During a long career of successful piracy, the port of Algiers had accumulated an extensive and powerful system of defences.  These had doubtless suffered in condition from the nonchalant fatalism of Turkish rule, encouraged by a long period of impunity; but they constituted still, and under all the shortcomings of the defenders, a most imposing menace to an attacking fleet.  To convey a precise impression of them by detailed verbal description would be difficult, and the attempt probably confusing.  It may be said, in brief, that the town faces easterly, rising abruptly up a steep hill; that from its front there then projected a pier, nearly a thousand feet long, at whose end was a circular fort, carrying seventy guns in three tiers; from that point a mole extended at right angles to the southward,—­parallel, that is, in a general sense, to the town front, but curving inward through the southern half of its length, so as better to embrace and shelter the vessels inside.  This mole was somewhat over a thousand feet in length, and had throughout two tiers of guns, linked at their northern extremity to the circular fort at the pier end.  These principal works were flanked and covered, at either end and on the hillside, by others which it is unnecessary to particularize.  The total number of guns bearing seaward numbered near three hundred, of very respectable size for that day.  The basin formed by the pier and the mole constituted the port proper, and in it, at the time of the attack, was collected the entire Algerine navy, nine frigates and corvettes and thirty-seven gunboats, the paltry force that had so long terrorized the Mediterranean.

In prevision of his present enterprise, Lord Exmouth before leaving the Mediterranean had despatched a light cruiser to Algiers, on a casual visit similar to those continually made by ships of war to foreign ports.  Her commander, Captain Charles Warde, received from him very precise and most secret instructions to examine closely into the defences and soundings; to do which it was necessary not only to observe every precaution of seeming indifference,—­even to the extent of appearing engrossed with social duties,—­but also to conduct under this cover measurements and observations of at least approximate correctness.  This duty was performed with singular diligence and success, with the double result of revealing the hopeless inaccuracy of existing charts and of placing in Exmouth’s hands a working plan of the ground, perfectly trustworthy for his tactical dispositions.

As before remarked, in the sketch of Lord St. Vincent, the defence and attack of seaports, involving as they do both occupation of permanent positions and the action of mobile bodies, are tactical questions.  They differ much, though not radically, from operations in the open sea, or in the field, where positions may be taken incidentally, but where the movements of mobile bodies are the principal factor.  In this way, though without using the word tactical,