The great advantage of an entrenching battalion was quickly seen by the rest of the Army, since the battalions that came out of the front line were relieved of working during their rest. It had formerly been the custom for resting battalions to dig reserve lines, but now this duty was taken over by the entrenching battalion. All reserve trenches were made by it; emplacements for field-guns, howitzers, and machine-guns constructed, brushwood cut for revetting, roads repaired, carrying parties for all materials necessary for trench warfare supplied. The staff of the Battalion was kept as permanent as possible, but the Battalion itself was used as a stepping-stone from the base battalion to the Battalions in the front line. The training the officers received was invaluable, as it accustomed them to shell-fire. One or two shells invariably fell near the working-parties; sometimes as many as thirty to forty shells would explode in the neighbourhood. This showed the officers that the effect was local, unless the shell happened to strike a hard surface. It gave them confidence, and they gradually became used to unaimed shell-fire. At the end of December 1915 Captain Bullough was ordered to join his Battalion, and Captain M. K. A. Lloyd, Grenadier Guards, succeeded him as Adjutant. [Sidenote: 1916.] In January 1916 the Entrenching Battalion was employed on the second-line trenches, and in constructing gun emplacements for the artillery. This latter duty involved technical knowledge on the part of the officers, who had to work from plans supplied to them by the gunners. About this time it was found that the Amiens--Somme Canal afforded better means of transport for rations and road-making material than the lorries, which had hitherto been used for that purpose; and it was necessary to make a light railway across some marshy ground between Bray road and the Canal. The Entrenching Battalion was employed in making 3000 fascines for this purpose, and the men became so expert at their work that there was keen competition between the various companies as to which should turn out the most fascines.