To the schemes of the enemy there appeared to be no end; neither did they lack hope nor want confidence. They had failed to obtain the submission of the garrison by famine; equally so, by a protracted bombardment; nor was their tremendous attack by a bomb-proof flotilla, assisted by their formidable land batteries, attended with better success. They now attempted a fourth stratagem, to mine a cave in the Rock by which to blow up the north front, and thus make a breach for their easy entrance into the fortress. Chimerical as the project might appear, it was conducted with some spirit, and occasioned the garrison much employment. Information of the infatuated design was, in the first instance, given by a deserter from the enemy, which, however, was cautiously received; and as it was impracticable to perceive the miners at work, doubts still existed whether the enemy had actually embarked in the scheme. These doubts were at length removed by sergeant Thomas Jackson,[31] of the artificer company, by whose enterprising efforts the movements of the enemy were rendered indisputable. It was his duty to reconnoitre[32] the north front, in addition to other services for which he was held responsible. Anxious to ascertain the cause of so much mysterious activity at the Devil’s Tower, he descended the steep and rugged rock by means of ropes and ladders. The attempt was as bold as it was hazardous. Stopped by an opening very near to the base of the cliff he explored the entrance, and hearing the hum of voices and the busy strokes of hammers and picks he was well assured of the purpose for which the excavation was intended. Climbing the steep again, he reported what he had discovered. A stricter watch was therefore kept upon the Tower to prevent communication between it and the Rock. Hand-grenades and weighty fragments of stone were frequently hurled over the precipice to terrify the workmen below, and choke up the entrance to the gallery; and though these means did not make the intrepid miners relinquish their project, they yet greatly interrupted its progress. The notion of the engineer who proposed the mine must have been the result of desperation, for what must have been its nature to crumble in its explosion a huge mass of compact rock, nearly 1,400 feet of perpendicular height, into a roadway, by which to enter the fortress as through a breach? ----- Footnote 31: Joined the company August, 1776, from the 56th Foot, in which he had served eleven years. Discharged about 1789. Footnote 32: