It would be hopeless within the limits of such a treatise as this to attempt to explain the different uses to which the forces inherent in the manifold varieties of this elemental essence can be put by one who has been trained in their management. The v^st majority of magical ceremonies depend almost entirely upon its manipulation, either directly by the will of the magician, or by some more definite astral entity evoked by him fGr that purpose. By its means nearly all the physical phenomena of the seance -room Sre produced, and it is also the agent in most cases of stone-throwing or bell-ringing in haunted houses, such results as these latter being brought about either by blundering efforts to attract attention made by some earth- bound human entity, or by the mere mischievous pranks of some of the minor nature-spirits belonging to our third class. But the"elemental ” must never be thought of as itself a prime mover ; it is simply a latent force, which needs an external power to set it in motion. It may be noted that although all classes of the essence have the power of reflecting images from the, astral light as desc'ribSd above, there are varieties which receive^ certain impressions much more readily than others—which have,