Let us first consider the theory held by a very large number of persons--that the board is moved by some kind of "electricity." We must suppose that the generally recognized electricity is meant, because, if not, the motive force would be electricity _plus something_, and the "something" would be the explanation. And yet, if the force moving the board be "electricity," how comes it that this "electricity" can answer back, and possess an individuality so independent from that of the writer; capable, too, of giving a vast mass of information to the sitters, on occasion, of which they knew nothing? Then, again, it must be remembered that a ouija or planchette is almost universally made of _wood_--not metal or any well-known good conductor of electricity, but of wood--which is generally recognized to be an exceedingly bad conductor. Obviously the theory is absurd. And when we come to remember those cases in which the board gave information previously unknown to the writer having his hands on the board at the time, the theory sinks into its proper place--oblivion. Then there is the theory of a floating, ambient mentality. This theory is held by many, and it is contended by them that this mentality is clothed, by some mysterious process, with a force similar to that which it possessed in the living organism; and that, in its expression of the combined intelligence of the circle, it generally follows the strongest mind, or the mind that is best qualified or conditioned to give correctly the thought. This theory found its champion in the person of Dr. Joseph Maxwell (see his _Metapsychical Phenomena_), and must be taken into account seriously. But an objection, and to my mind a fatal objection, to this theory is the fact that the intelligence seems to possess, not a collective but a decidedly personal character--one which is sufficiently stable and individual to argue back and to maintain its own opinions and beliefs in the face of great opposition from all the members of the circle. Is there anything in all this that suggests a floating, compound mentality; or does it not rather bear the marks of being a theory made up for the occasion, in order to evade some alternative explanation, objectionable, perhaps, to the sitters or critics? All that has been said above also applies to the theory of a _spiritus mundi_, or spirit of the universe, which formed so large a part in the cosmological theories of many ancient philosophers. It is supposed to be a sort of all-pervading nervous principle, having, however, a mind of its own, when occasion demands--for otherwise how are the results to be accounted for? I think this and the preceding theory can best be met, perhaps, by asking its supporters to produce one iota of evidence in its behalf. When this has been forthcoming it will be time enough to consider it seriously.