of the 24th Division managed to bomb a short way down Edge Trench, which was almost invisible after the recent bombardments. On 1 September, the battalion attacked again but made little progress against German bombers and snipers. The 7th Division was due to attack Ginchy on 3 September but the Germans in Ale Alley, Hop Alley and the east end of Delville Wood commanded the ground over which the attack was to cross. A preliminary attack was arranged with the 24th Division, to begin five minutes before the main attack to recapture the ground. The 7th Division bombers used "fumite" grenades but these were too easy to see and alerted the German defenders and the 24th Division battalion received such contradictory orders that its attack north of Ale Alley failed. Attacks on 4 September by two companies at the east end of the wood also failed and next day two companies managed to reach the edge of the wood close to Hop Alley and dig in. On the night of 5 September, the 24th Division was relieved by the 55th Division and the 166th Brigade dug in beyond the north-east fringe of the wood unopposed. Air operations The first attack on Longueval and Delville Wood from was conducted under the observation of 9 Squadron, which directed counter-battery artillery-fire, photographed the area and flew contact-patrols to report the positions of infantry. During the morning a patrol of F.E. 2bs from 22 Squadron escorted the corps aircraft but no German aeroplanes were seen. The British aircraft carried new "Buckingham" tracer ammunition, which made aiming easier and began to attack German targets on the ground. The crews machine-gunned German infantry near Flers, cavalry sheltering under trees and other parties of German troops to the south-west. During the XV Corps attacks on 24 August, 3 Squadron aircraft brought back detailed information about the progress of the infantry, who had lit many red flares when called on by contact-aircraft. Fourteen flares were seen by an observer at to the north of the wood, which showed that the troops had overrun their objective and were under shrapnel fire from British artillery. The information was taken back and dropped by message-bag, which got the barrage lifted by . The crew returned to the wood, completed the contact-patrol and reported to the XV Corps headquarters by showing that the 14th Division was held up on the east side