Some one was bending over me and looking into my face.

"Thank God, he is not dead," I heard in whispered tones. Then, with a flash, memory returned to me.

"What has happened?" I asked.

"You may well ask that, sir," said the Inspector gravely. "It has been touch and go with you for the last quarter of an hour; and a near thing for me too."

I sat up and looked around me. Daylight was just beginning to break, and I saw that we were at the bottom of the steps that led up to the signal-box. My teeth were chattering with the cold and I was shivering like a man with ague.

"I am better now," I said; "just give me your hand."

I took his arm, and holding the rail with the other hand staggered up into the box and sat down on the bench.

"Yes, it has been a near shave," I said; "and a big price to pay for solving a mystery."

"Do you mean to say you know what it is?" asked Henderson eagerly.

"Yes," I answered, "I think I know now; but first tell me how long was I unconscious?"