That night Kalliboas came to me as I sat alone in our guest-room, and rated me soundly for allowing Poyning to stray from the flying school, and over a forbidden quarter at that. The old man seemed to regard me, being a good deal the elder, as responsible for both of us; and I judged well at that moment to pretend a contrition I assuredly didn't feel. I particularly wanted to be in the good graces of Kalliboas, for I was determined to extract from him the secret of those mysterious boxes, if it were humanly possible. But it wasn't. 'They contain,' said the old man icily, in answer to my question, 'a force not to be understood of untaught minds. Beware lest you pry too deeply into our secrets, stranger, and the knowledge be too strong for you.' With that he was gone, leaving me to solve the riddle as best I might. I lay awake hour after hour, striving to imagine what that force could be, and when at last I had exhausted every possibility suggested by my scant knowledge of natural science, and come to the only conclusion left, I had to confess that my solution was more bewildering than the riddle itself. Kalliboas had mentioned, as I remembered, what he conceived to be the greatest force in the world, and I had long suspected that those healing boxes and the mechanism of the power-driven wings were only different manifestations of the same thing. It seemed to me that by some wizard process--perhaps analogous to the way electricity is imprisoned in the material substances of an accumulator--_both had been charged with the force of the human mind_. Poyning awoke in the following forenoon, remembering nothing of what had happened after he swallowed the draught. I stayed beside his couch most of that day, doing what I could to cheer him, but Poyning was curiously moody and depressed, and beyond remarking absently once or twice that Philipson's betrothed seemed to him to be an uncommonly pleasant lady and that it was a lucky disaster, after all, that had dropped him into the wrong courtyard--I didn't think worth while to let him know the views of Kalliboas on this point--he said little.