Note AA — JOURNAL (continued 2)

[Footnote AA: James Bridger was famous for the marvelous stories he was accustomed to relate of his mountain life and experiences. He once told me that he had seen a river which flowed so rapidly over the smooth surface of a descending rock ledge in the bottom of the stream, that the water was "hot at the bottom." My experience in crossing the Firehole river that day, leads me to believe that Bridger had had, at some time, a similar experience. He well knew that heat and fire could be produced by friction. Like other mountain men, he had doubtless, many a time, produced a fire by friction; and he could not account for the existence of a hot rock in the bed of a cold stream, except upon the theory that the rapid flow of water over the smooth surface evolved the heat, by friction. N.P. LANGFORD.]