The Margaret Cheney biography entitled _Tesla: Man Out of Time_, 1981,
Prentice
Hall, does document the Tesla/Twain relationship in more depth than Twain
biographers have apparently done.  Cheney provides good bibliography and
references to document her assertion of their closeness-- references that
could be explored more in depth from the Twain point of view.

It is easy to conclude that Tesla was the man who played the embarrassing
joke on Twain and not Edison.

Barb