On 1st August, the 152nd Infantry Brigade relieved the 153rd, and the 154th Brigade moved forward to the support brigade area. It had now become quite clear that no good purpose could be served by ordering the Division to carry out any further local attacks. There was no reason to suppose that such attacks would meet with any more success than their predecessors. The 152nd Infantry Brigade was therefore instructed to adopt a vigorous policy of peaceful penetration. By that is meant that the policy was to be the acquisition of more ground by digging and by minor operations, without the delivery of any set piece attack involving a large number of troops.
Orders were thus issued for as much ground as possible to be gained in High Wood by sapping forward. Progress was also to be made between High Wood and the Divisional right boundary, by digging-in posts in advance of the existing front line during the night, and ultimately connecting them up into continuous trenches.
The actual labour of digging in the wood was considerable, as beneath the soil there lay a tangled mass of thick roots, in many cases too stout to be severed by a spade. The work, therefore, was slow and arduous, axes and billhooks having to be employed as well as picks and shovels. The enemy, however, paid little attention to the working parties.
On the right it was considered likely that, as there was no cover, the enemy would interfere considerably with digging operations. An apparatus was therefore employed, known as the Bartlett Forcing Jack. The Bartlett Jack was designed to drive iron pipes loaded with tin canisters of ammonal (containing two lb. of ammonal per foot run) through the ground at a depth of from four to five feet. When a sufficient length of pipe had been driven into the ground in the required direction, the charge was exploded. The explosion blew a fissure in the ground which served as a trench. In this instance the labour of carrying the pipes and ammonal up to the line, and of working the task, proved incommensurate with the results obtained. This was particularly so when it became evident that considerable liberties could be taken by working parties without interference from the Boche.