was wasted; but with the atmospheric system what was there? A rope of air, without weight or friction-positively nothing but the carriages to carry-so that very nearly the full dynamic effect of the power generated was obtained; they had no additional resistance but what the friction of the piston in the tube and the opening of the valve might create; this, added to the friction of the carriages, was all that there was to overcome. On the locomotive lines, fully half of a train, on the average, consisted of the engine and tender; besides which, there was to be considered the expense of locomotive power, compared with stationary. It would be ridiculous in him, in Cornwall, to attempt to enlarge on the benefits of stationary over locomotive power. On the Blackwall Rail

way, the rope and pulley system was carried to the utmost possible perfection; but what was the peculiar result? It was admitted that this line was working at double the expense of many of the ordinary railways.

The ex

pense of carrying a train there was 78. per train per mile, which was double of what it was on the North Union and Dublin and Kingstown Railways. The expense on the Belgian railways was about 48.; the average of the American lines, only 38.; the average in England was about 48. to 48. 6d. But here, what was the moving power?-it was a column of air. And what was the retarding power?-A column of air, also. The moving and retarding powers were alternately columns of air; and every engineer knew, that, if it were possible to apply an atmospheric buffer, it would be the most efficacious of all buffers. In the atmospheric system, a rope of air was substituted for one of hemp or iron, so that the minimum of friction, with the maximum of useful effect, was obtained. * * Now for the price to be paid for this. He ventured to state, on his professional reputation and experience as an engineer, that the sum of from 10,000/. to 12,000l. a mile would make a most excellent railway, in any part of the country between Falmouth and Exeter. * * * * * *

*

Then came the advantage of getting rid of the heavy rail and expensive apparatus required for the locomotive engines. The rail about to be placed on the extension of the Dublin and Kingstown line would probably weigh only about 18 lbs. per yard; and such a rail, for an atmospheric engine, was greatly stronger, in proportion, than the ordinary rail now used for a locomotive. He must be understood to speak always of a single line for the atmospheric railway; on that system it was impossible that two trains

could travel together in the same direction, except they were at least one station, or three miles, apart-neither could trains travel in opposite directions, so as to approach each other within that distance therefore, collision, and overtaking, and such causes of accident, were perfectly impossible. It was also clear that, from the construction of the apparatus, carriages could not get off the line of railway. Single lines would, therefore, be perfectly sufficient.

NOTES AND NOTICES.

The Smoke Nuisance.—Williams' Argand Furnace. -The impulse given to the consideration of means for the removal of the smoke nuisance, by the late meeting to consider the subject, in this town, (Leeds,) and particularly by the provisions of our Improvement Act, which comes into operation next January, is as important as to many it may appear surprising. The other day we visted, in company with the Town Clerk, the Patent Argand Furnaces of C. W. Williams, Esq., erected at the works of Mr. William Hill, flax spinner, Mabgate. We saw the plan in operation applied to a wagon boiler, only completed last week; but beside it there is a Cornish boiler, to which the same principle has been applied for above nine months, with the disadvantage, however, of previously working to the chimney common to both boilers, so that the prevention of smoke from the fire attached to the Cornish boiler has hitherto been very imperfectly distinguishable by the chimney. On Tuesday, however, when the wagon boiler only was in use, the smoke was very dense when the operation of the patent air distributor was cut off, and entirely removed on its again being put in action. The coal was small, a common kind of slack; the method of firing was very simple, no precaution being used more than in ordinary firing. The issuing or nonissuing of smoke from the chimney depended on the action of the apparatus, as was repeatedly tested, and always with the same effect. The whole plan seems to consist in admitting the air to the boiler fire by a peculiar method of dividing it into small streams or jets, thereby mixing it immediately with the crude coal gas as it escapes from the fire grate over the bridge. This mixture being highly inflammable, the flues (as we observed by the sight-holes provided at the exterior of the sideflues,) became filled with smokeless flame. The extensive adoption of Mr. C. W. William's method speaks much in its favour; we learn that it has been put on board nine steam-boats, and has been adopted for 140 furnaces in different parts of the kingdom during the last eighteen months.-Leeds Mercury.

The Great Western.-It has been announced “by authority," that at the late quasi sale of this vessel, she was bought in for the original proprietors. There were some bona fide offers, but none which came up to the minimum price which the Directors of the Great Western Company had made up their minds to accept.

INTENDING PATENTEES may be supplied gratis with Instructions, by application (postpaid) to Messrs. J. C. Robertson and Co., 166, Fleet-street, by whom is kept the only COMPLETE REGISTRY OF PATENTS EXTANT from 1617 to the present time).

[The chief manufacturers as well as champions of the four-wheeled locomotive engine, as most of our readers are, no doubt, aware, are Messrs. Bury, Curtis, and Kennedy, of the Clarence Foundry, Liverpool, who make for the London and Birmingham Railway. "To show the process of reasoning, by which, aided by experience and the closest observation, they have arrived at the conclusion of preferring the four-wheeled to the six-wheeled engines," they have recently sent forth a Circular vindicatory on the subject, accompanied with engravings of the "Albert," one of their latest and best specimens of a first-rate four-wheeler. They were the more induced to do this, they say, because "there have not been wanting those whose anxiety to feed the public prejudice, and to profit by the effect of it, has led them to allege many things against four-wheeled engines, which are both untenable in principle and untrue in fact:" and because, also, "in all the discussions which have taken place on the subject, none, or scarcely any stress has been laid on that which is substantially the main feature of the whole case," namely, "the different effects of inside and outside bearings." Having ourselves taken a somewhat decided part in favour of the six-wheeled engine-though assuredly from no such motives as those glanced at above-we deem it only fair to make our readers acquainted with all that Messrs. B. C. and K. have to say on the opposite side. Our own opinions, certainly are not in the least shaken by this Circular; but we desire that our readers should judge for themselves. We would merely remind them, that the point in dispute (so far as the public are concerned) is, not which sort of engine is the cheapest, but which the safest; and beg also their attention to this remarkable fact, that Messrs. B. C. and K. do not touch once, throughout their Circular, upon what has been always considered the most serious objection to the four-wheeled engines -their tendency to jump off the rails. We published two or three weeks ago (Mech. Mag., Oct. 8,) a communication from a "Practical Engineer," (a gentleman of as high authority on railway matters as Messrs. B. C. and K. themselves,) in which there are some facts stated about the jumping tendency of the four-wheelers, which may perhaps serve to show, why it is deemed prudent by the apologists of this class of engines to say nothing about it.-ED. M. M.]

The Manchester and Liverpool Railway was the first that ventured upon the use of steam locomotive power, for the conveyance of passengers at a rapid rate, and the first engine made for that great and spirited undertaking, in 1828, had six wheels. This engine, however, failed to give satisfaction, and a premium of 5007. was, in the same year, offered by the directors for the best engine. After many trials the premium was awarded to a four-wheeled engine.

The four-wheeled engines of that day had all of them outside frames, and were used on the Liverpool and Manchester Railroad for four or five years, without other objections than the loss from the breakage of axles, arising from the defective plan of the frame, viz., in its being placed outside the wheels.

Experiments were subsequently made, intended to show that economy of fuel resulted from the use of a large fire-box; but the consequence was, that this part of the engine became so heavy as to require support behind it, and hence arose the re-introduction of a third pair of wheels, which had been previously abandoned as highly objectionable.

The engine-makers generally of the country had no choice of the form of engine, but had to conform to the plans of the directors or engineer of the company, and did not examine minutely the merits of the new plan of construction, and engines continued, for some years, to be made ordinarily with outside frame, large fire-box, and six wheels.

It was the good fortune of the conductors of this foundry to originate the construction of four-wheeled engines, with inside framing, crank axles, and cylinders, placed in the smoke-box-all the practical and mechanical objections to the sixwheeled engines, and particularly with outside framing, having been foreseen at the earliest period. The first engine made upon this principle was manufactured in this foundry, in 1829, prior to the opening of the Liverpool and Man

chester Railway. As the principle of the four-wheeled engine thus made gained publicity, great alterations have been introduced, from time to time, in ordinary six-wheeled engines, and at last we find, which we may be pardoned for adverting to with some satisfaction, that in the latest invention of an eminent engineer the outside framing is now being abandoned, or at least that the inside framing has been adopted in that instance, and the large fire-box dispensed with.

The frequent variations in the construction of locomotives serve to prove that the designers of the six-wheeled engines, with outside framing, are convinced that their plan was not a perfect one whilst, in this foundry, the same plan has been continued with which we began, and to which others are now coming round.

This being, in brief, the history of passenger locomotives up to the present time, we think it due to ourselves to give the reasons why we have so perseveringly adhered to our plan of engine with four wheels only, and inside frames, and we cannot do better than give the following compiled extract from a paper published in the Transactions of the Society of Civil Engineers, and read before the society 17th March, 1840. It contains the statement of our opinions, of the soundness of which we had then had ample experience, and which still remain not only unchanged, but strengthened.

"Next to a good boiler, which governs the economy of fuel, the most important point in the construction of a locomotive engine (inasmuch as it most materially influences the cost of repairs) is to connect all the parts firmly together by a strong and well-arranged framing, so that they shall retain their relative positions when the engine is in motion, and that it shall receive and bear the strain, and the concussions to which every part is subject. The inside framing possesses a great superiority in this respect over the outside framing, as it forms a stronger and more direct connexion between the cylinder, the crank axle, and all the moving parts; and it bears all the strain of the engine, without throwing any portion of it on the boiler, as is the case with the outside framing.

"These advantages are best described by comparing it with the ordinary outside framing submitted to the principal strains which it has to resist.

"The most important is that caused by the whole power of the engine acting as a direct strain upon the crank as it passes over either centre.

"With the inside framing the centre line of the connecting rod is only 10 inches distant from the centre line of the frame, and the total distance between the bearings is 43 inches; but where the framing is outside the wheels, these dimensions are necessarily 20 inches and 72 inches respectively, and the effects of the strain on the crank, in this case, would be, to its effect with the inside framing, as 14 is to 8.

"For this reason, when the principal frame is placed outside the wheels, it becomes necessary to have an additional inside framing, to prevent the fracture of the axle. These additional inside frames not only cause an increase of friction on the bearings of the cranked axle, but also throw a considerable strain on the boiler, which then becomes the medium of connexion between the inside and outside frames, the inside frames being fixed at one end to the bottom of the smoke-box, and at the other end to the fire-box, while the principal frame is attached, by long brackets, to the body of the boiler.

"The fact, that the use of four additional inside frames occasions six bearings on the axle, (that axle being only 6 feet long,) renders the system of principal outside framings so objectionable, that that circumstance alone should suffice to cause their rejection, for it is well known to practical men, that it is impossible to key so many bearings perfectly true, and to maintain them so, when the engine is working; and even if this precision were attained, the aggregate friction on the four inside, and the two outside bearings, would be much greater than when it is all thrown upon two bearings, because, in the first place, all the friction due to the weight of the boiler is borne by the two outside bearings alone, and that which results from the pressure of the steam, through the medium of the connecting rod, is thrown upon the four inside bearings; the pressure on the outside bearings is vertical, and the mean pressure on the inside bearings is nearly horizontal. So that, if instead of acting separately, these two amounts of pressure were thrown on the same bearings, the friction would only be due to the resultant of the pressures, and would, consequently, be much reduced,

GG 2

outside the wheel, the weight of the boiler tends to bend the axle upwards, and a strain on the flange of the wheel acting in the same direction and in addition to it; when the breakage of an axle takes place, these joint actions tend to force the wheels under the engine, and there being no flange on the outside of the wheel to prevent it, the engine is thrown off the rails, which, it is evident, cannot happen with an engine having inside framing, because the weight of the bearings presses the flange of the wheel against the rail, and assists the length of the journal in keeping it from falling or being thrown off the rails.

"Several instances have occurred on the London and Birmingham Railway, when an axle has broken, that not only have the wheels remained on the rails, but the driver has been able to proceed with the train to the nearest station.

"The stiffness of the single inside framing is not only a remedy against the excessive wear and tear which are consequent on a less perfect union between the parts of the engine, but its simplicity allows the whole machinery to be arranged in a more compact form, and constructed with greater solidity, with this additional advantage, that the engine-driver, while standing on the foot-plate, can inspect the whole of the machine, and detect any derangement requiring his attention.

"It is evident that the round form of fire-box possesses great advantages over the square fire-box: first, it is much safer than the square fire-box, being made nearly in that shape which an excess of pressure beyond its stiffness would tend to bring it to, if made in any other form; moreover, the safety of the boiler with a square fire-box is nearly dependent on the strength, individually, of each of the stays which is fixed in it, (of which there are a great number;) whereas the pressure in the round fire-box is borne equally by the whole area of the plates of which it is composed: again, the corners in the square fire-box, in which the combustion is always languid, and consequently injurious, are avoided in the round fire-box.

"A lead plug is placed at the culminant point of the round fire-box, and will therefore melt before any other part is left dry, and, as the top row of tubes is placed two or three inches below the culminant point, it is almost certain that the extinction of the fire will prevent the