A straight line, 260 miles long, drawn from a point on the Rhine midway between Cologne and Bonn, and terminating at the French coast about six miles north of Boulogne, will pass through Brussels and Ypres. That heroic town, in other words, the ‘great nerve-ganglion,’ as it has been called,[30] was not merely the symbol and shrine of Belgium’s resistance to the invader; it was also a necessary stage in the German attempt at the Channel ports. They battered the line up and down, in the hope of breaking a way through, but their worst and heaviest blows were levelled at Ypres itself, which they wrecked but they did not capture. The second of these desperate assaults opened as we saw, at Hill 60, two and a half miles to the south-east of Ypres, where it flared into the horror of poison-gas on April 22nd. A week of heroism and endurance brought this episode to a close by the withdrawal of the defence to a depth of about two miles on a semi-circular front of nearly eight. An intensified fierceness of attack marked the renewal of the battle in May. The hottest days were the 13th and 24th, between which there was a kind of lull; and thereafter the centre of fighting sagged away a few miles to the south, where the 49th Division was in waiting. The assault on Ypres had failed. Exhaustion-point had been reached on either side, but the defenders had paid an awful price. Their casualties numbered tens of thousands, and thousands had died in choking agony. The salient or semi-circle of troops, Belgian, French, Indian, Canadian and English, which had never stretched more than five miles out from its diameter on the Yser Canal, was flattened in even at the furthest to as little as two or three. Langemarck, the pivot of the first episode, which had lain on the rim of the salient, now lay more than two miles outside it; Bellewaarde Lake, the pivot of the second, which had lain two miles inside the rim, was now on the edge of it or without. If the last stronghold of Belgium was to be saved, and the gate to the Channel ports kept locked, at least an equal power of resistance was required from the defenders in the next phase. [Illustration]