Before the frost set in, all work had been concentrated on keeping the trenches in a habitable condition. But, with the frost, such work became temporarily unnecessary, even had it been possible. Meanwhile, new theories of how a line should be held were developing. The gradual increase of fire power, due to the introduction of Lewis guns and the growth of the British artillery, made it unnecessary to keep so many men in the front line; the increase in the strength of the enemy artillery and trench mortars made it inadvisable to do so. Instead of a line in which practically every fire-bay was manned, the system of semi-isolated posts was coming in. To adapt the old trenches to this new idea of defence, now became the chief form of work. Derelict trenches had to be filled in; the trenches which were to be preserved had to be adapted for all round defence by platoon or section posts. This was mainly carried out by filling the disused trenches with wire, so that they could not be occupied by the enemy. Bombing too had had its day, and the utility of the numerous saps, which covered most front lines, was discounted. Among other improvements in the Battalion’s sector, it was decided to fill in the T head sap which lay only about forty yards from the enemy, on the right company front. This was a delicate task. The order was to fill it in with earth; but it approached so near to the German line that the least stroke of a pick on that iron-bound ground could easily be heard. What was to be done? As luck would have it, the enemy was engaged in wiring his sap just opposite; and so it became the nightly custom to assemble a working party in the British front line and wait until the enemy party was heard. Then the work of filling in the T head sap would begin, for no fire was likely to come from the enemy while his own party was out. This went on for several nights without incident; but the work progressed very slowly, owing to the frozen condition of the soil. On the last night the Battalion was in the line it changed its tactics. Instead of sending out a working party, it trained a Lewis gun on the enemy sap and opened fire as soon as the wiring party was heard. Whether any casualties were caused cannot be said; but the wiring came to an abrupt conclusion. Had the Battalion remained longer in that sector, it would probably have been called upon to do a raid on the enemy line. Much time had been expended on reconnaissance for that purpose, and the order was fully expected. Perhaps it was due to its own intentions that the Brigade was so nervous about the enemy; whatever the cause, it seemed most anxious to ascribe to the Germans designs on the British line. A sign of this nervousness was the great interest taken in a gap in the enemy wire near the Berles-Monchy Road. It is probable that the gap was an old one, which had escaped notice up till then; but the amount of paper that flew about on the subject was enormous. Of course, nothing happened.