Harper's New Monthly Magazine, No. XXVI, July 1852, Vol. V

Harper's New Monthly Magazine, No. XXVI, July 1852, Vol. V
Various

Various

Harper's New Monthly Magazine, No. XXVI, July 1852, Vol. V

THE ARMORY AT SPRINGFIELD

BY JACOB ABBOTT

SPRINGFIELD

The Connecticut river flows through the State of Massachusetts, from north to south, on a line about half way between the middle of the State and its western boundary. The valley through which the river flows, which perhaps the stream itself has formed, is broad and fertile, and it presents, in the summer months of the year, one widely extended scene of inexpressible verdure and beauty. The river meanders through a region of broad and luxuriant meadows which are overflowed and enriched by an annual inundation. These meadows extend sometimes for miles on either side of the stream, and are adorned here and there with rural villages, built wherever there is a little elevation of land – sufficient to render human habitations secure. The broad and beautiful valley is bounded on either hand by an elevated and undulating country, with streams, mills, farms, villages, forests, and now and then a towering mountain, to vary and embellish the landscape. In some cases a sort of spur or projection from the upland country projects into the valley, forming a mountain summit there, from which the most magnificent views are obtained of the beauty and fertility of the surrounding scene.

There are three principal towns upon the banks of the Connecticut within the Massachusetts lines: Greenfield on the north – where the river enters into Massachusetts from between New Hampshire and Vermont – Northampton at the centre, and Springfield on the south. These towns are all built at points where the upland approaches near to the river. Thus at Springfield the land rises by a gentle ascent from near the bank of the stream to a spacious and beautiful plain which overlooks the valley. The town is built upon this declivity. It is so enveloped in trees that from a distance it appears simply like a grove with cupolas and spires rising above the masses of forest foliage; but to one within it, it presents every where most enchanting pictures of rural elegance and beauty. The streets are avenues of trees. The houses are surrounded by gardens, and so enveloped in shrubbery that in many cases they reveal themselves to the passer-by only by the glimpse that he obtains of a colonnade or a piazza, through some little vista which opens for a moment and then closes again as he passes along. At one point, in ascending from the river to the plain above, the tourist stops involuntarily to admire the view which opens on either side, along a winding and beautiful street which here crosses his way. It is called Chestnut-street on the right hand, and Maple-street on the left – the two portions receiving their several names from the trees with which they are respectively adorned. The branches of the trees meet in a dense and unbroken mass of foliage over the middle of the street, and the sidewalk presents very precisely the appearance and expression of an alley in the gardens of Versailles.

THE ARMORY GROUNDS

On reaching the summit of the ascent, the visitor finds himself upon an extended plain, with streets of beautiful rural residences on every hand, and in the centre a vast public square occupied and surrounded by the buildings of the Armory. These buildings are spacious and elegant in their construction, and are arranged in a very picturesque and symmetrical manner within the square, and along the streets that surround it. The grounds are shaded with trees; the dwellings are adorned with gardens and shrubbery. Broad and neatly-kept walks, some graveled, others paved, extend across the green or along the line of the buildings, opening charming vistas in every direction. All is quiet and still. Here and there a solitary pedestrian is seen moving at a distance upon the sidewalk, or disappearing among the trees at the end of an avenue; and perhaps the carriage of some party of strangers stands waiting at a gate. The visitor who comes upon this scene on a calm summer morning, is enchanted by the rural beauty that surrounds him, and by the air of silence and repose which reigns over it all. He hears the distant barking of a dog, the voices of children at play, or the subdued thundering of the railway-train crossing the river over its wooden viaduct, far down the valley – and other similar rural sounds coming from a distance through the calm morning air – but all around him and near him is still. Can it be possible, he asks, that such a scene of tranquillity and loveliness can be the outward form and embodiment of a vast machinery incessantly employed in the production of engines of carnage and death?

It is, however, after all, perhaps scarcely proper to call the arms that are manufactured by the American government, and stored in their various arsenals, as engines of carnage and destruction. They ought, perhaps, to be considered rather as instruments of security and peace; for their destination is, as it would seem, not to be employed in active service in the performance of the function for which they are so carefully prepared; but to be consigned, when once finished, to eternal quiescence and repose. They protect by their existence, and not by their action; but in order that this, their simple existence, should be efficient as protection, it is necessary that the instruments themselves should be fitted for their work in the surest and most perfect manner. And thus we have the very singular and extraordinary operation going on, of manufacturing with the greatest care, and with the highest possible degree of scientific and mechanical skill, a vast system of machinery, which, when completed, all parties concerned most sincerely hope and believe will, in a great majority of cases, remain in their depositories undisturbed forever. They fulfill their vast function by their simple existence – and thus, though in the highest degree useful, are never to be used.

THE BUILDINGS

The general appearance of the buildings of the Armory is represented in the engraving placed at the head of this article. The point from which the view is taken, is on the eastern side of the square – that is, the side most remote from the town. The level and extended landscape seen in the distance, over the tops of the buildings, is the Connecticut valley – the town of Springfield lying concealed on the slope of the hill, between the buildings and the river. The river itself, too, is concealed from view at this point by the masses of foliage which clothe its banks, and by the configuration of the land.

The middle building in the foreground, marked by the cupola upon the top of it, is called the Office. It contains the various counting-rooms necessary for transacting the general business of the Armory, and is, as it were, the seat and centre of the power by which the whole machinery of the establishment is regulated. North and south of it, and in a line with it, are two shops, called the North and South Filing Shops, where, in the several stories, long ranges of workmen are found, each at his own bench, and before his own window, at work upon the special operation, whatever it may be, which is assigned to him. On the left of the picture is a building with the end toward the observer, two stories high in one part, and one story in the other part. The higher portion – which in the view is the portion nearest the observer – forms the Stocking Shop, as it is called; that is the shop where the stocks are made for the muskets, and fitted to the locks and barrels. The lower portion is the Blacksmith's Shop. The Blacksmith's Shop is filled with small forges, at which the parts of the lock are forged. Beyond the Blacksmith's Shop, and in a line with it, and forming, together with the Stocking Shop and the Blacksmith's Shop, the northern side of the square, are several dwelling-houses, occupied as the quarters of certain officers of the Armory. The residence of the Commanding Officer, however, is not among them. His house stands on the west side of the square, opposite to the end of the avenue which is seen opening directly before the observer in the view. It occupies a very delightful and commanding situation on the brow of the hill, having a view of the Armory buildings and grounds upon one side, and overlooking the town and the valley of the Connecticut on the other.

A little to the south of the entrance to the Commanding Officer's house, stands a large edifice, called the New Arsenal. It is the building with the large square tower – seen in the view in the middle distance, and near the centre of the picture. This building is used for the storage of the muskets during the interval that elapses from the finishing of them to the time when they are sent away to the various permanent arsenals established by government in different parts of the country, or issued to the troops. Besides this new edifice there are two or three other buildings which are used for the storage of finished muskets, called the Old Arsenals. They stand in a line on the south side of the square, and may be seen on the left hand, in the view. These buildings, all together, will contain about five hundred thousand muskets. The New Arsenal, alone, is intended to contain three hundred thousand.

THE WATER SHOPS

Such is the general arrangement of the Arsenal buildings, "on the hill." But it is only the lighter work that is done here. The heavy operations, such as rolling, welding, grinding, &c., are all performed by water-power. The stream which the Ordnance Department of the United States has pressed into its service to do this work, is a rivulet that meanders through a winding and romantic valley, about half a mile south of the town. On this stream are three falls, situated at a distance perhaps of half a mile from each other. At each of these falls there is a dam, a bridge, and a group of shops. They are called respectively the Upper, Middle, and Lower Water Shops. The valley in which these establishments are situated is extremely verdant and beautiful. The banks of the stream are adorned sometimes with green, grassy slopes, and sometimes with masses of shrubbery and foliage, descending to the water. The road winds gracefully from one point of view to another, opening at every turn some new and attractive prospect. The shops and all the hydraulic works are very neatly and very substantially constructed, and are kept in the most perfect order: so that the scene, as it presents itself to the party of visitors, as they ride slowly up or down the road in their carriage, or saunter along upon the banks of the stream on foot, forms a very attractive picture.

THE MUSKET BARREL

The fundamental, and altogether the most important operation in the manufacture of the musket, is the formation of the barrel; for it is obvious, that on the strength and perfection of the barrel, the whole value and efficiency of the weapon when completed depends. One would suppose, that the fabrication of so simple a thing as a plain and smooth hollow tube of iron, would be a very easy process; but the fact is, that so numerous are the obstacles and difficulties that are in the way, and so various are the faults, latent and open, into which the workman may allow his work to run, that the forming of the barrel is not only the most important, but by far the most difficult of the operations at the Armory – one which requires the most constant vigilance and attention on the part of the workman, during the process of fabrication, and the application of multiplied tests to prove the accuracy and correctness of the work at every step of the progress of it, from beginning to end.

The barrels are made from plates of iron, of suitable form and size, called scalps or barrel plates. These scalps are a little more than two feet long, and about three inches wide. The barrel when completed, is about three feet six inches long, the additional length being gained by the elongating of the scalp under the hammer during the process of welding. The scalps are heated, and then rolled up over an iron rod, and the edges being lapped are welded together, so as to form a tube of the requisite dimensions – the solid rod serving to preserve the cavity within of the proper form. This welding of the barrels is performed at a building among the Middle Water Shops. A range of tilt hammers extend up and down the room, with forges in the centre of the room, one opposite to each hammer, for heating the iron. The tilt hammers are driven by immense water-wheels, placed beneath the building – there being an arrangement of machinery by which each hammer may be connected with its moving power, or disconnected from it, at any moment, at the pleasure of the workman. Underneath the hammer is an anvil. This anvil contains a die, the upper surface of which, as well as the under surface of a similar die inserted in the hammer, is formed with a semi-cylindrical groove, so that when the two surfaces come together a complete cylindrical cavity is formed, which is of the proper size to receive the barrel that is to be forged. The workman heats a small portion of his work in his forge, and then standing directly before the hammer, he places the barrel in its bed upon the anvil, and sets his hammer in motion, turning the barrel round and round continually under the blows. Only a small portion of the seam is closed at one heat, eleven heats being required to complete the work. To effect by this operation a perfect junction of the iron, in the overlapping portions, so that the substance of iron shall be continuous and homogeneous throughout, the same at the junction as in every other part, without any, the least, flaw, or seam, or crevice, open or concealed, requires not only great experience and skill, but also most unremitting and constant attention during the performance of the work. Should there be any such flaw, however deeply it may be concealed, and however completely all indications of it may be smoothed over and covered up by a superficial finishing, it is sure to be exposed at last, to the mortification and loss of the workman, in the form of a great gaping rent, which is brought out from it under the inexorable severity of the test to which the work has finally to be subjected.

RESPONSIBILITY OF THE WORKMEN

We say to the loss as well as to the mortification of the workman, for it is a principle that pervades the whole administration of this establishment, though for special reasons the principle is somewhat modified in its application to the welder, as will hereafter be explained, that each workman bears the whole loss that is occasioned by the failure of his work to stand its trial, from whatever cause the failure may arise. As a general rule each workman stamps every piece of work that passes through his hands with his own mark – a mark made indelible too – so that even after the musket is finished, the history of its construction can be precisely traced, and every operation performed upon it, of whatever kind, can be carried home to the identical workman who performed it. The various parts thus marked are subject to very close inspection, and to very rigid tests, at different periods, and whenever any failure occurs, the person who is found to be responsible for it is charged with the loss. He loses not only his own pay for the work which he performed upon the piece in question, but for the whole value of the piece at the time that the defect is discovered. That is, he has not only to lose his own labor, but he must also pay for all the other labor expended upon the piece, which through the fault of his work becomes useless. For example, in the case of the barrel, there is a certain amount of labor expended upon the iron, to form it into scalps, before it comes into the welder's hands. Then after it is welded it must be bored and turned, and subjected to some other minor operations before the strength of the welding can be proved. If now, under the test that is applied to prove this strength – a test which will be explained fully in the sequel – the work gives way, and if, on examination of the rent, it proves to have been caused by imperfection in the welding, and not by any original defect in the iron, the welder, according to the general principle which governs in this respect all the operations of the establishment, would have to lose not only the value of his own labor, in welding the barrel, but that of all the other operations which had been performed upon it, and which were rendered worthless by his agency. It is immaterial whether the misfortune in such cases is occasioned by accident, or carelessness, or want of skill. In either case the workman is responsible. This rule is somewhat relaxed in the case of the welder, on whom it would, perhaps, if rigidly enforced, bear somewhat too heavily. In fact many persons might regard it as a somewhat severe and rigid rule in any case – and it would, perhaps, very properly be so considered, were it not that this responsibility is taken into the account in fixing the rate of wages; and the workmen being abundantly able to sustain such a responsibility do not complain of it. The system operates on the whole in the most salutary manner, introducing, as it does, into every department of the Armory, a spirit of attention, skill, and fidelity, which marks even the countenances and manners of the workmen, and is often noticed and spoken of by visitors. In fact none but workmen of a very high character for intelligence, capacity, and skill could gain admission to the Armory – or if admitted could long maintain a footing there.

The welders are charged one dollar for every barrel lost through the fault of their work. They earn, by welding, twelve cents for each barrel; so that by spoiling one, they lose the labor which they expend upon eight. Being thus rigidly accountable for the perfection of their work, they find that their undivided attention is required while they are performing it; and, fortunately perhaps for them, there is nothing that can well divert their attention while they are engaged at their forges, for such is the incessant and intolerable clangor and din produced by the eighteen tilt hammers, which are continually breaking out in all parts of the room, into their sudden paroxysms of activity, that every thing like conversation in the apartment is almost utterly excluded. The blows of the hammers, when the white-hot iron is first passed under them and the pull of the lever sets them in motion, are inconceivably rapid, and the deafening noise which they make, and the showers of sparks which they scatter in every direction around, produce a scene which quite appalls many a lady visitor when she first enters upon it, and makes her shrink back at the door, as if she were coming into some imminent danger. The hammers strike more than six hundred blows in a minute, that is more than ten in every second; and the noise produced is a sort of rattling thunder, so overpowering when any of the hammers are in operation near to the observer, that the loudest vociferation uttered close to the ear, is wholly inaudible. Some visitors linger long in the apartment, pleased with the splendor and impressiveness of the scene. Others consider it frightful, and hasten away.

FINISHING OPERATIONS. – BORING

From the Middle Water Shops, where this welding is done, the barrels are conveyed to the Upper Shops, where the operations of turning, boring and grinding are performed. Of course the barrel when first welded is left much larger in its outer circumference, and smaller in its bore, than it is intended to be when finished, in order to allow for the loss of metal in the various finishing operations. When it comes from the welder the barrel weighs over seven pounds: when completely finished it weighs but about four and a half pounds, so that nearly one half of the metal originally used, is cut away by the subsequent processes.

The first of these processes is the boring out of the interior. The boring is performed in certain machines called boring banks. They consist of square and very solid frames of iron, in which, as in a bed, the barrel is fixed, and there is bored out by a succession of operations performed by means of certain tools which are called augers, though they bear very little resemblance to the carpenter's instrument so named. These augers are short square bars of steel, highly polished, and sharp at the edges – and placed at the ends of long iron rods, so that they may pass entirely through the barrel to be bored by them, from end to end. The boring parts of these instruments, though they are in appearance only plain bars of steel with straight and parallel sides, are really somewhat smaller at the outer than at the inner end, so that, speaking mathematically, they are truncated pyramids, of four sides, though differing very slightly in the diameters of the lower and upper sections.

The barrels being fixed in the boring bank, as above described, the end of the shank of the auger is inserted into the centre of a wheel placed at one end of the bank, where, by means of machinery, a slow rotary motion is given to the auger, and a still slower progressive motion at the same time. By this means the auger gradually enters the hollow of the barrel, boring its way, or rather enlarging its way by its boring, as it advances. After it has passed through it is withdrawn, and another auger, a very little larger than the first is substituted in its place; and thus the calibre of the barrel is gradually enlarged, almost to the required dimensions.

Almost, but not quite; for in the course of the various operations which are subsequent to the boring, the form of the interior of the work is liable to be slightly disturbed, and this makes it necessary to reserve a portion of the surplus metal within, for a final operation. In fact the borings to which the barrel are subject, alternate in more instances than one with other operations, the whole forming a system far too nice and complicated to be described fully within the limits to which we are necessarily confined in such an article as this. It is a general principle however that the inside work is kept always in advance of the outside, as it is the custom with all machinists and turners to adopt the rule that is so indispensable and excellent in morals, namely, to make all right first within, and then to attend to the exterior. Thus in the case of the musket barrel the bore is first made correct. Then the outer surface of the work is turned and ground down to a correspondence with it. The reverse of this process, that is first shaping the outside of it, and then boring it out within, so as to make the inner and outer surfaces to correspond, and the metal every where to be of equal thickness, would be all but impossible.

TURNING

After the boring, then, of the barrel, comes the turning of the outside of it. The piece is supported in the lathe by means of mandrels inserted into the two ends of it, and there it slowly revolves, bringing all parts of its surface successively under the action of a tool fixed firmly in the right position for cutting the work to its proper form. Of course the barrel has a slow progressive as well as rotary motion during this process, and the tool itself, with the rest in which it is firmly screwed, advances or recedes very regularly and gradually, in respect to the work, as the process goes on, in order to form the proper taper of the barrel in proceeding from the breech to the muzzle. The main work however in this turning process is performed by the rotation of the barrel. The workman thus treats his material and his tools with strict impartiality. In the boring, the piece remains at rest, and the tool does its work by revolving. In the turning, on the other hand, the piece must take its part in active duty, being required to revolve against the tool, while the tool itself remains fixed in its position in the rest.

Among the readers of this article there will probably be many thousands who have never had the opportunity to witness the process of turning or boring iron, and to them it may seem surprising that any tool can be made with an edge sufficiently enduring to stand in such a service. And it is indeed true that a cutting edge destined to maintain itself against iron must be of very excellent temper, and moreover it must have a peculiar construction and form, such that when set in its proper position for service, the cutting part shall be well supported, so to speak, in entering the metal, by the mass of the steel behind it. It is necessary, too, to keep the work cool by a small stream of water constantly falling upon the point of action. The piece to be turned, moreover, when of iron, must revolve very slowly; the process will not go on successfully at a rapid rate; though in the case of wood the higher the speed at which the machinery works, within certain limits, the more perfect the operation. In all these points the process of turning iron requires a very nice adjustment; but when the conditions necessary to success are all properly fulfilled, the work goes on in the most perfect manner, and the observer who is unaccustomed to witness the process is surprised to see the curling and continuous shaving of iron issuing from the point where the tool is applied, being cut out there as smoothly and apparently as easily as if the material were lead.

THE STRAIGHTENING

One of the most interesting and curious parts of the process of the manufacture of the barrel, is the straightening of it. We ought, perhaps, rather to say the straightenings, for it is found necessary that the operation should be several times performed. For example, the barrel must be straightened before it is turned, and then, inasmuch as in the process of turning it generally gets more or less sprung, it must be straightened again afterward. In fact, every important operation performed upon the barrel is likely to cause some deflection in it, which requires to be subsequently corrected, so that the process must be repeated several times. The actual work of straightening, that is the mechanical act that is performed, is very simple – consisting as it does of merely striking a blow. The whole difficulty lies in determining when and where the correction is required. In other words, the making straight is very easily and quickly done; the thing attended with difficulty is to find out when and where the work is crooked; for the deflections which it is thus required to remedy, are so extremely slight, that all ordinary modes of examination would fail wholly to detect them; while yet they are sufficiently great to disturb very essentially the range and direction of the ball which should issue from the barrel, affected by them.

The above engraving represents the workman in the act of examining the interior of a barrel with a view to ascertaining whether it be straight. On the floor, in the direction toward which the barrel is pointed, is a small mirror, in which the workman sees, through the tube, a reflection of a certain pane of glass in the window. The pane in question is marked by a diagonal line, which may be seen upon it, in the view, passing from one corner to the other. This diagonal line now is reflected by the mirror into the bore of the barrel, and then it is reflected again to the eye of the observer; for the surface of the iron on the inside of the barrel is left in a most brilliantly polished condition, by the boring and the operations connected therewith. Now the workman, in some mysterious way or other, detects the slightest deviation from straightness in the barrel, by the appearance which this reflection presents to his eye, as he looks through the bore in the manner represented in the drawing. He is always ready to explain very politely to his visitor exactly how this is done, and to allow the lady to look through the tube and see for herself. All that she is able to see, however, in such cases is a very resplendent congeries of concentric rings, forming a spectacle of very dazzling brilliancy, which pleases and delights her, though the mystery of the reflected line generally remains as profound a mystery after the observation as before. This is, in fact, the result which might have been expected, since it is generally found that all demonstrations and explanations relating to the science of optics and light, addressed to the uninitiated, end in plunging them into greater darkness than ever.

The only object which the mirror upon the floor serves, in the operation, is to save the workman from the fatigue of holding up the barrel, which it would be necessary for him to do at each observation, if he were to look at the window pane directly. By having a reflecting surface at the floor he can point the barrel downward, when he wishes to look through it, and this greatly facilitates the manipulation. There is a rest, too, provided for the barrel, to support it while the operator is looking through. He plants the end of the tube in this rest, with a peculiar grace and dexterity, and then, turning it round and round, in order to bring every part of the inner surface to the test of the reflection, he accomplishes the object of his scrutiny in a moment, and then recovering the barrel, he lays it across a sort of anvil which stands by his side, and strikes a gentle blow upon it wherever a correction was found to be required. Thus the operation, though it often seems a very difficult one for the visitor to understand, proves a very easy one for the workman to perform.

OLD MODE OF STRAIGHTENING

In former times a mode altogether different from this was adopted to test the interior rectitude of the barrel. A very slender line, formed of a hair or some similar substance, was passed through the barrel —dropped through, in fact, by means of a small weight attached to the end of it. This line was then drawn tight, and the workman looking through, turned the barrel round so as to bring the line into coincidence successively with every portion of the inner surface. If now there existed any concavity in any part of this surface, the line would show it by the distance which would there appear between the line itself and its reflection in the metal. The present method, however, which has now been in use about thirty years, is found to be far superior to the old one; so much so in fact that all the muskets manufactured before that period have since been condemned as unfit for use, on account mainly of the crookedness of the barrels. When we consider, however, that the calculation is that in ordinary engagements less than one out of every hundred of the balls that are discharged take effect; that is, that ninety-nine out of every hundred go wide of the mark for which they are intended, from causes that must be wholly independent of any want of accuracy in the aiming, it would seem to those who know little of such subjects, that to condemn muskets for deviating from perfect straightness by less than a hair, must be quite an unnecessary nicety. The truth is, however, that all concerned in the establishment at Springfield, seem to be animated by a common determination, that whatever may be the use that is ultimately to be made of their work, the instrument itself, as it comes from their hands, shall be absolutely perfect; and whoever looks at the result, as they now attain it, will admit that they carry out their determination in a very successful manner.

CINDER HOLES

Various other improvements have been made from time to time in the mode of manufacturing and finishing the musket, which have led to the condemnation or alteration of those made before the improvements were introduced. A striking illustration of this is afforded by the case of what are called cinder holes. A cinder hole is a small cavity left in the iron at the time of the manufacture of it – the effect, doubtless, of some small development of gas forming a bubble in the substance of the iron. If the bubble is near the inner surface of the barrel when it is welded, the process of boring and finishing brings it into view, in the form of a small blemish seen in the side of the bore. At a former period in the history of the Armory, defects of this kind were not considered essential, so long as they were so small as not to weaken the barrel. It was found, however, at length that such cavities, by retaining the moisture and other products of combustion resulting from the discharge of the piece, were subject to corrosion, and gradual enlargement, so as finally to weaken the barrel in a fatal manner. It was decided therefore that the existence of cinder holes in a barrel should thenceforth be a sufficient cause for its rejection, and all the muskets manufactured before that time have since been condemned and sold; the design of the department being to retain in the public arsenals only arms of the most perfect and unexceptionable character.

At the present time, in the process of manufacturing the barrels, it is not always found necessary to reject a barrel absolutely in every case where a cinder hole appears. Sometimes the iron may be forced in, by a blow upon the outside, sufficiently to enable the workman to bore the cinder hole out entirely. This course is always adopted where the thickness of the iron will allow it, and in such cases the barrel is saved. Where this can not be done, the part affected is sometimes cut off, and a short barrel is made, for an arm called a musketoon.

THE GRINDING

After the barrel is turned to nearly its proper size it is next to be ground, for the purpose of removing the marks left by the tool in turning, and of still further perfecting its form. For this operation immense grindstones, carried by machinery, are used, as seen in the engraving. These stones, when in use, are made to revolve with great rapidity – usually about four hundred times in a minute– and as a constant stream of water is kept pouring upon the part where the barrel is applied in the grinding, it is necessary to cover them entirely with a wooden case, as seen in the engraving, to catch and confine the water, which would otherwise be thrown with great force about the room. The direct action therefore of the stone upon the barrel in the process of grinding is concealed from view.

The workman has an iron rod with a sort of crank-like handle at the end of it, and this rod he inserts into the bore of the barrel which he has in hand. The rod fits into the barrel closely, and is held firmly by the friction, so that by means of the handle to the rod, the workman can turn the barrel round and round continually while he is grinding it, and thus bring the action of the stone to bear equally upon every part, and so finish the work in a true cylindrical form. One of these rods, with its handle, may be seen lying free upon the stand on the right of the picture. The workman is also provided with gauges which he applies frequently to the barrel at different points along its length, as the work goes on, in order to form it to the true size and to the proper taper. In the act of grinding he inserts the barrel into a small hole in the case, in front of the stone, and then presses it hard against the surface of the stone by means of the iron lever behind him. By leaning against this lever with greater or less exertion he can regulate the pressure of the barrel against the stone at pleasure. In order to increase his power over this lever he stands upon a plate of iron which is placed upon the floor beneath him, with projections cast upon it to hold his feet by their friction; the moment that he ceases to lean against the lever, the inner end of it is drawn back by the action of the weight seen hanging down by the side of it, and the barrel is immediately released.

The workman turns the barrel continually, during the process of grinding, by means of the handle, as seen in the drawing, and as the stone itself is revolving all the time with prodigious velocity, the work is very rapidly, and at the same time very smoothly and correctly performed.

DANGER

It would seem too, at first thought, that this operation of grinding must be a very safe as well as a simple one; but it is far otherwise. This grinding room is the dangerous room – the only dangerous room, in fact, in the whole establishment. In the first place, the work itself is often very injurious to the health. The premises are always drenched with water, and this makes the atmosphere damp and unwholesome. Then there is a fine powder, which, notwithstanding every precaution, will escape from the stone, and contaminate the air, producing very serious tendencies to disease in the lungs of persons who breathe it for any long period. In former times it was customary to grind bayonets as well as barrels; and this required that the face of the stone should be fluted, that is cut into grooves of a form suitable to receive the bayonet. This fluting of the stone, which of course it was necessary continually to renew, was found to be an exceedingly unhealthy operation, and in the process of grinding, moreover, in the case of bayonets, the workman was much more exposed than in grinding barrels, as it was necessary that a portion of the stone should be open before him and that he should apply the piece in hand directly to the surface of it. From these causes it resulted, under the old system, that bayonets, whatever might have been their destination in respect to actual service against an enemy on the field, were pretty sure to be the death of all who were concerned in making them.

The system, however, so far as relates to the bayonet is now changed. Bayonets are now "milled," instead of being ground; that is, they are finished by means of cutters formed upon the circumference of a wheel, and so arranged that by the revolution of the wheel, and by the motion of the bayonet in passing slowly under it, secured in a very solid manner to a solid bed, the superfluous metal is cut away and the piece fashioned at once to its proper form, or at least brought so near to it by the machine, as to require afterward only a very little finishing. This operation is cheaper than the other, and also more perfect in its result; while at the same time it is entirely free from danger to the workman.

No mode, however, has yet been devised for dispensing with the operation of grinding in the case of the barrel; though the injury to the health is much less in this case than in the other.

BURSTING OF GRINDSTONES

There is another very formidable danger connected with the process of grinding besides the insalubrity of the work; and that is the danger of the bursting of the stones in consequence of their enormous weight and the immense velocity with which they are made to revolve. Some years since a new method of clamping the stone, that is of attaching it and securing it to its axis, was adopted, by means of which the danger of bursting is much diminished. But by the mode formerly practiced – the mode which in fact still prevails in many manufacturing establishments where large grindstones are employed – the danger was very great, and the most frightful accidents often occurred. In securing the stone to its axis it was customary to cut a square hole through the centre of the stone, and then after passing the iron axis through this opening, to fix the stone upon the axis by wedging it up firmly with wooden wedges. Now it is well known that an enormous force may be exerted by the driving of a wedge, and probably in many cases where this method is resorted to, the stone is strained to its utmost tension, so as to be on the point of splitting open, before it is put in rotation at all. The water is then let on, and the stone becomes saturated with it – which greatly increases the danger. There are three ways by which the water tends to promote the bursting of the stone. It makes it very much heavier, and thus adds to the momentum of its motion, and consequently to the centrifugal force. It also makes it weaker, for the water penetrates the stone in every part, and operates to soften, as it were, its texture. Then finally it swells the wedges, and thus greatly increases the force of the outward strain which they exert at the centre of the stone. When under these circumstances the enormous mass is put in motion, at the rate perhaps of five or six revolutions in a second, it bursts, and some enormous fragment, a quarter or a third of the whole, flies up through the flooring above, or out through a wall, according to the position of the part thrown off, at the time of the fracture. An accident of this kind occurred at the Armory some years since. One fragment of the stone struck the wall of the building, which was two or three feet thick, and broke it through. The other passing upward, struck and fractured a heavy beam forming a part of the floor above, and upset a work-bench in a room over it, where several men were working. The men were thrown down, though fortunately they were not injured. The workman who had been grinding at the stone left his station for a minute or two, just before the catastrophe, and thus his life too was saved.