The Professor hesitated. Yet, after all, he was in this man’s power. So far as he could see, his only chance of escape lay in gaining time, until by some miracle a belated labourer should come past within hailing distance. It was the most unlikely thing in the world to happen, but there was just a chance. Consequently, since the sailor seemed disposed to talk, it was best to humour him.

“I guessed it first when I heard the name Copperdock again,” he replied. “I could not remember at first where I had heard it before, but finally, the whole scene came back to me.”