There was no arguing with such a man, especially when he was sleepy. So Harry submitted, very quietly, to being put into a cell. He was not treated like a common prisoner; that much he was grateful for. His cell was really a room, with windows that were not even barred. And he saw that he could be very comfortable indeed.

"You'll be all right here," said one of the constables. "Don't worry, my lad. You'll be let off with a caution in the morning. Get to sleep now—it's late, and you'll be roused bright and early in the morning."

Harry smiled pleasantly, and thanked the man for his good advice. But he had no intention whatever of taking it. He did not even take off his clothes, though he did seize the welcome chance to use the washstand that was in the room. He had been through a good deal since his last chance to wash and clean up, and he was grimy and dirty. He discovered, too, that he was ravenously hungry. Until that moment he had been too active, too busy with brain and body, to notice his hunger.

However, there was nothing to be done for that now. He and Dick had not stopped for meals that day since breakfast, and they had eaten their emergency rations in the early afternoon. In the tool case on his impounded motorcycle Harry knew there were condensed food tablets—each the equivalent of certain things like eggs, and steaks and chops. And there were cakes of chocolate, too, the most nourishing of foods that are small in bulk. But the knowledge did him little good now. He didn't even know where the motorcycle had been stored for the night. It had been confiscated, of course; in the morning it would be returned to him.

But he didn't allow his thoughts to dwell long on the matter of food. It was vastly more important that he should get away. He had to get his news to Colonel Throckmorton. Perhaps Dick had done that. But he couldn't trust that chance. Aside from that, he wanted to know what had become of Dick. And, for the life of him, he didn't see how he was to get away.

"If they weren't awfully sure of me, they'd have locked me up a lot more carefully than this," he reflected. "And of course it would be hard. I could get out of here easily enough."

He had seen a drain pipe down which, he felt sure, he could climb.

"But suppose I did," he went on, talking to himself. "I've got an idea it would land me where I could be seen from the door—and I suppose that's open all night. And, then if I got away from here, every policeman in this town would know me. They'd pick me up if I tried to get out, even if I walked."

He looked out of the window. Not so far away he could see a faint glare in the sky. That was London. He was already in the suburban chain that ringed the great city. This place—he did not know its name, certainly—was quite a town in itself. And he was so close to London that there was no real open country. One town or borough ran right into the next. The houses would grow fewer, thinning out, but before the gap became real, the outskirts of the next borough would be reached.

Straight in front of him, looking over the housetops, he could see the gleam of water. It was a reservoir, he decided. Probably it constituted the water supply for a considerable section. And then, as he looked, he saw a flash—saw a great column of water rise in the air, and descend, like pictures of a cloudburst. A moment after the explosion, he heard a dull roar. And after the roar another sound. He saw the water fade out and disappear, and it was a moment before he realized what was happening. The reservoir had been blown up. And that meant more than the danger and the discomfort of an interrupted water supply. It meant an immediate catastrophe—the flooding of all the streets nearby.