843. The aura on the one side, and the spirit on the other, are inert unless associated. Thus the volition of the spirit gives activity to an effluvium, by itself, so devoid of efficacy that it wholly escapes the perception of the possessor or the observation of his mundane companions. It has been already alleged, that the usual reference to mundane electricity must be wholly unsatisfactory to all acquainted with the phenomena and laws associated under that name; since no such movements have ever been produced by such electrical means, nor is it consistent with those mundane electrical laws, nor the facts which electricians have noticed, that such movements should be produced. Those movements which have been produced by electricity have never been effected without surfaces oppositely charged, nor, of course, without the means of charging them. Neither are there associated with the spiritual manifestations means at hand of creating nor of holding charges either much more minute than those which display perceptible force or cause audible sound. 844. Electro-magnetic phenomena require the use of powerful galvanic batteries or magnetic metals. Galvanic series, of the most powerful kind, do not act at the minutest distance without contact. 845. Even lightning could not move a table backward and forward, though it might shatter it into pieces, if duly interposed in a circuit. 846. Electrical sparks produce _snapping_ sounds in the air, not _knockings_ or _rappings_ upon sonorous solids. ON THE INFLUENCE OF THE ILL-TREATMENT OF MEDIA, ON SPIRITUAL MANIFESTATIONS.—OF COUNTER-MEDIUMSHIP. 847. Allusion has been above made to the unfavourable influence upon manifestations of the demeanour and incredulity of the investigator, displayed in suspicious, cold, scrutinizing looks, such as would be merited only by a cheat or pickpocket. All this has a deteriorating influence upon mediumship, and likewise repels the spirits. While communicating through a medium, a near blood relative, much beloved by the communicating spirit while in this world, coming into the circle, an immediate departure of the spirit was the consequence. It was subsequently alleged in explanation that there existed a repulsiveness between him and the spirit, founded on the idea that his opinions were under the influence of worldly considerations, whence a predetermination to disbelieve, as far as possible, by an unfavourable view of the evidence. 848. An incredulity liable to be overcome by the reason by which it has been created does not form a bar; but where an impregnable bigotry has been introduced merely by education, so that the person under its influence would have been a Catholic, Calvinist, Unitarian, Jew, or Mohammedan by a change of parentage, cannot usually be changed by any evidence or argument. Spirits will not spend their time subjecting their manifestations to such impregnable bigotry, or to predetermined malevolence.