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injured. Few wooden steamers, I may add, can be placed in thegraving-dock without first slackening the holding-down bolts of theengines, to allow the vessel to spread out, lest the framing shouldbe broken. The case is wholly different with iron vessels—in which,if properly built, there is no fear of twisting or settling. Theengineer may, with perfect safety, firmly unite the vessel and theengine. Having to design both, and being responsible for the suc-cess of the whole, he will not allow one part to suffer for the benefitof the other, but take an interest in so combining both that they maymutually support each other. The various resources with whichhis profession furnishes him, enable him to carry out one uniformand consistent plan. The lines, the trim, the draft of water,f thestrength, the power—all may be adapted to each other, and a degreeof excellence be attained of which we can as yet form no adequateidea. Then, indeed, we may expect to see a complete steamer.

Let us again direct our unbiassed attention to wooden ships,and, viewing the subject dispassionately while we examine them, weshall be struck with surprise at the means employed in their con-struction, and the extraordinary complication of the frames, especiallyin large ships. It has been the work of ages to determine uponthe several systems adopted, yet it is well known that one and allin them are still very far from being efficient; and nothing provesmore clearly the difficulty that surrounds the question, than thefact, that, to this day, with all the time, talent, and experience thathave been brought to bear upon it, it is by no means decided whichpeculiar principle of building is the most advantageous, and it iswithin only the last few years that a total revolution has been madein the science,—affording internal evidence that timber is deficientin many of the qualities requisite for ship-building. The force ofcustom is indeed strong; and had we throughout adopted ironalone as a material, it would have been naturally thought asimpracticable to employ timber for such a purpose, as it now is touse iron plates.

+ As a proof of how much this is required, I may instance the case of a timber steamerwhich drew about two feet six inches more water, when her engines were put in, than was con-templated,—an error of probably 200 tons in the total weight. Very few, indeed, approachnearer than 6 or 12 inches to the line originally intended. This may, in some measure, beattributed to the uncertainty as to the specific gravity of the timber to be used. With iron thedraft may be attained with greater certainty. I have, myself, calculated the draft of water of asteamer of 470 tons measurement before her keel was laid, and when she was completed withengines, and a given weight of cargo,-no perceptible variation from the depth named could bediscovered.