There is a story that John Napier had a pet black rooster that his staff believed was a familiar spirit. One day, a theft occurred on his property and everyone denied any knowledge of it. Apparently, Napier gathered his staff, placed his rooster in a darkened room, and announced that each person was to enter the room alone and place his/her hands on the rooster and come out. The rooster would then tell him who had been involved in the theft. All entered the room and returned, but only one servant returned with clean hands. Napier had covered his pet rooster with lamp black.
