far to prove-not, as some assert, that the power of steam is in its nature unsuited to the purpose of travelling on common roads; but only that the ingenuity, or science, or practical skill, hitherto brought into the field, have not been equal to the task, and that the subject has not yet been viewed in its proper light.

II. In proceeding to a review of the present state and future prospects of land carriage by steam, it will merely be necessary, in forming our opinion of the various inventions that have been made use of for this purpose, to apply to them the five tests we have already endeavoured to establish as criteria of their value. The task of exposing errors is always an ungrateful one, but we hope, in the present case, will not be found to be pursued in an unfair or improper spirit.

Since the commencement of the present century, when Mr. Trevithick first established the practicability of steam-carriages, in as far as their progressive motion merely was concerned, probably not less than a hundred steam-carriages have been constructed for the purpose of moving on the common roads, resembling each other only in the sameness of their results. One after another the inventors seem wholly to have mistaken the object, which was, not merely to construct a powerful steam-carriage, but one that should be so economical both in the consumption of fuel, tear and wear, and original expense, as advantageously to supersede horses. They do not seem to have considered, that unless the original price of the engine, and the expense of keeping it up, were less than that of horses, however amusing it might be as a spectacle, or interesting as a philosophical problem, the invention would be useless, and wholly unprofitable. They ought to have recollected, that even if their engines had attained, on their first construction, a speed of thirty miles an hour, yet if they were thereby to be so seriously injured as to be disabled from further use, in such case the speed or security of the conveyance would be of no earthly utility. A mile in two minutes is, we know, the speed of some race horses, and by placing a series of them at each mile, along a distance of thirty miles, that space might be overtaken in one hour. The cost of such expedition would, however, be so enormous as to render it of no use; yet it would not be more enormous than that of a steam-engine of the ordinary construction on a road, at the same rate.

The inquiry therefore is altogether one of economy and durability, rather than of possibility; and instead of inventors claiming for themselves any merit when they had succeeded in making a carriage propelled with a moderate velocity, they should rather have kept the matter to themselves, until they had manufactured

one really economical and useful, uniting advantage to the public and remuneration to themselves.

The labour of passing in detail over every one of these inventions is much diminished by the circumstance that the greater number of them have already sunk into oblivion. The only carriages that still remain before the public are those of Mr. Stephenson on the Liverpool and Manchester railway, and on the common road those of Mr. Gurney, Mr. Hancock, and Messrs. Ogle and Summers. We shall consider each of these in succession.

Mr. Stephenson's name will be handed down to posterity in conjunction with those of the projectors of the Liverpool and Manchester railway, as having given to travelling by steam its most powerful impetus. Long previous to this period Mr. Stephenson had been well known as one of the most talented practical engineers in Britain, minutely acquainted with the details of railroads, and their construction, and familiar with the whole face of the country as to its capabilities-a man whose opinion on such subjects deservedly carries with it the very highest weight. It is to Mr. Stephenson's talent alone that he is indebted for having raised himself from the humbler walks of life to his present respectable and honourable eminence, and the rail-road he has constructed for the Company, though not upon the line originally proposed by himself, is as beautiful a piece of work as we should ever wish to look upon. His acquaintance with machines for rapid motion had its commencement, however, only with this railroad, those which he had previously been engaged in constructing having been used at velocities much lower. Familiar with works requiring strength and solidity, he entered upon a department to which he was an entire stranger, when he undertook the superintendence of vehicles in which lightness and elasticity were the highest requisites. This will account for many imperfections that still adhere to these engines, the principal excellence of which indeed consists in a peculiarity in the boiler, which is not the invention of Mr. Stephenson, but of Mr. Booth, treasurer to the Company. This boiler has been found more powerful and economical within a given space than any of its predecessors; it is, in fact, a practical exemplification of some of the methods and principles which have been explained in the previous pages of this article. In the first place, the fire is within the boiler, and is so large as to act directly on a surface of about twenty feet; the flame then passes, not immediately into the chimney, but through a second division of the boiler placed in immediate connection with the other, and in the form of a large cylindrical cask laid on its side, and so placed that the part of the boiler that

contains the burning fuel is at one end of the cask, and the chimney at the other end. To reach the chimney, therefore, the flame must pass through this cask, which it does, not by one large pipe, but by 50 or 100 small pipes, like gun-barrels. It is in this cylindrical part of the boiler that the greater portion of the steam is generated, the heated air in its passage is, as it were, filtered of every particle of its heat, the flame heats immediately on almost every particle of the water, and an ample and most rapid supply of very powerful steam is obtained. The smoke then passes up the chimney into the atmosphere. As from the shortness of the chimneys that are necessary in locomotive engines, the draught would be exceedingly slight, for the purpose of increasing it the waste steam of this engine is suffered to escape up the chimney through the mouth of a pipe; from its great elasticity, it forces its way rapidly, and impels along with it the smoke and air in a violent current, by which the combustion and generation of steam are rendered very rapid.

These boilers, therefore, possess two of the requisite qualities in a high degree-power and smallness of bulk; but they do not possess the last-lightness. They require to be formed of metal half an inch thick, so that the weight of an engine is from four to six or eight tons. Again, the mode of inserting the tubes is such, that their expansion by heat or other circumstances soon loosens them, and necessitates frequent repairs.

We have now said all that we can in favour of these engines. In the other parts of them we have not been able to discover either novelties, improvements, or the necessary adaptations to rapid motion. Let our readers apply the criteria we have given them. The passages should be short and direct; these are long and interrupted. The cylinders should be large and powerful; these are small and confined. The engine should be hung on springs; this is so nominally, but in reality is not. There should be some provision for the ascent on a change of level; here there is none, and the engine requires to be assisted up hill. The want of proper suspension on springs appears to be the most radical defect in these engines, and its consequences are most destructive. Every one knows that the effect of a spring depends upon its length and its thinness; the springs of these are short and thick, in fact, nothing more than compound blocks of metal, forged in the shape of springs, but possessing scarcely any of their qualities. Indeed the very nature of the mechanism used for propelling the engines renders it necessary that the springs should not act to the requisite extent; the wheels are turned by a crank in the axle, which could not act if the springs were allowed to vibrate. To prevent their vibration, an iron

guide blocks them before and behind from any motion, either backward or forward. They are necessarily incapable of lateral motion, and their own stiffness prevents any thing like adequate vertical action. It is difficult to say whether these defects are most injurious to the engines or to the road on which they run. It does not seem to be generally understood that every possible facility of vibration is at least as necessary on a rail-road as it is on a common road.

A rail-road is not by any means what many suppose it to be, a perfectly smooth and even road of metal; it is composed of separate bars of iron, united to each other at intervals of not more than six yards, so that there are frequent joinings. Now these joinings are necessarily imperfect, as an opening must be left between the successive rails to admit of their expansion and contraction with the variation of temperature; besides, the rails are not supported uniformly by laying on the surface of the road, but rest upon stone pillars, or sleepers, as they are called, placed at distances of a yard from each other, and as the great weights pass over them with considerable velocity these sleepers are driven deeper into the ground, so that the rail-road soon becomes uneven, one rail having one direction and the next a different one. Though these defects are not easily detected by the eye, yet they are very sensible upon close inspection with instruments, and still more so by the carriages that pass over them, as the wheels, on passing over a joining of two rails, receive a severe jolt, and also a change of direction; driven first to one side of the road, then to the other, the carriage rocks like a ship at sea, whilst at every swing one wheel or the other strikes a rail with considerable violence; the motion is thus rendered rough and unsteady, and the carriage requires most eminently the use of springs-really acting, unfettered springs-so placed that, whether the wheel be jolted in passing over a joining, or in striking the alternate sides of the road, the shock may be prevented from passing to the body of the vehicle, which may thus keep its uniform line. The damage sustained by the Liverpool and Manchester rail-way from these causes is by no means trifling. On examining the last half-yearly statement, printed for the use of the subscribers, we find that the repairs of the rail-way cost 7,3317. in six months, being more than 14,000/. per annum. But the evil effects of this action are by no means confined to the railway itself; they are still more destructive to the engines that run upon it, as well as to the carriages, as the former, from their delicate mechanism, receive the shocks with unmitigated violence, by which every bolt is shaken loose, and even the strongest parts of the machinery are speedily torn to pieces. The cure for this imperfection has not been, as it ought

to have been, the invention of new expedients to allow the extensive action of springs; the remedy has only increased the evil. They have gone on accumulating the bulk and weight of every part of the engine, in the hope of rendering it more able to stand these shocks, which are themselves increased by the very weight thus superadded, so that instead of according with the hope at first held forth, that they would be rendered lighter, as further experience gave opportunity, they are daily becoming worse and worse. The jolting they receive is very violent. We have stood on one of them for hours watching the action of the springs, and have experienced on our own body every jolt of the rail-way. The effect produced is most sensibly perceived where it is most sorely felt, in the revenue of the company; for even at this moment, when their engines are new and in the best order, the expense incurred for their support and repair is 10,5827. in six months, or above 21,000l. per annum, making, with the maintenance of the road, 35,000l. of yearly expenditure, the greater part of which is occasioned by the imperfections we have been describing. This expense is easily accounted for, when we consider that the company have twenty-four engines, out of which there are seldom more than six fit for use, the others undergoing the progress of thorough repair. Our readers will also recollect that some provision is necessary for adapting engines to the change of direction in the road, a greater force being requisite for ascending hills than for their descent. There is no such adaptation in Mr. Stephenson's engines; they are helped up the hills by auxiliary engines stationed at the foot of them, and the velocity in descending is suffered to wear the engines, without making any use of their power. These defects have been serious drawbacks on the prosperity of the company, whom they serve to rob of much of that benefit to which their enlightened spirit of mercantile enterprise has given them a well merited claim.

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It requires no elaborate statement to show how hopeless are the schemes of some individuals, who have proposed that such engines as those on the rail-road should be applied to the common road. The project is utterly absurd. They could as much run on a common road as an elephant could dance on a tight rope. Their very deficiencies, when applied to the rail-road, increase tenfold on the common road. The circumstance of their enormous weight, and above all, their imperfect suspension on springs, renders any such adaptation perfectly impossible. Let any one who has paid attention to the progress of coach building during the last hundred years, compare the ponderous frame-work of a royal equipage of that date with the exquisitely elegant and astonishingly light structure of a private carriage, or even a stage-coach