We may look at the map again. The Battle of Arras was fought on a front of sixteen or seventeen miles, stretching, roughly, nine miles to the north and seven or eight to the south of Arras. Arras, as we know, was within the British line; its cellars and sewers, as a fact, had been prepared for the accommodation of our troops, though they were not long in request. The British line to the south of Arras (we are writing of the opening of the battle) crossed the Arras-Cambrai main road almost immediately below the town, facing Tilloy-les-Mofflaines on the right, and running down to Croisilles and Ecoust, which looked across the line to Bullecourt. Below Bullecourt, two miles or so to the right, and about three miles above the Bapaume-Cambrai road, the village of Quéant should be observed for the sake of its trench-connection with Drocourt in the north (east-south-east of Lens), which formed a switch to the Hindenburg Line, in case of German accidents behind Arras. It was the Quéant-Drocourt trench-system which made Bullecourt so important to its defenders. The British line to the north of Arras (still at the opening of the battle, but outside of our original quadrangle) crossed the River Scarpe in the eastern suburbs of the town, and ran up with a bearing to the left between Souchez and Givenchy, turning to the right again between Loos and Lens. Vimy, with all its fortifications, both natural and artificial, was the key to an advance in this area. The situation should be studied on a larger map, but it is useful to see it, too, in miniature; and for this purpose we repeat once more our sketch on page 90 above. On the rough square, Arras-Bapaume-Cambrai-Douai, we erect now on the northern side the road-junctions from Arras to Douai through Souchez and Lens. The British line ran up, as we have said, between Souchez and Givenchy, with Vimy and its ridges on the right, and ran down to the west of Bullecourt, which helped to guard the Quéant-Drocourt switch. It only remains to observe that from Lens to Ypres was a journey of less than thirty miles, and that an attack at Messines and Wytschaete formed an obvious corollary to successes at Bullecourt and Vimy. [Illustration]