, and rendered unnecessary a fly-wheel, which had hitherto been used. Still, it was encumbered with toothed-wheels and other complex machinery. Another engine was constructed, and tried in March, 1815, having the working parts much simplified, and was found to work proportionably better; and this engine, or one of a similar construction, but adopting always successive improvements, has continued ever since to travel on this railway, transporting the coals from the pit mouth, for about four miles, to the banks of the Tyne.

We saw and travelled on these engines, for the first time, in 1826, and although the railway was of the older and imperfect kind, with numerous joinings, and was, besides, in many places worn out or in a bad state of repair, and the engines, also, old and imperfect, compared with what they have since been brought to, the spectacle

of

of these machines, moving of themselves, and drawing after them a train of waggons upwards of one hundred feet in length, each carrying, besides its own weight, a load, of three times that of a common cart, formed a spectacle alike singular and magnificent. The load usually drawn by the Killingworth engine was twelve waggons, amounting to thirty-three tons, of coal, besides fourteen tons in the waggons; and it travelled at the average rate of four or five miles an hour, and this, from the circumstances of the railway and of the ascents and descents, might be reckoned a fair estimate for the ordinary work of such engines on a perfect level. It was on the model of these engines that all the others which were afterwards constructed were formed. It would be needless here to enter into the details. The principal, and by far the most prominent, part of the engine, were the boiler and furnace, for generating the steam, which consisted of a large cylinder of iron, set on its side on four wheels, about three or four feet diameter, and eight or nine feet long, with a fire-tube, eighteen inches or two feet diameter, running through its centre, and issuing at its extremity, where it was bent up, and terminated in the chimney, twelve or fourteen feet high. The engine itself was so small, as to be almost lost in the magnitude of the other parts. Its cylinder was nine inches diameter, and the stroke of the piston two feet. Like all the others, it was of the high-pressure kind, and, according to the usual calculation, and allowing for the pressure of the steam, would have the power of seventeen horses; the steam was raised to forty or fifty pounds on the inch. The great defect of these engines, which chiefly retarded their general introduction, was their enormous weight, amounting to six or eight tons, exclusive of the tender for water and fuel; such a load, moving with any degree of velocity, was sure to occasion serious damage to the railway.

It was on the Stockton and Darlington railway, which was opened on the 27th September, 1825, that they were first tried on a scale adequate to display their powers of traction; this railway presenting a continued level, or at least a line of very gentle declination, for the space of twenty miles, from Brusselton Plain to the town of Stockton. We had occasion to visit this railway in the summer of the following year, and we then found two of these machines constantly at work, each of which drew after it twenty, and frequently twenty-four waggons, containing each a chaldron of fifty-three hundred weight of coals, besides the weight of the waggon, itself of twenty-four hundred weight, forming in all a mass of seventy-seven tons in the one case, and ninety-two in the other; and this load was then regularly conveyed from Brusselton Plain to Stockton, a distance of twenty

miles, if no material or unusual stoppage occurred, in about four hours. In returning with the empty waggons, the engine occupied about five hours. The reason of this is, that the railway presented, in returning, a continual ascent. This, at an average, is about one in two hundred and eighty, which would make the actual gross load, on a level, thirty-eight tons; but in many parts the ascent was equal to one in one hundred and forty, and it was one in one hundred and twenty for more than a mile, On these, the draught of the engine must have been equal to fiftythree tons, and fifty-eight tons on a level, and moving at a rate of four miles an hour.

The

These facts will be sufficient to place in a striking light the extent of power which the railway system places at our command, for the purposes of draught. It is not only, however, in this department of internal communication, but in another, still more important, namely, in travelling, and where speed is required, that the locomotive carriage will be found to exhibit its vast superiority over every other mode of conveyance. brilliant success of the recent experiments on the Liverpool and Manchester railway has given an entirely new aspect to this whole question, and affords rational ground to anticipate, at no very distant period, the introduction of these wonderful machines, at least on the principal thoroughfares throughout the kingdom. Hitherto, the greatest difference of opinion had existed, even among engineers, as to the advantages of the locomotive engine, even for the purposes of slow draught; and as for travelling by it with any extraordinary degree of speed, the idea was ridiculed by almost every practical man. It is now proved, that by the action of steam on the railway carriage we can advance with a facility and speed never before equalled either on land or water, and to which, indeed, we can hardly assign any limits, except in so far as the safety of the carriage and passengers may be concerned.

Our readers are aware, that in October last, the time fixed for trying the powers of the engines which were to contend for the prize offered by the directors of the Liverpool and Manchester railway, an immense assemblage of spectators, comprising men of science and practical engineers, from various parts of the country, were collected, to witness the competition. The spectacle was one of deep interest, whether we regard it as a display of scientific and mechanical skill, or look to its practical effects on the commerce and general business of the country. The task finally assigned to the engines was to traverse, backwards and forwards, a distance of thirty-five miles, on a space one mile and a half, marked out for the purpose; a stoppage

of

was

was then allowed, when additional fuel and water were taken in, and the journey was repeated. The speed was not to be less than ten miles an hour, and the engines were required to draw three times their own weight, which last was not to exceed six tons. Of the engines which came forward, there were two which excited the principal attention; namely, the Rocket, constructed by Messrs.

Robert Stephenson and Co., of Newcastle-on-Tyne, and the Novelty, by Messrs. Braithwaite and Erickson, of London. The first, as might have been expected, from the talents of Messrs. Stephenson, and their long experience in the construction of such engines, was, unquestionably, far superior to any which had hitherto appeared. It was formed on the same general plan with the others produced at the same manufactory, but included various striking improvements, the principal of which was, a new method of generating the steam. Instead of allowing the heat from the fire and the heated air to rush in one unbroken volume through the fire-tube, under which circumstances the greater part of it escaped up the chimney,-it was made to pass through a great number of small pipes, running longitudinally through the boiler, and all immersed in the water; the effect of this was, to expose a much larger surface of the water in the boiler to the action of the fire, by which means the heat was almost entirely absorbed by the water, instead of being dissipated, as heretofore; and thus the steam was generated freely, an object which had hitherto not been attained in these engines. The cylinders of this engine are of eight inches diameter, and seventeen inches stroke, shewing a power, according to the The 'Rocket' boiler was the invention of Mr. H. Booth, of Liverpool.

usual

usual calculation, of thirteen horses. Another improvement in the engine was, its great lightness, weighing only four tons five hundred weight. The engines formerly in use weighed, as we have already stated, most of them six or seven tons, and some eight or ten. In short, this engine was, in every respect, the most perfect of this particular kind.

But great was the surprise of the engineers, and the interest excited among all classes of the assembled multitude, by the appearance of the London engine, the Novelty, of Messrs. Braithwaite and Erickson, so very different in its general structure

and aspect, and so vastly superior in lightness, elegance, the per fection of its machinery, and the form, arrangement, and compactness of its various parts. The boiler, which, in other engines, makes so prominent a figure, was of such small dimensions, that it required some attention to discover, at first, where it was placed. It consisted of a long tube, twelve inches only in diameter, under the frame of the engine, nearly on a level with the axles of the wheels; and the chimney, instead of a tube fifteen or eighteen inches in diameter, and rising fifteen feet above the ground, formed merely a pipe, not exceeding four inches diameter, issuing from the end of the boiler, and not rising more than seven feet above the ground; and this arrangement, if it be found practicable, is of peculiar advantage, not merely in the appearance of the machine, or in giving it additional lightness or steadiness, by diminishing the top weight; but, what is of far more consequence, in enabling us to reduce the height of all the bridges under which the engine must pass, in crossing any of the public as well as private roads. It will admit of a deduction of seven or eight feet from the height of the mason-work in every such bridge. What a saving must this produce in the original cost of a railway, through a cultivated country, where these bridges must frequently occur! This of itself must strongly recommend the use of such an engine. The end of the boiler, opposite the chimney, terminates in the furnace and

steam