The third, intended to cover a forced embarkation, extended from Passo d’Arcos on the Tagus to the tower of Junquera on the coast. Here an outer line, constructed on an opening of three thousand yards, enclosed an entrenched camp designed to cover the embarkation with fewer troops, should the operation be delayed by bad weather; and within this second camp, Fort St. Julian’s (whose high ramparts and deep ditches defied an escalade) was armed and strengthened to enable a rear-guard to protect both itself and the army. The nearest part of the second line was twenty-four miles from these works at Passo d’Arcos, and some parts of the first line were two long marches distant; but the principal routes led through Lisbon, where measures were taken to retard the enemy and give time for the embarkation. Of these stupendous Lines, the second, whether regarded for its strength or importance, was undoubtedly the principal, and the others only appendages, the one as a final place of refuge, the other as an advanced work to stem the first violence of the enemy, and to enable the army to take up its ground on the second line without hurry or pressure. Massena having, however, wasted the summer season on the frontiers, the first line acquired such strength, both from labour and from the fall of rain, that lord Wellington resolved to abide his opponent’s charge there. The ground presented to the French being, as it were, divided into five parts or positions, shall be described in succession from right to left. 1º. From Alhandra to the head of the valley of Calandrix. This distance, of about five miles, was a continuous and lofty ridge, defended by thirteen redoubts, and for two miles rendered inaccessible by a scarp fifteen to twenty feet high, executed along the brow. It was guarded by the British and Portuguese divisions under general Hill, and flanked from the Tagus by a strong flotilla of gun-boats, manned by British seamen. 2º. From the head of the vale of Calandrix to the Pé de Monte. This position, also five miles in length, consisted of two salient mountains forming the valley of Aruda, that town being exactly in the mouth of the pass. Only three feeble redoubts, totally incapable of stopping an enemy for an instant, were constructed here; the defence of the ground was entrusted to general Crawfurd and the light division.