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.
FINISHING.
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.
DEPARTURE OF THE PACIFIC FOR EUROPE.
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.