HISTORY OF MARINE ARCHITECTURE.

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working of the ship, soon lose their hold, and drop out.” To this observationmay be added one other remark, which contributes very materially to raise thecharacter of the ancients, not only as marine architects, but as being very con-siderable adepts in those refined parts of the science, which may very justly beconsidered as improvements. Soon after the restoration of king Charles theSecond, a project for sheathing all ships with lead was introduced to publicnotice, and no inconsiderable pains were used to render the adoption of itgeneral, in the British navy. The attempt, however, failed; but though sub-sequent experience may have introduced a more efficacious system, and ledmoderns to despise a practice which would evidently have been less beneficialthan that which recent improvement, and extended experience, has renderedgeneral, yet it must be allowed, that the principle of preservation is in bothinstances precisely the same. It certainly matters not, in respect to the pri-mary method of contrivance for preserv ing a ship’s bottom, whether the mate-rial employed, is a thin plank of deal, a sheet of lead, or a plate of copper.

Philosophical as the investigation certainly is, and ill adapted to the pur-suits of early navigators, they seem to have bestowed the most marked atten-tion to the rudder, and to have applied themselves, with the utmost earnestness,towards the discovery of those interesting arcana which produced its effects.Not satisfied with the advantages derived from discovery itself, they stoppednot till they considered themselves in possession of that theoretical know lege,which explained to them all its laws of action. The ancients found, by obser-vation and experiment, that the fluid which opposed the passage of the stem,or prow, was raised to a greater or less height in opposition against the bow,in proportion to the velocity with which a vessel was impelled, or driventhrough the water. Reflection also taught them, that such increased heightof fluid, so raised and divided by the prow, and afterwards by the sides of thevessel, again joined at the stern, and fell in constant succession into thatcavity, or vacuum, which the passage of the floating, moving body was neces-sarily making without intermission. Though totally uninformed, perhaps, ofthe doctrine of centripetal forces, their observation had taught them, that allbodies acquired a progressive velocity in proportion to the length of theirdescent; of course, that the fluid acquired its utmost rapidity when it ap-proached so sufficiently near to the stern, that it was not affected by that eddy,or revulsion of the fluid, if the words be allowed, which will be more clearlyexplained to moderns by the term dead water.

Let