Bill had come back, and had reported, rather breathless, that Cayley was still at the pond.  
“But I don’t think they’re getting up much except mud,” he said. “I ran most of the way back so as to give us as much time as possible.”
 
Antony nodded.
 
“Well, come along, then,” he said. “The sooner, the quicker.”
 
They stood in front of the row of sermons. Antony took down the Reverend Theodore Ussher’s famous volume, and felt for the spring. Bill pulled. The shelves swung open towards them.
 
“By Jove!” said Bill, “it is a narrow way.”
 
There was an opening about a yard square in front of them, which had something the look of a brick fireplace, a fireplace raised about two feet from the ground. But, save for one row of bricks in front, the floor of it was emptiness. Antony took a torch from his pocket and flashed it down into the blackness.
 
“Look,” he whispered to the eager Bill. “The steps begin down there. Six feet down.”
 
He flashed his torch up again. There was a handhold of iron, a sort of large iron staple¹, in the bricks in front of them.
 
“You swing off from there,” said Bill. “At least, I suppose you do. I wonder how Ruth Norris liked doing it.”
 
“Cayley helped her, I should think.... It’s funny.”
 
“Shall I go first?” asked Bill, obviously longing² to do so. Antony shook his head with a smile.
 
“I think I will, if you don’t mind very much, Bill. Just in case.”
 
“In case of what?”
 
“Well, in case.”
 
Bill, had to be content with that, but he was too much excited to wonder what Antony meant.
 
“Righto,” he said. “Go on.”
 
“Well, we’ll just make sure we can get back again, first. It really wouldn’t be fair on the Inspector³ if we got stuck down here for the rest of our lives. He’s got enough to do trying to find Mark, but if he has to find you and me as well—”
 
“We can always get out at the other end.”
 
“Well, we’re not certain yet. I think I’d better just go down and back. I promise faithfully not to explore.”
 
“Right you are.”
 
Antony sat down on the ledge⁴ of bricks, swung his feet over, and sat there for a moment, his legs dangling⁵. He flashed his torch into the darkness again, so as to make sure where the steps began; then returned it to his pocket, seized the staple in front of him and swung himself down. His feet touched the steps beneath him, and he let go.
 
“Is it all right?” said Bill anxiously.
 
“All right. I’ll just go down to the bottom of the steps and back. Stay there.”
 
The light shone down by his feet. His head began to disappear. For a little while Bill, craning down the opening, could still see faint splashes of light, and could hear slow uncertain footsteps; for a little longer he could fancy that he saw and heard them; then he was alone....
 
Well, not quite alone. There was a sudden voice in the hall outside.
 
“Good Lord!” said Bill, turning round with a start, “Cayley!”
 
If he was not so quick in thought as Antony, he was quick enough in action. Thought was not demanded now. To close the secret door safely but noiselessly, to make sure that the books were in the right places, to move away to another row of shelves so as to be discovered deep in “Badminton” or “Baedeker” or whomever the kind gods should send to his aid—the difficulty was not to decide what to do, but to do all this in five seconds rather than in six.
 
“Ah, there you are,” said Cayley from the doorway⁶.
 
“Hallo!” said Bill, in surprise, looking up from the fourth volume of “The Life and Works of Samuel Taylor Coleridge.” “Have they finished?”
 
“Finished what?”
 
“The pond,” said Bill, wondering why he was reading Coleridge on such a fine afternoon. Desperately⁷ he tried to think of a good reason.... verifying a quotation⁸—an argument with Antony—that would do. But what quotation?
 
“Oh, no. They’re still at it. Where’s Gillingham?”
 
‘The Ancient Mariner’—water, water, everywhere—or was that something else? And where was Gillingham? Water, water everywhere...
 
“Tony? Oh, he’s about somewhere. We’re just going down to the village. They aren’t finding anything at the pond, are they?”
 
“No. But they like doing it. Something off their minds when they can say they’ve done it.”
 
Bill, deep in his book, looked up and said “Yes,” and went back to it again. He was just getting to the place.
 
“What’s the book?” said Cayley, coming up to him. Out of the corner of his eye he glanced at the shelf of sermons as he came. Bill saw that glance and wondered. Was there anything there to give away the secret?
 
“I was just looking up a quotation,” he drawled. “Tony and I had a bet about it. You know that thing about—er—water, water everywhere, and—er—not a drop to drink.” (But what on earth, he wondered to himself, were they betting about?)
 
“‘Nor any drop to drink,’ to be accurate.”
 
Bill looked at him in surprise. Then a happy smile came on his face.
 
“Quite sure?” he said.
 
“Of course.”
 
“Then you’ve saved me a lot of trouble. That’s what the bet was about.” He closed the book with a slam, put it back in its shelf, and began to feel for his pipe and tobacco. “I was a fool to bet with Tony,” he added. “He always knows that sort of thing.”
 
So far, so good. But here was Cayley still in the library, and there was Antony, all unsuspecting, in the passage. When Antony came back he would not be surprised to find the door closed, because the whole object of his going had been to see if he could open it easily from the inside. At any moment, then, the bookshelf might swing back and show Antony’s head in the gap. A nice surprise for Cayley!
 
“Come with us?” he said casually¹⁰, as he struck a match. He pulled vigorously at the flame as he waited for the answer, hoping to hide his anxiety, for if Cayley assented¹¹, he was done.
 
“I’ve got to go into Stanton.”
 
Bill blew out a great cloud of smoke with an expiration¹² which covered also a heartfelt sigh of relief.
 
“Oh, a pity. You’re driving, I suppose?”
 
“Yes. The car will be here directly. There’s a letter I must write first.” He sat down at a writing table, and took out a sheet of notepaper.
 
He was facing the secret door; if it opened he would see it. At any moment now it might open.
 
Bill dropped into a chair and thought. Antony must be warned. Obviously. But how? How did one signal to anybody? By code. Morse code. Did Antony know it? Did Bill know it himself, if it came to that? He had picked up a bit in the Army—not enough to send a message, of course. But a message was impossible, anyhow; Cayley would hear him tapping it out. It wouldn’t do to send more than a single letter. What letters did he know? And what letter would convey anything to Antony?.... He pulled at his pipe, his eyes wandering from Cayley at his desk to the Reverend Theodore Ussher in his shelf. What letter?
 
C for Cayley. Would Antony understand? Probably not, but it was just worth trying. What was C? Long, short, long, short. Umpty-iddy-umpty-iddy. Was that right? C—yes, that was C. He was sure of that. C. Umpty-iddy-umpty-iddy.
 
Hands in pockets, he got up and wandered across the room, humming ............