I have damaged my intellect trying to imagine why a man should want to invent a repeating clock, and how another man could be found to lust after it and buy it. The man who can guess these riddles is far on the way to guess why the human race was invented - which is another riddle which tires me.
Mark Twain's Correspondence with Henry Huttleston Rogers, 1893-1909 (ed. Univ of California Press, 1969) - ISBN: 9780520905061