In man the middle sphere between mind and matter is occupied by emotion or feeling. The instability of human emotion is well symbolized by the element of water which is continually in motion and whose peaceful surface can be transformed into a destroying fury by forces moving above its broad expanse. This emotional nature of man is closely associated with the astral light or magical sphere of the ancient and mediæval magicians. In this plane illusion is particularly powerful. As one writer has wisely observed, "It is a land of beauty, a garden of flowers but a serpent is entwined about the stem of each." Among the Oriental mystics this sphere of the astral light is considered particularly dangerous, for those who are aspiring to an understanding of spiritual mysteries are often enmeshed in this garden of Kundry and, believing that they have found the truth, are carried to their destruction by the flow of this astral fluid.