Tanks are usefully employed in the pursuit, as artillery, the only effective enemy of the tank, is unlikely to remain in action with the rearward troops of a disorganised enemy; and a new terror has been added to the pursuit by the advent of self-propelled, man-carrying Aircraft, armed with machine guns and bombs, and possibly even with light quick-firing artillery. During the final stages of the victorious _Allied Advance_ in November, 1918, the retreating German Armies were continuously harassed from the air. "Throughout the day (November 5, 1918) the roads, packed with the enemy's troops and transport, afforded excellent targets to our airmen, who took full advantage of their opportunities, despite the unfavourable weather. Over 30 guns, which bombs and machine-gun fire from the air had forced the enemy to abandon, were captured by a battalion of the 25th Division in the field near Le Presau" (Sir D. Haig's Dispatches). THE ROYAL ENGINEERS.--The position and employment of the Royal Engineers will be determined by the commander who issues orders for the Attack, and as the main function of this corps in the Attack is the removal or bridging of obstacles to the advance, and the strengthening of the position when captured, the Royal Engineers will probably remain with the troops to which the decisive attack is entrusted. MEDICAL ARRANGEMENTS.--The position of hospitals and clearing stations will be settled in consultation with the S.M.O. Aid posts and advanced dressing stations will be established under battalion arrangements in connection with the medical officer of the units concerned. SUPPLY.--The position of the Train, with its reserve supplies of ammunition and of food for men and horses, will depend upon facilities for communication with the attacking force and upon security against artillery fire {68} or surprise attack from the air or land. The position will probably be well in rear, and at the junction of roads leading forward to the attacking troops. Rations will be brought up to units under arrangements by the commanders of the battalion or other units concerned.