Doug and Richard,
Thanks for posting Muir's account of his second ascent (1875). Sounds to me like Muir's group made it to Iceberg Lake (East Face Lake). But then they did not go up the long Chute which Muir did on October 21, 1873 and Clyde later called the Mountaineers Route. Rather for safety, Muir lead the team over Whitney Russell Pass, down to a lake, and then "gradually climbed higher, mounting a spiral around the northwest shoulder of the mountain, then directly to the summit.
Doug,
I've searched a bit for a Soda Springs in the Big Whitney Meadow area, but only find a Soda Springs considerably to the SSE near Monache Mountain. This Saturday I'll be at Muir's house in Martinez and will try to see if I can learn something there (though the the University of the Pacific seems to be ground zero for collecting historical papers/materials on Muir).
Jim