The most important in-trench duty, as well as the most wearisome one for the men, is their period on "sentry-go." Eight hours in twenty-four--four two-hour shifts--each man stands at his post on the firing-bench, rifle in hand, keeping a sharp lookout over the "front yard." At night he observes as well as he can over the top of the parapet; in the daytime by means of his periscope. Most of our large periscopes were shattered by keen-sighted German snipers. We used a very good substitute, one of the simplest kind, a piece of broken pocket mirror placed on the end of a split stick, and set at an angle on top of the parados. During the two hours of sentry duty we had nothing to do other than to keep watch and keep awake. The latter was by far the more difficult business at night. "'Ere, sergeant!" Tommy would say, as the platoon sergeant felt his way along the trench in the darkness, "w'en is the next relief comin' on? Yer watch needs a good blacksmith. I been on sentry three hours if I been a minute!" "Never you mind about my watch, son! You got another forty-five minutes to do." "Will you listen to that, you blokes! S'y! I could myke a better timepiece out of an old bully tin! I'm tellin' you straight, I'll be asleep w'en you come 'round again!" But he isn't. Although the temptation may be great, Tommy isn't longing for a court-martial. When the platoon officer or the company commander makes his hourly rounds, flashing his electric pocket lamp before him, he is ready with a cheery "Post all correct, sir!" He whistles or sings to himself until, at last, he hears the platoon sergeant waking the next relief by whacking the soles of their boots with his rifle butt. "Wake up 'ere! Come along, my lads! Your sentry-go!" CHAPTER IX BILLETS Cave life had its alleviations, and chief among these was the pleasure of anticipating our week in reserve. We could look forward to this with certainty. During the long stalemate on the western front, British military organization has been perfected until, in times of quiet, it works with the monotonous smoothness of a machine. (Even during periods of prolonged and heavy fighting there is but little confusion. Only twice, during six months of campaigning, did we fail to receive our daily post of letters and parcels from England, and then, we were told, the delay was due to mine-sweeping in the Channel.) With every detail of military routine carefully thought out and every possible emergency provided for in advance, we lived as methodically in the firing-line as we had during our months of training in England.