The creators of the possessed board had to scare their way to a patent:
[T]he chief patent officer demanded a demonstration—if the board could accurately spell out his name, which was supposed to be unknown to [investor Elijah] Bond and [his sister-in-law Helen] Peters, he’d allow the patent application to proceed. They all sat down, communed with the spirits, and the planchette faithfully spelled out the patent officer’s name. Whether or not it was mystical spirits or the fact that Bond, as a patent attorney, may have just known the man’s name, well, that’s unclear, Murch says. But on February 10, 1891, a white-faced and visibly shaken patent officer awarded Bond a patent for his new “toy or game.”
How it works:
Ouija boards work on a principle known to those studying the mind for more than 160 years: the ideometer effect. In 1852, physician and physiologist William Benjamin Carpenter published a report for the Royal Institution of Great Britain, examining these automatic muscular movements that take place without the conscious will or volition of the individual (think crying in reaction to a sad film, for example). Almost immediately, other researchers saw applications of the ideometer effect in the popular spiritualist pastimes. In 1853, chemist and physicist Michael Faraday, intrigued by table-turning, conducted a series of experiments that proved to him (though not to most spiritualists) that the table’s motion was due to the ideomotor actions of the participants.
The Dish 
