To prevent this occurring men are kept in the ends of all the passages listening for the tap-tap of the picks that spells danger! If the picks are heard for a while and then stop, there are anxious moments, for it may mean that the enemy has located our workers and decided to blow first and wreck our galleries, or it may mean the explosive is already in place and ready for firing, or perhaps only a change in the direction of the enemy's tunnel. The situation is not a pleasant one for either the men in the trench above or the sappers in the galleries below, and on the mining officer's decision much depends. It was while we were breakfasting one morning that the corporal in charge of the underground sentries reported that the enemy could be heard working in No.--gallery. This was the third time since taking over the mine that tapping had been reported, and both the preceding times had proved to be the result of overstrained imaginations. Captain H----, our skipper, had on both occasions descended to the bowels of the earth and listened patiently for half an hour, emerging again disgusted with things in general. This time he motioned to the writer to accompany the corporal, and together we made our way to the mine, shedding our jackets and belts at the head of the shaft, and taking only our electric pocket lamps we crawled along the muddy galleries to No.--. The noise had stopped, the listener whispered to us when we touched him gently on the leg, so we lay there all three listening for it to start again, the tick-ticking of our wrist-watches and the pulsing of our hearts sounding loud to our strained ears. Three--five--seven minutes passed by without a sound, and then suddenly there came a slight thud. The man in front of me stiffened slightly like a well-trained setter and the corporal behind me pinched my leg in the height of his exultation. The thud-thud continued (there was no mistaking it now), then a pause--and a voice, distinctly guttural, was heard, and a sound, easily distinguishable from the muffled reports of the rifles some thirty feet overhead--the scraping of a shovel on the wooden floor of a gallery not more than eight feet away! Passing the sentry a revolver and torch, we blew out his candle and crept away as noiselessly as we had come. On reaching the head of the shaft we met the mining officer, who crawled down and returned to confirm our judgment. Then followed some mysterious telephoning to the "higher authority" while a charge was hastily laid, and permission was at last secured to "blow" the mine. No time was lost, and in half an hour all was ready, the mining officer returning from his final inspection with the news that the enemy was still digging blissfully away. Remembering the mine at Givenchy, we cleared the trench in the danger zone and had this party "stand by to repel boarders" and, if necessary, man the crater. At 2.30 the mine was fired.