The X-ray Sense
Another phase of clairvoyant phenomena of this general class is that
which may be called "the X-Ray Sense," for indeed it enables the
clairvoyant to see through a brick wall, or other material obstacle, or
through a sealed letter, etc. The higher psychic vibrations easily pass
through the most solid object, just as do the X-Rays, and consequently
the clairvoyant is able to see what is going on on the other side of a
brick wall, or the walls of a house. Likewise, the clairvoyant vision is
able to pierce through the dense earth, and to perceive veins of mineral
or metal lying concealed beneath.