The Sub-Commissioner who reports on the South Staffordshire and Shropshire districts is of opinion that there is no necessity whatever for working the calcining furnaces on Sundays.

"At many works all the furnaces, including the calciners, are on Sundays suspended from active operations, and simply kept on "deadfire," as it is termed, attended only by watchmen, one of whom generally serves two or more of such fires, until the hands resume their regular work on the Sunday night or Monday morning. In my own opinion, very little is actually required to be done on Sunday in order to keep the copper-works in action, and none, of necessity, on the parts of children, young persons, or females."

Sir, It is a fearful thing, although perhaps necessarily consequent on the terrific powers which man has undertaken to use and control, that we are destined to acquire such useful knowledge in respect to safe railway conveyance, only at a tremendous cost of human suffering; but it is a monstrous and a cruel thing, that only through such a medium can men's minds be sufficiently impressed to arouse them to seek and adopt all possible precautions against the recurrence of those accidents by which it has been produced. To rely on science and scientific men in these matters is a dangerous fallacy. What is wanted is, a power to imagine and provide against all conceivable combinations of events out of which accidents can arise; but they frequently result from a concurrence of minute or apparently trivial circumstances, far removed from the meagre generalities of science, and more within the scan of, and the probability of suggestion, to the practical minds of the men engaged in the occupation. I would, indeed, give greater attention to the statements even of the drivers and stokers of the engines, however illiterate they may be, if shrewd VOL. XXXVI.

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and observant men, than I would to those of the most accomplished mathematician. I am not aware that the official report of the accident on the Brighton railway, occasioned by a four wheel engine running off the rails, threw any particular light on the cause of the unsteadiness of the engine on that occasion; but I know very well that the remarks made by the enginedriver at the Coroner's Inquest, were well deserving attention. I am inclined to think that there is a greater outcry against four-wheel engines than they altogether deserve, although upon the whole, the six-wheel arrangement may be much the best.

There are not wanting, however, practically-minded men of a higher class than engine drivers, who are sufficiently conversant with the technicalities of the subject, and whose opinions and suggestions ought to meet with greater attention from Directors of Companies, than it is in general their fate to receive. But the practice is, in the case of an accident, to send a scientific man to report on the affair, and there the matter ends. In that most appalling and awful calamity on the Paris and Versailles railway, the Academy of Sciences sent two of their members* to investigate and report on the subject, and what have they done? We are just as ignorant of the real cause of the accident as we were before. They have pointed out for reprehension, practices which have often and often been reprehended before, and but for which, the destruction of life would probably have been much less than it was; but the mystery of the breaking of the axle is not cleared up, and for aught that appears was not even investigated.

It seems, from the accounts which have been published, that Mr. George and M. Milhan, the General Engineer and the Inspector, were apprehensive from the faulty arrangements, that an accident might happen, and thought it necessary to be themselves with the engines to conduct them. So much were they on the alert, that M. Milhan, seeing something that he thought amiss, sounded his alarm whistle to draw Mr. George's attention, who instantly had recourse to his break, and as instantly was the axle

These gentlemen appear also to fill some official situations connected with the inspection of roads and railways,-gentlemen, no doubt, of very respectable scientific acquirements.

FF

broken "

on each side." This was not,

nor was it likely to have been, a case of weakness from wear and tear; neither did it result from a flaw in the axle, for it is stated to have been perfectly sound, both the iron and the manufacture being excellent. It is not to be supposed that the axle was wanting in the usual proportion of strength; besides, it must often have been tested in this manner. What, then, caused it to break? There evidently must have been a peculiar concurrence of circumstances which put an unusual stress upon it. What were those circumstances? A light locomotive was in advance; a ponderous one was immediately behind; a huge train of carriages was in the rear; they were going down an incline, going, it is said, at a great velocity, passing over a road, and passing also round a curve of too short a radius, it is to be feared. Under these circumstances, the conductor for the time being, sensitively alive to danger, and unfitted to display probably his usual coolness and presence of mind, and unaccustomed to the task, hastily and suddenly uses the break, and the accident instantly happens.

If the axle broken on this occasion was connected with the break, of which there is every probability, this conduct of Mr. George must have been the primary and fatal error, although no doubt the other circumstances were accessory, to an unusual stress having on this occasion been put upon the axle. The curve on the railroad, for instance, must have added a lateral strain; the vibration produced by crossing the road, if it exactly coincided with the application of the break, must have increased the tendency to a fracture; and the greater velocity induced by descending the incline, must have augmented the stress in a percussive point of view. Yet there was nothing in these circumstances of an unusual character, taken either singly or combined; for the incline, the curve, and the crossing of the road, are connected localities, and the increased velocity was a necessary consequence of the incline, so that the concurrence of these circumstances must be constant and unavoidable; and doubtless it was quite the ordinary practice to apply the break at this part of the line. Such application, however, would be under peculiar if not unusual circumstances, and at a time when the strain on the axle would be the greatest; any additional

circumstances, therefore, combined on this occasion, must be just the one thing more that caused it to fail; and that is to be found only in the mode of handling the break; for as to the second engine, and the great length of the train, they are circumstances which do not bear upon the point.

The more than ordinary amount of momentum to be checked by the action of the break, does not add to the straining or breaking force operating on the axle, for that is equal only to the force of resistance, which, through the break, opposes the mass in motion; which again is equal to the friction of the wheels on the rail, and this, excepting as the load in the tender may vary, is always a constant quantity; so that the force to break the axle is the same, whether the train be large or small, or there be no train at all. This force is, after the moment of impact, to be viewed as a dead pressure, wherein velocity is not brought into consideration; and if viewed as a percussive force, as in the moment of impact, then the velocity of the force is that of the train; but the mass of the train forms no part of the force.

By the light then of all the recognised and calculable laws of force and motion, we are unable to discover any cause why the axle should have been broken upon this occasion. By this light we may perceive, although unable to calculate, the influence of a peculiar conjuncture of circumstances, but we cannot find any reason why it should have come into action at this particular time rather than in past times. So the two French Academicians appear to have thought, and true to their breeding in not looking about them in any other direction, they did not attempt to assign a reason for it, or even to moot the point. But there is a circumstance behind, which being on the surface of things and merely of a practical character, was on that very account likely to be overlooked by scientific men-just as the cause of the wabbling jumping motion of a locomotive, in the want of a perfect equilibrium in the revolving parts, was undetected by them-a circumstance which being important in itself, and imparting additional force to the other circumstances, will, I think, satisfactorily explain the cause of this accident. It is simply that of the suddenness with which the break was brought into action, by

which the stress on the axle was rendered almost instantaneous.

It most commonly happens in practical matters that we are unable to calculate forces in the way of the mathematicians, but must estimate them as well as we can -for calculate them we cannot-by the effects which experience, or special experiments, teach us to expect under certain circumstances. It is so in this case. In the science of statics, the forces of pressures are regarded in the single aspect of their equilibrium; their effects on the molecular forces, in causing the disruption of materials, is altogether a practical question, left to be investigated in a practical manner by practical men, and just because the subject is one which science is unable to fathom. Science, potentially speaking, is truly applicable to it, but it is beyond our ability to apply it. So also in Dynamics, the forces of bodies in motion, are regarded solely in the aspect of their producing the same kind of motion in other bodies; their effects on the adhesive and cohesive forces, in the production of intestine motion, and especially the peculiarity of those effects, as resulting from a percussive instead of a pressing force, belong to another eminently practical, and a perpetually occurring subject, with which science cannot cope. It may have been expected à priori, that as we have thus one science whose subject matter is force simply considered, and another wherein it is combined with velocity in the simple power of that velocity, that there would have been a third in which it is measured by the square of the velocity. There is accordingly a class of effects corresponding to that measure alone, but we have no science of that kind, not even a name for such an investigation, whether scientific or practical; nay, so little is science conversant with such matters, that we have not even a distinctive term for such a product as the mass multiplied into the square of the velocity; for the word impetus, which would seem to be most appropriate, is generally confounded with momentum. I do not refer to this matter, in the same sense in which it was the subject of the celebrated controversy on the vis viva among the mathematicians of the last century, and which, after all-who would believe it?-was found to be little better than a verbal dispute; but I allude to it

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as a distinct science-potentially at least -with a class of effects peculiar to it, and peremptorily requiring this expression of force as its proper and only measure; a class of effects different from either the equilibrium or the motion of masses, with which only mathematicians concern themselves.

There is another very important class of effects, which has not been made the subject even of a practical and experimental inquiry, but with which practical men are fully conversant, and are continually taking into account, in what might be called their rough estimate of things, if that estimate, through a natural and an educated tact for such matters, were not so frequently found to be wondrously exact. In this class of effects, the disintegration of bodies is to be found, as influenced, not exclusively by the conditions of the acting force-not by its magnitude, not by its velocity, nor by its power in combination, proportional to any particular power of the velocity, but by the conditions of the action itself, in regard to the element of time, whether as influenced by the mechanical or the physical circumstances of the body acted on or by the peculiar state of its molecular forces. Thus the same force-identical in every particular-shall produce different effects on the same body, according as the time of its action is varied by these circumstances. This is no subject for calculation, and scarcely for reasoning; for that bodies should be taken by surprise, as it were-that they should be more or less powerfully affected, according to the warning they receive, is, indeed, if properly reflected on, a mysterious and a wondrous thing. It is, however, a fact, that the molecular forces are inclined to give way, by the mere suddenness of a shock, however it may be brought about. Of course it will be most usually effected through the velocity of the acting force; still, any circumstance that gives or withholds time for the percussive action to be distributed among the other particles of the mass has a corresponding effect. Of this truth, many familiar instances may be cited, but it would be tedious ;* the prin

I may mention one instance, which has not, that I am aware, been explained on this principle; and that is, the mode of blasting rocks by placing loose sand on the gunpowder. The result is not what at first sight would be anticipated, because

cipal object is to bring it in explanation of the cause of the accident in question.

The stress on the axle, when the break is applied, is of course very considerable; at the moment of impact it is at once a percussive and a constant force, but afterwards it is merely a continuous pressure. Now it is in the moment and for the reason mentioned, that the greatest danger is to be apprehended; and it is imminent in some unknown ratio of the approach to instantaneousness in the action. In practice, the springs of the tender and the deliberate handling of the break, render the impact gradual, both in force and suddenness, and the strain is little greater than is due to the continuous pressure. Had the tender in this case any springs ? The break at any rate appears to have been hastily and powerfully brought into action, and hence, as I conceive, the accident arose.

The distinguishing and characteristic error of theorists and mere scientific men is, to view every subject solely in the light of the rule and method knowledge acquired at school or college. It is the case here; the two French savans commissioned by their brother savans can find nothing in the circumstances of this sad event to occasion the breaking of the axle. It was an accident, an ultimate fact, which is no more to be accounted for than it is in future to be prevented, and is only to be mitigated in its dreadful consequences by palliative measures. Mathematically speaking, they are right; by all the rules of science the axle ought not to have broken; but as it did break, and as the supremacy and allsufficiency of the mathematics is not to be impugned, and as it is impossible to slander the maker and the material, the only way to save the credit and the assumed competency of scientific acumen for a satisfactory investigation of such matters, is in pointing out merely the conditional and the aggravating circumstances of the accident, to make it appear that they had detected therein its real and efficient causes. Although every one of the faults adverted to by these gentlemen as having been committed on this occasion had been avoided, still the accident would have been likely to occur,

different times are required for the production of effects of different kinds. The rock is rent before motion can be propagated among loose particles, to the effect of blowing the sand out of the hole.

and with consequences less dreadful only in extent. Thus if I am right in my conjecture as to the cause of the breaking of the axle, and as to the particular axle broken being that to which the break is applied, the substitution of six-wheel locomotives for four-wheel ones, as recommended by them, would not prevent a similar disaster, for it was occasioned by the breaking down of the four-wheel tender. The recommendation, to be good for any thing, ought to have gone to the extent of advising the adaptation of six wheels to every description of earriage. I apprehend, however, there is no necessity for this, although, in regard to locomotives, it may in other respects be preferable; for surely there is no difficulty in devising the mechanical expedient, which I believe has in some instances been adopted, of supporting and sliding the carriage on a sledge, in case either a wheel or an axle should fail.

The preceding observations are based upon the assumption, raised solely from the circumstances of the case as reported, that the axle which failed must have been that to which the break is applied; but since they were written, I have seen a statement in the Times, which asserts that such was the fact.

The instruction that we ought more particularly to gather from this accident, is the great importance of selecting well qualified men to act as engine drivers, the qualifications, however, being those of the mind rather than of the hand, and of the necessity of providing the means for carefully instructing them in the duties they have to perform; and then of insisting that none other than the regularly appointed driver, be allowed on any pretence to interfere in the management of the engine. The office ought to be held as sacred and as important as that of the pilot. The men should receive a respectable pay, and they should be allowed to take apprentices. In regard to the instruction that ought to be given them, we are liable to go astray ; we are liable to be led away by that delusive and really illiterate notion, which none but the half-informed should be found to entertain, that scientific knowledge is more to be depended on in the conduct of the active affairs of life, than practical knowledge and experience. I would rather trust my life to the watchfulness, the presence of mind, the quick