HISTORY OF MARINE ARCHITECTURE.

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An attempt was made towards the end of the seventeenth century, that is tosay, about the year 1075, to introduce sheet lead, for the thin deal, as a morelasting substitute; but after some experiments, which proved not so successfulas were wished, the project was totally abandoned, and the original methodcontinued to be persevered in. Some years afterwards an addition was madeto the Wood covering, from which much advantage was looked for, and noinconsiderable benefit derived : the bottom of the ship having first received ucoat of pitch, the whole was completely covered with brown paper, w hich, ofcourse, closely adhered to it; a second paying of pitch, mixed with tar, wasthen laid On the paper, and a fourth coating of short hair carefully attached to thetar ; the deal sheathing was then brought over the whole, and being firmly fast-ened to the bottom by an almost incredible number of nails, the whole operationwas rendered complete. A number of experiments with various materialsintroduced between the wood sheathing and the bottom, among which, thatof coating the latter with lime is to be remembered, have been tried atdifferent times ; but none of them have proved so effectual, or useful, as thatjust described. About the year 1758, a trial was made on a small Britishfrigate, of the effect which a covering or sheathing of copper would producein the double purposes of preserving the bottom from the injury occa-sioned by the worm, and contributing to the swift sailing of the vessel.It was conjectured, and, as experience proved, with truth, that no adhesionof barnacles or any other substances, the collection of which became soquickly and extensively detrimental to the speed of ships sheathed with wood,could take place on the copper; so that not only the expense as well as timeof graving and cleaning them would be saved, but that they might remain,so long as they continued fit for service in other respects, in the same con-dition with respect to sailing, as they were the first hour when they were sentto sea. The hope was realised in every respect, and the new practice wasfound to be unattended by any inconvenience except one, which subsequentcare easily removed, but the explanation of which is necessarily deferred till theensuing chapter, the remedy not having been applied till after the dispute withthe American colonics, which seriously commenced in 1774? had taken place.

In conformity with the custom usually adopted in all experiments, the prac-tice of sheathing with c6pper extended not beyond' the vessel first selected tomake the trial upon ; so that the advantages which were subsequently found toresult from the introduction of the new method, were not brought forwardduring the course of the pending war, with any effect against the enemy, andVol. III. D d “ the