It was hoped that the flames would communicate from this frigate to the rest of the Algerine shipping; but she burnt from her moorings, and passing clear of her consorts, drifted along the broadsides of the Queen Charlotte and Leander, and grounded a-head of the latter, under the wall of the town.  The gun-boats, and the Queen Charlotte’s launch, then opened with carcass-shells upon the largest frigate, which was moored in the centre of the other ships, too far within the Mole to be attempted safely by boarding.  They soon set her on fire, and notwithstanding the exertions of the Algerines, she was completely in flames by six o’clock.  From her the fire communicated, first to all the other vessels in the port, except a brig and a schooner, moored in the upper part of it, and afterwards to the storehouses and arsenal.  At a little past seven, she came drifting out of the harbour, and passed so close to the flag-ship as nearly to involve her in the same destruction.

About sunset, a message was received from Rear-Admiral Milne, requesting that a frigate might be sent to divert from the Impregnable some of the fire under which she was suffering.  She had anchored more to the northward than was intended, and consequently became exposed to the heavy battery on the point of rock beyond the lighthouse, and which was covered from the fire of the rest of the fleet.  The Glasgow weighed immediately, but the wind had been driven away by the cannonade, and she was only able, after three-quarters of an hour’s exertion, to reach a new position between the Severn and Leander; a better for annoying the enemy, but where she was herself more exposed, and suffered in proportion.  As it was found impossible to assist the Impregnable, Lord Exmouth sent on board Mr. Triscott, one of his aides-de-camp, with permission to haul off.  The Impregnable was then dreadfully cut up; 150 men had been already killed and wounded, a full third of them by an explosion, and the shot were still coming in fast; but her brave crew, guided and encouraged by the Rear-Admiral and Captain Brace, two of the most distinguished and successful officers in the service, would not allow her to go thus out of battle; and she kept her station, maintaining an animated fire to the last.  To relieve her in some degree, an ordnance sloop, which had been fitted at Gibraltar as an explosion-vessel, with 143 barrels of powder, was placed at the disposal of the Rear-Admiral.  She had been intended for the destruction of the Algerine fleet, but this service had already been effected by other means.  Conducted by Lieutenant Fleming, who had been commanding a gun-boat near the Queen Charlotte, with Major Reed, of the Engineers, and Captain Herbert Powell, a volunteer on board the Impregnable, the explosion-vessel was run on shore under the battery which had annoyed her, where, at nine o’clock, she blew up.