In 1938, Wilfrid Miles, the British official historian, wrote that by 12 October, the Germans were used to afternoon attacks; British battalions were at half-strength with only many being poorly-trained recruits. Lacking air observation for reconnaissance and artillery-observation in the poor weather, the infantry had struggled to advance towards German defences. The German machine-guns had been moved back to concealed positions beyond the depth of the British barrages, to sweep the attack front from long range. Rawlinson decided that the German defences would have to be subjected to a methodical bombardment and that the infantry must prepare more routes of supply from the rear and dig assembly trenches parallel to their objectives; Cavan suggested beginning a creeping barrage just beyond objectives and firing lots of smoke shells to hamper German observation but none were available. By mid-October, air reconnaissance was impossible because of rain and mist and artillery-observation could not be conducted on any great scale.