Get Camille Flammarion's 1900 The Unknown
All of us live, without knowing it, in a psychic environment we do not understand. The atmosphere contains not only chemical elements - oxygen, nitrogen, carbonic-acid gas, watery vapor, et cetera - but also psychic elements. Everywhere there are souls. There is a constant mingling of animism and spiritism in the experiments of which we are speaking; it is extremely difficult to separate them, to isolate them. Let us try to do this here, however.
Manifestations of the Dead in Spiritistic Experiments by Camille Flammarion