In March, 1915, the Allies began what has been described as a tentative offensive. Between March 10 and March 12, 1915, the British advanced about a mile on a front of three miles at Neuve Chapelle, but the aim of the operations, which were directed against Lille, could not be achieved. Early in April the French carried the heights of Les Eparges, which commanded the main communications of the Woevre, an action that led to a general belief that the Allies' summer offensive would be aimed at Metz. But the plan--if it ever was entertained--was abandoned toward the end of April, 1915, when the critical situation of the Russians in Galicia made it imperative to create a diversion in another area, where the effects would be more quickly felt. Before the French attack could mature, however, the second battle of Ypres was developing. The Germans began shelling Ypres on April 20, 1915, to prevent reenforcements from entering the salient, and in the evening of April 22, 1915, they made their first attack with poisonous gas. A French division lying between the canal and the Pilken road had the first experience of this new horror added to the methods of warfare. Much has been written in condemnation of employing poisonous gas, and the practice has been widely discussed from the "moral" and "humane" point of view. The Germans claim that the French used it first--a contention not supported by evidence. "On the general moral question," says Mr. John Buchan, the well-known English writer on military subjects, "it is foolish to dogmatize." He points out that all war is barbarous in essence, and that a man who died in torture from the effects of poison gas might have suffered equal agony from a shrapnel wound. Hence he draws the conclusion that the German innovation, if not particularly more barbarous than other weapons, was at least impolitic, since its employment raised a storm of indignation and exasperated the feelings of Germany's enemies. Be that as it may, the poison clouds proved very effective at Ypres during April and May, 1915. The French line was driven in and the left brigade of the Canadians on their right was forced back in a sharp angle. For the first five days the northern side of the salient was steadily pressed in by gas and artillery attacks. This, the second battle of Ypres, ended about May 24, 1915; it had lasted practically as long as the first battle, though the fighting had been less continuous. The Germans were meanwhile striving desperately to force a decision in Galicia and Poland, simultaneously fighting a long-range holding battle in the west with fewer men and more guns.