I tore open the Tide Tables and found Bradgate. High tide there was at 10.27 p.m. on the 15th of June.

“We’re on the scent at last,” I cried excitedly. “How can I find out what is the tide at the Ruff?”

“I can tell you that, sir,” said the coastguard man. “I once was lent a house there in this very month, and I used to go out at night to the deep-sea fishing. The tide’s ten minutes before Bradgate.”

I closed the book and looked round at the company.

“If one of those staircases has thirty-nine steps we have solved the mystery, gentlemen,” I said. “I want the loan of your car, Sir Walter, and a map of the roads. If Mr MacGillivray will spare me ten minutes, I think we can prepare something for tomorrow.”

It was ridiculous in me to take charge of the business like this, but they didn’t seem to mind, and after all I had been in the show from the start. Besides, I was used to rough jobs, and these eminent gentlemen were too clever not to see it. It was General Royer who gave me my commission. “I for one,” he said, “am content to leave the matter in Mr Hannay’s hands.”

By half-past three I was tearing past the moonlit hedgerows of Kent, with MacGillivray’s best man on the seat beside me.

Chapter X.
Various Parties Converging on the Sea

A pink and blue June morning found me at Bradgate looking from the Griffin Hotel over a smooth sea to the lightship on the Cock sands which seemed the size of a bell-buoy. A couple of miles farther south and much nearer the shore a small destroyer was anchored. Scaife, MacGillivray’s man, who had been in the Navy, knew the boat, and told me her name and her commander’s, so I sent off a wire to Sir Walter.

After breakfast Scaife got from a house-agent a key for the gates of the staircases on the Ruff. I walked with him along the sands, and sat down in a nook of the cliffs while he investigated the half-dozen of them. I didn’t want to be seen, but the place at this hour was quite deserted, and all the time I was on that beach I saw nothing but the seagulls.