manded the naval expedition, was advanced in rank; these officers were destined to command his forces against Gibraltar, where the Spaniards and French had collected upwards of 40,000 troops, and forty-seven sail of the line, besides floating batteries, frigates, and other vessels of war. For the more effectual means of reducing the fortress, the Chevalier D’Arçon, a French engineer of high repute and abilities, made a proposition to the Spanish Court to project floating batteries, that should be constructed on such a principle that they could neither be sunk nor set on fire by shot. The first of these properties was to be acquired by the extraordinary thickness of timber with which their keels and batteries were to be fortified; and which was to render them proof to all danger in that respect, whether from external or internal violence. The second danger was to be opposed by securing the sides of the ships wherever they were exposed to shot, with a strong wall composed of timber and cork, a long time soaked in water, and including between a large body of wet sand; the whole being of such a thickness and density, that no cannon ball could penetrate within two feet of the inner partition. A constant supply of water was to keep the parts exposed to the action of fire always wet; and the cork was to act as a sponge in retaining the moisture.
“For this purpose, ten large ships, from 600 to 1400 tons burden, were cut down to the state required by the plan, and 200,000 cubic feet of timber, with infinite labour, worked into their construction. To protect them from bombs, and the men at the batteries from grape, or descending shot, a hanging roof was contrived, which was to be worked up and down by springs, with ease and at pleasure: the roof was composed of a strong rope-work netting, laid over with a thick covering of wet hides; while its sloping position was calculated to prevent the shells from lodging, and to throw them off into the sea before they could take effect. To render the fire of these batteries the more rapid and instantaneous, the ingenious projector had contrived a kind of match to be placed, so that all the guns on the battery were to go off at the same instant.
“But as the red hot shot from the fortress was what the enemy most dreaded, the nicest part of this plan seems to have been the contrivance for communicating water in every direction, to lessen their effect. In imitation of the circulation of the blood, a great variety of pipes and canals perforated all the solid workmanship in such a manner, that a continued succession of water was to be conveyed to every part of the vessels, a number of pumps being adapted to the purpose of an unlimited supply. By those means it was expected that the red hot shot would operate to the remedy of its own mischief; as the very action of cutting through those pipes would procure its immediate extinction. So that these terrible machines, teeming with every source of outward destruction, seemed in themselves invulnerable, and entirely secure from all danger.
“General Elliot having observed that the enemy’s works were nearly completed on the land side, and some of them pretty far advanced towards the fortress, resolved to try how far a vigorous cannonade and bombardment, with red hot balls, carcasses, and shells, might operate to their de-