water into the boiler, at such times and in such quantities as may be required. The two beams are connected at one end with the piston rods, and at the other

with the rocking standards H H. At about one-fourth of the length of the beams from the piston rods are the two connecting rods gg, their lower ends

being attached to two cranks, formed at angles of 90° from each other on the hind axle, giving, by the action of the steam, a continued rotatory motion to the wheels, without the necessity of a fly-wheel. The four coach wheels are attached to the axles nearly as in common coaches, except that there is a ratchet wheel formed upon the back part of the nave, with a box wedged into the axle, containing a dog or pall, with a spring on the back of it, for the purpose of causing the wheels to be impelled when the axle revolves, and at the same time allowing the outer wheel, when the carriage describes a curve, to travel faster than the inner one, and still be ready to receive the impulse of the engine as soon as it comes to a straight course.

"The patentees have another method of performing the same operation with the further advantage of backing the coach when the engines are backed. In this plan, the naves are cast with a recess in the middle, in which is a double bevelled clutch, the inside of the nave being formed to correspond. The clutches are simultaneously acted upon by connecting levers, and springs, and which, according as they are forced to the right or left, will enable the carriage to be moved forward or backward. To the fore nave are fixed two cylindrical metal rings, round which are two friction bands, to be tightened by a lever convenient for the foot of the conductor, and which will readily retard or stop the coach when descending hills. K is the seat of the conductor, with the steering wheel L in the front, which is fastened on the small upright shaft 1, and turns the two bevel pinions 2, and the shaft 3, with its small pinion 4, which working into a rack on the segment of a circle on the fore carriage, gives full power to place the two axles at any angle necessary for causing the carriage to turn on the road, the centre of motion being the perch pin I.

"The fore and hind carriage are connected by a perch, which is bolted fast at one end by the fork, and at the other is screwed by two collars, which permit the fore and hind wheels to adapt themselves to the curve of the road. To ascend acclivities, and particularly where the carriage is used on railways, or to drag another behind it, it is presumed that greater friction will be required on the road than the two hind wheels will give, and there is, therefore, a contrivance to turn all the four wheels. This is done by a pair of mitre wheels 4, one being on the hind axle, and the other on the longitudinal shaft 6, on which shaft is a universal joint, directly under the perch pin I, at 7. This enables the small shaft 7 to be turned, though the carriage should be on the lock. On one end of the shaft 7, is one of a pair of bevel wheels, the other being on the fore axle, which wheels are in the same proportion to one another as the fore and hind wheels of the carriage are, and this causes their circumference to move on the ground at the same speed. The engines were calculated at ten horses' power, and it was purposed to use steam of the highest pressure, which was to be let off into a separate vessel, and the quantity emitted to be regulated by one or more cocks."

"From the foregoing description," (observes the editor of the before-mentioned journal) we think we are warranted in saying, that there is considerable degree of ingenuity, as well as originality, in many of the details, and also in the general arrangement of the machinery. In this light we regard their mode of allowing the several wheels to move simultaneously at different velocities; the convoluted form given to the steam and water pipes, by which the injurious effects of jolting are avoided by very simple means; and the mode of injecting water into the boiler by means of compressed air."

"By the present improvements, the boiler is to be placed upon an additional pair of wheels, so that the whole machine may run upon six wheels instead of four. The patentees claim two distinct modes of employing this extra pair of wheels, either of which may be adopted. By the first mode, the back end of the boiler is bolted to the axletree of the extra wheels, and the front end rests and turns upon a pivot, fixed to the axle of the middle pair of wheels. By the second mode, the axle of the hind wheels turns upon a centre, and the boiler is attached to a frame, which encompasses it; this frame is suspended upon springs or not according to the nature of the road,) the part of it being bolted to the axle of the middle pair of wheels. By either of these contrivances, the carriage

containing the boiler may be made to adapt itself to the bends in the road, without incurring injurious strains.

"The next improvement of material importance, consists in the construction of the steam pipes, which have sliding and movable knee-formed joints, to admit of their extension and contraction, when the carriage is passing over rough or undulating ground; thus constructed, the pipes also accommodate themselves to bends and irregularities in the road. The third improvement relates to the mode of steering the carriage, which is effected by a chain circumscribing the steering wheel the ends of the chain then passing round pulleys fixed to the carriage frame, are attached to the opposite extremities of the fore axletree."

Shortly after the publication of the foregoing announcement in the Edinburgh

Journal of Science, we had an opportunity of inspecting a working model con

structed upon a scale of three inches to the foot, which embraced these improvements. It was publicly exhibited in Edinburgh, and afterwards in London, where it was made to travel round a circle of 17 feet diameter, on an uneven deal floor, with a speed equal to about 7 miles per hour. A deal platform, 18 feet long, rising 1 foot at the end (or 1 in 18) was fixed, which the carriage ran rapidly up without apparent effort. On the outside of the circle was a deal bank which rose 5 in 25, in the cross section, which was used to show that there was no liability of upsetting the carriage even by such uneven ground, owing to the position of the centre of gravity being very low. The representation of this model, on the preceding page, and the description of the machine, we extract from the Register of Arts published at that period. "The length of the model is 5 feet, and its height 22 inches. The steersman sits in front, and by turning a circular horizontal plate c gives the first pair of wheels a direction to the right or the left, as may be required. The boiler b is of a conical form, and is supported by an iron frame, extending from the second to the third pair of wheels. The fire is in the middle of the cone, and the water and steam outside. The engines are of the high pressure kind, and the boiler is of copper, calculated to sustain ten times the force of the intended working pressure of the steam. Two cylinders are employed, they occupy the hind boot, and rest on the axle of the middle wheels; in the model the cylinders are three inches in diameter, and have a three-inch stroke. The cistern is at a, whence the water is pumped by the engine, and forced into the boiler; e is the induction steam pipe, i the eduction pipe, leading to the chimney, wherein the waste steam being expanded by the heat, escapes invisibly, while it increases the draught, and combustion of the fuel. When the writer saw this interesting model at work, he was informed by the partner of Mr. Burstall, that it had. during the preceding eight days, ran as many times round its circular course as amounted to 250 miles; and that during all that period it required no fresh packing or repair whatever.

On the 15th 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 separate engines was that each wheel might have a motion independent of any of the other 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 for the engine connected 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 axletree 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 axletree stood at right angles to the perch (i. e. when the carriage was proceeding in a straight line) it admitted equal quantities of steam to each engine; but whenever the axletree stood obliquely to the perch (as in making curves) it caused the stop-cock 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 passed over: but in roads of ordinary undulations, two engines were deemed sufficient; 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 engines to the boiler and exit passages, by means of hollow axles moving in stuffing-boxes, which, together with the body of the carriage, is suspended upon springs, 'that are bolted to the axletrees.

Fig. 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 bb, above which is connected to the body of the carriage c c, and forms its support; dd 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 ff are affixed thereto, and are connected in one piece with each of the crank shafts gg, by which one wheel is made to revolve independently of the other. Each of these engines has two cylinders