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XXI.-A SECOND DAY AT A SHIP-YARD.

Ir will be remembered that, after speaking of the occupation of the ship's draughtsman, we explained the arrangemeut of the buildingslip, the laying-down of the keel on the blocks, and the erection of the curved frame-timbers of a vessel. The form of the hull is thus given; in a rude manner it is true, but still with a degree of certainty which determines the character of the vessel. The numerous pieces subsequently added, whether of British or African oak, elm, or fir, are sawn at the pits, under the supervision of the converter;' and are afterwards, in most cases, trimmed, or, as it is termed, 'dubbed,' with an adze. In common carpenter's work, the only tool used, after the saw, for paring away and levelling the surface of wood, is generally the plane; but in the work of the shipwright, where more bulky materials are operated on, where almost every piece is to be hollowed or rounded in some part or other, and where great neatness is not required, the adze becomes a valuable instrument. The various kinds of joints whereby one timber or plank is connected with another, such as tenon and mortice, &c., are made by the aid of nearly the same tools as those employed in carpentry, but of a larger size and stronger make. As may be reasonably supposed, these prepared timbers are often very bulky and ponderous; and the conveyance of them from the sawpit to the building-slip requires the aid of horses. There is a whimsical anecdote given by Strype, in his edition of Stow's 'Survey of London,' which, while it immediately illustrates this subject, also carries us back to an early period in the history of the Blackwall ship-yard, introducing us to this scene of bustle as it was in the seventeenth century : "In the time of the elder Sir Henry Johnson, Knt., ship-builder, an horse belonging to his yard was wrought there thirty-four years, driven by one man; and he grew to that experience, that at the first sound of the bell for the men in the yard to leave off work, he also would cease labouring, and could not by any means be brought to give one pull after it; and when the bell rang to work, he would as readily

come forth again to his labour, which was to draw planks and pieces of timber from one part of the yard to another." We believe that a public-house in Blackwall has received the sign of the 'Old Hob,' in honour of the horse which bore that name, and which took this very independent mode of showing his importance.

But to return. The keel, the stern-post, and the stem, form the three great supports of the frame of the vessel; the first being horizontal, the second rising from it almost perpendicularly at one end, and the third rising in a curve at the other. Among the timbers which are subsequently adjusted to the vessel are three, called the keelson,' the 'sternson,' and the 'stemson,' which are in some sense interior representatives of the three just named. The keelson is fixed on the floor timbers, immediately over the keel, and forms that part on which the steps or blocks of wood are placed which support the masts: it is secured down to the keel by means of bolts three feet in length, which pass entirely through both, as well as the intervening wood. The stemson and the sternson rise from the two ends of the keelson, and form internal supports to the ends of the vessel. The timbers are often strengthened within by pieces called riders; but in modern vessels they are frequently secured and braced one to another by diagonal iron plates, from half an inch to an inch in thickness, passing nearly from the top to the bottom of the hull, inside the vessel. Being bent round the concavity of the ship's side in an oblique direction, each piece of iron crosses several different frames of timbers, and is securely bolted to them all.

The small portion of the hull of a vessel which is seen above the level of the water presents to view a surface covered with horizontal or nearly horizontal ranges of planking; and if we could see lower down towards the keel, we should find a similar approach to a horizontal direction in the pieces of wood with which the hull is covered. Withinside, too, a similar arrangement is observable. The vertical frames of timbers of which we have been speaking do not present themselves to the eye of a person viewing a finished vessel, either within or without. The whole are covered with planking, laid in nearly horizontal rows or 'strakes.' The planks may be regarded as forming the skin with which the ribs of the ship are covered; and, indeed, the shipwrights, who almost seem to regard their ship as a living being, apply the term 'skinning' to the operation of laying on these planks; an opposite sense, it is true, to that in which we are in the habit of using

this term. Nor is this skin by any means a trifling affair, for the thickness of the planks which form it varies from about three to six inches. The planks are formed of sound and durable oak, and are often nearly thirty feet in length. They are brought, while at the sawpit, as nearly to the required form as may be practicable; and are afterwards worked with the adze, to give them the proper contour. This must not be supposed to imply that the planks are hollowed or curved by the adze to the exact shape of the vessel, but that the width and thickness of adjoining planks are adjusted to each other. When a prepared plank is laid against the outside of a vessel, the convexity of the latter causes the ends of the planks to stand out several inches from it; and on the other hand, when laid on the inside, the concave surface to be in contact with the timbers, and the middle to be several inches away from them. The planks require, therefore, the aid of powerful instruments to force them close to the timbers previous to bolting; and this operation is further assisted by bringing the plank to a heated and moistened state by steam.

The parts of the planking vary in thickness, and receive distinctive names, according to the places which they occupy; but all are treated nearly in the same way-sawn, dressed with an adze, steamed, forced to the curvature of the ship, and fastened to the timbers with bolts. The trenails, which are more numerous than the bolts, are not driven in till a subsequent stage in the operations. In adjusting the planks to the ship's sides care is always taken that the adjoining ends of two planks in one row or strake shall not occur at the same part of the ship's length as a joint in the row next above or below it, a caution similar to that observed in laying the courses of bricks in a wall, or the rows of slates on a roof, and the object of which is sufficiently obvious in relation to the strength of the structure. Whoever has an opportunity of seeing the whole hull of a vessel will observe that the planking is ranged with great regularity, each strake or row diminishing in width towards the ends, to conform with the diminishing size of the vessel.

In the building of a ship matters are so arranged that many different parts are in progress simultaneously; some workmen making preparations for the beams of a vessel withinside, while others are planking the exterior, and others perhaps engaged at various parts of the head and stern. The beams are stout and well finished timbers stretching across the vessel from side to side, at intervals of a few feet, and