On the 29th the 55th Division took over from the 61st Brigade the ground up to Villers Guislains inclusive. The front occupied by the 20th Division was even then a long one, but the formation of the ground made it possible to defend it without holding a continuous system of trenches. It will be seen from Map III that the line crossed several spurs and valleys. The spurs were held as defended localities, fortified for all-round defence and each occupied by one battalion; places of tactical importance in the position were held by a number of small strong points. At the heads of the valleys machine guns were so placed as to cover both the low ground and the slopes of the spurs on each side. Preparations for an attack to be launched on the 20th of November were then begun, but with the greatest secrecy, as the success of the operation depended on the Germans being surprised. The scheme was revealed to brigade commanders and their staffs early in the month, but no other officers in the brigades were told until a week before the battle, and then only under a strict pledge of silence, which was faithfully kept. Not until the day before the attack were the details generally disclosed. It was, of course, impossible in the later stages to conceal these preparations from the troops. When battalions were withdrawn to the rear to train with tanks, gun positions reconnoitered close to the German line, new ammunition dumps formed in forward positions and all the familiar measures carried out, it became clear that an operation of some magnitude was at hand. Among the many arrangements made to facilitate the advance of the artillery, bridges were constructed and carried forward to enable the guns to cross the trenches. During the four nights before the attack the guns were moved up to positions in the open close behind the front line, camouflaged and left there. By the night of the 19th/20th only two guns remained in the original line to cover the front of the Division. The task of providing signal communication for the three attacking divisions on the Divisional front fell almost entirely on the 20th Divisional Signal Company. 137 miles of armoured cable were laid out to the front line and to the various battle headquarters of all arms. As the day of attack drew nearer the normal five to seven hundred messages per day received at the Divisional Headquarter office at Sorel grew to two thousand a day, which severely taxed the powers of the Signal Company.