These perfectly interpenetrate the one the other, if we may help ourselves with the language of space.
"Edward Caldwell Moore Outline of the History of Christian Thought Since Kant"
Edward Moore
In it all alike-gods, Tuatha De Danann, fairies, demons, shades, and every sort of disembodied spirits-find their appropriate abode; for though it seems to surround and interpenetrate this planet even as the X-rays interpenetrate matter, it can have no other limits than those of the Universe itself.
"The Fairy-Faith in Celtic Countries"
W. Y. Evans Wentz
When the condition of the atmosphere, of the medium, and of the circle is proper, the spirit exerts that will power, and, in accordance with natural law, attracts to its spirit form the floating particles in the air, and they condense upon and interpenetrate the spirit form or body so as to materialize it, making bone, muscle, skin, hair-every part, and making the spirit body, for the time being, a solid, palpable one.
"Witchcraft of New England Explained by Modern Spiritualism"
Allen Putnam