In drawing up the present comparative statement, we have left altogether out of consideration the particular competition which called forth the performances here contrasted, and have looked simply to the performances themselves without reference to any conditions or stipulations whatever. It by no means follows that because the judges in this competition thought fit to require that each engine should run a distance of seventy miles, it is only from the performance of such a distance continuously we can form a right judgment of the capabilities of an engine, or that, because "The Rocket" was the only engine which accomplished that distance, it is superior to every other. All that is requisite is, that the distance should be such as to exclude the possibility of our mistaking a momentary for a permanent display of power; and a distance of twenty or thirty miles is aS good for this purpose as one of sixty or seventy. The case will, perhaps, be set in a clearer light, if we substitute time for distance. No one would think of calling an hour's running at a time a mere momentary display; nor can any reason be imagined why an engine that can go fifteen, twenty, or thirty miles in one hour, should not go at the same rate for any number of hours. A steam-engine is not like a horse, which becomes gradually exhausted by exertion; it is as strong and fresh at the end as at the beginning of any journey, however long that journey may be. It has its source of power in the steam generated by the boiler, and the the quantity of steam which boiler generates at one time it must be capable of generating at any other time (the supply of water and fuel remaining always the same). The durability of the materials of which the boiler consists may be affected by the continuity of the process; but that is an evil which would scarcely in any case be felt till after the lapse of a considerable period. It is not, at least, such a drawback as would be taken into account in any experimental trial of the description contemplated by the late competition. Now, though "The Novelty, "The Rocket," and "The Sans Pareil" did not all run 70 miles each, as required by the "ordeal" of Messrs. Rastrick and Wood, they all ran uninterruptedly for more than an hour at once, and to contrast what they did in this equal and adequate space of time, is manifestly a much surer and fairer method of determining their comparative services, than to rank them according to the total distances they ran in different times.

Neither "The Cycloped" and "Perseverance" did perform for an hour continuously, and they are not therefore included in our comparison.

I. The first point to which we have to attend is the respective weight of the engines, since according to their weight must be the degree of friction which they have to overcome. For the reasons we gave in our 323rd Number (pp. 137—141) there must be included in this weight the whole working power of each engine that is, the whole of the machinery and the whole of the materials necessary for putting and keeping it in motion; and, for the sake of greater clearness, we shall reduce this weight into pounds. Each engine is supposed to be fully equipped for a journey of 35 miles continuance.

	Tons.	Cwts.	lbs.
"The Novelty" weighed, according to the canal carrier's receipt	2	15	0
Add for water in the boiler	0	4	2
Water in the tank	0	11	12
Coke baskets and coke	0	0	76
(The three last items estimated by Mr. Vignoles)	____	____	____	lbs.
	3	10	90	=7,930
"The Rocket," according to the official list of the carriages entered for the competition, weighed	4	3	0
The additional tender, with its contents, was stated to weigh	1	13	0
	____	____	____
	5	16	0	=12,992
"The Sans Pareil" weighed, according to the same official list	4	8	0
Add for tender and its contents	1	13	0
	____	____	____
	6	1	0	= 13,652

From this comparison it appears that the working power of "The Novelty" weighs little more than one half that of either of the other engines. It must of course have to the extent less friction to overcome, and do less injury to the rails. It may be supposed that as it weighs less, it will exert proportionably less power: but this is not the case; the area of the cylinder being nearly, and the pressure on each piston precisely the same, in all the three engines.

II. We have next to consider the quantity of fuel consumed by each engine.

The owners of "The Novelty" professed to be able to go one trip of 36 miles with 4 bushels of coke; and what they did perform leaves no doubt on our minds that this is a fair estimate of the quantity that would be required for such a distance.

The fuel consumed by "The Rocket" in performing its two trips of 35 miles each, was stated to be about half a ton.

Of the quantity which "The Sans Pareil" consumed in going its 25 miles, we have no exact account, but we have been informed that it was nearly as much as "The Rocket" required for performing double the distance. The different construction of the boilers of the two engines furnishes a sufficient reason for believing that "The Sans Pareil" must consume a great deal more fuel than "The Rocket;" and we shall not probably err much if we assume then the difference amounts to one-fourth more.

The quantity and cost of the fuel expended by each engine per mile will according to these data stand as follows:-

The saving of expense is not the only advantage gained by reducing the expenditure of fuel; there may be situations indeed where fuel is so cheap as to make any saving in this respect of no moment. A matter of far greater importance is the increased facility which is thus given to the employment of steam power for the accomplishment of long distances at sea particularly. An engine which, like "The Novelty," is worked with two-thirds less fuel than any other engine, will of course go three time the distance with the same quantity and have only to stop once to take in a new supply, while the others have to stop three times.

A reduction so great as has been realized in the case of "The Novelty" was never before accomplished, nor ever we believe supposed to be within the limits of attainment Mr. Gurney was thought to have done wonders, when it was announced the he only consumed half a bushel of coke per mile, at an expense of two pence; but here we have a mile performed with less than the fourth of half a bushel, at an expense of only one farthing!

III. We now proceed to compare the rate of speed accomplished by the different engines.

"The Novelty" went on the second day of the competition, with three times its weight attached to it, 20¾ miles in one hour. The total weight moved, including the carriage, was about 15 tons. In calculating the weight in this instance, no deduction was made on account of the engine's carrying its own water and fuel, but when prepared for its intended trials on the subsequent days of the competition due allowance was made for this circumstance. The load then assigned to it by the judges was 6 tons 2 cwt.* When it accomplished the trips recorded by Mr. Vignoles, (p. 138) the total weight moved, including that of a number of persons on the engine and waggons, was only 10 tons 6 cwt. 1 qr., and the speed which it then realized was nearly equal to 22 miles an hour. It will be observed, that though some increase of velocity was thus acquired, it was by no means proportional to the reduction of the weight; a circumstance which is doubtless to be ascribed to the very imperfect working order in which the engine was at the time of this second trial When the weight drawn was reduced to merely that of a waggon containing 45 persons — equal to about 3½ tons — and the total weight moved to about 9 tons, the velocity was increased to 30 and 32 miles per hour; a rate which though unprecedentedly great, is still less than what the previous performances of this engine, with double that weight, might have warranted us to expect from it.

* In our account of the seventh day's competition we stated, that the weight assigned was 5 tons 16 cwt.; the difference arises from our omitting to include the weight of the water in the boiler.

The total weight moved by "The Rocket" when it went the 70 miles continuously was 17 tons; and the greatest number of miles which it traversed in any one hour was 12½. Stripped of all weight, and carrying just as much matériel as would suffice for a couple of trips of a mile and a half each, it went at the rate of 30 miles an hour. Drawing a carriage loaded with passengers, it went at a velocity which sometimes reached 24 miles an hour.

The weight drawn by "The Sans Pareil," if calculated in the same way as that assigned to "The Rocket," must have been 13 tons 6 cwt. (and not 1800 tons, as stated in our account of the sixth day's proceedings) — the total weighed moved 17 tons 14 cwt. The greatest speed which it accomplished in one hour was 12½ miles.

The comparative speed of the three engines, as verified by the recent experiments, stands therefore as follows:-

The superiority of "The Novelty" is least apparent in the instance of its drawing the least weight; but that as we have before said, must have been owing to its being in a less efficient state on that occasion. Since "The Rocket" doubled its rate of speed when it had only a carriage and passengers to draw, we can see no reason why "The Novelty" should not have done the same, had its machinery continued in an unimpaired state.

"The prize has been at length awarded, and as you rightly conjectured in your last, to Mr. Stephenson. The directors had no alternative, since "The Rocket" was the only engine which fulfilled the conditions of the competition. There are people here, however, who think that the interests of the public would have been quite as well served, had the directors adjudged the premium on a more general view of the matter, and conferred it on that engine which is, upon the whole, "the most improved." I have seen at the Railway- office the Report of the Judges: but cannot say that I have been at all gratified by the perusal. It is confined to a simple report of die performances of the different engines, drawn up with but little discrimination, and in some instances (as I imagine) rather ignorantly. It might have been expected of two gentlemen, who were called in to aid a body of directors with their scientific knowledge on the occasions that they would have made it their business to point out the improvements which the competition has been the means of producing in locomotive machinery, by whom they have been effected, and to what results they lead. But there is nothing of the kind. The directors are left to cull conclusions for themselves out of the facts presented to them; and for aught that appears in the face of the report it might be inferred that all the novelty is on the side of the Rocket, and that the Rocket is the only real Sans Pareil. I need not, however, enlarge on the merits of this document; it will, of course, be soon given to the public, and speak for itself. The directors have offered to purchase both the unsuccessful engines — unsuccessful, at least, as regards the prize; but the offer does not seem to have been viewed in the same light by their respective owners. Ackworth, who had embarked all his means in the building of "The Sans Pareil," has gladly accepted the offer; Messrs. Braithwaite and Ericsson have declined it, under an impression that it might seem their engine was bought less for its merit than on account of its misfortunes. They say they want nothing in the way of favour; and that if they can prove, as they trust to do, that their engine is better adapted to railway purposes than any other which has yet appeared, it will not be an order for one, or a dozen or yet fifty engines, that will satisfy the wants of our railway. "The Novelty" is still here, undergoing a general repair, and is expected to exhibit again on the railway in the course of next week, when it will be brought to a final test, whether it can maintain, for a length of time, the extraordinary speed which its partial performances during the competition displayed."

"THE RAILWAY CONTEST. - On Tuesday last, the judges appointed to report on the performances of the locomotive carriages at Rainhill, gave in their report to the directors, and in consequence of the opinion expressed by them, the prize of 500 was adjudged by the directors to Mr. Robert Stephenson, of Newcastle. It has not yet been decided whether the report of the judges shall be published or not: we understand, however, that it expresses no opinion as to the principle of Messrs. Braithwaite and Ericsson's carriage, but merely gives a statement of the respective performances of the different carriages.— Messrs. Braithwaite and Ericsson, the proprietors of "The Novelty," and Mr Robert Stephenson, the proprietor of "The Rocket," are both engaged in improving and perfecting their carriages. The former is now repairing at Messrs Fawcett's yard; and it is said that it will be tried again on the railway when finished. A considerable alteration, has also been made in Mr. Robert Stephenson's engine, which has greatly increased its powers. It was tried again on Saturday, when it drew the enormous weight of 20 tons, at the rate of from 18 to 20 miles per hour."