“General Ponsonby and his G.S.O.I. sat on an old packing-case with a map spread out before them on another, lit by the dancing flicker of two guttering candles stuck into German beer bottles. General Elles and Colonel Baker-Carr were there with a chorus of Commanding Officers, Company Commanders and Reconnaissance Officers from the 1st Tank Brigade. “An armed sentry stood at the breach in the wall that served for doorway--signallers and orderlies entered and left the little circle of yellow light, stirring up the dust from the fallen débris on the broken floor. “One felt uneasily conscious of forming part of a Graphic picture entitled ‘Advanced Headquarters,’ or ‘Planning the Battle.’ “Anyway, the battle _was_ eventually planned and to the satisfaction of all parties present. The G.S.O.I. finished writing his operation orders for the morning’s attack, the conference dissolved, and we stumbled out once more into the night, each of us with some job to get done before the dawn. “To me it fell to push on to the advanced Headquarters of the Infantry Brigades concerned to explain the plans for the morrow’s battles and to deliver certain necessary maps to the Tank Commanders who would be co-operating. “I slung the maps for easier porterage along a pole that I and my orderly shouldered and from which they dangled in swaying white packages to the great interest and mystification of passing troops, to whom the bearers and the pole were invisible in the inky dark. “It was a weary way up to Graincourt with nothing but gun flashes and infrequent star-shells to light the way, but at last we reached it. “Two of the Infantry Brigades had, we found, established their Headquarters in a sort of catacomb underneath the ruined church--a wonderful place, part mediæval and part the work of the industrious Hun. “Down and down you went--the old vaulted brickwork giving place to stout German timbering--until at the very bottom, some hundred feet below the floor of the church, the steep stairway ended in a gallery off which opened a whole street of little chambers. “The place was insufferably hot and stuffy to one fresh in from the cold of the outer night; there was haze and reek of tobacco smoke and cooking, half drowning the stale dank smell, inseparable from a deep dug-out that has been long occupied--especially by Germans. “Graincourt had been taken by surprise and had changed hands so quickly that we had taken over these very eligible Headquarters as a going concern ‘ready furnished for immediate occupation.’ “So sudden, indeed, had been the change of tenancy that the two Boche engineers whose job it was to run the electric lighting plant had been captured in their own subterranean engine-room and were even now stolidly carrying on their old duties, seemingly but little concerned by the fact that they were now ‘under entirely new management.’