In an essay on 19th century humor, writer E. F. Bleiler mentions the
frequent use of pain in humor and the use of practical jokes.  To illustrate
his point, he gives an example of Edison's delight at Twain being lured upon
a vibration device with dire consequences.  Other references to the Twain/
Edison relationship refer only to voice recordings and moving pictures.
Were Twain and Edison close enough to engage in practical joking or is
Bleiler mistaken on this point?

Barb