While these discussions and misunderstandings were distracting the councils of the besiegers, a master hand was guiding the preparations for the defence within the fortress. Every emergency that might occur was provided for, every danger that could be foreseen averted, and the garrison itself reënforced by a marine brigade of six hundred men under command of Brigadier Curtis. In the first week of September the land works of the enemy had progressed with gigantic strides, immense batteries, some containing as many as sixty-four guns, only waited to be unmasked, and long strings of mules streamed hourly into the trenches, laden with shot, shell, and ammunition. The advanced works were not, except in some instances, yet armed, and large masses of material which had accumulated in their vicinity cumbered the embrasures and rendered their parapets liable to destruction by fire. Seizing upon the opportunity thus afforded by the negligence of the Spaniards, General Boyd wrote to the governor recommending the use of red-hot shot against these works. Though the distance was great, and the effect of heated shot had not then been thoroughly ascertained, Eliot acquiesced in the proposition, and Major Lewis, commanding the artillery, was ordered to execute the attack. On September 8th the preparations were completed, and at 7 A.M. the guards having been relieved, a tremendous fire was opened from all the northern batteries. Throughout the day this fiery cannonade was kept up with unabated fury. By 10 A.M. the Mahon battery and another work of two guns were in flames and by five in the evening were entirely consumed, with all their gun-carriages, platforms, and magazines. The effect of the red-hot shot exceeded the most sanguine expectations; the damage done was extensive and for a time irreparable; the greater part of the communication to the eastern parallel was destroyed, and the batteries of St. Carlos and St. Martin so much injured that they were no longer serviceable. At one moment the works were on fire in fifty places, and the flames, lifted by the wind, spread with terrible rapidity; but by the prodigious exertions of the enemy's troops, who, notwithstanding the galling fire from the garrison to which they were exposed, displayed a reckless intrepidity, the work of destruction was arrested and many of the batteries saved from ruin. Irritated at this unexpected attack upon works which had cost him so much labor and anxiety, Crillon was precipitated into a premature bombardment, which, while it exposed to view the hitherto masked batteries, and thus gave General Eliot an opportunity of preparing counter-works upon the Rock, at the same time did considerable damage to the unfinished lines.