It was after these raids, to which reference is made later, that General Harper in an increasing degree emphasised in training his troops the necessity for fighting with their wits, and not by a mere display of seeing red and brute courage. During the period in which the Division held the line prior to the attack few incidents worthy of note occurred. The enemy employed "oil-can" trench-mortars and aerial darts freely, in his usual wooden way of shooting--at the same place, at the same hours daily--without doing much damage. He had, however, one successful shoot, when snow was on the ground. A machine-gun team living in a concrete dug-out in Bidot Trench lit a fire inside it. In consequence the snow quickly melted from the top of it, and it stared out a squarish black mass in the midst of the snow. The Germans were quick to observe this, and bombed it with "oil-cans." A direct hit was scored, the dug-out collapsed, and the machine-gun team was wiped out. This incident afforded a good example of one of the many precautions that must necessarily be taken if snow is not to disclose occupied portions of the trenches. Sniping was also prevalent. In the left sector there was a particularly good German sniper. It was his custom to start work just after dawn when the sun was rising behind his back. In the morning mist, to persons facing the sun, observation appeared bad; on the other hand, they themselves were clearly visible when looked at by a person with the sun behind him. The troops facing east were therefore inclined to expose themselves, having a false sense of security. In this manner Lieut.-Colonel W. MacL. Macfarlane, D.S.O., H.L.I., commanding the 5th Seaforth Highlanders, was killed by this sniper. A few days later another officer was killed in the same place, also just after dawn, probably by the same German. Lieut.-Colonel Macfarlane was the third Seaforth commanding officer to be killed in this sector. When the wire-cutting necessary for certain big raids began, the Germans became very free in the use of their artillery. In fact, in the fortnight preceding the attack, when numbers of men were employed in the trenches both cable-burying and filling dumps, the sector became a most unpleasant one. Many of the communication trenches, badly enfiladed by enemy artillery, were continually bombarded, and movement in the trench area became a hazardous occupation. During the preparations for the Arras battle, in another part of the front a most important event occurred. Between Soissons and Arras the enemy voluntarily retired. His rearward movement began about 24th February, and extended almost as far north as the village of Thilloy les Mouflaines. News of this retirement reached the Division at about 11 P.M. on 24th February, and orders were at once issued to the 152nd Brigade to patrol their whole front and see if the enemy showed any signs of withdrawing. He was, however, found to be maintaining his usual alertness.