I may have commented upon my friend’s power of mental detachment, but never have I wondered at it more than upon that spring morning in Cornwall when for two hours he discoursed upon Celts, arrowheads, and shards, as lightly as if no sinister mystery were waiting for his solution. It was not until we had returned in the afternoon to our cottage that we found a visitor awaiting us, who soon brought our minds back to the matter in hand. Neither of us needed to be told who that visitor was. The huge body, the craggy and deeply seamed face with the fierce eyes and hawk-like nose, the grizzled hair which nearly brushed our cottage ceiling, the beard — golden at the fringes and white near the lips, save for the nicotin stain from his perpetual cigar — all these were as well known in London as in
