August 21 Wednesday – Sam hired a carriage and the group continued on to Interlaken, Switzerland.
From Sam’s notebook: “Left in 4-horse ambulance. Proprietor gave children box”

Rodney observes it was a “rugged journey” with “primitive roads past mountain chalets, through enticing villages, up and over the Brünig Pass, and down to Lake Brienz and Interlacken at the foot of the High Alps.” The sixty mile trip took ten hours. They took rooms at the Jungfrau Hotel.
(Day By Day)

From page 261 The Life of Mark Twain - The Middle Years 1871-1891:

On August 21 Sam and his family left Lucerne in a four-horse diligence for Interlaken, forty miles away, where they registered at the Jungfrau Hotel, “one of those huge establishments which the needs of modern travel have created in every attractive spot on the continent.” The windows in their rooms opened to a "superb view” of “the mighty dome,” the mountain named "virgin" in German, “softly outlined” against the southern sky “and faintly silvered by the starlight.” Sam sketched the Jungfrau in his notebook during his brief stay in Interlaken, though he admitted the sketch “gives me a bellyache.”

Pages 261-2:

On the morning of August 23 Sam and Joe left Livy, Susy, Clara, and the servants in Interlaken and traveled by buggy—a concession to Sam's theumatism—through the Kiental and Frutigen to Kandersteg at the foot of the Gemmi Pass. On August 24 they “skirted the lonely little lake called the Daubensee” and trudged over the pass to Leukerbad. Much as he remembered retreating in time by climbing the volcanoes in Hawaii in 1866, Sam wrote to Livy that evening,

Joe & I have had a most noble day. Started to climb (on foot) at 8.30 this morning among the grandest peaks! Every half hour carried us back a month in the season. We left them harvesting 2d crop of hay. At 9 we were in July & found ripe strawberries; at 9.30 we were in June & gathered flowers belonging to that month; at 10 we were in May... ;at 11.30 we were in April (by the flowers); at noon we had rain & hail mixed, & wind & enveloping fogs, & considered it March; at 12.30 we had snow-banks above us & snow-banks below us, & considered it February.