A A, which enters the well; but the cylinder I being lifted by the handle K, yet not so far as to come out of the mercury, the air within the pipe A A will be rarefied, and the pressure of the atmosphere will force the water from the well up the pipe A A, so as to pass the valve B, which opens for its passage. When the cylinder I is brought down, the valve B shuts, the air is compressed, and the water having no other way of escape, passes through the tube C, through the valve E, and into the air vessel D, thence up the pipe and becomes discharged at the orifice F. The advantage of this pump is, that little friction is encountered, and for every inch of stroke of the handle K, the water will be raised one foot high. JAMES MILLS. Glasgow, 13, Clyde Terrace, March 30, 1838. AMERICAN STEAM-BOAT RACES. **That these steam-boat accidents mainly arise from a headlong impetuosity, and childish rivalry, seems clear enough. The Ben Thersod caught fire in running a race. The American public ought to put down this practice on the contrary, it is sanctioned, and stimulated by paragraphs like this:"There was a beautiful trial of speed last night between the steam-boat Swallow and Rochester, which are undoubtedly the two fastest boats in the world. They came out of their berths in New York together, and for twenty miles ran neck and neck, neither gaining or losing a foot." This voyage, which is about 150 miles, appears to have been made in between eight and nine hours! We have, in another paper, a description, by a passenger on board the Franklin, from Louisville up the Ohio to Cincinnati, of a race carried on the whole of that distance, which is also about 150 miles, by this boat with a rival one, named the Phillips. In this case, there was a wager of 100 dollars between the captains that the Franklin would beat by an hour. The other boat had a half-hour's start. At fifty miles she was nearly "over-hauled;" at thirty more she was passed (having slight stoppages to make with the mails), but by only five or six lengths. The passengers of the leading boat, some sixty, including ladies, now entered into the sport, which they had hardly understood before:-"The contagion spread -'Go, ahead, captain-keep her in the wake-huzza for the Phillips!' was in every mouth. Nothing could exceed the spirit of the firemen and deck hands. The hatches were thrown open, pine knots covered the deck, and two or three axes kept going in splitting and breaking them; the deck passengers were huddled into the bow, to give the boat more dip; the chain waggons were hauled from the tops of the chimneys, while dense clouds of black smoke filled the atmosphere over us. It was plain that no less excitement prevailed on board the Franklin. Thus far she had been queen of the waters." And so they keep on for the next twelve or fifteen miles. In passing Warsaw, the two boats were neck and neck,' and we were saluted with loud and continued cheers. No response was sent back from either boat-not a sound was heard save the sonorous breathings of the scape-pipes, and the whirl of the waterwheels."-After this, "the boats, which till now had been abreast, and from ten to fifty feet apart, struck each other with a slight concussion. The ladies, of whom there were twelve or fifteen on board the Phillips, became alarmed, and besought their husbands to interfere. While this consternation prevailed in the ladies' cabin and state rooms, a different scene was witnessed without: the two boats seemed to be lashed together, the officers of each shaking hands across the railings, and the firemen and crew looking defiance. The river in front of the boats, from the light of the furnaces, seemed a sheet of fire, while the sky continued overclouded with the dense volumes of smoke which poured forth from the chimneys. In passing Petersburgh, the boats again struck with a more violent concussion than before; the alarm of the ladies increased," and so on. Now, what an atrocious game is this to be played with human life! That the passengers encouraged it, only aggravates the case; and so do the cheers from the shore. We fear that the Americans are too careless of life. Their driving habits of business, and the adventurous frontier character of a part of their population, may account for it. The great number of their steam-boats has familiarized them with scenes such as we have here described. Think of more than forty boats on Lake Erie alone-of nearly 400 on the Mississippi-for it must be allowed, as we said of the burning of buildings, that the Americans are as enterprising in one way, as destructive in another. But none of these circumstances can excuse the practices referred to, though they go some way to account for them. On the contrary, the great number of the steam-boats, and the usual comparative lightness of their construction, is the strongest argument for a more careful management on board, and for the interference of the public and the government.-Athenæum. ON THE FALLACIES 192 OF THE ROTATORY STEAM-ENGINE. BY JOHN SCOTT RUSSELL, ESQ., M.A., F.R.S., ED., LECTURER ON NATURAL PHILOSOPHY. [Abridged from the Second Part of the Transactions of the Society of Arts for Scotland.] It has been represented to me by the secretary, that the objects of this society will be materially promoted by any disquisition in which the fallacious views that are sometimes entertained upon important mechanical subjects shall be clearly analysed, and the errors pointed out into which the authors of supposed improvements have been drawn, either by reasoning accurately on false grounds, or making erroneous deductions from established principles. I feel it, therefore, to be my duty to make such contributions to the efforts of this most valuable association, as my humble abilities enable me to produce: and I have selected for this purpose the rota'ory steam-engine, as a subject upon which erroneous views are widely prevalent, upon which much ingenuity and mechanical skill is every day expended, and which belongs to the same category of fallacies to which the quadrature of the circle and the perpetual motion have long been assigned. To any one who compares the state of the mechanical arts in Great Britain at this instant, with their condition at the commencement of the century, the progress of these arts will undoubtedly appear more rapid in their approach to perfection, and more extensive in their range of application, than during any former period in the history of civilization; but if he will direct his attention more closely to these wonderful effects, and, looking below the surface of events, will examine into their causes; if he will consider how large and wealthy a portion of our population have directed their whole talents and energies solely to the purpose of attaining perfection in these arts, he will be disposed to question whether the results have been at all proportioned to the means, and whether, by such mighty interests judiciously directed, more would not have been judiciously achieved, had these resources been devoted exclusively to legitimate problems of real improvement, instead of being expended on the ignes fatui of mere visionary speculations; and had the talents which have been permitted to daviate from their proper channel been devoted to such ends only as should permanently benefit society, and form decided steps in the advancement of civilization, or valuable additions to the truths of science. To direct the enterprise and resources of one part of this empire into the legitimate avenues of valuable improvement, and to afford the means of distinction and encouragement to the mechanical talent of Scotland, is the object of this society: and when I reflect how many men there are, even within the limited sphere of my acquaintance, whose inventive genius is of the highest order, and whose labours are yet abortive, I cannot but feel convinced that there must be either a misapplication of talent to objects which others with better opportunities, and possessed of peculiar advantages, have better accomplished, or a misdirection to subjects containing in their own nature something either impracticable or impossible. Were it possible on the other hand, for such men to unite their exertions for promoting the real advantage of society, and were every individual, by a proper division of mental labour, to direct his mind to the object most congenial to it, I cannot imagine but that, with such means, so directed, changes and improvements in the state of the arts would be produced in this country much more rapid and astonishing than all that we have already witnessed. I am led to make these general remarks by their applicability to a series of inventions which have successively appeared under the generic appellation of rotatory steamengines. Their principle has assumed various forms and modifications, and has seduced, and still continues to seduce, many a bright genius from the straight path of useful industry and accurate invention. I have the pleasure of personal acquaintance with several men of eminent talent, who have sacrificed the energies of great minds to this ruinous fallacy. With one or two, my arguments have been successful in dissuading them from a pursuit sure to end in disappointment, but there still remain others of them, and many beyond the sphere of my knowledge, of whose talents and exertions the world is still deprived by the fallacies of the rotatory steam-engine. It is the object of this paper to show that the whole principles of the rotatory engine, as an improvement upon the common reciprocating engine, whether condensing or noncondensing, is radically false, and mechanically fallacious: that it is false in its mathematical principles, fallacious as a mechanical structure, and can never be attended with any mercantile advantage in its application; and thus to dissuade men of mechanical talent from devoting themselves to so unworthy an object. Before requesting acquiescence to be given to me on any opinion so decided as this, I ought to premise, for the purpose of obtaining the confidence of practical men, that, although the views which I am about to develope were first suggested to me in the course of an investigation where I found it necessary to bring the battery of the higher analysis to bear upon this subject, and employ the powers of the calculus to raze the foundations of prevalent error in the steamengine; yet, as such men are apt to use the word " practical experience," as antithetical to scientific skill, I ought to mention that, during the last ten years, I have been continually engaged in the practical solution of the most difficult problems of the steamengine, that I myself invented, and had constructed for me, several rotatory engines, which were sufficiently successful to convince me that the principle, and not the mere application I had made of the rotatory principle, was radically wrong. I have also had the opportunity of examining and working the most successful engines of this kind ever produced, and therefore conclude that, had theory never led me to any such result a priori, I must have been convinced that practical experience was opposed to the rotatory construction of the steam-engine. In what follows I shall endeavour to adduce my arguments in a form as little technical as is consistent with precision. 1. It is first of all my wish to show that the subject of the rotatory steam-engine is not so new and untried an invention as some who attempt the problem for the first time may be led to imagine;-for this purpose I adduce the names of more than ninety inventors, most of them patentees. 2. By an arrangement of these inventions, I have endeavoured to show that five different classes comprehend them all, and that the others are mere repetitions of the same principle, and attended with the same failure; so that an inventor may know whether his invention contains an entirely new principle, and if it do not, that it has already been tried and failed. 3. By showing, in one view, the names of inventors of unsuccessful rotatory engines, I endeavour to convince the inventor that the five classes already invented have not failed from want of genius, skill, or practical experience, in those who have made the trial, for the list contains the names of eminent practical men. 4. I endeavour to show that the ordinary crank engine does not possess the defects attributed to it, and which it is the sole object of the rotatory engine to remedy,—that the use of the crank causes no loss of power. 5. In a practical point of view the rota tory engine is every way inferior to the reciprocating engine;-in simplicity, and cheapness, and ease of construction,-in durability and economy in use,-in uniformity of action and equable motion. 6. The rotatory engine is peculiarly inapplicable to the great purposes of terrestrial locomotion and steam navigation-objects to which it has been considered peculiarly suitable. 7. That the present steam-engine is practically perfect as a working machine, being within ten per cent. of mathematical perfection. 8. That the crank of the common steamengine possesses certain remarkable properties of adaptation to the nature of matter, of motion, of steam, and the human mind; from which its supremacy as an elementary machine is derived,-properties which cannot possibly belong to any species of rotatory engine. The common or reciprocating steam-engine is distinguished from the rotatory steamengine by the nature of certain parts of its mechanism, which convey the motion of the steam to the machinery which is to be moved. There are a cylinder, a piston-rod, and a crank-axle. Now, the root of the whole of the fallacies of the rotatory engine will be found in certain radical misconceptions of the nature of the crank, as the simple elementary instrument by which the revolving motion of the axis, or great wheel of the steam-engine, is immediately produced. Nothing can be simpler than the crank. We wish to turn an axle round; we bend a part of the end of it at right angles to itself; we take hold of this end, and by this means turn round the axle. The bent part is the crank, and may be seen every day in winding up a clock, or in turning any wheel on its axle, by holding a spoke; likewise in the handle of a coffee-mill, at the top of a draw-well, or in the handle of any winch or crane for raising weights. Now, in the same manner as the hand of the operator takes hold of the handle, and, by drawing it towards him or pushing it from him, makes the axle or wheel turn round,so does a rod from the piston of a steamengine take hold of the end of a crank, and alternately draw and push it round in its circle of revolution. The crank is indeed so simple that it can scarcely be called an addition to the axle of which it forms a part; it is merely a bend or crook in it, which the word crank originally implies, and has been used to move the pistons of the cylinders of common pumps, since the days of Aleotti, in precisely the same way as it now moves in the steam-engine. Now, it is owing to a radical misconception of the nature of this elementary machine, that hosts of scheme's have arisen for the production of circular motion, without the intervention of the crank, either by giving to the steam itself an immediate circular action, or by the substitution of some other less elementary mechanism, between the reciprocating piston and the revolving axis, as the means of producing its rotation. In the rotatory engine, on the other hand, the cylinder, piston, rod, and cranked axle are superseded, in the most common form, by a cylinder, valves, s'op, and axis. In the same way as a millwheel is compelled to move in a circle, either by the direct action of water or wind upon it, so is the drum or wheel, with valves, fans, or other projections on its circumference, urged round by the force of the s'eam, and, enclosed in an outer cylinder or cse, gives revolution to an axis to which it is atached. This direct rotating action of the steam will, it is imagined, give out its effect more powerfully, uniformly, and economically, than the common mode of repiprocating action, when converted by the crank into revolution. Rotatory engines may be arranged according to the mode of action into four classes. Class I.-Rotatory engines of simple emission. Class II.-Rotatory engines of medial effect. Class III.-Rotatory engines of hydrostatical reaction. Class IV.-Rotatory engines of the revolving piston. As closely connected with the rotatory engines in the fallacy which has given rise to both of them, we may add a series of inventions forming, Class. V.-Revolving mechanism substituted for the crank. Class I.-The rotatory engine of simple emission forms the earliest, as well as the most rude and elementary method of giving motion to mechanism, by the escape of vapour or steam. It is described by Hero of Alexandria, in his Pneumatika, upwards of 120 years hefore Christ, and depends, for its effect, upon the same principle which gives to a rocket its career, and makes a fire-wheel revolve in giving off its beautiful lights. In these, as in all instances where fire, or steam, or any fluid or gas is genera'ed in a chamber from which it is permitted to issue with violence, it will, in its exit, drive the vessel from which it issues away from it in the opposite direction, and is, in fact, merely an application of the principle of recoil,-where the gas, generated by the explosion of the powder, urges the ball outwards in one directiou, and forces the breech of the gun backwards in the opposite one. The same recoil is felt in all cases of simple emission of a fluid from a reservoir; and if it be so arranged that water, steam, air, or the gaseous productions of gunpowder, shall rush out of a chamber through the arms of a revolving wheel, the openings of escape being properly directed, the recoil will urge round the wheel, and we shall have a revolving engine of simple emission. By availing himself of this principle, the mechanist of Alexandria produced an efficient engine, merely by heating a vessel containing water and air, and allowing the vapour to rush from the two opposite orifices at the end of two arms proceeding from a sphere which the emission was employed to move. Instead of using the principle of recoil, the force of steam issuing with violence as we see it from the mouth of a kettle or boiler, may be directed upon the vanes of a wheel, so as to blow them round; and thus we have a second variety in the manner of converting the simple issue of steam into a moving power. This second species of the rotatory steam-engine of simple emission was invented by Branca, in 1629. Since that time the engines of this class have been frequently re-invented and slightly modified. Inventors of Rotatory Steam-Engines of the First Class. 1. Hero of Alexandria.... 2. Branca....、、 3. Kircher 4. Daslesme.. 5. Kempel 6. James Sadler 7. Richard Trevithic 8. Alexander Craig... B.C. 130 A.D. 1629 1643 1699 1785 1791 1813 1834 The theory of machines of simple emission has been frequently and fully investigated, and the result is, that there is no possibility of obtaining, by simple emission, more than one-half of the whole power of the steam, so as to make it available to useful mechanical effect. The other half is wasted in giving off its impulsion to the air, or is expended in a current equally unavailing. Practical experience corroborates the predictions of theory. Smeaton and Pelletan made the machines of simple issue the subject of careful experiment, and found that 3 parts out of 11, 8 parts out of 27, and 2 parts out of 5, are the highest measures of practical effect that it has been found practicable to attain, and by no possible improvement can more than one-half of the whole power be turned to a useful effect. Class II-Rotatory engines of medial effect are those which do not immediately give revolution to an axis by the action of steam upon the wheel, but have a medium of communication between the power and the effect, which medium is the direct agent in circular motion. This class of engines will be well understood by taking as its type any simple steam machine, such as Savary's and Newcomen's, used for raising water, which water by falling on the floats of a common mill-wheel will then give rotatory motion to it. The engine of Savary raises water by pressing directly on its surface, and it is only necessary to allow this water to fall on a wheel, when it will be made to revolve and form an engine of the 2nd class. A variety of this class has been invented of which the fire-wheel of Amontons is a type. The stream pushes water through certain channels that form the arms of the wheel, from a set of chambers on one side of the wheel, to a corresponding set of chambers on the opposite; and thus the side filled with water preponderates over the other, and the wheel revolves. The water being constantly driven off by the steam from a given side of the wheel to that opposite, uniform revolution is the result of the weight of the water. In this state, although steam is the agent, water is the medium of communicating the rotatory motion. Solids have also been made the medium of effecting rotation in this manner; weights of solid matter, in the form of pistons, have been transferred by the force of steam to a considerable distance from the centre on one side of a wheel, and drawn nearer to it on the other side, so as, by bringing about a continual preponderance on one side, to effect revolution. Watt and Witty have designed rotative mechanism of this nature. Inventors of Rotatory Steam-Engines of the Second Class. is subtracted from useful effect, and becomes power lost. In those which move weights from and towards the circumference, there are mere groups of reciprocating pistons without cranks, and share the evils to be explained in Class V.; in fact, in the engines of Watt and Witty of this class, we have a series of reciprocating engines ranged round a wheel to do the work of one. In the case of the fluid medium, we have not only a loss of all the power expended in moving the medium itself, but also the additional loss of effect encountered in all modes hitherto adopted for applying a fluid to the rotation of a wheel, a loss, in the best examples ever presented, amounting of itself to more than one-sixth part of the power. Class III.-The engine of hydrostatical reaction is more effective than either of the former classes. As invented by Watt in 1769, it consisted of steam-vessels in the form of hollow rings, or circular channels, with proper inlets and outlets for the steam, mounted on horizontal axles, like the wheels and buckets of a water-mill, and wholly immersed in some fluid. This wheel was made of iron, six feet in diameter, and the reaction of mercury was employed to give revolution to it; the engine moved, but was found to be inefficient, and abandoned, although it had been tried in very favorable circumstances. The principle of action is this: steam is admitted into a circular channel or chamber on the circumference of a wheel; this chamber is partially filled with some liquid, the pressure of the steam is expended in pushing the mercury in one direction, and the end of the chamber in the opposite way, so that while the liquid is thus forced out of the chamber, the chamber is by an equal force pushed away from the liquid; the wheel is thus turned round. It is apparent that a part of the force is employed in propelling the wheel, and the remainder is expended in overcoming the resistance of the liquid of reaction, and expelling it from the chambers, which remainder is a large portion of the power withdrawn from useful effect. Inventors of Rotatory Steam-Engines of the Third Class. |