are
many channels through which the "_induction_" of the latter may
take place, and the channel of ordinary visualisation in the persons
just mentioned is different from that through which their visions
arise.

The following is a good instance of this condition. A friend writes:
--

"These visions often appear with startling vividness, and so far
from depending on any voluntary effort of the mind, [10] they remain
when I often wish them very much to depart, and no effort of the
imagination can call them up. I lately saw a framed portrait of a
face which seemed more lovely than any painting I have ever seen,
and again I often see fine landscapes which bear no resemblance to
any scenery I have ever looked upon. I find it difficult to define
the difference between a waking vision and a mental image, although
the difference is very apparent to myself. I think I can do it best
in this way. If you go into a theatre and look at a scene--say of a
forest by moonlight--at the back part of the stage you see every
object distinctly and sufficiently illuminated (being thus unlike a
mere act of memory), but it is nevertheless vague and shadowy, and
you might have difficulty in telling afterwards all the objects you
have seen. This resembles a mental image in point of clearness. The
waking vision is like what one sees in the open street in broad
daylight, when every object is distinctly impressed on the memory.
The two kinds of imagery differ also as regards voluntariness, the
image being entirely subservient to the will, the visions entirely
independent of it. They differ also in point of suddenness, the
images being formed comparatively slowly as memory recalls each
detail, and fading slowly as the mental effort to retain them is
relaxed, the visions appearing and vanishing in an instant. The
waking visions seem quite close, filling as it were the whole head,
while the mental image seems farther away in some far-off recess of
the mind."

[Footnote 10: The details and illustrations of four other
experiments with the image of a rosebud have been given me. They all
vary in detail.]

The number of sane persons who see visions no less distinctly than
this correspondent is much greater than I had any idea of when I
began this inquiry. I have received an interesting sketch of one,
prefaced by a description of it by Mrs. Haweis. She says:--

"All my life long I have had one very constantly-recurring vision, a
sight which came whene