These celebrated lines, constructed to protect an embarkation should it be necessary, and cover the capital from attack, were planned by Lord Wellington, and executed chiefly by Colonel Fletcher and Captain Jones of the engineers—and to describe them, the features of the country over which they extended must be briefly noticed.
The Peninsula on which Lisbon stands, is traversed by two lofty heights, which stretch from the Tagus to the ocean, varying in altitude and abruptness, and running in a parallel direction, at a distance of from six to nine miles. Through the passes in these mountains, the four great roads that communicate between Lisbon and the interior run. The line on the Sierra next the capital is the stronger of the two. It commences at Ribumar, on the Rio Lorenzo, runs by Mafra, Cabeca de Montachique, and the pass of Bucellas, and descends precipitously on the plain, about an English league from the Tagus. This latter is the only weak point—and every means that skill and labour could effect, was exhausted to fortify every spot that Nature had left open, and thus render Torres Vedras—its extent considered—the strongest position in Europe.[122]
“In front of Via Longa, upon an eminence rising from the plain, at a short distance from the river, six redoubts were constructed, so situated, in consequence of the nearly circular formation of the plateau, as to command the approaches in every direction within the range of their artillery. Three of these immediately domineered the great route from Alhandra to Lisbon, to the right of which, upon a knoll, in front of the town of Povoa, another work was formed, sweeping the communication in the direction of Quintella. On the bank of the Tagus, a redoubt, armed with four twelve-pounders, terminated the line at its eastern extremity. Fifty-nine redoubts, containing two hundred and thirty-two pieces of cannon, estimated to require seventeen thousand five hundred men to garrison them, protected the weaker points, enfiladed the roads, or swept the ascent to the escarped mountains in the range of this extended position, occupying a front of twenty-two miles.”
“The front line had been originally intended for one of isolated posts, rather than an unbroken extent of defensive ground, which it was subsequently made. It rests also on the Atlantic at the mouth of the Lozandra; its weakest point being in the rear of the village of Runa, where it stretches to Monte Agraça, and ample care was taken to correct this natural defect.”
“On the Sierra, in the rear of Sobral, was constructed a redoubt of great magnitude, armed with twenty-five pieces of artillery, and prepared for a garrison of one thousand men. This formidable work, from its commanding and centrical situation, was the constant daily resort of Lord Wellington. There he came every morning, and continued until it was ascertained that no hostile movement had taken place, and until light permitted a reconnaissance of the enemy’s troops encamped opposite. From the redoubt on Monte Agraça, the line continued, crossing the valleys of Arruda and Calhandriz, until it rested on the Tagus at Alhandra.”
“Nature and art had rendered the ground from Calhandriz to the river particularly strong; but to make the defences still more formidable, and to form an intermediate obstruction, redoubts were thrown up extending to the rear, nearly at right angles with the front line. These swept the whole portion of the valley, by which a column of infantry must penetrate, even had it succeeded in forcing an entrance into the ravine. Sixty-nine works of different descriptions fortified this line; in these were mounted three hundred and nineteen pieces of artillery, requiring upwards of eighteen thousand men to garrison them; and the extent, in a direct line from flank to flank, was twenty-five miles.”
Colonel Leith Hay explains the mode in which those formidable lines would have been defended. “It has been erroneously supposed that the regular army was, in the event of an attack, to occupy the redoubts and other works in the lines, or, at all events, that a large proportion of the troops would of necessity defend these temporary fortifications. In this calculation of probable circumstances, no British soldiers, with the exception of artillery, would have acted within their walls. Some Portuguese infantry, with the militia and ordonanza, were destined to compose the garrisons; while the whole allied army, numerous, brilliant in equipment, high in spirit, confident in its great commander, was prepared to move in every direction to cover the summits of mountains, to descend into valleys, or to pour in torrents on any luckless column, that with diminished numbers might have forced past the almost impenetrable obstacles of this grand position.”
“In addition to the works thrown up in either line, or in the intervening points of communication, rivers were obstructed in their course, flooding the valleys and rendering the country swampy and impassable; trenches were cut from whence infantry, perfectly protected, might fire on the advancing columns of an enemy; these being also flanked by artillery, sweeping the approaches to them in every direction. Mountains were scarped as above stated; abattis of the most formidable description, either closed the entrance to ravines, impeded an approach to the works, or blocked up roads, in which deep cuts were also marked out for excavation; routes conducting from the front were rendered impracticable; others within the lines either repaired, or formed to facilitate communication, to admit the passage of artillery, or reduce the distance by which the troops had to move for the purposes of concentration or resistance; bridges were mined, and prepared for explosion. Telegraphs erected at Alhandra, Monte Agraça, Socorra, Torres Vedras, and in the rear of Ponte de Rol, rapidly communicated information from one extremity of the line to the other. These signal stations were in charge of seamen from the fleet in the Tagus. To complete the barriers, palisades, platforms, and planked bridges, leading into the works, fifty thousand trees were placed at the disposal of the engineer department, during the three months ending on the 7th of October, 1810.”
“The cannon in the works were supplied by the Portuguese government. Cars, drawn by oxen, transported twelve-pounders where wheels had never previously rolled. Above three thousand officers and artillerymen of the country assisted in arming the redoubts, and were variously employed in the lines. At one period, exclusive of these, of the British engineers, artificers, or infantry soldiers, seven thousand peasantry worked as labourers in the completion of an undertaking only to have been accomplished under the most favourable circumstances, both with regard to cordiality of assistance, neighbouring arsenals, a British fleet in the Tagus, constant uninterrupted communication with a great capital, a regular remuneration to the labourers, an anxious and deep interest in the result to be accomplished by the assistance of the works in progress, and, above all, an intelligence and firmness in command that could at the same time extract the greatest benefits from these combinations, and urge exertion where it appeared to relax.”
Such was the matchless position to which Wellington retired—and the allied army thus occupied the several posts. Monte Agraça was held by Pack, and a Portuguese brigade. The fifth division encamped on the reverse of the heights, behind the grand redoubt. Hill occupied Alhandra. The light division was posted at Arriada. The first, fourth, and sixth, were at Zibriera, Ribaldiera, and Runa; their right in contact with Leith; their left with Picton—who, with the third division, occupied Torres Vedras, and defended the Zezandra.