The cloud rolled on, and as it got quite close to us I noticed that it was about eight feet or twelve feet high, a deep, dense yellow at the bottom, and becoming lighter towards the top, so diffuse, indeed, that it was almost indistinguishable from the atmosphere. It is not easy exactly to convey an understanding of what the cloud really was, because few men have ever seen anything like it; but it might well be described as a moving mass of yellow, fat filth, insufferably loathsome. The poison-gas, the chief constituent of which I took to be chlorine, was about twice as heavy as air, and, consequently, it travelled along the surface of the ground. I saw the yellow cloud come, I watched it as it enveloped us, and I observed it as it rolled away behind us and went towards Ypres, gradually losing force as it was absorbed in the air. In addition to being so favourably situated, we had just had a rum ration--and plenty of it. I do not know whether the spirit did us any good, but it certainly did not do us the least harm, and may have helped to nullify the effects of the poison-gas. Our salient, vulnerable and undoubtedly attractive to the Germans, was rushed by them, and they succeeded in breaking through and occupying a trench about a hundred yards away from our own and parallel with it. They came on with wonderful steadiness, advancing just as if they were on parade, scarcely breaking step at all. They came out of their trenches about a dozen at a time, formed two long lines, and literally seemed to walk over into the trench, though we were peppering at them all the time. They kept up an excellent covering fire, with the result that a good many of our own men were shot. This was fair, open fighting, the sort of thing that a soldier expects, and into the spirit of which he can enter. It gave opportunities, too, for the display of the best qualities of warfare, and these were shown by a man I knew very well, Company Sergeant-Major F. W. Hall, of my company. In spite of a very heavy and at that time fatal fire, the sergeant-major rushed out from the shelter of his trench to bring in a wounded man who was lying in the open. He seemed to bear a charmed life, for he got clear of the trench and was untouched by the fire of the enemy.