HISTORY OF MARINE ARCHITECTURE.

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In commenting on the contrivance of Duilius, Folard enters into a full expla-nation, or rather translation, of the foregoing passage of Polybius, which verynearly agrees with that already given :—

“ The corvus (says he) was a machine that bore a strong resemblance to thecrane, which is now used for lifting heavy weights. It had a mast, or uprightbeam, four fathom in height, and three palms in diameter, which stood on theprow, or forecastle, and served at its top as an axis for the long piece of woodwhich, in cranes, is called the arm, and to which the corvus, or cone of iron, wassuspended. This arm turned with facility on every side, and was properlysecured by means of the ropes which w'ere fixed to it. At the end of thearm there was a pulley for the passage of the cord which suspended the corvus .”The author observes, that the iron was pointed, wherefore it could not havebeen made in the form of a pestle, as the Greek word implies, but

rather, of the reversed cone or pyramid. “ This cone was of cast iron, andexceedingly heavy, so that falling by its own weight, it might pierce the deckor prow : but, as it might have returned through the hole by which it entered,and thus released the vessel, it was furnished with moveable hooks of iron,attached by hinges, to the end that, when the corvus had pierced the deck, thehooks, or grapples, which yielded to the previous resistance, might open of them-selves, and lay hold of whatever should be within their reach. It is obvious,too, though no mention has been made of this particular by the author, that tothe end of the rope was added an iron chain. As soon as a vessel thus fur-nished approached another within the reach of this machine, the rope wasloosened to permit the elevated end of the arm fall down ; the instant thecorvus had made its stroke, the bridge was dropped, and at the outer endwere claws of iron to secure its hold.

The author is equally clear in his explanation of the bridge, or platform. Hesays, “ that in the middle of the drawbridge was an oblong aperture, throughwhich the beam passed, and thus permitted it to turn as on a center. Theaperture was at the end of the bridge ; and, from this circumstance, the bridgemight be raised to any required height. At the other extremity of the bridge,and at the two sides, were attached two small chains, which ended in a semicir-cular iron like the handle of a pail.

This account appears so intelligible, and so well warranted by the text ofthe author, that to recount the objections which have been made to it, or enterin any manner into that controversy which has already taken place on the sub-ject, appears wholly unnecessary. It will be infinitely more interesting to make

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