<p>The Sideric Pendulum is an obscure pamphlet or article about a unique divination tool ? a pendulum used for psychic communication ? which includes an introductory note by Arthur Conan Doyle. In this piece, Doyle introduces the concept of the "sideric pendulum," explaining that spiritualists have employed it as a medium of communication with the unseen. The pendulum, typically a weighted object on a string, is said to swing in response to quest...