West of the Yperlee Canal, however, it soon became known to the commanders of the allied forces that the Germans were in such a strong position that it would be impossible to dislodge their enemy until much greater preparations had been made. In the meantime the communications of the Allies were in danger. Hence Sir John French on May 1, 1915, ordered Sir Herbert Plumer to retreat. The wisdom of this order, the execution of which contracted the southern portion of the salient, was seen when the Germans again attempted to force their way through the allied front by the use of gas. The attempt this time was made between Zonnebeke, on the Ypres-Roulers railroad, and Boesinghe on the Yperlee Canal on Sunday, May 2, 1915. Though the British had been supplied with respirators of a sort, these means of defense were not as effective as they should have been nor as adequate as what was provided later. The Germans, however, suffered large losses in this attack because, as soon as the wall of gas began to approach the British trenches, the men there fired into it, well knowing from past experience that the Germans were following the gas. In this manner many of the Teutons were slain. The Allies adopted other tactics which were quite as effective. On seeing the gas approaching, the soldiers in some parts of the line proceeded to execute a flank movement, thereby getting away from the gas and subjecting the Germans to a deadly fire from a direction least expected. Between Fortuin and Zonnebeke and south of St. Julien the allied line broke, but the supports with two cavalry regiments were rushed from Potijze, a mile and a half from Ypres on the Zonnebeke Road, and regained the lost ground. By night the Germans decided to discontinue their attempt to advance and left their dead and wounded on the field. CHAPTER XVII THE STRUGGLE RENEWED The Germans had only stopped the struggle for a breathing spell. On the following morning, Monday, May 3, they made an attempt to force the allied position back again. This attempt was made on the British left, west of the Bois des Cuisenirs, between Pilkem and St. Julien. The Germans cut their wire entanglements and, leaving their trenches and lying down in front of those protecting places, they were ready to advance; but, before they could start forward, the artillery of their enemy did such effective work that the Teutons returned to their trenches, and gave up an attack at that point. But they made an assault against the northern side of the salient which had by this time become very narrow. A German bomb wrecked a section of the British trenches, and the defenders of that part of the line had to go back of a wood that was a little to the northwest of Grafenstafel, where they were able to stop the German onrush.