In correspondence of Bill Nye in March/April of 1890, he writes to a cousin
about his plans to get Twain and Joe Goodman together with himself for a
"seance".  Twain responds to Nye with a letter of April 17, 1890 in
anticipation of the visit.  However, it appears the word "seance" may be
used interchangeably for "get together".  Although William Gillis does
devote one chapter in his book _Memories of Mark Twain and Steve Gillis_ to
actual seances held in Virginia City as sorts of entertainment, are there any
other sources that would shed light on when the word "seance" is used, if the
19th century correspondent used it only to indicated a  "visit" rather than
something related to me spiritual contact with the dead?

Barb