The attack on 15th September proved highly successful and not too costly in life, a depth of over a mile being made good, including the villages of Courcelette, Martinpuich, and Flers. Communications held well throughout the day, and the good liaison between infantry and artillery so secured played an important part in the result. The recently introduced Power Buzzers for transmitting high-power buzzer signals through earth to be picked up by Valve Amplifying Receivers at distances up to three thousand yards, were used with fair success in the advance. These sets were controlled by the Wireless Section, but the forward stations were manned by signallers of the attacking battalions. The comparative inexperience and lack of special training of these signallers prevented the best being got out of the instruments, but the limited establishment of the Signal Service prevented any other procedure. The advance rendered a further extension of the cable trench urgent, but for the moment suitable cable for a permanent bury was not available. Another section of trench, however, was dug immediately in order that units might have the benefit of its protection in running temporary field cables forward. This section extended from York Trench through the corner of Delville Wood to Switch Trench, and the digging proved a gruesome task, as Delville Wood and neighbourhood was a huge graveyard. In the sides of the trench were visible more than one pitiful reminder that our heroic comrades of the Infantry Brigade had fought and died there. To prevent confusion and facilitate maintenance, the left-hand side of the new trench was assigned to divisions and the right to the Heavy Artillery, the Headquarters Signals of which prepared and erected along the trench fixtures for cables in the shape of angle iron high-wire entanglement pickets, each having a piece of two-inch by two-inch wood screwed to it with a dozen diagonal slots cut in it for the cable. The cutting and slotting of so many pieces—upwards of one thousand five hundred—was a task beyond hand methods, but was accomplished in three days by obtaining a power-band saw from a factory in Albert, and connecting it up with the water wheel at Vivier Mill by a belt extemporized from the driving bands of the cable wagon winding gears. During this period occurred a noteworthy performance in rapid repair of cable routes. The main cable trench about midnight received a direct hit from a large shell, severing all communication; but fortunately a party of B.E. section was returning down the trench from forward work, and came on the shell crater soon afterwards. Though already worn out with a long day’s work and struggling through the mud, they at once started to dig up the cable ends, sending a man to summon assistance by tapping in at the next test point in the trench, and succeeded in getting all the forty-five pairs of wires rejointed and working again in _three hours_.