were engulfed in flames. Soon after, Spanish cavalry were observed coming up; they faced a Hanoverian battalion but did not charge. The Spanish under Alvarez had no plans and were neither expecting nor prepared for a British sortie. With the objective completed, the British withdrew back inside their fortifications. The total British and Hanoverian casualties in the sortie were two killed and 25 wounded. Spanish losses were over 100 men, which included thirty prisoners; a number of these were blue-coated Walloon soldiers of the Walloon Guards. The British did damage to the extent of two million pounds to the besiegers: fourteen months of work by the Spanish and a considerable quantity of ammunition had been destroyed. British troops and pioneers spiked ten 13-inch mortars and eighteen 26-pounder guns in the Spanish siege works. In addition the platforms and beds on which the guns were based were destroyed. As the British returned after their victorious sortie, the garrison watched in amazement as huge explosions from the ammunition ripped through the Spanish lines and destroyed what was left of them. This sortie postponed the great Spanish assault for several months. In that time the British began building an extensive tunnel network through the Rock of Gibraltar. The work was carried out by hand, aided by gunpowder blasts, which was dangerous. It took thirteen men five weeks to dig a tunnel with a length of . Embrasures were blasted overlooking the Spanish lines. Additionally, a new type of cannon mount was invented that allowed a cannon to fire at a downward angle: the new depressing gun-carriage devised by George Koehler allowed guns to be fired down a slope. This was demonstrated on 15 February 1782 at Princess Royal's Battery. This new carriage enabled the defending guns to take advantage of the height of the Rock of Gibraltar: they could strike out far, but also be angled downward to fire on approaching attackers. At the beginning of March news of the surrender of the Minorca garrison was received, lowering morale for the besieged. The Spanish and French at Gibraltar would soon be reinforced by the victors of Minorca. Life in Gibraltar, however, was able to carry on with relief from merchants who ran the Spanish blockade. British ships arrived unmolested to bring in reinforcements, taking away the sick, prisoners and civilians. Portuguese vessels with lemons, wine and vegetables helped the garrison, and gave valuable