"I am not at all happy about this," said Pariset, after a brief silence.
"We haven't learnt very much, certainly," said Kenneth.
"I don't mean that. We have learnt enough if that is your man. But I see no means of preventing the destruction of the bridge."
"We might fly to Charleroi and send a squadron of lancers back. There are only five men to deal with, apparently."
"That's not the difficulty. The point is that at the first sign of molestation they would fire the mine. You may depend upon it that they are picked men, with resolution enough to do their job, even at the cost of their lives. It would not be much use to capture them after the mischief was already done."
"The mine is to be fired on receipt of a marconigram."
"You didn't tell me that. It may happen at any minute, then. They must have wireless rigged up in the mill-house. We might have cut a wire, but with wireless we are helpless."
"Unless we could get into the mill," Kenneth suggested.
"Ah, if we could! But there's no chance of it. The fellow is on the qui vive: I don't like the way he looked after us."
"Wouldn't the old miller, as the landlord, have a right to go in?"
"I daresay, but the old man couldn't do anything. Even if he knew anything about wireless or mines, he would only get flustered; he certainly would quite fail to do any damage."
"Perhaps he could tell us of another way into the mill, so that we could do it ourselves."
"That could only be in the darkness, and they may fire the mine before night. I see nothing for it, after all, but to bring some cavalry from Charleroi and take care the men don't escape. We can do that, if we can't save the bridge."
"Why not wait a little? If the order to fire the mine comes suddenly, any time before night, we can't prevent it. But if it doesn't come before night, we still have a chance. In any case we ought to get some lancers over, to be in the neighbourhood at nightfall. It won't take long for one of us to get into Charleroi and back."
"That would be risky after that fellow's question about the aeroplane. The best course will be to send in a message by the drayman. I'll write a note as soon as we get back."
The drayman readily agreed to carry Pariset's note to the commandant of the Charleroi garrison. When he had departed, the miller was taken into consultation.
"Is there any other entrance to the millhouse besides the front door?" asked Pariset.
"There is a door to the stables, but that has long been nailed up," the old man replied.
"Describe the interior as well as you can."
"Well, monsieur, I lived there fifty years, so I ought to know something about it. You go in by the door; well, first there's the lobby; beyond that, straight ahead, is the kitchen, and beyond that again, looking on the stream, is the storeroom with the mill above. To the left of that is the hoist; and this side of it, overlooking the yard, is the big room, dining-room and parlour in one. There you have the ground-floor; the bedrooms are upstairs."
"And the wall goes all round?"
"Yes, right down to the stream on each side, and along the bank, except where the wheel juts out into the waterway. The old wheel is dropping to pieces; it hasn't been used these twenty years."
"Couldn't we get in that way?"
"Ma foi! That's an idea, now. Many's the time I got in that way as a boy, when the wheel was stopped--just a boy's devilry, you understand. You could get in that way yet, if the woodwork isn't too rotten to bear your weight. You would have to wade the stream, but that isn't deep or swift except in winter. Old as I be I'll show you the way myself."
"We could get in without being heard?"
"To be sure, if the woodwork doesn't crack and give way. The kitchen is the nearest room; old Jules, the handy man, is as deaf as a post, and his wife, who does the cooking, isn't much better."
"And where is the entrance to the underground passages?"
"To the left of the kitchen, in the floor of the hoist."
As the miller answered his questions, Pariset sketched a rough plan of the building.
"Is that something like it?" he asked, handing the paper over.
The old man put on his spectacles deliberately, and examined the sketch.
"Near enough," he said. "Ma foi! But I couldn't have done that myself."
"Now the question is, when shall we try to get in?" asked Pariset. "The best time would be when the men are having a meal. The Germans take their meals seriously; if they are ever to be caught off their guard it is when they are feeding."
"That's true," said the miller. "They have their supper somewhere about seven o'clock. I know that because one evening I met old Jules coming back from the village all puffing and blowing. I asked him why he was in such a hurry for an old man; had to ask three times before he heard me; and he told me he'd forgotten the vinegar, and the gentlemen were very angry."
"Well, it's dusk at seven; the lancers will be here by half-past. We'll make our attempt then."
"Better go a little earlier, while it's light enough to see our way," suggested the miller. "I'm not so young as I was, and I doubt whether I could find my way in the dark."
"Very well. It's now nearly five; we have nearly two hours to wait. You'll give us a meal, miller?"
"To be sure; the best I have. I'd feed a regiment to capture a German spy."
Just before seven Pariset and Kenneth left the house with the miller. Pariset had given the farmer a note addressed to the officer of the expected lancers, asking him to leave the horses at the farm, and post his men behind the hedge lining the road in the neighbourhood of the mill, ready to break in if they were called upon, or to intercept the Germans if they tried to escape.
The miller led the way across the fields, by a route which did not expose them to view from the mill-house until they arrived within a few yards of the bank of the stream opposite the wheel. The last part of the journey lay through a cornfield, the wheat growing so high that by stooping they completely hid themselves.
All was silent in the mill-house. Dusk was just falling. A lamp had already been lit in the kitchen, sending a ray of light across the yard to the left. The rear of the building, facing the stream, was dark.
Following the miller, the two young fellows stepped into the stream, and waded across knee deep till they stood below the wheel. It was an undershot wheel. The chains confining it were deeply rusted. Some of the floats had fallen away; others were broken; all were more or less decayed.
"I've done my part," the miller whispered. "You must squeeze through into the wheel and slide along the axle. Where it is let into the brickwork you'll find a hole big enough to crawl through. Climb up, and you'll find yourselves in a little room that used to be the tool-shop. Take care you don't stumble over the tools on the floor. At the further side there's a door into the storeroom. I can do no more. Que le bon Dieu vous protège!"
He shook hands with them in turn, recrossed the stream, and disappeared among the wheat stalks.
With some difficulty Pariset squeezed his body between two of the floats, hoisted himself up, and stood in the interior of the wheel. The rotten woodwork creaked, and the wheel itself groaned slightly as it moved an inch or two; but the movement was checked by the rusty chains. Kenneth followed more easily. They swung themselves on to the axle, jerked their way along it, came to the hole of which the miller had spoken, and clambering up through it, stood on the floor of the toolroom. Hands and clothes were coated with red rust.
The room was lit by a small window overlooking the stream. To their surprise, it was not empty except for a few rusty implements, as they had expected from the miller's description. A new deal bench stood against the wall, flanked by a turning lathe, and an elaborate engineering equipment.
"Electrical!" Pariset whispered.
Treading very carefully, they gently opened the door, took a look round, and passed into the capacious storeroom. Here they found the plant of a wireless telegraphy installation. The antennae passed through holes in the ceiling, emerging, as they guessed, under cover of the parapet, on the flat roof of the mill.
In the fast-fading light they were just able to see a doorway on the right, leading, as they knew from the miller's description, to the hoist and shoot. In front of them was another door, now open, giving access to a passage between the kitchen and the dining-room. Pariset slipped off his wet boots.
"Wait here," he whispered.
Stealing along the passage, he came to a door on the right. He put his ear against it, and heard the clink of knives and forks mingled with guttural conversation. Creeping back again, he whispered:
"They are feeding. Come along!"
They passed from the storeroom into the chamber which had formerly contained the hoist. Here they noticed a tall heap of earth.
"They dug that out when continuing the underground passage to the bridge," said Pariset.
"Here's the trap-door," returned Kenneth. "Look! There's a wire running through it, connecting with the room behind."
"It's all very thorough, confound them!" said Pariset. "I hope the trap-door won't creak."
They lifted it gently, and found that it moved on a central axis, well oiled. Peering into the dark depths, Kenneth discovered a wooden ladder. They crept down this, into a large underground chamber flagged with stone, and ventilated by narrow gratings in the brick walls, above the level of the stream.
"We had better not both go on," said Pariset. "I'll go up and keep watch. You proceed, and cut the wires at the further end of the passage."
"Why not here?" said Kenneth. "It would save time."
"But if the word should come to fire the mine, and they find the apparatus doesn't work, they'd soon discover the cut here and repair it. Much better do the damage at the other end."
"Very well. You'll use your revolver if they come before I get back?"
"Yes. I'll take my chance. They probably won't guess that there's any one below, if I shut down the trap-door. You know what to do: cut the wire, or disconnect the terminals."
With the trap-door closed, it was pitch dark in the chamber. Kenneth struck a match, and making his way carefully over the flagstones found himself in a narrow passage, which led into another large chamber like the first. This again was connected with a third by a short passage. The floor of the third was heaped with newly excavated earth, and the sole outlet from it was a low tunnel, which a man could enter only by bending low.
Kenneth crept into it, breathing with difficulty in the stuffy atmosphere impregnated with the smell of earth. It seemed endless, and must have cost prodigious labour. On and on he went, his back and legs aching, his breathing more and more oppressed. The thought came to him, what if the tunnel were obstructed at the further end? When the wire had once been laid, the Germans would have no interest in keeping the passage clear. What if the roof fell upon him? What if--direst possibility of all!--the mine were fired while he was still in the tunnel? At this thought he felt a momentary "sinking," and dropped his match-box. Taking a grip upon himself he waited a few moments until his nerves were steadied, groped for the match-box, struck another match, and went on.
A few yards more brought him to an enlargement of the tunnel, where he could stand upright. And here he found that the wire, laid along the floor, ended in a metal case, which he guessed to contain a detonating apparatus, like the floating mines employed at sea. It was the work of a moment to sever the wire. Then, turning his back on this terrible agent of destruction, Kenneth hurried along as fast as possible towards the open end of the tunnel.