A brief interval of repose followed, in which the detachment was occupied in fortifying the eastern entrance of Passages, also in barricading the advanced picket-house near that point, and in completing the batteries on Santa Clara. Four men were likewise detached to the river Nervion, and, with the crews of the ‘Scylla’ and ‘Savage,’ restored the works of the Desierto convent which protected the communication with Bilbao. On the return of the men, the commander of the ‘Savage’ brig spoke most favourably of their conduct. In the operations of the army under Espartero on the 14th May, fifteen of the detachment were present and assisted in working the guns of the royal artillery. On the 17th they embarked to act in an attack on Fuentarabia, and were present at its capitulation on the 18th May. Here the detachment restored one of the ruined bastions of the fortress, and, besides making embrasures for two heavy guns, cleared away the debris from other parts of the defences and placed them in temporary repair. At Oyarzun the Carlists were in the habit of creeping up to the town and annoying the troops. To prevent this, the hill above was crowned with a square redoubt for two guns. Ten of the detachment superintended its construction, and the work was executed in so excellent a manner, that experienced officers spoke of it with unqualified satisfaction. The working party consisted of peasants who were skilful in the construction of earth-works, and zealous in the use of the spade and pickaxe. At the solicitation of General O’Donnell of the Spanish service, nineteen of the sappers, under the command of Lieutenant Vicars, were attached to his force. The party reached Aindoin on the 11th September, and were set to work with a company of Gastadores under them, on a height on the extreme left of the position. Very rapidly, a large hedge surrounding the height was turned into a parapet; and in places where it was too high to cut down, loopholes were formed. A dense wood that joined the hedge was partly felled, and from its ample resources abattis were thrown out in front of the line of hedge. For three days the work progressed; at intervals under heavy rain; and on the 13th September a formidable work of more than half a mile in length was ready to obstruct the advance of the enemy. At daylight on the 14th the Carlists opened fire on Aindoin, and the first shot went through the house where the sappers were quartered. At once they were withdrawn to the church, and ultimately removed to a circular fort to attend to orders either from Lord John Hay or General O’Donnell. Scarcely had they commenced the movement before the enemy approached the church with irresistible impetuosity, and drove the forces of O’Donnell from the town with signal disaster. The escape of the detachment of sappers was almost miraculous; a few moments later would have thrown them wholly into the hands of the Carlists.