
letter to William Colby (4 February 1912); published in " John Muir — President of the Sierra Club http://archive.org/stream/sierraclubbullet1019sier#page/n17/mode/2up", by William E. Colby, Sierra Club Bulletin, volume 10, number 1 (John Muir Memorial Issue, January 1916) pages 2-7 (at page 6); and in John Muir's Last Journey, edited by Michael P. Branch (Island Press, 2001), page 160
1910s