The Twenty-fifth Division lay at this time with the Forty-seventh London Division as its northern neighbour, the one forming the left-hand unit of the Third Army, and the other the extreme right of the First. Upon the 19th the Londoners took over the new position from the 74th, and found it to be an evil inheritance, for upon May 21, when they were in the very act of relieving the 7th and 75th Brigades, which formed the front of the Twenty-fifth Division, they were driven in by a terrific bombardment and assault from the German lines. On the front of a brigade the Germans captured not only the new ground won but our own front line and part of our supporting line. Old soldiers declared that the fire upon this occasion was among the most concentrated and deadly of the whole War. With the new weapons artillery is not needed at such short range, for with aerial torpedoes the same effect can be produced as with guns of a great calibre. In the early morning of April 30, there was a strong attack by the Germans at Wulverghem, which was the village to the west of Messines, to which our line had been shifted after the attack of November 2, 1914. There is no doubt that all this bustling upon the part of the Germans was partly for the purpose {21} of holding us to our ground while they dealt with the French at Verdun, and partly to provoke a premature offensive, since they well knew that some great movement was in contemplation. As a matter of fact, all the attacks, including the final severe one upon the Canadian lines, were dealt with by local defenders and had no strategic effect at all. In the case of the Wulverghem attack it was preceded by an emission of gas of such intensity that it produced much sickness as far off as Bailleul, at least six miles to the west. Horses in the distant horse lines fell senseless under the noxious vapour. It came on with such rapidity that about a hundred men of the Twenty-fourth Division were overcome before they could get on their helmets. The rest were armed against it, and repelled the subsequent infantry attacks carried out by numerous small bodies of exploring infantry, without any difficulty. The whole casualties of the Fifth Corps, whose front was attacked, amounted to 400, half by gas and half by the shells. In May, General Alderson, who had commanded the Canadians with such success from the beginning, took over new duties and gave place to General Sir Julian Byng, the gallant commander of the Third Cavalry Division.