When the engine arrived at the post, No. 1, in returning, it was found that the pipe conveying the water from the forcing pump to the boiler had been burst open; occasioned, Mr. Erickson said, by the cock which opens or shuts the communication from the pump with the boiler, having been accidentally shut while the pump was working. This being repaired, it was too late to go on with the experiment this day, but the engine, (according to a statement by Mr. Vignoles, published in the Mechanics' Magazine,) with a calculated weight of ten tons six cwt. and one quarter, traversed the eastward trip of one mile and a half in four minutes thirtynine seconds, being at the rate of seventeen miles and a half per hour, and the westward trip in five minutes fifty-four seconds, being at the rate of fifteen miles an hour. The loaded carriages being detached, the engine made a trip with passengers, going at the rate of between twenty and thirty miles an hour. Two or three days being allowed to get the engine into complete working order, (as many as Messrs. Braithwaite and Erickson requested,) it was again, on the 14th, put upon its trial.

On the arrival of the judges at Rainhill at the appointed time, they found that several parts of the engine having been taken to pieces, were not put together, and a considerable time elapsed before this was done; to prevent unnecessary delay, therefore, no account was taken of the quantity of fuel necessary to raise the steam to the proper degree of elasticity. The engine being ready, made a trip to see if every thing was right, and then came up to the starting-post. It was then set off upon its task in the same way as the others, and the following Table will shew its performance.

In returning westward, the second trip, some of the joints of the steam generator gave way, and put an end to the experiment; after which, Mr. Erickson declared to the judges his wish to withdraw from a further competition for the prize.

No conclusion whatever could be formed from these experiments, of the power of this engine; none of the experiments were continued sufficiently long to shew the quantity of steam which could be raised in a given time, or the fuel required to generate it.

The "Perseverance," of Mr. Burstall, having met with an accident in its conveyance to Liverpool, and having been found, on trial, not to be adapted for the purposes of the company, this gentleman, in a very handsome manner, withdrew from competing for the prize.

The prize was then awarded to the "Rocket," of Mr. Stephenson, as having performed all the conditions and stipulations required of the competitors.

We shall, in the first place, give a brief sketch of the construction of the different engines, and then offer a few remarks on the important improvements, to which these experiments have led.

Art. 11.-Description of the "Rocket" Engine.

The "Rocket" engine, of Mr. R. Stephenson, shewn in the engraving, No. 7, opposite, differs from the locomotive engines previously described in this work, in the mode of raising steam. The boiler, a, is cylindrical, with flat ends, six feet long, and three feet four inches diameter. To one end of the boiler is attached a square box, or furnace, в, three feet long, by two feet broad, and about three feet deep; at the bottom of this box, the fire-bars, F, are placed, and it is entirely surrounded by a casing, except at the bottom, and on the side next the boiler, leaving a space of about three inches between this casing and the furnace, which space is kept constantly filled with water; a pipe, c, on the under side, communicating with the boiler, supplies it with water; and another pipe, D, at the top, allows the steam to pass off into the boiler. The upper half of the boiler is used as a reservoir for steam, the lower half being kept filled with water. Through the latter part of the boiler, copper tubes reach from one end of the boiler to the other, shewn in No. 8, being open to the fire-box, at one end, and to the chimney at the other. In the boiler of the "Rocket," there were twenty-five tubes, three inches in diameter. The cylinders were placed, one on each side of the boiler, as shewn in the drawing, and worked one pair of wheels only; were eight inches diameter, with a stroke of sixteen inches and a half; diameter of large wheels, four feet eight inches and a half. A slight inspection of the

No. 8.

drawing will shew that the principle of generating steam by this engine, is the exhausting power of the chimney, which is aided by the impulse of the steam

No. 7.

from the cylinders, being thrown into the

chimney by two pipes, E, one from each of the cylinders. The area of surface of water, exposed to the radiant heat of the fire, was twenty square feet, being that surround

ing the fire-box or furnace; and the surface exposed to the heated air or flame from the furnace, or what we shall call communicative heat, 117.8 square feet; the area of the grate-bars being six square feet. The end view, No. 8, will shew the disposition of the tubes in the end of the boiler, with the fire-box surrounding the end.

Art. 12.-Description of the "Sans Pareil" Engine.

The "Sans Pareil," of Mr. Hackworth, is of the same principle as the "Rocket;" the combustion of the fuel being effected by the exhausting power of the chimney, and the ejection of the steam from the cylinders into the chimney.