History’s Detectives did a very entertaining segment about Edison’s machine (thank you for the pointer, Winifer Skattebol). You can see it here. It’s the first historical mystery they try to solve and it’s really worth watching.
And, one of their Edison authorities, Paul Israel, the Director and General Editor of the Thomas A. Edison Papers Project at Rutgers, didn’t try to downplay Edison’s interest in the possibility of life after death.
So there you go!