From page 264 The Life of Mark Twain - The Middle Years 1871-1891:

Sam had been so impressed with Chamonix during his visit [with Twichell] that he returned there with Livy on September 10. They had “a wonderfully enjoyable trip, Livy wrote her mother, “although it was a rather wearing one,” They left their daughters with Rosina Hay, rode in a two-horse wagon for nine hours one way, remained a day, and returned to Geneva on September 12, otherwise, the remainder of their visit to the city was uneventful. The local attractions were “not numerous,” Sam complained in A Tramp Abroad. “I made one attempt to hunt up the houses once inhabited by those two disagreeable people, Rousseau and Calvin,” he allowed, “but had no success.” Privately he was even more disparaging, The “principal features of Swiss scenery,” he noted in his journal, were “Mont Blanc and the goiter.”