To swell this amount, Colonel Dickson offered a reward for bringing in any shot fired by the enemy. He found that the enemy’s 16-pounder shot fitted his own 18-pounder guns, and that his 8-pounder shot would fit the 9-pounders of the English field brigades. Before the end of September, about 1400 shot were brought in, in this way. Colonel Dickson also obtained detachments from the Horse and Field Brigades occasionally, to give his siege artillerymen relief; but the duties of the Field Artillery were so active at this time round Burgos that men could with difficulty be spared. The names of the officers of the Royal Artillery engaged in the siege were as follows:-- Lieutenant-Colonel Robe, commanding. Lieutenant-Colonel Dickson, in immediate charge of the operation. Captain Power } Lieutenant Robe } Present during Lieutenant Pascoe} the whole Lieutenant Elgee } operation. Lieutenant Hough } Captain Greene } Belonging to Captain Dansey } Field Brigades, Captain Gardiner } but Lieutenant Monro } occasionally Lieut. Johnstone } employed. Captain Blachley, joined 1st October. Of the Royal Artillery, small in numbers, the casualties were very great in proportion. Fifteen men were killed, and forty wounded, during the siege, and in the operations immediately attending or succeeding it. The officers who were wounded were Colonel Robe, Captains Dansey and Power, Lieutenants Elgee and Johnstone. After severe loss, a hornwork in front of the castle had been carried by assault on the night of the 19th September, and on the following night a battery for five guns was commenced. This battery was armed on the night of the 22nd with two 18-pounders and three 24-pounder howitzers, in readiness to open on the inner lines, in the event of an assault, which had been determined on for that evening on the outer line, proving successful. At the same time, a second battery for six guns was commenced to fire against the keep of the castle. The assault, which was premature, failed; and its leader was killed. On the night of the 24th, the two 18-pounders were taken out of No. 1 Battery, and drawn along a trench, part of the way towards No. 2, being replaced in the former by howitzers. On the 25th, the five howitzers in No. 1 Battery opened a fire to destroy some palisades, which were used to flank the works of the castle. The fire was not successful; the howitzers were found to be very deficient in precision when firing round shot; and the result was inadequate to the expenditure of ammunition,--141 rounds,--a consideration of some importance under the existing circumstances.[38] Lord Wellington, conscious of the deficiency of his guns, worked now by means of mining; and on the night of the 29th September, a mine was sprung which threw down part of the outer wall. An assault was immediately ordered; but from the darkness of the night the detachment missed its way, and those who were leading--having gained the top of the