Before the battle, the English and Canadians held a line from Broodseinde to half a mile north of St. Julien on the crest of the Grafenstafel Ridge. The French prolonged the line to Steenstraate on the Yperlee Canal. The Germans originally planned the attack for Tuesday, April 20th, but with satanic ingenuity the offensive was postponed until between 4 and 5 o'clock on the afternoon of Thursday, the 22d. During the morning the wind blew steadily from the north and the scientists attached to the German Field Headquarters predicted that the strong wind would continue at least twelve hours longer.

The Canadian division held a line extending about five miles from the Ypres-Roulers Railway to the Ypres-Poelcapelle road. The division consisted of three infantry brigades, in addition to the artillery brigades. Upon this unsuspecting body of men the poison fumes were projected by means of pipes and force pumps. The immediate consequences were that the asphyxiating gas of great intensity rendered immediately helpless thousands of men. The same gas attack that was projected upon the Canadians also fell with murderous effect upon the French. The consequences were that the French division on the left of the Canadians gave way and the Third brigade of the Canadian division, so far as the left was concerned, was "up in the air," to use the phrase of its commanding officer.

It became necessary for Brigadier-General Turner, commanding the Third brigade, to throw back his left flank southward to protect his rear. This caused great confusion, and the enemy, advancing rapidly, took a number of guns and many prisoners, penetrating to the village of St. Julien, two miles in the rear of the original French trenches. The Canadians fought heroically, although greatly outnumbered and pounded by artillery that inflicted tremendous losses. The Germans, as they came through the gas clouds, were protected by masks moistened with a solution containing bi-carbonate of soda.

The tactics of General Turner off-set the numerical superiority of the enemy, and prevented a disastrous rout. General Curry, commanding the Second brigade of Canadians, repeated this successful maneuver when he flung his left flank southward and, presenting two fronts to the enemy, held his line of trenches from Thursday at 5 o'clock until Sunday afternoon. The reason the trenches were held no longer than Sunday afternoon was that they had been obliterated by heavy artillery fire. The Germans finally succeeded in capturing a line, the forward point of which was the village of St. Julien. Reinforcements under General Alderson had come up by this time and the enemy's advance was suddenly checked. Enemy attacks upon the line running from Ypres to Passchendaele completely broke down under the withering fire of the reinforced and reformed artillery and infantry brigades. The record officer of the Canadians makes this comment of the detailed fighting:

The story of the second battle of Ypres is the story of how the Canadian division, enormously outnumbered—for they had in front of them at least four divisions, supported by immensely heavy artillery, with a gap still existing, though reduced, in their lines, and with dispositions made hurriedly under the stimulus of critical danger, fought through the day and through the night, and then through another day and night; fought under their officers until, as happened to so many, those perished gloriously, and then fought from the impulsion of sheer valor because they came from fighting stock.

The enemy, of course, was aware—whether fully or not may perhaps be doubted—of the advantage his breach in the line had given him, and immediately began to push a formidable series of attacks upon the whole of the newly-formed Canadian salient. The attack was everywhere fierce, but developed with particular intensity at this moment upon the apex of the newly-formed line, running in the direction of St. Julien.

It has already been stated that some British guns were taken in a wood comparatively early in the evening of the 22d. In the course of that night, and under the heaviest machine-gun fire, this wood was assaulted by the Canadian Scottish, Sixteenth battalion of the Third brigade, and the Tenth battalion of the Second brigade, which was intercepted for this purpose on its way to a reserve trench. The battalions were respectively commanded by Lieutenant-Colonel Leckie and Lieutenant-Colonel Boyle, and after a most fierce struggle in the light of a misty moon they took the position at the point of the bayonet. At midnight the Second battalion, under Colonel Watson, and the Toronto regiment, Queen's Own, Third battalion, under Lieutenant-Colonel Rennie, both of the First brigade, brought up much-needed reinforcement, and though not actually engaged in the assault, were in reserve.

All through the following days and nights these battalions shared the fortunes and misfortunes of the Third brigade. An officer who took part in the attack describes how the men about him fell under the fire of the machine guns, which, in his phrase, played upon them "like a watering pot." He added quite simply "I wrote my own life off." But the line never wavered. When one man fell another took his place, and with a final shout the survivors of the two battalions flung themselves into the wood. The German garrison was completely demoralized, and the impetuous advance of the Canadians did not cease until they reached the far side of the wood and intrenched themselves there in the position so dearly gained. They had, however, the disappointment of finding that the guns had been blown up by the enemy, and later on in the same night a most formidable concentration of artillery fire, sweeping the wood as a tropical storm sweeps the leaves from a forest, made it impossible for them to hold the position for which they had sacrificed so much.

The fighting continued without intermission all through the night, and, to those who observed the indications that the attack was being pushed with ever-growing strength, it hardly seemed possible that the Canadians, fighting in positions so difficult to defend and so little the subject of deliberate choice, could maintain their resistance for any long period. At 6 A. M. on Friday it became apparent that the left was becoming more and more involved, and a powerful German attempt to outflank it developed rapidly. The consequences, if it had been broken or outflanked, need not be insisted upon. They were not merely local.

It was there decided, formidable as the attempt undoubtedly was, to try and give relief by a counter-attack upon the first line of German trenches, now far, far advanced from those originally occupied by the French. This was carried out by the Ontario First and Fourth battalions of the First brigade, under Brigadier-General Mercer, acting in combination with a British brigade.