as those of the Victoria and others, and that is by attaching a glass guage to every boiler, such as are affixed to the patent boilers of Upton, Nicholls & Co., of Battersea.

If this instrument had been attached: to the boilers of the Victoria, any one on board might have seen the water and steam in the boilers by a glance, the water and steam being always visible; for if the water was a hair's breadth higher or lower than the proper level assigned, it would be visible, not by any index or other uncertain guage, but the water itself is seen in its boiling state, and the steam inside the boiler also.

Any person desirous of directing their sight to this safe, neat, and most important little instrument, could, on perceiving the water decreasing below its assigned level in the boiler, say instantly, "Stop the engine, open the safety valves, and lower the fires; the water guages show the pumps are deranged," &c.

At the same place may be seen one of the safest boilers, and the quickest in getting up steam, that has yet been invented; and which is by far the best for a ship, inasmuch as it is smaller and lighter, and, by not carrying the water in one boiler, but in several compartments, safe beyond all comparison.

This boiler would do well at sea, if external condensation was adopted; and it could be very easily repaired if required, even at sea. As to its saving properties, a ten-horse power one has been known to produce steam of 45lb. to the inch in fifteen minutes, and the boiler is proved to bear a pressure of 1000ths to the square inch.

A rupture in such a boiler could not be attended with any bad consequences. If any rent was to take place, as those of the Victoria, and the Union at Hull, it would only put out the fire. Nor is it possible for it to explode altogether, and disperse the water instantaneously, as is the case with all those boilers which carry their water in bulk.

Now, so long as the owners of steamers continue to follow the plan of rejecting the best boilers and engines for the sake of getting the lowest priced ones, and which are the least to be depended on, the public must expect to have their lives put in jeopardy.

Even the simple water guage abovementioned would have prevented all

Now, as all common boilers are liable to similar accidents, I would strongly urge the necessity of fitting them up with large and very capacious safety valves, capable of allowing the escape of much greater volumes of steam than is at present the case. Besides which precaution, a metallic alloy, fusible at any number of assigned degrees of heat, might and ought to be used on board of every steamer. This being appended to the lever of a very capacious valve, would, by allowing the steam to escape, prevent the bursting of every kind of boiler. This was mentioned to me by Mr. Upton as the plan to be adopted by them for all sea-going boilers.

I am, Mr. Editor,

Your obedient servant,
SCRUTATOR.

MILLS'S MERCURIAL PUMP. Sir,-Some time since I constructed a mercurial pump, on what I conceive to be a new plan. I presented a working model to Mr. Grier, lecturer of Natural Philosophy in the Baronial Hall, who exhibited it to his class, and the action was so satisfactory to the lecturer and his audience, that I have been solicited to transmit you an account of the pump, which I hope you will not consider unworthy of notice in your excellent periodical.

The pump is of the suction kind, A A is a pipe not more than 30 feet in length, open at both ends, the undermost of which is inserted in the well to be drained. At B there is a clack valve opening upwards, immediately above which a branch pipe C leads off, and opens into an air vessel D, of the ordinary construction. The top of the pipe C is furnished with a valve E, opening upwards into the air vessel, and the ejection pipe is terminated at the required height F. Immediately above the branch pipe C, the main pipe A A is begirt with a cylinder G G of iron or glass. The cylinder is of greater diameter than the

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 mer cury, 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.

M 8

192

SCOTT RUSSELL,

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 f 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 adduce the names of more than ninety inventors, most of them patentees.

I

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