What we have to remember is that by far the greater part of the physical phenomena which is said to occur at a _séance_ is really nothing extraordinary. All physical occurrences are normal that are capable of being produced by a clever conjurer; and there is no doubt that with due preparation such a one could achieve table rapping, introduce flowers and move furniture. But the problem is, how, under the stringent conditions imposed, and in the face of the close scrutiny, to which these manifestations are subjected, they can be done. As Sir Oliver Lodge says: "I am disposed to maintain that I have myself witnessed, in a dim light, occasional abnormal instances of movement of untouched objects." He goes on to say that "suppose an untouched object comes sailing or hurtling through the air, or suppose an object is raised or floated from the ground, how are we to regard it? This is just what a live animal could do, and so the first natural hypothesis is that some living thing is doing it: (_a_) the medium himself, acting by tricks or concealed mechanism; (_b_) a confederate--an unconscious confederate perhaps, among the sitters; (_c_) an unknown and invisible live entity, other than the people present. If in any such action the extraordinary laws of nature were superseded, if the weight of a piece of matter could be shown to have _disappeared_, or if fresh energy were introduced beyond the recognised categories of energy, then there would be no additional difficulties; but hitherto there has been no attempt to establish either of these things. Indeed, it must be admitted that insufficient attention is usually paid to this aspect of ordinary, commonplace, abnormal physical phenomena. If a heavy body is raised under good conditions, we should always try to ascertain" (he does not say that it is easy to ascertain) "where its weight has gone to--that is to say, what supports it--what ultimately supports it. For instance, if experiments were conducted in a suspended room, would the whole weight of that room, as ascertained by outside balance, remain unaltered when a table or person was levitated inside it? Or, could the agencies operating inside affect the bodies outside?--questions, these, which appear capable of answer, with sufficient trouble, in an organised physical laboratory; such a laboratory as does not, he supposes, yet exist, but which might exist and which will exist in the future, if the physical aspect of experimental psychology is ever to become recognised as a branch of orthodox physics."