The Novelty, which was not tried until the 10th, owing to unavoidable circumstances, carried its own water and fuel; and, therefore, to place it on the same footing as the other engines, the same proportion of useful load was assigned to it when compared to the engine, as the useful loads taken by the other engines have to their weight. The power and its load were accordingly as follow:-
Weight of the Novelty, with water in the boiler ..............
Tank, water, and fuel ......................................................
Two loaded carriages attached ......................................
Total weight in motion ...............................................
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The Perseverance, after a short trial, was proved unsuited to the railway, and was immediately withdrawn by the proprietor.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 500/., 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 be properly 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.
To discover the cause of the great increase of speed, and the variable quantities of fuel consumed by the different locomotive engines, which competed for the prize at the Manchester and Liverpool railway, Mr. Wood instituted the comparative view of each, which is exhibited in the following table:-
Names of Engines.
Fire-grate in feet.
Area of radiant Surface, in feet.
Area of communicative
Surface, in feet.
Cubic feet of
Water evaporated per hour.
Rocket . . .
Sans Pareil .
Novelty. . .
"In examining the above, we find a very important effect in the economy of fuel, produced by the Rocket over the old engines, in the proportion of 11.7 to 18.34, supposing the heating powers of coke and coal be equal. The cause of this is very obvious, and is entirely attributable to the use of the tubes of small diameter, presenting such an area of surface to the water in the boiler. These tubes were used at the suggestion of Mr. Booth, treasurer to the Liverpool and Manchester Railway Company, and nothing, since the introduction of those engines, has given such an impulse to their improvement.
"With a less area of fire-grate than the old engines, the surface exposed to the radiant heat of the fire is as 20: 11.5, and the surface exposed to the communicative power of the heated air and flame, as 117.8: 29.75, nearly four times as great.
"Nor is this the only difference; in the old engines the area of the tube (of 22 inches diameter) for the passage of the flame and heated air to the chimney, was 380.13 inches; and of this large body of flame and air passing through the tube, only an extent of surface of 69.11 inches was exposed to the water in the boiler. In the Rocket engine, the area of heated air and flame in 25 tubes, 3 inches each in diameter, was 176.7 inches, while the surface exposed was 235.6 inches.
"It is not necessary, perhaps, to pursue the comparison further. The economy of fuel which must result from the exposure of so much greater surface to the water, cannot fail to insure a more perfect abstraction of the heat, and thus not only save the fuel, but prevent great part of the previous destruction of the chimney, by the intense heat of the wasted caloric.
"The same remarks apply to the Sans Pareil of Mr. Hackworth, as to the old engine, though in a less degree. In the Rocket, the surface exposed to the radiant heat of the fire, compared with the area of fire-grate, is as 3 1/3: 1, while in the Sans Pareil, it is only 1 1/2: 1; the same proportion as in the old engines. In the Rocket, the surface exposed to the heated air and flame, compared with the area of fire-grating, is as 19 2/3: 1; while, in the Sans Pareil, the proportion is only 7 1/2: 1. The bulk of air passing through the tube of the latter, will, at its exit into the chimney, be 176.7 square inches, the exposed surface being 47.12, or .25: 1, nearly; while, as before stated, the bulk of air passing through the tubes of the Rocket, is 176.7 inches, or precisely that of the Sans Pareil, while the surface exposed, is 235.6 inches, or l 1/3: 1. These will sufficiently account for the great difference'in the economy of fuel between the two engines, the Rocket requiring only 11.7 lbs. to convert a cubic foot of water into steam, while the Sans Pareil required 28.8 lbs."
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 the engines previously used; but the furnace and boiler have considerable claims to novelty and effectiveness.
The furnace at A is a square box, about 3 feet wide and 2 feetdeep. This furnace has an external casing, between which and the fire-place there is a space of 3 inches filled with water, and communicating by a lateral pipe with the boiler The heated air, etc. 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 communicating by their piston rods, through the media of connecting rods E, motion to the running wheels. P G 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.