"No. And you can bet that Cayley knows that. Anyway, he'd bang on it, and you wouldn't answer, and then what would he think?"

Bill was silent; crushed.

"Then I don't see how we're going to do it," he said, after deep thought. "He'll obviously come to us just before he starts out, and that doesn't give us time to get to the pond in front of him."

"Let's put ourselves in his place," said Antony, puffing slowly at his pipe. "He's got the body, or whatever it is, in the pa.s.sage. He won't come up the stairs, carrying it in his arms, and look in at our doors to see if we're awake. He'll have to make sure about us first, and then go down for the body afterwards. So that gives us a little time."

"Y-yes," said Bill doubtfully. "We might just do it, but it'll be a bit of a rush."

"But wait. When he's gone down to the pa.s.sage and got the body, what will he do next?"

"Come out again," said Bill helpfully.

"Yes; but which end?"

Bill sat up with a start.

"By Jove, you mean that he will go out at the far end by the bowling-green?"

"Don't you think so? Just imagine him walking across the lawn in full view of the house, at midnight, with a body in his arms. Think of the awful feeling he would have in the back of the neck, wondering if anybody, any restless sleeper, had chosen just that moment to wander to the window and look out into the night. There's still plenty of moonlight, Bill. Is he going to walk across the park in the moonlight, with all those windows staring at him? Not if he can help it. But he can get out by the bowling green, and then come to the pond without ever being in sight of the house, at all."

"You're right. And that will just about give us time. Good. Now, what's the next thing?"

"The next thing is to mark the exact place in the pond where he drops whatever he drops."

"So that we can fish it out again."

"If we can see what it is, we shan't want to. The police can have a go at it to-morrow. But if it's something we can't identify from a distance, then we must try and get it out. To see whether it's worth telling the police about."

"Y-yes," said Bill, wrinkling his forehead. "Of course, the trouble with water is that one bit of it looks pretty much like the next bit. I don't know if that had occurred to you.

"It had," smiled Antony. "Let's come and have a look at it."

They walked to the edge of the copse, and lay down there in silence, looking at the pond beneath them.

"See anything?" said Antony at last.

"What?"

"The fence on the other side."

"What about it?"

"Well, it's rather useful, that's all."

"Said Sherlock Holmes enigmatically," added Bill. "A moment later, his friend Watson had hurled him into the pond."

Antony laughed.

"I love being Sherlocky," he said. "It's very unfair of you not to play up to me."

"Why is that fence useful, my dear Holmes?" said Bill obediently.

"Because you can take a bearing on it. You see-"

"Yes, you needn't stop to explain to me what a bearing is."

"I wasn't going to. But you're lying here," he looked up "underneath this pine-tree. Cayley comes out in the old boat and drops his parcel in. You take a line from here on to the boat, and mark it off on the fence there. Say it's the fifth post from the end. Well, then I take a line from my tree we'll find one for me directly and it comes on to the twentieth post, say. And where the two lines meet, there shall the eagles be gathered together. Q.E.D. And there, I almost forgot to remark, will the taller eagle, Beverley by name, do his famous diving act. As performed nightly at the Hippodrome."

Bill looked at him uneasily.

"I say, really? It's beastly dirty water, you know."

"I'm afraid so, Bill. So it is written in the book of Jasher."

"Of course I knew that one of us would have to, but I hoped, well, it's a warm night."

"Just the night for a bathe," agreed Antony, getting up. "Well now, let's have a look for my tree."

They walked down to the margin of the pond and then looked back. Bill's tree stood up and took the evening, tall and unmistakable, fifty feet nearer to heaven than its neighbours. But it had its fellow at the other end of the copse, not quite so tall, perhaps, but equally conspicuous.

"That's where I shall be," said Antony, pointing to it. "Now, for the Lord's sake, count your posts accurately."

"Thanks very much, but I shall do it for my own sake," said Bill with feeling. "I don't want to spend the whole night diving."

"Fix on the post in a straight line with you and the splash, and then count backwards to the beginning of the fence."

"Right, old boy. Leave it to me. I can do this on my head."

"Well, that's how you will have to do the last part of it," said Antony with a smile.

He looked at his watch. It was nearly time to change for dinner. They started to walk back to the house together.

"There's one thing which worries me rather," said Antony. "Where does Cayley sleep?"

"Next door to me. Why?"

"Well, it's just possible that he might have another look at you after he's come back from the pond. I don't think he'd bother about it in the ordinary way, but if he is actually pa.s.sing your door, I think he might glance in."

"I shan't be there. I shall be at the bottom of the pond, sucking up mud."

"Yes.... Do you think you could leave something in your bed that looked vaguely like you in the dark? A bolster with a pyjama-coat round it, and one arm outside the blanket, and a pair of socks or something for the head. You know the kind of thing. I think it would please him to feel that you were still sleeping peacefully."

Bill chuckled to himself.

"Rather. I'm awfully good at that. I'll make him up something really good. But what about you?"

"I'm at the other end of the house; he's hardly likely to bother about me a second time. And I shall be so very fast asleep at his first visit. Still, I may as well to be on the safe side."