Early in the morning of April 22nd the Germans launched at that part of the French line which lay in front of the little villages of Elverdinge and Brielen, a yellowish-green cloud of gas, which rolled slowly over the intervening ground between the trenches, carried on its way by a faint, steady breeze. I do not intend to describe the first use of that infamous invention--it has been done too often before. But, for the proper understanding of what follows, it is essential for me to go into a few details. Utterly unprepared for what was to come, the French divisions gazed for a short while spellbound at the strange phenomenon they saw coming slowly towards them. Like some liquid the heavy-coloured vapour poured relentlessly into the trenches, filled them, and passed on. For a few seconds nothing happened; the sweet-smelling stuff merely tickled their nostrils; they failed to realise the danger. Then, with inconceivable rapidity, the gas worked, and blind panic spread. Hundreds, after a dreadful fight for air, became unconscious and died where they lay--a death of hideous torture, with the frothing bubbles gurgling in their throats and the foul liquid welling up in their lungs. With blackened faces and twisted limbs one by one they drowned--only that which drowned them came from inside and not from out. Others, staggering, falling, lurching on, and of their ignorance keeping pace with the gas, went back. A hail of rifle-fire and shrapnel mowed them down, and the line was broken. There was nothing on the British left--their flank was up in the air. The north-east corner of the salient round Ypres had been pierced. From in front of St. Julian, away up north towards Boesienge, there was no one in front of the Germans. It is not my intention to do more than mention the rushing up of the cavalry corps and the Indians to fill the gap; the deathless story of the Canadians who, surrounded and hemmed in, fought till they died against overwhelming odds; the fate of the Northumbrian division--fresh from home--who were rushed up in support, and the field behind Fortuin where they were caught by shrapnel, and what was left. These things are outside the scope of my story. Let us go back to the gap. Hard on the heels of the French came the Germans advancing. For a mile or so they pushed on, and why they stopped when they did is--as far as I am concerned--one of life's little mysteries. Perhaps the utter success of their gas surprised even them; perhaps they anticipated some trap; perhaps the incredible heroism of the Canadians in hanging up the German left caused their centre to push on too far and lose touch; perhaps--but, why speculate? I don't know, though possibly those in High Places may. The fact remains they did stop; their advantage was lost and the situation was saved. * * * * *