The important improvement effected on the Penryhn Railway, by Mr. Wyatt, described at page 381, naturally led to ameliorations in the structure of similar works elsewhere, which was especially observable on the banks of the Tyne and Wear. The expense of the transit of coals forms so considerable a proportion of their money cost, that the owners are always alive to any decided saving that may be effected therein. In the engravings in page 385, Fig. 1 represents a tide view, Fig. 2 a plan, and Fig. 3 a cross-section of a cast-iron edge-rail, of the form which has been extensively adopted in the districts above mentioned. The waggons run upon the rounded edge of the rail, which is smooth, and laid ae evenly and regularly as possible. The length of these rails is usually three feet, with a depth of about four inches and a half in the middle, and breadth of the top two inches; but in some railways the rails are four feet long. The ends of the rails meet in a piece of cast-iron, called a chair (see Fig. 4), and the chairs are fixed to stone blocks or sleepers, with a broad base, and weighing from one and a half to two hundred weight. These are firmly bedded in the ground, and adjusted to a proper plane for the road before the chairs are con nected to them. The goodness of the road of course depends much on fixing the sleepers in a sound, firm manner. In Fig. 1 the side view of the rail C is shown, supported at the extremities A B by cast-iron chairs E E, which rest on blocks of stone D D. called sleepers. Fig. 2, the plan, shows the scarf joints, where the ends of the rails meet in the iron chairs E E. Fig. 3, the cross section of the rail taken at C, in Fig. 1, which is the middle of its length. Fig. 4 is a cross section at B, through the joint chair and supporting blocks.
Up to the period to which our present history of railways relates, it does not appear that any other power of draught or propulsion was employed but that of horses, and, occasionally, of fixed engines up inclined planes.
In the year 1802 Messrs. Trevithick and Vivian invented and took out a patent for the first locomotive steam-engine, which was, in the second year afterwards, brought into practical operation. The merit of the first suggestion of steam-car riages has been attributed to different individuals; hut the probability is, that the idea of applying the steam-engine for the purposes of locomotion was coeval with its first invention. Thus Savery, from having considered its possi bility, and Dr. Robison, from having suggested it to Watt, have by some been regarded as the inventors ; but almost as well might we regard the Philosophic poet Darwin to have been the inventor, who prophesied— "Soon shall thy arm, unconquered steam! afar, Drag the slow barge, and drive the rapid ear I" In a note to a late edition of Dr. Robison's Mechanical Philosophy, Mr. Watt states,—" My attention was first directed in the year 1759 to the subject of steam-engines, by the late Dr. Robison, then a student in the Uni versity of Glasgow, and nearly of my own age. He at that time threw out the idea of applying the power of the steam-engine to the moving of wheel carriages, and to other purposes ; but the scheme was soon abandoned on his going abroad." In the patent granted to Mr. Watt in 1784, he gave an account of the adaptation of his mechanism to the propulsion of land carriages. The boiler of this apparatus he proposed should be made of wooden together, and fastened with iron hoops like a cask. The furnace to be of iron and placed in the inside of the boiler, so as to be surrounded on every side witg water. The boiler was to be placed on a carriage, the wheels of which were to receive their motion from a piston working in a cylinder, the reciprocating motion being converted into a rotatory one, by toothed wheels, revolving with a sun and planet motion, and producing the required velocity by a common series of wheels and pinions. By means of two systems of wheel-work, differing in their proportion, he proposed to adapt the power of the machine to the varied resistance it might have to overcome from the state of the road. A carriage for two persons might, he thought, be moved with a cylinder of seven inches in diameter, when the piston had a stroke of one foot, and made sixty strokes a minute. Mr. Watt, never built a steam-carriage. It is well known that Mr. Watt retained, up to the period of his death, the most rooted prejudices against the use of high steam ; indeed, he says himself, " I soon relinquished the idea of constructing an engine on this principle, from being sensible it would be liable to some of the objections against Savery's engine, via. the danger of bursting the boiler, and also that a great part of the power of the steam would be lost, because no vacuum was formed to assist the descent of the piston."— Wafts Narrative.
In a bold deviation from the beaten track, it was the good fortune of Mr. Richard Trevithick and Mr. Andrew Vivian, two engineers residing at Cain borne, in Cornwall, to find the path which conducted them to their object ;— rejecting the absurd prejudices which had made high-pressure steam to be excluded from practice, they saw in the formidable qualities which had excited the fear of Watt and others, those very properties which fitted it to become the actuating principle of their mechanism. Above all other considerations which swayed them in their preference of steam of a high temperature, was the power it gave of dispensing with the use of the condenser altogether; a part which, from its cumbrousness, and the difficulty of supplying it with water, rendered it far inferior even to Newcomen's imperfect apparatus for locomotive purposes.
The specification of the patent ranted to Messrs. Trevithick and Vivian is descriptive of a high-pressure engine, the most simple and effective ever known, which has thus been characterised by the eloquent Mickleham :—" It exhibits in construction the most beautiful simplicity of parts, the most saga cious selection of appropriate forms, their most convenient and effective arrangement and connexion ; uniting strength with elegance, the necessary solidity with the greatest portability ; possessing unlimited power with a won derful pliancy to accommodate it to a varying resistance ; it may indeed be called THE gresic-EN ma." This machine • will be found under the article STEAM. Our present business is with the application of this engine, which the specification proceeds to show in connexion with a sugar-cane mill ' • and, lastly, it describes its employment in propelling " wheel carriages of every description,"—a purpose for which it is most admirably designed, as it contains ge.lerally those arrangements or combinations of mechanism which many of our present locomotionists call their own, and which are adhered to as essential to their machines. We shall now quote from the specification : "Fig l is a vertical section, and Fig. 2 the plan of the application of the improved steam-engine to give motion to wheel carriages of every description ; B represents the cue, having therein the boiler with its fireplace and cylinder (described by the patentees in the previous part of their specification). The piston-rod P Q, Fig. 2, is divided or forked so as to leave room for the motion of the extremity of the crank R; the said rod drives a cross piece at Q, backward and forward between guides ; and this cross-piece, by means of the bar Q R, gives motion to the crank with its fly F, and to two wheels TT upon the crank axis, which lock into two correspondent wheels U upon the naves of the large wheels of the carriage itself. The wheels T are fixed upon round sockets, and receive their motion from a striking box or bar S X, which acts upon a pin in each wheel ; S Y are two handles, by means of which either of the striking-boxes S X can be thrown out of gear, and the correspondent wheel W, by that means discon nected with the first mover, for the purpose of turning short, or admitting a backward motion of that wheel when required; but either of the wheels W, in ease of turning, can be allowed considerably to overrun the other without throwing S X out of gear, because the pin can go very nearly round in the forward motion before it will meet with any obstruction. The wheels U are moat commonly fixed upon the naves of the carriage-wheels W, by which means a revolution of the axis itself becomes unnecessary, and the outer ends of the said axis may consequently be set to any obliquity, and the other part fixed or bended, as the objects of taste or utility may demand. The fore-wheels are applied to direct the carriage by means of a lever H ; and there is a chink lever which can be applied to the fly, in order to moderate the velocity of progression when going down hill. In the vertical section is shown a springing lever, having a ten dency to fly forward. Two levers of this kind are duly and similarly placed near the middle of the carriage, and each of them are alternately thrown back by a short bearing lever upon the crank axis, which sends it home into a catch at the end, and afterwards releases it when the bearing lever comes to press upon V, in which case the springing lever flies back. A cross bar, or double handle is fixed upon the upright axis of the cock, from each end of which said cross bar proceeds a rod p q, which is attached to a stud q ; that forms part of the spring lever. This stud has a certain length of play, by means of a long hole or groove in the bar, so that when the springing lever is pressed up, the stud slides in the groove without giving motion to p. When the other springing lever is disengaged, it draws the opposite end of the handle, and causes p to draw the long hole at q up to its bearing against the stud, ready for the letting off of that first-mentioned springing-lever. When this last-mentioned lever comes to be disengaged, it suddenly draws p back, and turns the cock one quarter turn, and performs the like office of placing the horizontal rod of the other extremity of the handle ready for action by its own springing-lever. These alternations perform the opening and shutting of the cock, and to one of the spring ing levers is fixed a small force-pump lc, which draws hot t rater from the case by the pick back-stroke, and forces it into Me boiler by the stronger and more gra dual pressure of a lever on the crank axis. It is also to be noticed that in certain eases, make the external periphery of the wheels W uneven, by projecting heads of nails or bolts, or cross grooves, or fittings to railroads, when required; and that in cases of hard pull we cause a lever, bolt, or claw, to project through the run of one or both of the said wheels, so as to take bold of the ground ; but that in general the ordinary structure or figure of the external surface of these +Meth will be found to answer the intended purpose. And, moreover, we do observe and declare, that the power of the engine, with regard to its convenient application to the carriage, may be varied, by changing the relative velocity of rotation of the wheels W compared with that of the axis S, by shifting the gears or toothed wheels for others of different sizes, properly adapted to each other in various ways, which will readily be adopted by any person of competent dull in machinery. The body of the carriage M may be made of any conve
nient size or figure, according to its intended uses. And, lastly, we do occa sionally use bellows to excite the fire, and the said bellows are worked by the piston-rod or crank, and may be fixed in any situation or part of the several engines herein described, as may be found most convenient.' Such admirable combinations of inventive skill were never before contained in the specification of a patent ; yet they are described with that unassuming brevity which belongs to matters of common occurrence. What an extraordinary contrast does the modesty of these truly clever men present, when compared with the boastings of several of our recent locomotion fists, who hate derived almost every thing that is of a useful character in their carriages from the foregoing specification, and from the subsequent practical application of the inventions by the patentees themselves. There are thousands of persons now living in London who saw the steam-coaches of Messrs. Trevithick and Vivian running about the waste ground in the vicinity of the present Bethlehem Hospital ; and likewise in the neighbourhood or site of Boston Square. This was thirty-four years ago; nevertheless, Dr. Lardner says, at page 246 of his Treatise on the Stearn-engine, "First and most prominent in the history of the application of steam to the pro pelling of carriages on turnpike roads, stands the name of Mr. Goldsworthy Gurney Numerous other projectors, as might have been expected, have followed in his wake. Whether they, or any of them, by better fortune, greater public support, or more powerful genius, may outstrip him in the career on which he has ventured, it would not perhaps at present be easy to predict. But whatever may be the event, to Mr. Gurney is due, and will be paid, the honour of first proving the practicability of the project ; and in the history of the adaptation of the locomotive engine to common roads, his name will stand before all others in point of time ; and the success of his attempts will be recorded as the origin and cause of the success of others in the same race." We know not to what cause to attribute ouch an obvious misstatement of facts ; for it is impossible for any one who attends to the chronology or history of the sub ject, not to see at once that there are about as many untruths in this panegyric as there are lines. It is extremely painful to us to make these observations upon a gentleman of such high scientific attainments as the learned Doctor ; but his just influence upon the public mind, renders it imperative upon us to notice this common error which he has fallen into, in order that the fairly earned honours of those truly eminent mechanics, Trevithick and Vivian, be not thus sacrilegiously trampled in the dust Mr. Gurney's first patent for a steam-carriage was in the year 1825, and will be found described in its proper chronological poirition. We will, however, in this place, merely observe, that the mechanic who peruses the said specification, will instantly recognise the chief arrangements of Trevithick and Vivian ; and if he reads on to the end of the specification, he will find that the sole claims to invention in this steam-carriage, are in the words following :—"I claim the use of a roller or rollers, wheel or wheels, to the upper ends of my said propellers, reacting against a straight and smooth rail or plane affixed under, and being a part of the carriage, such rail or plane being parallel, or nearly so, to the soles or bottom of the carriage wheels, whereby the carriage itself is enabled to be rolled over the upper ends of the said propellers, crutches, or feet, by the mechanical power employed." It is worthy of observation, that however a patentee may be disposed to vaunt and puff before the "enlightened public," there is too much risk attending the making of unfounded pretensions in the specification of a patent, wherein the claims to invention must be exactly defined; for if any thing be claimed that is not new, the whole patent is thereby rendered void. In the claims, therefore, of a specification, we look for the naked truth ; and in this case we find it to be not a steam-carriage, but a useless roller put under the body of the vehicle! These appendages, however, of guide rollers, it may be remarked, were first applied to preserve the rectilineal motion of the piston-rod in the beautiful high-pressure engines of Trevithick and Vivian, and they have been applied in a thousand similar ways ever since. Mr. Gurney thinks, how ever, that nobody put rollers to their crutches before him, and that, conse. quently, he invented steam-carriages. And can it be for proposing to use these crutches, which it is notorious were long before patented and used, and found wanting, (by Brunton, in 1813, Baynes, in 1820, Gordon, in 1824, &c.) that Dr. Lardner scatters to the winds all the skill and talent, not only of the gen tlemen we have named, but of all others who preceded Mr. Gurney in the building of steam-carriages! The inquiry naturally follows, what became of the celebrated crutches of " the powerful genius!" To answer it, we have referred to M r. A lex an der Gordon's interesting Treatise on Elemental Locomotion, and we there find it stated at page 55, that they were " entirely abandoned, the wheel being found not only to be sufficient for impelling the carriage, but also to allow con siderable free traction." Now it is of importance to notice, that although Trevithick and Vivian stated in the plainest language in their specification, twenty-four years prior, that the ordinary wheels alone were sufficient to propel ; Dr. Lardner and other writers, nevertheless, lead their readers to suppose that Trevithick and Vivian were the authors of this error. At page 247 of his Treatise, the Doctor observes,—" The mistake which so long prevailed in the application of locomotion on railroads, and which, as we have shown, materially retarded the progress of that invention, was shared by Mr. Gurney. Without reducing the question to the test of experiment, he took for granted, in his first attempts, that the adhesion of the wheels to the road was too slight to propel the car riage. He was assured, he says, by eminent engineers, that this was a point settled by actual experiment. It is strange, however, that a person of his quickness and sagacity did not inquire after the particulars of these actual experiments. So, however, it was ; and taking for granted the inability of the wheels to propel, he wasted much labour and skill in the contrivance of levers and propellers, which acted on the ground in a manner somewhat resembling the het of horses, to drive the carriage forward. A fter various fruitless attempts of this kind, the experience acquired in the trials to which they gave rise, at last forced the truth upon his notice, and he found that the adhesion of the wheels was not only sufficient to propel the carriage heavily laden on level roads, but was capable of causing it to ascend all the hills which occur on ordi nary turnpike roads." This unqualified admission, by Dr. Lardner, of the entire uselessness of the only invention claimed by Mr. Gurney in hi, patent steam-carriage of 1825, also shows that the Doctor conceived that Mr. Gurney was the individual who "found out" this error of "eminent engineers;" whereas the fact is incontrovertible that hundreds of thousands of miles had been pre viously travelled with plain wheels upon railways, where the adhesion of the former to the surface is not one-tenth of that upon the common road. It also show. that the learned author was entirely unacquainted with the many plans for locomotion, by numerous ingenious men (hereafter noticed) who never entertained the idea that the adhesion of the wheels upon the surface was insufficient to propel. And thus it appears that he, whose brilliant talents we are told had dispelled an age of darkness, was the only individual who could not see the perfect inutility of confessedly his only contrivance in the specification to which we have alluded ; and for which he has been called the inventor of steam•carriages ! We must, however, terminate this digression from the path we set out upon, by making another extract from Dr. Lardner's Treatise ; the first portion of which (page 179) we are pleased to add, because the admirable clearness with which the knowledge it conveys is given, is, in some degree, compensatory for the latter part, to which our complaint alluded. " It is a singular fact, that in the history of this invention considerable time and great ingenuity were vainly expended in attempting to overcome a difficulty which, in the end, turned out to be purely imaginary. To comprehend distinctly the manner in which a wheel carriage is propelled by steam, suppose that a pin or handle is attached to the spoke of the wheel at some distance from its centre, and that a force is applied to this pin in such a manner as to make the wheel revolve; if the face of the wheel and the surface of the road were absolutely smooth and free from friction, so that the face of the wheel would slide without resistance upon the road, then the effect of the force thus applied would be, merely to cause the wheel to turn round; the carriage, being stationary, the surface of the wheel would slip or slide upon the road as the wheel is made to revolve. But if, on the other hand, the pressure of the face of the wheel upon the road hi such as to produce between them such a degree of adhesion as will render it impossible for the wheel to slide or slip upon the road by the force which is applied to it, the consequence will be, that the wheel will only turn round in obedience to the force which is applied to it ; the consequence will be, that the wheel will roll upon the road, and the carriage will be moved forward through a distance equal to the circumference of the wheel each time it performs a complete revolu tion. It is obvious that both of these effects may be partially produced ; the adhesion of the wheel to the road may be insufficient to prevent slipping alto gether, and yet it may be sufficient to prevent the wheel from slipping as fast as it revolves. Under such circumstances the carriage would advance, and the wheel would slip. The progressive motion of the carriage during one complete revolution of the wheel, would be equal to the difference between the complete circumference of the wheel and the portion through which, in one revolution, it has slipped.