“Very good, sir,” but the C.O. had rung off with a jerk, and only a singing remained in my ears. “Got to go down and explain in person why the officer in charge of ‘B’ Company wirers did not get out twenty coils last night,” I said to Edwards as I hurried off down Old Kent Road. “The C.O.’s in an ‘I gave a distinct order’ mood. Cheero!” On entering the Headquarters’ dug-out in Maple Redoubt, I found the C.O. engaged in conversation with an artillery officer: there had been another raid last night on the left, and our artillery had sent a lot of stuff over. This was the subject under discussion. “I think you did d--d well,” said the C.O. as the officer left. “Well, Adams, I thought it would be easiest if you came down. Here’s our friend from the underworld, and he’ll explain exactly what he’s going to do”; and I saw the R.E. officer for the first time. He had been standing in the gloom of the further end of the dug-out. “Look here,” began the Colonel, as he laid out the trench map on the table. “_Here_ is where we blow to-night at 6.0” (and he made a pencil dot in the middle of the grass of No Man’s Land midway between the craters opposite the Loop and the Fort. See Map III). “And here, all round here” (he drew his pencil round and round in a blacker and yet blacker circle) “is roughly where the edge of the crater will come. Isn’t that right, Armstrong?” “Yes,” was the reply, “the crater edge won’t come right up to the front trench, but I don’t want anyone in the front trench, as it will probably be squeezed up in one or two places.” “Exactly,” said the Colonel. “Do you think this blow will completely connect up the two craters on either side?” “Oh, certainly,” was the answer. “There’s no question of it. You see, we’ve put in” (here followed figures and explosives incomprehensible to the lay mind). “It’ll be the biggest mine we’ve ever blown in this sector.” “A surface mine, I suppose?” I asked. “Almost certainly,” said the R.E. officer. “You see, their gallery is only ten feet above ours, and they might blow any minute. But they’re still working. We wanted to get another twenty feet out before blowing, but it isn’t safe. Anyway, we are bound to smash up all their galleries there completely, though I doubt if we touch their parapet at all.” He spoke almost impatiently, as one who talks of things that have been his main interest for weeks, and tries to explain the whole thing in a few words. “But,” he added, “I don’t want any men in that trench.” The mining officers always presumed that the infantry clung tenaciously like limpets to their trench, and had to be very carefully removed in case a mine was going up. As a matter of fact, the infantry always made a rule of clearing the trench half as far again as the mining officer enjoined, and were always inclined to want to depart from the abhorred spot long before the time decided upon!