Warren stopped suddenly, and, looking straight before him, appeared plunged in thought.  Then, passing his hand over his forehead, he repeated, in an absent manner, “Yes, of smoking so much.  I also took to another habit,” he added, somewhat hastily; “but that has nothing to do with my story.  The theory which especially occupied my thoughts was that of the oscillations of an ideal instrument of my own imagining, to which, in my own mind, I gave the name of the Philosopher’s Pendulum.  To this invention I owe the quietude of mind which has supported me for many years, and which, as you see, I now enjoy.  I said to myself that my great sorrow—­if I may so call it without presumption—­had arisen merely from my wish to be extraordinarily happy.  When, in his dreams, a man has carried presumption so far as to attain to the heights of celebrity, or to being the husband of Ellen Gilmore, there was nothing wonderful if, on awaking, he sustained a heavy fall before reaching the depths of reality.  Had I been less ambitious in my desires, their realization would have been easier, or, at any rate, the disappointment would have been less bitter.  Starting from this principle, I arrived at the logical conclusion that the best means to avoid being unhappy is to wish for as little happiness as possible.  This truth was discovered by my philosophical forefathers many centuries before the birth of Christ, and I lay no claim to being the finder of it; but the outward symbol which I ended by giving to this idea is—­at least I fancy it is—­of my invention.

“Give me a sheet of paper and a pencil,” he added, turning to his friend, “and with a few lines I can demonstrate clearly the whole thing.”

Hermann handed him what he wanted without a word.  Warren then began gravely to draw a large semicircle, open at the top, and above the semicircular line a pendulum, which fell perpendicularly and touched the circumference at the exact point where on the dial of a clock would be inscribed the figure VI.  This done, he wrote on the right-hand side of the pendulum, beginning from the bottom and at the places of the hours V, IV, III, the words Moderate Desires—­Great Hopes, Ambition—­Unbridled Passion, Mania of Greatness.  Then, turning the paper upside-down, he wrote on the opposite side, where on a dial would be marked VII, VIII, IX, the words Slight Troubles—­ Deep Sorrow, Disappointment—­Despair.  Lastly, in the place of No.  VI, just where the pendulum fell, he sketched a large black spot, which he shaded off with great care, and above which he wrote, like a scroll, Dead Stop, Absolute Repose.

Having finished this little drawing, Warren laid down his pipe, inclined his head on one side, and raising his eyebrows, examined his work with a critical frown.  “This compass is not yet quite complete,” he said; “there is something missing.  Between Dead Stop and Moderate Desires on the right, and Slight Troubles on the left, there is the beautiful line of Calm and Rational Indifference.  However, such as the drawing is, it is sufficient to demonstrate my theory.  Do you follow me?”