In the old Lone Ranger series, what did “kemosabe” mean? is one of those questions that Cecil(praise be his name) got 99% correct. But, with the coming of electronically searchable databases, we can go the last 1%.
Facts that Unca Cece got right:
l. It almost certainly is from the Ojibwa language.
2. It means “____ Scout.” More about that below.
3. It was chosen by Jim Jewell, the director of the radio program. Jewell said it was the name of a boy’s camp started by his father-in-law in 1911 in Mullet Lake, MI.
A search of Google Books indicates the earliest use of “Kee-Mo Sah-Bee” was by Ernest Thompson Seton, the famous naturalist, painter, Indian expert, Founder of the Boy Scouts of America, etc. Seton founded, around 1902, the Woodcraft Indians, an outdoor program for young boys. Seton based much of his program around the American Indian, of whom he was perhaps the largest champion in the period 1890-1940.
There is, again using Google Books, a full-text version of his 1912 The Book of Woodcraft and Indian Lore. On page 134, we see that he(Seton) said that the title “Kee-mo-sah-bee” meant “Scout Runner.” It was a title that a boy could receive by passing nine tests. There are many other titles, with Indian names, most? of which come from the Ojibwa.
As to Jewell’s claim that his father-in-law, Charles W. Yeager, founded camp Kee-Mo-Sah-Bee----he probably did, but did so around 1916. See A Handbook of American Private Schools(1916).
For those interested in an interesting profile/biography of Seton(which suggests that Lord Baden Powell blatantly stole many of the ideas that were devised by Seton, http://64.233.169.104/search?q=cache:mv01uAlwe-AJ:histclo.com/youth/youth/bio/b-ets.htm+"ernest+thomson+seaton"&hl=en&ct=clnk&cd=1&gl=us
As to where the name Tonto was obtained, as Cecil said,