The operations continued to be hampered by rain at each of the critical phases, but by the beginning of September the flanking corps had made the necessary progress and everything was in readiness for the great attack of 15th September. The vital importance of secure communication being fully appreciated by the Staff, the necessary labour was made available for a considerable buried scheme. A buried water-pipe laid by the enemy between Longueval and Montauban had been located, and considerable effort was expended by B.F. section in investigating the possibility of using this pipe for running cable through. It was finally decided that its exploitation would not be justified in view of the small depth of the bury, and the extensive damage already done by shell fire. The first section of the new bury consisted of a six-foot-deep cable trench, extending from Pommiers Redoubt _via_ the famous Cosy Corner, where the Carnoy and Mametz roads join outside Montauban, and thence to York Trench on the left of Longueval. This trench had nine framed test points let into the walls every four hundred and forty yards, and contained forty-five pairs of cable. The accumulation of the necessary quantities of cable suitable for the work presented great difficulty, and the trench probably set up a record for the number of different varieties it contained—from nineteen pair V.I.R., as thick and heavy as a hawser and supplied on drums weighing over half a ton each, to one pair G.P. Twin about as stout as a double boot-lace. The actual digging was done by a battalion of the 7th Division, the work being under the charge of Lieutenant Collins, assisted by Lieutenant Baker, with B.G. section and most of the sappers of B.E. and W.W. sections. The mud of the Somme will go down to history: and as the line of the trenches included some excellent samples of it, the distribution along the trench of the heavy cable drums and the pipes for crossing under tracks presented great difficulties. The jointing, terminating, and testing of the wires had to be completed against time, and with a limited number of expert men, as the maintenance of the widespread network for which the Company was responsible had absorbed many of the best men out of all sections. The lines were, however, ready in time for the divisions who had moved Headquarters up again to Fricourt and Pommiers Redoubt, with Advanced Headquarters at York Trench, and also for the Heavy Artillery, most of whose batteries took positions along the Mametz-Montauban ridge and in folds of the forward slope towards Caterpillar Wood and Longueval. To cope with the steady forward drift of the Corps units, and to provide another advance maintenance point, a new Corps Forward Exchange was established in a dug-out at Pommiers, and after the attack B.E. section staffed this exchange and maintained the area.