This sector presented many difficulties. The defences that had been constructed were so limited that the troops in the line were far too congested. They were therefore liable to suffer undue casualties in the event of bombardment. Moreover, the supporting posts being isolated sections of trenches clearly visible, particularly in air photographs, were in consequence liable to attract a considerable volume of artillery fire. Further, communicating trenches, as usual, were quite inadequate to meet the requirements of the garrison. General Bannatine-Allason therefore at once decided that the whole scheme of defence must be recast and largely augmented. Accordingly work was begun on a continuous support line, and on increasing the number of communication trenches. In fact, a considerable effort was demanded from the ranks to render the sector reasonably defensible. When the Division was relieved in July much progress had been made, General Willcocks expressing himself to the Divisional commander as very satisfied with the great improvements that had been effected in the defences. In this period the Division learnt many lessons in trench craft. On taking over the line enemy sniping was continuous. The hostile snipers were masters of the situation, and inflicted serious casualties. However, every effort was made to check the enemy's activities in this respect, with excellent results. Towards the end of the Division's tour in this sector, the Highlanders were at least on equal terms, if not superior to the enemy as snipers. In some cases telescopic rifles were bought by private enterprise. The men who were entrusted with these rifles were carefully selected from amongst the gamekeepers and stalkers in the infantry, and on several days they were able to register good bags. On 1st July the Division saw the first British mine exploded. At 3 A.M. two rounds were fired by the artillery as a signal; a moment later the mine exploded. The artillery and machine-guns then opened on the enemy's trenches for fifteen minutes. The German retaliation was slight. When day broke it was reported that about fifty yards of the German parapet was blown in. Later the Germans were seen with stretchers on and about the crater. The blow, therefore, appeared to have been successful. After daybreak, however, the enemy snipers killed several of our men who exposed themselves in trying to see the results of the explosion.