ROWLEY'S PATENT ROTARY ENGINE.

Sir, I herewith send you a copy of the specification and plans of the last, and as it appears in my humble opinion, about the best patent ever taken out for a rotary steam-engine, the production of Edmund Butler Rowley, Esq., Surgeon R. N., of Manchester. Although it comes upon the heels of your extracts from Mr. Russell's voluminous andpowerful article condemnatory of this application of steam power, I think it will stand well in the estimation of most practical men, and may not perhaps escape a compliment from Mr. Russell, (should it meet his eye) embracing, as it does completely, the most favourable principle that he professes under any circumstances to tolerate, as compared with the reciprocating engine.

I also send you an account of Mr. Rowley's patent buffing apparatus for insertion.* He is likewise the inventor of the pneumatic telegraph, favourably noticed some months ago in your Journal, but, being as diffident as he is ingenious, he takes little pains himself, to give his several inventions even common publicity. An engine of 6-horse power will soon be constructed according to his plan, to test the merits of his patent, and he will in the mean time be happy to show the model to any gentleman favouring him with a call, as well as glad to obtain, through the medium of your pages, the opinion of any of your scientific contributors, of its general merits. I am, Sir,

Your obliged, and obedient servant,
RICHARD EVANS.

7 Portland-street, Manchester,

July 9th, 1838.

Description of Mr. Rowley's Rotary Engine, abridged from his specification.Figs. 1, 2, 3 and 4, are representations of the various parts composing Mr. Rowley's rotary engine, which should be mounted in frame-work, for stationary purposes; it is shown as applied to a locomotive engine at fig. 5.

The engine is composed of a cylinder A, whose top and bottom or side-plates aa are precisely similar in every respect, and which are bolted to the said cylinder by means of the flanches with which they are provided; in the interior of each of these plates, or cylinder sides, there are

two grooves or races, formed as at bb and cc, the outer groove b being perfectly circular and concentric, whilst the inner groove c is partly circular and partly eccentric, as represented. There is a circular apparatus DD, formed with a rim and spokes or arms, similar to a wheel (or the same may be formed of one solid piece,) having two or more steam-tight chambers ec, formed in it, for the purpose of lodging the pistons ff, and allowing them to slide in or out. The whole of the apparatus is keyed firmly upon the central shaft g, which shaft revolves in proper bearings, and passes through and extends beyond the side plates aa; the outer rim DDD, of this revolving wheel fits exactly into the circular grooves or races bb, and forms the inner side or wall of the steam-chamber LL, whilst the guidepins of the pistons ii (which guide-pins may be furnished with rollers) travel in the eccentric grooves or races cc. Thus it will be seen, that as the expansive force of the steam introduced through the inlet pipe j exerts itself against the pistons, it will drive round the wheel D D, and as the guide-pins of the pistons travel in the eccentric grooves cc, the pistons will be alternately drawn in towards the centre of the wheel, to enable them to pass the abutment K, after which they are gradually forced into the steam-chamber, and so again allow the steam to act against them; the steam, after exerting its force upon the pistons, escapes by the exit pipe k.

In order to assist the parallel motion of the pistons, the guide-pins ii run in parallel grooves, or mortises mm, in the pistons chambers; each piston is also furnished with a guide-rodh,which works in an opening in the central shaft g.

It will be readily seen by reference to fig. 5, that if this revolving wheel or engine be applied to a locomotive carriage, as at aa, the central shaft g will drive the wheels of the said carriage, by means of the bevelled gearing bb, and if applied to stationary purposes as at figs. 1, 2, 3 and 4, the main driving-wheel must be keyed upon the central shaft g, and revolve with it.

The sides of the pistons and the abutment are to be furnished with suitable metallic packing.

The reason for having two or more pistons is very obvious, for if the wheel had been furnished but with one, it might so happen as to be arrested when

opposite the abutment, in which case, the steam would enter and escape without producing any effect upon the piston; but as it is here proposed to construct the apparatus with two or more pistons, and as it is impossible for more than one of them to be retracted at the same moment, the steam must act against some one of them, and thus produce a continuous rotatory motion.

Fig. 6.

AA

Fig. 6 represents an induction and eduction-pipes, constructed with two branches, one of each proceeding from and leading to both sides of the abutment. At the division of the pipes there is a stop-cock, or tap, which is so constructed as to allow the steam to enter and escape through one of the branches of the induction and eductionpipes only. It is intended that both pipes shall be worked by one rod, and which, when turned to the right, allows the steam to enter on the right side of the abutment, and escape on the left; when turned to the left it allows the steam to enter on the left side of the abutment and escape on the right; and thus the steam-wheel is caused to revolve to the right or left at pleasure; so that, when applied to locomotive purposes, the engine may be driven either backwards or forwards, as may be required.

Mr. Rowley states, that his improvement in the rotary engine consists in inclosing a wheel, having two or more pistons encased in it, in a cylindrical steamtight vessel; and which pistons work in a circular path-chamber or steam-chamber-and which steam-chamber has a division or partition in it, constituting an abutment for the steam; and to enable the pistons to pass this abutment they are gradually drawn in, or retracted within the wheel, and often passing the said, they are as gradually pushed forward into the steam-chamber; and this

gradual retraction from, and protrusion into the steam-chamber is self-acting, and is effected by causing the two guidepins with which each piston is furnished to travel in the two excentric grooves, or races, contained in the interior of the said cylindrical vessel-also the admission and escape of the steam from either side of the abutment, and which can be regulated at pleasure.

THE THAMES TUNNEL WORKS.

Sir, The report of Mr. Walker on the Thames Tunnel (No. 779, p. 252,) may well be styled an "extraordinary" document. It is extraordinary in all its features, but the measures it recommends to be taken for the completion of the work are most extraordinary. It now appears that it is impossible to carry the tunnel through with the means at present employed;-that Mr. Brunel's shield, of which all the world has heard so much, has met with more than its master in the oozy bed of the river; that a most egregious blunder has been committed from the first, in endeavouring to tunnel under the Thames at so short a distance from its bottom,and that, if the undertaking is ever to be completed, it must be not as a tunnel under the Thames, but as a tunnel through a mass of clay thrown for the purpose, where the Thames ought to bel Truly, these matters alone are sufficient to make the report "extraordinary" enough, without the addition of the many others which Mr. Walker adds, with a prodigal hand, in every sentence of his singular production.

Mr. W. was desired, in the letter from the Treasury, to attend particularly to the question of cost, but the chief gist of his report seems to be to recommend the completion of the work, as he phrases it, "without reference to cost," that is, without at all considering what it may come to. He observes, indeed, that "no prudent man would commit himself to the accuracy of an estimate of this work," yet, strangely enough, he almost immediately proceeds to calculate that the total expense (supposing those measures to be adopted whose cost cannot be calculated) will be 614,000l. or triple the original estimate. It is pretty certain, we may take it for granted, that the tunnel could not be com

pleted under this estimate; and yet we are told, in the last paragraph of the report, that "almost any course would be better than letting the complaint be repeated," (it has been once made,)" that the engineer has been deprived of the proper means of completing the work at the estimated cost." The meaning of this complaint of Mr. Brunel's it is impossible to fathom. From the passage above quoted it would appear, that the "original estimate" was about 200,000l. Mr. Walker tells us that "the amount of the Company's capital expended" amounted to 180,000l. previous to any application to Government, and that " 83,9001. of public money" have been expended up to the 2nd of November." From this it follows that the engineer has already expended upwards of 60,000l. over and above his original estimate for the whole of the works, although he has not yet completed one half of his task, and has brought the tunnel to such a pass that it cannot possibly be finished without impeding the navigation of the river to a most serious degree, and at an expense, at the very least, of 350,000l. more!! What on earth, such being the position of affairs, can be the meaning of this complaint of Mr. Brunel's, backed as it is by Mr. Walker? It passes the philosophy of common folks to find it out. One would think it far more natural for the Government to complain of the engineer, than the engineer of the Govern

ment.

Another of Mr. Brunel's proposals is a little more modest than this grand one, that the public purse should be handed over to him without controul. This is, that he should be allowed to commence his great bore again on the Middlesex side of the river: in plain English, having got over all the plain sailing on the Surrey shore, and finding himself in a dilemma from which his wonder-working shield will not extricate him, he proposes to get rid of his present miseries by leaving the middle of the river, where all the difficulty lies, and very comfortably commencing de novo on the other side, where all would be plain-sailing again, for some months to come at any rate. But where would be the utility of all this? In due time the inevitable middle of the stream would be again approached, and precisely the same difficulty would occur,-the projecting en

gineer coming precisely to the same conclusions that the navigation prevented his having sufficient thickness in his roof, a conclusion, pretty well founded, probably, but one which he would have done well to have come to before, rather than after, it was quite evident to the world at large; and which might have been arrived at even previous to the commencement of the works, seeing that the Thames was just as deep then as now, and was even in those times a navigable river. The only difference, were the new plan acceded to, would be that we should then have two holes to look at, instead of one as at present, and a still deeper hole in the public purse, affording a stronger argument than ever of the necessity of completing the work "without reference to the cost," if we would not become the laughing-stock of Europe for twice beginning that which we knew not how to finish. The lords of the Treasury are surely provided with a sufficient answer to Mr. Brunel. point is now arrived at when the practicability of the plan is to be put to the test: let the tunnel be conducted past the middle of the river before the funds for its completion are applied for. As to commencing again on the opposite shore, that is not required, as the part already finished demonstrates quite satisfactorily that a tunnel under the side of the Thames is quite practicable, and the proposed excavation from the Wapping shore could prove no more.-Let Mr. Brunel get past the middle, and then

The

But, if the tunnel is to be proceeded with, why not take the work out of the hands of Mr. Brunel? It is hard to say for what reason he should be continued as its engineer, dissatisfied as he seems to be with the backwardness of the Government in matters pecuniary. It will be said that Mr. B. is entitled to the preference, as the projector of the undertaking. This, however, is a small merit. It would be easy enough to propose a suspension-bridge from Dover to Calais, but rather difficult to execute it, notwithstanding Smeaton pronounced it possible, if no regard were had to the Besides, the idea of tunnelling under the Thames is every thing but a novelty, so that Mr. B. can bring forward no very valid claim on that score. His principal other claim rests on his being the inventor of "the shield," of which

cost.

so much has been said, and which was to have rendered the performance of the work perfectly easy. But the shield, we have Mr. Walker's authority for saying, is not able to overcome the difficulties that now present themselves. Is Mr. B., therefore, to be continued in his office, because he is the inventor of a machine whose inefficiency is proved just at the pinch-Again, it will be laid down as unfair that the work should be completed by another hand, after Mr. Brunel had overcome all its difficulties. The publicity of this objection, however, is evident from every line of Mr. Walker's report. So far from getting over the difficulties, Mr. Brunel has only brought the work to the most difficult part-and there left it-at least unless it be determined to proceed regardless of expense. Mr. B.'s own admission, that he finds his roof too thin, is itself a strong condeinnation of his capabilities as an engineer, backed as it is by his monstrous proposition to fill up the Thames with an artificial bed purposely for the tunnel to be worked in! It hardly requires a first-rate engineer so to miscalculate, as to render the prosecution of his proposed work, in its proposed form, absolutely impossible; and assuredly first-rate abilities are not required to work a tunnel through a bed made for the especial purpose. In no point of view does it appear necessary that Mr. Brunel's services should be retained, expensive as they have already been to the Company and the country. It is needless to remark, that Mr. B.'s estimates for the future are just as likely to be realized as those for the past have been. It even seems rather too gross an experiment on public credulity to estimate that the Middlesex shaft to be made, would only cost one-third of the sum which that on the Surrey side has actually been found to come to, and Mr. Walker only acts prudently in taking the expense of "the great descents" at double Mr. Brunel's estimate. To talk of estimating the cost at all, where the tunnel is concerned, is indeed altogether ridiculous-but more than ever to talk of it in Mr. Brunel's style. He estimates the cost of his artificial roof, for instance, at 1,800l., a sum, the total inadequacy of which must be evident at a glance. The reference, however, to the Kilsby Tunnel, was probably meant to

put the reader on his guard,-the actual expense in that instance being only just six times the original estimate!

If the Thames Tunnel is to be completed at all, the Government had better grapple with the work at once, and begin by taking it into their own hands: it has surely been quite long enough in those of its present directors, of whose doings the public only hear through the almost periodical accounts of fresh irruptions in the newspapers. It may indeed well admit of question whether it be worth while to finish it at all. It serves very well for one of the "lions of London" as it is, and it would probably be no more when quite completed-its utility as a medium of communication between the opposite shores of the river being very problematical, when the necessity of going down the "great descent" on one side, and up the equally "great ascent" on the other, is taken into consideration. It would, perhaps, be best for all parties, (John Bull among the number) to let matters remain as they are: the work might continue to exercise its principal functions of "attracting much of the public attention in this, and still more in other countries;" Mr. Brunel might repose in the enjoyment of his fame as the inventor of the highlyeffective shield, and as the engineer who would have finished the tunnel at the original estimate, if he could have got the money from a niggardly Government; and, better than all, John Bull would keep his cash where he best likes to keep it,-in his own pockets, instead of seeing it literally sunk in the bottom of the Thames.

And, I am, Sir,
Your most obedient servant,
AQUARIUS.

London, August 8, 1838.

CYLINDRICAL STEAM BOILERS.

Sir, I freely acknowledge my blunder (see No. 780, p. 264); it never occurred to me that a recommendation of a boiler should be dependent on distilled or nondeposit water: especially as tubular or chambered boilers often claim an entire exemption from the injurious effects of either deposit or over-heated flues, in consequence of the supposed rapid water circulation.