On the lath of May, 1824, Mr. W. H. James (a gentleman of superior mechanical talents) of Birmingham, obtained patents for an improved method of constructing steam carriages ; " the chief peculiarity in the arrangement of which consisted in adapting separate engines to the gear of each of the propelling wheels, instead of actuating them uniformly by the same engine, whether the latter consists of one or two cylinders. Mr. James's design was to use very small cylinders, and work them with steam of very high pressure, so as to obtain the utmost compactness, and the least weight that might be practicable. The motive of employing to engines was that each wheel might have a motion independent of any wheels, so that their powers or velocities might be varied at pleasure, which he considered to be essential in passing round curves, or turning corners of the road, because, when a carriage moves in the . arc of a circle, the outer wheel moves over a greater space of ground than the inner wheel, and would consequently render it necessary far the engine con nected with the outer wheel to work so much faster than the engine connected with the inner wheel. Mr. James's mode of effecting this operation was by a very simple contrivance : he caused the fore azletree to be connected with a stop-cock placed in the main pipe, through which the steam passes from the boiler to the respective engines ; and this stop-cock was so constructed, that when the fore azletree stood at right angles to the perch (L e. when the carriage was proceeding in a straight line) it admitted equal quantities of steam to each engine; but whenever the azletree stood obliquely to the perch (as in making curves) it caused the stopcock to admit a greater quantity of steam to the engine connected with the outer wheel, so as to cause that wheel to revolve faster, and a diminished quantity to the engine connected with the inner wheel, so as to make it revolve slower, in exact proportion to the curve around which the carriage was moving.
Upon roads having steep ascents, Mr. James proposed to employ four engines, or one to each wheel, for the purpose of obtaining a greater degree of resistance upon the surface over: but in roads of ordinary undulations, two engines were deemed ntfltcient; the wheels do not require. to be thrown out of gear, but in passing round curves may be kept constantly in action, so as to preserve the amount of friction upon the surface pretty uniform. In passing down a hill, however, or whenever it may be desired, a wheel may be locked or dragged, as in other carriages.
Another leading object with Mr. James was to put the whole of the machinery upon springs, to prevent the injurious consequences to the acting parts, by the concussions of a stony road, and at the same time allow of the uniform operation of the engines upon the running wheels, when passing over rugged surfaces. To this end Mr. James caused the engines and their frame-work to vibrate altogether upon the crank shafts as a centre; at the same time connecting these engmes to the boiler and exitby means of hollow axles moving in stuffing-boxes, which, together of the carriage, is suspended upon oprings,'that are bolted to the axletrees.
Bp. 1, in the following cuts, exhibits a plan of the machinery of a carriage, as applied to the hind wheels. Fig. 2 is a cross section, giving an end view of the boiler and the cranks, showing the manner in which the former is suspended, its mode of attachment to the body of the carriage, and the situation of the springs on which it rests: similar letters of reference apply to the corresponding parts in each of the figures. a a is the boiler suspended to the frame 6 6, above which is connected to the body of the carriage c c, and forms its support ; d d is the axletree, the form of which is best seen in Fig. 2 ; it has four supports e e e e; the axles of the running wheels f f are affixed thereto, and are connected in one piece with each of the crank shafts g g, by which one wheel is made to revolve independently of the other. Each of these engines bas two cylinders is 6, which operate by their piston rods upon the cranks ; to these separate engines steam is applied from the boiler a a, by means of the pipe k, which enters at the stop-cock 1 into the steam-box as; from this box the steam passes into the pipes a a, which move steam-tight through stuffing-boxes; from thence the steam proceeds through the pipes o o o to the slide boxes p p p, the slides being worked by eccentrics q q q, in the crank shafts, in the usual manner, and thence to the cylinders. The exhaustion pipes r r lead into the hollow axles a a,
before described, in which there are partitions a s, to separate the steam from the exit passages, which pass through the said hollow axles to the boxes a t, from which there are pipes u u leading to the chimney v, where it is thrown off in a jet, which has the effect of increasing the draught, and of exciting com bustion of the fuel. The rods x x are attached to the fore axle of the running wheels, and also to the two handles of the cock 1, so that the fore axle and the cock move simultaneously, and parallel to each other; • x a represent part of the frame-work extended, for tying the engine together by means of a bolt, and so as to allow the body of the carriage to have a slight lateral motion upon its springs, independently of the engines, by means of the hollow axles sliding longitudinally through the stuffing-boxes.
The principal arrangements in this locomotive engine are ably designed to accomplish the object in view ; but the intelligent inventor (owing, we believe, to some pecuniary disappointments) was not enabled to prosecute the under taking of building carriages until some time afterwards. In the interim, how ever, he was engaged in other scientific pursuits connected with locomotion, and in the construction of a boiler capable of generating steam of very high pressure, with perfect safety : be also occupied himself in the application and adaptation of small high-pressure engines to the generating apparatus; and on the 5th of March following he took out a patent for a tubular boiler, which was decidedly the most effective machine of the kind that had then been invented. It consisted of a series of annular tubes, of equal capacity and diameter, placed aide by side, and bolted together, so as to form by their union a long cylindrical boiler, somewhat similar in external figure to that shown in Fig. 1, but from being made of small tubes, capable of resisting full one hundred times the pres sure pf an ordinary cylindrical boiler. This excellent apparatus being fully described at page 202, in our article BOILERS, we shall not here extend the description, and have only to observe that it was with boilers of that description, and a carriage slightly modified from the one just described, that Mr. James, about two years after, commenced the construction of steam carriages. This undertaking, in its progress, promised the most favourable results, the experi ments that were made demonstrating the certainty of the ultimate accomplish ment of perfect success; but a failure in his pecuniary resources prevented its consummation. Some friends of ours assisted at some experiments made with the first carriage, on the 5th of March, 1829, over a rough-gravelled road in Epping Forest, which it traversed, with fifteen passengers, at a speed varying from twelve to fifteen miles per hour. This carriage was exceedingly clumsy, having been repeatedly cut and altered, as successive changes were made in the disposition of its parts for experiment, and it weighed, including the machinery, rather more than three tons. It had two working cylinders, only 31 inches diameter, the power of which was applied to the hind running-wheels. The steam was supplied by two tubular boilers, of the before-mentioned kind, each being a cylindrical annulus of one-inch tubes, 4 feet 6 inches long, and 1 foot 9 inches internal diameter, wherein the fire was placed. During the experiments, one of the tubes (which were the common gas pipes) opened in its seam, and consequently all the water of that boiler escaped, extinguished its fire, and reduced the intensity of the other, there being a communication between them. Thus circumstanced, with only one boiler in operation, the carriage returned home, at the rate of seven miles an hour, with more than twenty passengers, demonstrating thereby this remarkable fact,—that a sufficient power of steam can be generated in so small a boiler, as to be adequate to the propulsion of about 41 tons weight on the common road.