Harper's New Monthly Magazine, Volume 2, No. 12, May, 1851.. Various
Чтение книги онлайн.

Читать онлайн книгу Harper's New Monthly Magazine, Volume 2, No. 12, May, 1851. - Various страница 4

Название: Harper's New Monthly Magazine, Volume 2, No. 12, May, 1851.

Автор: Various

Издательство: Public Domain

Жанр: Журналы

Серия:

isbn:

isbn:

СКАЧАТЬ to the right, is one of the trip hammers, in the act of striking. The trip-hammer is a massive hammer carried by machinery. The machinery which drives it may at any time be thrown in or out of gear, so that the blows of the hammer are always under the control of the workman. The iron bar to be forged is far too heavy to be held by hand. It is accordingly supported as seen in the engraving, by a crane; and only guided to its place upon the anvil by the workmen who have hold of it. The chain to which this bar is suspended comes down from a little truck which rests upon the top of the crane, and which may be made to traverse to and fro, thus carrying whatever is suspended from it further outward, or drawing it in, as may be required. All the cranes, both in the smith's shop and in the foundry, are fitted with the same contrivance. These trucks are moved by means of a wheel at the foot of the crane.

      On the extreme right of the picture, and somewhat in the distance, may be seen another trip-hammer with a bar upon the anvil beneath it, this bar being suspended likewise from a crane. When the iron becomes too cold to yield any longer to the percussion, the hammer is stopped, the crane is swung round, and the iron is replaced in the forge to be heated anew; and at length, when heated, it is brought back again under the hammer as before.

      The forging of shafts requires heavier machinery even than this. The enormous mass of iron that is in this case to be forged, is bricked up in a furnace to be heated, and remains there many hours. The masonry is then broken away and the red hot beam is swung round under the hammer, as seen below. It is suspended from the crane by heavy chains, and is guided by the workmen by means of iron handles clamped to it at a distance from the heated part, as seen in the engraving in the adjoining column. The hammer is lifted by means of the cam below it, as seen in the engraving below. This cam is a projection from an axis revolving beneath the floor, and which, as it revolves, carries the cams successively against a projection upon the under side of the hammer, which is partly concealed in the engraving by the figure of the man. When the point of the cam has passed beyond the projection it allows the hammer to fall.

      While the process of forging such a shaft is going on, one man throws water upon the work, to effect some purpose connected with the scaling of the iron, while another, with an instrument called the callipers, measures the diameter of the shaft, to regulate the size, as the forging proceeds.

      The shafts, when forged, are to be turned in a lathe, and the engine used for this purpose is represented on the left in the engraving below. The shaft itself is seen in the lathe, while the tool which cuts it as it revolves, is fixed firmly in the "rest," which slides along the side. The point of the tool is seen in the engraving, with the spiral shaving which it cuts falling down from it. The shaft is made to revolve by the band seen coming down obliquely from above, at the hither end of the engine. The wheel by which the band turns the lathe has different grooves at different distances from the centre, in order that the workmen may regulate the velocity of the rotation – as different degrees of velocity are required for the different species of work. The rest, to which the cutting tool is attached, is brought slowly along the side of the shaft as the shaft revolves, by means of a long screw which is concealed in the frame of the lathe, and which is turned continually by the mechanism of the small wheels which are seen at the hither end of the engine.

      On the right hand of this view is represented another kind of lathe called a face lathe, which is employed for turning wheels, and flat plates, and interiors of cavities, and such other pieces of work as do not furnish two opposite points of support. In the fore-ground are a company of men drawing a massive piece of iron upon a truck, destined apparently to be turned in the left hand lathe.

      Although thus a great part of the work in respect to all the details of the engine, is performed by machinery, much remains after all to be wrought and fashioned by hand. In passing through the establishment the visitor finds the workmen engaged in these labors, in every conceivable attitude and position. One man is filing a curved surface with a curved file, another is hidden almost wholly from view within a great misshapen box of iron: a third is mounted upon a ladder, and is slowly boring through the wall of some monstrous formation, or cutting away excrescences of iron from some massive casting with a cold chisel. In a word, the details are so endlessly varied as to excite the wonder of the beholder that any human head should have been capable of containing them all, so as to have planned and arranged the fitting of such complicated parts with any hope of their ever coming rightly together.

      They do come together, however, at last, and then follows the excitement of the trial. There is nothing more striking in the history of the construction of a steam engine than this, that there can be no partial or private tests of the work by the workmen in the course of its progress – but every thing remains in suspense until all is complete, and the ship and the machinery are actually ready for sea. The immense and ponderous masses which constitute the elements of the mighty structure are hoisted slowly on board and let down into their places. Multitudes of men are incessantly employed for many weeks in arranging the limbs and members of the monster, and in screwing and bolting every thing into its place. Still nothing can be tried. The machinery is too ponderous and massive to be put in action by any power less than that of the mighty mover on which its ultimate performance is to depend; and this mover has not yet been called into being.

      At length the day of trial arrives. The engineers, the workmen, the owners, and perhaps many spectators, have assembled to watch the result. The boiler is filled; the fires are lighted. Hour after hour the process goes on of raising the force and pressure of the steam. All this time, however, the machinery lies inert and lifeless. It is a powerless mass of dead and heavy brass and iron. At length an engineer, standing upon a platform, with a lever in his hand, receives the signal, opens the valve, and breathes into the monstrous body the breath of life. The ponderous piston slowly rises; the beam descends; the crank turns; the vast paddles revolve, and the monster walks away through the water with its enormous burden, having leaped suddenly, at its first breath, into the complete and full possession of its gigantic powers.

      In due time the equipment is complete, and the ship having received on board its burden of costly cargo and valuable lives, moves away from the shore, with a certain expression of calm and quiet dignity in her appearance and demeanor, which almost seems to denote a consciousness on her part of the vast responsibilities which she is assuming, and of the abundant power which she possesses fully to sustain them all.

      CHARLES WOLFE

      It is probable that to many of our readers the name which stands at the head of this sketch is unknown, and that those who recognize it will only know it as that of the author of the well-known lines upon the death of Sir John Moore – a lyric of such surpassing beauty, that so high a judge as Lord Byron considered it the perfection of English lyrical poetry, preferring it before Coleridge's lines on Switzerland – Campbell's Hohenlinden – and the finest of Moore's Irish melodies, which were instanced by Shelley and others. Yet, unknown as the Rev. Charles Wolfe is, it is unquestionable that he was a man possessing the highest powers of imagination, and a powerful intellect, cultivated to a very high point of perfection, and fitting him to become one of the brightest stars of the world of literature. Why he is unknown is then probably a question which will suggest itself to the minds of many, and the answer must be, because he did so little for the world to remember him by. The whole of his literary remains, including his sermons, and a biographical sketch, which fills one half of the book, is contained in a moderate sized octavo volume, published after his death by the Rev. J. A. Russell, Archdeacon of Clogher, whose affection for the memory of Mr. Wolfe prompted him to edit and give to the world the fragmentary manuscripts, which are the only lasting and appreciable records of the residence of a great spirit among us. But it may be asked why, with such capabilities and powers as we have stated Mr. Wolfe to possess, he did so little? and to that interrogation many replies may be given. Mr. Wolfe died at the early age of 32, just when the powers are in their full vigor – and in the later years of his life he had devoted himself enthusiastically to the duties which devolved upon him as the curate of a large and populous parish in the north of Ireland. Neither of these reasons, however, is sufficient, for we know that the poetic intellect is precocious, and brings forth fruit early. Shelley, who died younger, СКАЧАТЬ