When the next light flared, he found that he could see the opposite wall and perhaps a third of the bottom of the hole, with the head and shoulders of two or three men moving about it.  When the light died, he hitched forward and again lay still.  This time the light showed him what he had come to seek:  the black opening of a tunnel mouth in the wall of the crater nearest the British line, a dozen men busily engaged dragging sacks-full of earth from the opening, and emptying them outside the shaft.  He waited while several lights burned, marking as carefully as possible the outline of the ridge immediately above the mine shaft, endeavoring to pick a mark that would locate its position from above it.  It had begun to rain in a thin drizzling mist, and although this obscured the outline of the crater to some extent, its edge stood out well against the glow of such lights as were thrown up from the British side.

It was now well after midnight, and the firing on both sides had slackened considerably, although there was still an irregular rattle of rifle fire, the distant boom of a gun and the scream of its shell passing overhead.  A good deal emboldened by his freedom from discovery and by the misty rain, Ainsley slid backwards, moved round the crater, crept back to the barbed wire and under it, ran across the opening on the other side and dropped into the hole where he had left his men.  He found them waiting patiently, stretched full length in the wet discomfort of the soaking ground, but enduring it philosophically and concerned, apparently, only for his welfare.

His sergeant puffed a huge sigh of relief at his return.  “I was just about beginning to think you had ‘gone west,’ sir,” he said, “and wondering whether I oughtn’t to come and ’ave a look for you.”

Ainsley explained what had happened and what he had seen.  “I’m going back, and I want you all to come with me,” he said.  “I’m going to shove every bomb we’ve got down that mine shaft.  If we meet with any luck, we should wreck it up pretty well.”

“I suppose, sir,” said the sergeant, “if we can plant a bomb or two in the right spot, it will bottle up any Germans working inside?”

“Sure to!” said Ainsley.  “It will cave in the entrance completely; and then as soon as we get back, we’ll give the gunners the tip, and leave them to keep on lobbing some shells in and breaking up any attempt to reopen the shaft and dig out the mining party.”

“Billy!” said one of the men, in an audible aside, “don’t you wish you was a merry little German down that blinkin’ tunnel, to-night!”

“Imphim,” answered Billy, “I don’t think!”

Ainsley explained his plan of campaign, saw that everything was in readiness, and led his party out.  The misty rain was still falling, and, counting on this to hide them sufficiently from observation if they lay still while any lights were burning, they crawled rapidly across the open, wriggled underneath the wires, cut one or two of them—­especially any which were low enough to interfere with free movement under them—­and crawled along to the crater.