Appearances Coincident with Death.
Others not Coincident with Anything.
In "crystal-gazing" anybody can make experiments for himself and among such friends as he thinks he can trust.

They are hallucinations consciously sought for, and as far as possible, provoked or induced by taking certain simple measures.

Unsought, spontaneous waking hallucinations, according to the result of Mr.Galton's researches, though not nearly so common as dreams, are as much facts of _sane_ mental experience.

Now every ghost or wraith is a hallucination.

You see your wife in the dining-room when she really is in the drawing- room; you see your late great-great-grandfather anywhere.