Amelia sent them upstairs to wash their hands—which, in the Professor's case, was certainly desirable, for his fingers were grimed with earth and dust from the rocks he had been investigating. As soon as we were left alone Charles drew me into the library.
"Seymour," he said, "more than ever there is a need for us strictly to avoid preconceptions. We must not make up our minds that this man is Colonel Clay—nor, again, that he isn't. We must remember that we have been mistaken in both ways in the past, and must avoid our old errors. I shall hold myself in readiness for either event—and a policeman in readiness to arrest them, if necessary!"
"A capital plan," I murmured. "Still, if I may venture a suggestion, in what way are these two people endeavouring to entrap us? They have no scheme o
