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the chief of the railway department, and who had been commissioned to inquire into the means of ensuring safety in railway transit, we find the sources of danger thus indicated: "On analyzing the strain upon the axles it was found to consist-first, of a vertical strain, due either to the portion of the weight of the engine bearing upon that point, in consequence of the position of the centre of gravity, or to the action of the springs of the hinder axles in the six-wheeled engines. This strain being thus defined, even supposing that the parts upon which it acts are as near as possible to the point d'appui formed by the wheels, it tends nevertheless to bend the axle in a vertical direction. Secondly, a tension arising from the conoidal form of the peripheries of the wheels, and inequalities in the inclination of the rails; from which it happens that the peripheries of two wheels fixed upon one axle never touch the rails at the same point at the same time, and consequently each of the wheels will slip alternately upon the rails. If the twist resulting therefrom is not too violent, it keeps all the molecules in a constant state of vibration. Thirdly, shocks arising from inequalities in the road caused by the undulations of the rails at their points of junction, on the passage of a train. These shocks increase in violence in proportion to the speed, and act in a direction at right angles to the axis of the axle. Fourthly, a strain of another description, arising from the oscillations of the carriages, acts upon the axles both in the direction of their length and at right angles thereto; increasing in force in proportion to the diameter of the wheels."

Some of the dislocating forces here described increase as stated, in direct proportion to the increase of velocity; others in a much higher ratio. The great cause of disturbance may be traced to the mode in which the expansive power of the steam is transmitted, through the axle, to the driving wheels, by means of a pair of piston-rods working upon cranks in the axle, and placed upon opposite sides of the line passing through the centre of gravity. Of necessity the two cranks cannot lie in the same plane, but must form a right angle with one another. Their forces, therefore, can never be in counterpoise. While the right-hand piston is at its dead point, the left-hand will be at a maximum; and while the axle is pushed forward on one side, it is pulled back on the other; and these interchanges of impulse, when at high speed, recur several times in every second. Enormous tendency to oscillation is thus produced,

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and the irregularity of motion, when once. evolved, tends by the natural relation of the several parts and actions, to cause or to increase every other variety of eccentric force, The improvement, if such be possible, which should throw the axle of the driving wheels into revolution by some continuous and symmetrical impulse, will remove by far the largest part of the sources of danger, and open wider limits to the possibility of greater speed.

In the process of weaving by the powerloom we find an analogous example of velocity limited by the broken or alternating motion of the acting forces. The rapidity with which the shuttle can be thrown from side to side between the threads of the warp, is limited by the strength of the woof-thread it carries across. When the strain is so great as to cause more than a certain average number of breakings, the nett product of the machine will be increased by working at a lower velocity. By a recent improvement, the shuttle is made at every vibration or "shot," to commence its motion slowly and and increase in velocity as it proceeds; thus diminishing the strain upon the thread, and economizing time, even in the four or six feet that constitute the average extent of each "shot." And by this means the looms are sometimes worked at a rate of 180 threads per minute, or 3 in every second. This will constitute the absolute limit of speed, under the existing form of construction. To extend it we must introduce a new principle, and discover some method of weaving the tissue in a cylindrical web; when the oscillation of the shuttle might be transformed into a continuous revolution, and the strain upon the woof, arising from the perpetual stoppage and change of motion, be annihilated.

The history of the first invention of the power-loom contains a curious proof, how much more difficult is the discovery of any absolutely new principle, by which the old forms and processes of manipulation are entirely superseded, than the mere contrivance of means to imitate by machinery what has been already done by hand. The latter requires only a very common endowment of the inventive faculty; the former demands the presence of creative genius. More than a hundred years before the invention of the steam-loom, in the Philosophical Transactions for August, 1678, there was given some account of "a new engine to make woolen cloths without the help of an artificer”— being a communication from a M. de Genues,

an officer belonging to the sea." Much ingenuity is exhibited in the mechanical construction of this engine,' considering the time when it was produced; but in those days the only method of passing the woofthread through the warp, was by the fingers of the weaver, assisted occasionally by a notched stick. And accordingly M. de Gennes, or whoever was the inventor of the machine, could hit upon no better plan than a complicated imitation of the human hand and arm, by which his shuttle is carried from side to side. Long afterwards, a common weaver invented the 'fly' shuttle, which is shot to and fro by springs; and modern inventors, having the benefit of this capital discovery, started from a high vantageground, and have succeeded in bringing the power-loom to its present state of excellence.

But the difficulty with which a novel idea is caught or worked, is not the only one that stands in the way of the inventor. Improve our mechanism as we may, the human operator will always form an important element in our combinations; and will often prove by far the most intractable of our materials. Once let the workman be inured to the routine performance of duties on one machine, and it becomes a work of much time and cost to transfer him to another. The dearly acquired skill which constituted his chief capital is rendered useless, and the apprenticeship to his new tasks must be completed at much labor to himself and expense to his employers. We are assured by high authority that little short of a whole generation must expire, before the change can be thoroughly established. When some of the more remarkable inventions, like that of Arkwright's spinning jenny, 'were first introduced, it was found necessary to discard the whole of the trained operatives, and to intrust the attendance upon the new machines either to young children, or to recruits drawn from rustic neighborhoods, who had never touched a spindle. It was no wonder that the "skilled laborer" of the old system denounced and resisted the new; just as the old English archer resisted the introduction of the musket, after having acquired by incessant practice from earliest childhood his unerring skill as a marksman, and so great muscular power that he could be recognized a mile off, merely from the size of his arms. The spinning jenny, indeed, presented such an enormous increase in speed and economy, that the old workers gave in without a struggle. But the weaving machines did not at

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first appear so hopelessly superior. hand-loom weavers found themselves able to "live in the race" with the steam-engine, although at a terrible sacrifice. The competition has been persevered in, with melancholy pertinacity, to the present day; until society has the burden and the scandal of a numerous class of individuals, industrious but ill-judging, who have, even in good times, to battle for a bare subsistence against fearful odds; and who, in the frequently recurring periods of depression, present the most afflicting spectacles.

The machine maker, in his turn, will endeavor to frustrate the innovations that tend to render his capital and experience, like the skill of the operative, in a great measure valueless. If some new power should be discovered and trained to do for us more efficiently what steam does now, its adoption would be impeded by all the improvements. in the steam-engine, which four generations of engineers have combined to perfect. The most proper proportions of size and strength; the simplest arrangement of parts; the best form and construction of every valve and joint-even the machines that make the machines-have been long since ascertained and provided. The new power must be gifted with advantages very great and undeniable, if it can supersede, in all the rudeness of its primitive condition, the elaborate perfection of the established engines.

The common watch is in many of its parts a very ill-constructed machine. The train of wheel-work which transmits the motion of the main-spring, for example, is contrived on principles so faulty, that they would be scouted by every practiced mechanician. Yet there can be no doubt that any attempt to introduce a better machine would utterly fail, as a commercial enterprise. Long used methods and ingenious engines have been specially provided to fashion and cut every one of the minuter parts which go to compose the existing instrument. Mr. Dent, in a lecture delivered at the Royal Institution, stated that every watch consisted of at least 202 pieces, employing probably 215 persons, distributed among 40 trades-to say nothing of the tool-makers for all these. If we were now materially to alter the construction of the watch, all those trades would have to be relearnt, new tools and wheel-cutting engines to be devised, and the majority of the workmen to begin life again. During this interval the price of the new instrument would be enormously enhanced. We should again hear men speak, like Malvolio, of "winding

up their watches" as a token of their wealth. Thus in our complicated state of society, even machines in process of time come to surround themselves with a circle of "vested interests," which embarrass all our attempts at improvement.

Looking back on what we have written as to the limits of improvement, we come to the conclusion that it is impossible to lay down any general law upon the subject. Every invention must be judged by its own merits, and according to the special object in view. Nine times out of ten, probably, the object will be nothing more than economy, in a reduction of cost. In the tenth case, it may be for increased safety, simplicity, velocity, or power. But each case requires to be calculated for itself; and some of the elements for such calculations we have now endeavored to give. These elements are sometimes simple enough; yet it is astonishing how often they are overlooked. To give a familiar illustration. The art of flying has more or less occupied the inventive power of man, since the days of Daedalus. Here we may allow that cost and even danger may be left out of consideration, and that the question is one of simple practicability. The balloon offers the nearest approximation to a successful solution; since, though we could not properly fly, we might float suspended to those buoyant spheres; and efforts to steer balloons have accordingly been innumerable. Now a very simple calculation will show that a wind of fifteen miles an hour would exert, upon any sphere of useful size, a pressure greater than the weight it could sustain in the air. The power consequently which would be required to retain the machine stationary against such a wind-or, what is the same thing, propel it at a like rate through a still atmosphere-must be greater than that which would keep it up in the air without a balloon at all. A good three-fourths of prospective aëronauts, therefore, surrounded their task with unnecessary difficulty. And the remainder, who devised so many varieties of imitative plumage and pinions, might have saved their labor if they had but reflected that, before they could use their ingenious apparatus, they must possess some motive power which could support its own weight and something more, for a reasonable time. They were constructing new wings, while the thing wanted was a new steam-engine.

In many branches of manufacture mechanical improvement has been so rapid, that Mr. Babbage estimated the average duration of the machinery at only three years; by the expiration of which time it was superseded

by new apparatus. This ratio was of course temporary and accidental. Many of the large manufacturers in Lancashire and the West Riding find it worth their while to employ skillful mechanics at high salaries, for no other purpose than to suggest improvements in the machinery. The result is that their factories contain specimens of contrivance surpassing any other in the world. Some of the mechanism used in cotton printing, or in the " differential box" for supplying cotton to the spinning frames, is beyond comparison superior in delicacy and ingenuity to the most complex movements of a chronometer. And the human operative, in imitation and by the aid of the machine, acquires a perfection little less marvellous. The rapidity of his motion, the acuteness of his perception, render him a fitting companion for the intricate mechanism he employs. In astronomical observations, the senses of the operator are rendered so acute by habit, that he can estimate differences of time to the tenth of a second; and adjust his measuring instrument to graduations of which 5000 occupy only an inch. It is the same throughout the commonest processes of manufacture. A child who fastens on the heads of pins will repeat an operation requiring several distinct motions of the muscles one hundred times a minute for several successive hours. In a recent Manchester paper, it was stated that a peculiar sort of twist or "gimp," which cost three shillings making, when first introduced, was now manufactured for one penny; and this not, as usually, by the invention of a new machine, but solely through the increased dexterity of the workman.

To the inventive genius of her sons England owes the foundation of her commercial greatness. We will not go the length of asserting that she retains her proud pre-eminence solely upon the condition of keeping twenty years ahead of other nations in the practice of the mechanical arts; but there is no question that a fearful proportion of our fellow-subjects hold their prosperity upon no other tenure. And quite independently of what may be done by our rivals in the markets of the world, it is of vast importance to our increasing population that the conquest over nature should proceed unchecked. Towards this object we have thought we might contribute some slight assistance by indicating some of the principles upon which the warfare must be conducted, and the mental training of those engaged in carrying it on. That there should be so little provision for this training among our ordinary establishments for education, shows a neglect, at which, if

any anomaly of the sort could surprise us, we might well be surprised. With the exception of the College at Putney, confined to a few aspirants to the honorary degree of C. E. for practically the profession is not limited to such the scientific education of the young mechanist must be self-acquired, or, at best, irregularly obtained in the classes voluntarily formed among the members of literary institutions. Yet every day the necessity for practical and technical instruction is becoming more manifest. We see it marked as strongly in the success of the few who succeed, as in the failure of the many efforts of ignorant and mistaken ingenuity.

Blind intuition has now little hope of success in the work of invention. Mere chance has still less it never, indeed, had so much as popular reputation gave it credit for. Chance might have set in motion the chandelier suspended in the Pisa cathedral; but if chance also suggested to Galileo the laws of the pendulum, it must have belonged to that multitudinous order of casualties, by which ideas are ordinarily propagated in fit and fertile minds. Two generations ago Mr. Watt observed, that he had known many workmen who had suggested some improved adaptation of mechanism, but never one who invented an instrument, involving a principle, like that of his centrifugal 'governor.' Machines that do not involve a principle are now grown so rare, that the range of invention is almost annihilated for the mere workman. On the other hand, we observe how singularly, when

the principle is once fairly studied, mechanical inventions are simultaneously made in many places at once. The honors of the electrotype processes, of the Daguerreotype, the electric telegraph, the screw-propeller, and a host besides, are disputed by a hundred rival claimants. Chance, we thus perceive, did not produce those discoveries; and from the same facts we obtain a gratifying assurance that it could not have prevented their production. Well directed education will make the creations of the human mind more abundant, as printing has already secured their indestructibility.

Of the legal aids or hindrances to invention, it is not now our purpose to speak, although the anomalies of the laws in relation to the subject are confessedly flagrant. One suggestion for improvement we have already referred to. It is that every petitioner for a patent should deposit in a gallery or museum, accessible to the public, a working model, drawing, or specimen of his invention, whether in mechanism, art, or manufacture. Museums of this description would prove of infinite assistance towards that scientific education in which we are now so lamentably deficient. The public would then obtain some countervailing advantage from a system, of which it is hard to say whether it is more injurious by the monopoly that it confers or the privileges it denies; by the difficulties it imposes on an inventor who seeks to profit by his discovery, or by the hinderances which it puts in the way of his successors, who have devised improvements on the first invention.

SALE OF HAYDON'S WORKS.

ON Thursday a valuable collection of chalk tured marble bust of General Washington, drawings, by the late unfortunate Haydon, and a large number of miscellaneous sketches. was disposed of by public auction at the Several virtuosi were present. The bidding rooms of the Messrs. Robins, Covent Garden. was tolerably brisk, and, considering that the The collection consisted chiefly of sketches drawings were in a very crude and imperfect from the ancient masters, unfinished sketches state, the prices they realized were extremely of heads of his Royal Highness the Duke of good. Five finished heads of Lord Melbourne, Sussex, the late Mr. O'Connell, Lord J. Lord Stanley, Earl Grey, Lord Althorp, and Russell, and other eminent individuals. It Sir F. Buxton, were sold for 21. 7s. 6d. A also comprised the celebrated "sleeping head of Lord John Russell brought 21. 10s.; head," exhibited at the British Gallery in and the " sleeping head" was sold for 51. 58. 1822, which is considered by the cognoscenti Several anatomical studies, presented by Sir to be one of the most exquisite specimens of David Wilkie to Haydon, were sold at resnative art; an unfinished gallery painting of pectable prices, but many of the sketches Uriel and Satan, upon which the artist was realized very small sums. The whole of the engaged until a short time previous to his proceeds will be devoted to the relief of the decease; a painting of Napoleon and hat for family of the lamented artist. the studio of Sir Robert Peel; a finely sculp

From Hogg's Instructor.

THE LATE JOHN STERLING.

BY GEORGE GILFILLAN.

Essays and Tales by John Sterling. Collected and edited, with a Memoir of his Life, by JULIUS CHARLES HARE, Rector of Herstmonceux. London: Parker. 1848.

THE removal of a young man of high per- | formance and still higher promise is in all circumstances melancholy. It is more so, if with the youth has expired either a new vein of poetry or a new view of truth; and it is scarcely less so when the youth has been unconsciously the type of a large class of cultivated and earnest minds, and when his partial successes, baffled endeavors-his admitted struggles, and his premature fatehave been in some measure vicarious.

These three short and simple sentences appear to us to include, positively and negatively, the essence of the late John Sterling, and shall form the leading heads in our after remarks on his genius and character. He was, in the judgment of all who knew or had carefully read him, a person of very distinguished abilities, and of still more singular promise. He did not, in our view of him, exhibit indications of original insight or of creative genius. But he has, from his peculiar circumstances, from his speculative and practical history, from his exquisitely-tuned and swiftly-responsive symphonies with his age and its progressive minds, acquired a double portion of interest and importance; his experience seems that of multitudes, and in that final look of disappointed yet submissive inquiry which he casts up to heaven, he is but the foremost in a long, fluctuating, and motley file.

The external evidences of his powers and acquirements are numerous and irresistible. In his boyhood he discovered striking tokens of a mind keen, sensitive, and turned in the direction of those high speculations from which his eye, till death, was never entirely diverted. While barely eight, "he distinctly

remembered having speculated on points of philosophy, and especially on the idea of duty, which presented itself to him in this way-"If I could save my papa and mamma from being killed, I know I should at once do it. Now, why? To be killed would be very painful, and yet I should give my own consent to being killed." The solution presented itself as "a dim, awe-stricken feeling of unknown obligation.". When about nine, "he was much struck by his master's telling him that the word sincere was derived from the practice of filling up flaws in furniture with wax, whence sine cera came to mean pure, not vamped up." This explanation, he said, gave him great pleasure, and abode in his memory, as having first shown him that there is a reason in words as well as in other things. When a boy, he read through the whole "Edinburgh Review," of which his biographer says, "a diet than which hardly any could yield less wholesome food for a young mind, and which could scarcely fail to puff it up with the wind of self-conceit." We doubt the validity of this dictum. We conceive that, to a fresh elastic mind, the crossing of such varied territories of thought, the coming in contact with so many vigorous minds, the acquiring such stores of miscellaneous information, the mere reading of such a mass of masculine English, as the perusal of the entire "Edinburgh Review" implies, must have been beneficial, and tended to awaken curiosity, to kindle ambition, to stifle mannerism of style, and, as the likely result of the many severe criticisms in which the book abounds, to allay instead of fanning the feeling of self-conceit. Who but commends the industry of the boy who reads all the English

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