He had written "From receipt of this message S.O.S. lines will be as follows--" when he stopped. "Can't we shorten this preliminary verbiage?" he asked quizzically. "Castle made this opening phrase a sort of tradition when he was adjutant." "What about 'Henceforth S.O.S. lines will be'?" I replied, tilting my wooden stool backwards. "That will do!" said the colonel. And "henceforth" it became after that. For two more days we carried on this most tiring of all kinds of fighting: for the infantry, hourly scraps with a watchful plucky foe; for the gunners, perpetual readiness to fire protective bursts should the enemy suddenly seek to shake our grip on this most fateful stretch of front; in addition to day and night programmes of "crashes" that allowed the gun detachments no rest, and at the same time demanded unceasing care in "laying" and loading and firing the guns. And with the opposing infantry so close to each other, and the front line changing backwards and forwards from hour to hour, absolute accuracy was never more necessary. The Brigade had had no proper rest since the early days of August. The men had been given no opportunity for baths or change of clothing. Our casualties had not been heavy, but they were draining us steadily, and reinforcements stepped into this strenuous hectic fighting with no chance of the training and testing under actual war conditions that make a period of quiet warfare so valuable. And yet it was this portion of "the fifty days," this exhausting, remorseless, unyielding struggling that really led to the Boche's final downfall. It forced him to abandon the Hindenburg Line--the beginning of the very end. I was going to write that it was astonishing how uncomplainingly, how placidly each one of us went on with his ordinary routine duties during this time. But, after all, it wasn't astonishing. The moments were too occupied for weariness of soul; our minds rioted with the thought, "He's getting done! Let's get on with it! Let's finish him." And if at times one reflected on the barrenness, the wastefulness of war, there still remained the satisfying of the instinct to do one's work well. The pioneers had done their very best, and made quite a house of our mess, even finding glass to put in the windows. I don't know that the old wheeler understood me when I emphasised this thoroughness of the pioneers by adding, "You see, we British always build for posterity"; but before we went away he began to take a pride in keeping those windows clean.