In the early part of the trial with this engine, the water supply-pipe burst, and put an end to the experiment for that day. Two or three days afterwards the trial was renewed, but another unfortunate accident (that of one of the joints of the boiler giving way) terminated the proceedings, at the desire of Mr. Erricson, who voluntarily withdrew his carriage from the contest. The performance of the engine, while it lasted, indicated very excellent results; the design, arrangement, and execution of the work, were likewise highly creditable to the genius and talent of the proprietors.

The Perseverance, after a short trial, was proved unsuited to the railway, and was immediately withdrawn by the proprietor. The course was thus left clear for Mr. Stevenson to receive the fairly won prize of 500l., which was awarded to him by the judges.

The Cyclopede, though included in the foregoing list of rival machines, not being propelled by the power mentioned in the "stipulations and conditions," it could not properly be considered as entering the lists for the prize therein proposed; it was, however, an inquiry well worth the investigation, what degree of power horses could exert in a locomotive machine of the kind, and thereby determine its comparative economy with that of steam. For these reasons a trial of the Cyclopede took place; but it only attained a speed of five or six miles an hour, owing, as we believe, to the horses not having sufficient power to exert themselves in their stalls, as well as to an injudicious construction of some parts.

Having now stated the results of this memorable contest, it becomes necessary to give some account of the machines engaged therein.

The Rocket, constructed by Mr. Stevenson, of which an external side elevation is given in the following figure, possesses many of the characteristics of those

which were worked upon other railways, as already described. The furnace at A is a square box, about 3 feet wide, and 2 feet deep. This furnace has an external casing, between which and the fireplace there is a space of 3 inches filled with water, and communicating by a lateral pipe with the boiler. The heated air, &c. from the furnace passes through twenty-five copper tubes, 3 inches in diameter, arranged longitudinally on the lower half of the boiler, and then enters the chimney C. D represents one of the two steam cylinders, which are placed in an inclined position on each side of the boiler, and then enters the chimney C. D represents one of the two steam cylinders, which are placed in an inclined position on each side of the boiler, and communicating by their piston rods, through the media of connecting rods E, motion to the running wheels. PG are safety valves; E is one of two pipes on each side of the boiler, by which the eduction steam from the cylinders is thrown into the chimney, and, by the exhaustion thus caused in the latter, producing a rapid draft of air through the furnace. At M is exhibited part of the tender, which carries the fuel and water for the supply of the engine.

A little reflection upon the construction of this boiler will evidently show the great advantages it possesses of generating steam with rapidity, and hence the superior effects in propelling the carriage and its load. There are twenty square feet of heated metallic surface surrounding the furnace, the flames and heated matter from which infringe afterwards upon the twenty-five copper tubes lying immersed in the lower part of the boiler. These tubes contain 117 square feet of surface, making altogether 137 superficial feet of heated metal in contact with the water. We understand that Mr. Booth suggested the arrangement of the flue tubes leading from the furnace to the chimney; and we make no doubt that it was mainly owing to this contrivance that the prize was won by Mr. Stevenson's engine.

The Novelty, by Messrs. Braithwaite and Erricson, is exhibited in the subjoined sketch, representing a side elevation of the machine.

F is the carriage-frame; E, one end of a long horizontal cylinder, forming the principal part of the boiler, which extends to the large vertical vessel A, at the other end of the carriage, and contains forty-five gallons of water; L, a hopper to supply the fuel, (which is carried in small baskets placed on the carriage,) whence it is conducted by a tube in the centre of the steam-chamber A, into the furnace S, beneath. At C is a blowing machine, the air from which is conducted by a pipe under the carriage, and proceeding by the tube K enters the ash-pit M, under the furnace; Q is a pipe for the escape of the heated gases after the combustion, and forms the only chimney used; B is the water-tank; at D N are two working cylinders with their steam-pipes and valves; the cylinders are six inches in diameter, and have a twelve-inch stroke; O G are connecting-rods, which impart the force of the engines to the runningwheels. The axletrees are fixed to an iron rod, and slings are introduced to prevent the side action between the rod and the carriage frame; and to prevent the effect of the springs from counteracting the action of the engine, the connecting-rods are placed as nearly as possible in a horizontal position, and the motion is communicated to them by bell-cranks on each side of the carriage, being connected by the slings to the piston rods. The pistons used are the patent metallic of Barton (see PISTON); and the running wheels, the patent suspension kind, of Theodore Jones and Co. (see WHEELS.)

The figure, on page 514, exhibits a section of the boiler introduced by Messrs. Braithwaite and Erricson, into the Novelty steam-carriage, which we are induced to insert here, as it has been deemed, by some persons, to be the grand desideratum in this branch of practical mechanics. It is, therefore, desirable that its real merits should come under the consideration of the reader. S is the furnace, surrounded by water; and L the tube by which the fuel is supplied to feed the fire; M is the ash-pit, through which the air is forced by the pipe K from the bellows of the engine. The vessel containing the water that surrounds the furnace, and the long cylinder that proceeds horizontally from it, constitute the boiler, as shown at E E e. The flames and heated air from the furnace, after ascending by the action of the bellows, enter a long tortuous flue, which

makes three turns in the entire length of the horizontal boiler, escaping finally at the chimney. The fuel in the furnace has, therefore, a direct action upon

the water surrounding it; and the water in the long cylinder is operated upon by the gases in the flue, which gradually tapers from the furnace to the chimney, and has a constant inclination downward. This part of the arrangement seems to be good, as affording convenient means of cleansing the flues of any soot that may deposit itself in them, which, it is presumed, may be performed at any time, by an energetic application of the blowing machine; and as the whole of the furnace and flue is surrounded by the water of the boiler, there can evidently be very little of the heat from the fuel misapplied.

The Sans Pareil of Mr. Hack worth, (see the engraving on the opposite page,) does not materially differ from the Rocket, the most conspicuous variation being the vertical, instead of the inclined position, of the working cylinders. The boiler B is cylindrical, of the Trevithick kind, with one of its ends convex outwards, and the other flat. The fire-bars were of greater extent than usual, having an area of ten feet; and the flue-tube is returned to the front on one side of the fireplace, where it enters the chimney C. This fire-tube is of course entirely surrounded by the water in the boiler, and hence a considerable surface (though not so great as in the Rocket and Novelty) of heated metal is brought into contact with the fluid to be evaporated. D represents one of the two workingcylinders; these were seven inches in diameter, and had an eighteen-inch stroke. The piston rods, through the medium of the vertical connecting rods, operated upon the hind pair of wheels; and the latter being connected to the fore wheels by the horizontal connecting rods, shown acting in the manner of cranks, motion was communicated to both pair of wheels,-an arrangement which is designed to cause a greater adhesion of the wheels to the rails, and of enabling the carriage to draw a greater load, than if only one pair of wheels was operated upon.

The Cyclopede, by Mr. Brandreth, which was also tried upon the railway, is represented in the cuts on pp. 515, 516; Fig. 1 being a side elevation, and Fig. 2 a plan of the same. It consists in an endless chain a a a, made of planks, about an inch and a half thick, and four inches wide, extending across the bed of the carriage, attached at their extremities to ropes, and carried over a drum bb, at each end of the carriage, as shown in the plan at Fig. 2. To strengthen these cross pieces, and to prevent one of them from slipping down by itself, a cleat cc, is nailed on the end of each, and extends half-way across those next to it, on cach side: the position of these, as they pass over the drums bb, will best show their extent and attachments. The chain platform is supported on a series of anti-friction rollers e e e e. The horse is yoked to the frame, and, by treading