A methodical bombardment was commenced at 6 a.m. on September 12, 1916, and was continued steadily and uninterruptedly till the moment of attack. [Sidenote: Bombardment and infantry assault.] At 6.20 a.m. on September 15, 1916 the infantry assault commenced, and at the same moment the bombardment became intense. Our new heavily armored cars, known as "tanks," now brought into action for the first time, successfully co-operated with the infantry, and, coming as a surprise to the enemy rank and file, gave valuable help in breaking down their resistance. [Sidenote: Tanks enter Flers.] [Sidenote: High Wood carried.] [Sidenote: Capture of the Quadrilateral.] The advance met with immediate success on almost the whole of the front attacked. At 8.40 a.m. "tanks" were seen to be entering Flers, followed by large numbers of troops. Fighting continued in Flers for some time, but by 10 a.m. our troops had reached the north side of the village, and by midday had occupied the enemy's trenches for some distance beyond. On our right our line was advanced to within assaulting distance of the strong line of defense running before Morval, Les Boeufs, and Gueudecourt, and on our left High Wood was at last carried after many hours of very severe fighting, reflecting great credit on the attacking battalions. Our success made it possible to carry out during the afternoon that part of the plan which provided for the capture of Martinpuich and Courcelette, and by the end of the day both these villages were in our hands. On September 18, 1916, the work of this day was completed by the capture of the Quadrilateral, an enemy stronghold which had hitherto blocked the progress of our right toward Morval. Further progress was also made between Flers and Martinpuich. [Sidenote: Results of four days' fighting.] The result of the fighting of September 15, 1916, and following days was a gain more considerable than any which had attended our arms in the course of a single operation since the commencement of the offensive. In the course of one day's fighting we had broken through two of the enemy's main defensive systems and had advanced on a front of over six miles to an average depth of a mile. In the course of this advance we had taken three large villages, each powerfully organized for prolonged resistance. Two of these villages had been carried by assault with short preparation in the course of a few hours' fighting. All this had been accomplished with a small number of casualties in comparison with the troops employed, and in spite of the fact that, as was afterward discovered, the attack did not come as a complete surprise to the enemy. [Sidenote: Prisoners taken.] The total number of prisoners taken by us in these operations since their commencement on the evening of September 14, 1916, amounted at this date to over 4,000, including 127 officers. [Sidenote: General attack launched.] [Sidenote: Objectives taken.]