The Rev. Joseph H. Twichell and Mark Twain used to take many long walks together, and once they decided to walk from Hartford to Boston--about one hundred miles. They decided to allow three days for the trip, and really started one morning, with some luncheon in a basket, and a little bag of useful articles. It was a bright, brisk November day, and they succeeded in getting to Westford, a distance of twenty-eight miles, that evening. But they were lame and foot-sore, and next morning, when they had limped six miles or so farther, Clemens telegraphed to Redpath: "We have made thirty-five miles in less than five days. This shows the thing can be done. Shall finish now by rail. Did you have any bets on us?" He also telegraphed Howells that they were about to arrive in Boston, and they did, in fact, reach the Howells home about nine o'clock, and found excellent company--the Cambridge set--and a most welcome supper waiting. Clemens and Twichell were ravenous. Clemens demanded food immediately. Howells writes: "I can see him now as he stood up in the midst of our friends, with his head thrown back, and in his hands a dish of those scalloped oysters without which no party in Cambridge was really a party, exulting in the tale of his adventure, which had abounded in the most original characters and amusing incidents at every mile of their progress." The pedestrians returned to Hartford a day or two later--by train. It was during another, though less extended, tour which Twichell and Clemens made that fall, that the latter got his idea for a Mississippi book. Howells had been pleading for something for the January "Atlantic," of which he was now chief editor, but thus far Mark Twain's inspiration had failed. He wrote at last, "My head won't go," but later, the same day, he sent another hasty line. "I take back the remark that I can't write for the January number, for Twichell and I have had a long walk in the woods, and I got to telling him about old Mississippi days of steam-boating glory and grandeur as I saw them (during four years) from the pilot-house. He said, 'What a virgin subject to hurl into a magazine!' I hadn't thought of that before. Would you like a series of papers to run through three months, or six, or nine--or about four months, say?" Howells wrote at once, welcoming the idea. Clemens forthwith sent the first instalment of that marvelous series of river chapters which rank to-day among the very best of his work. As pictures of the vanished Mississippi life they are so real, so convincing, so full of charm that they can never grow old. As long as any one reads of the Mississippi they will look up those chapters of Mark Twain's piloting days. When the first number appeared, John Hay wrote: "It is perfect; no more, no less. I don't see how you do it."