More recent researches have led to some elucidation of the knowledge at which discarnate spirits have arrived with regard to gravitation. They hold that human science is crippled needlessly by its non-recognition of Motion as being in itself an entity distinct from Mass. They hold that Matter is just as much a compound of Mass and Motion as common salt is a compound of sodium and chlorine. They contend further that gravitation is due to the fact that Motion, like heat, may, where human observation is concerned, exist in either a latent or a sensible form; and they assert the practicability of adding to or subtracting from the quantity of Motion in any given bulk of Matter. In proof of the truth of this assertion they point to the phenomena of what is, by psychical enquirers, called “levitation”--phenomena which have been observed and recorded over and over again and may be seen by any person who takes the trouble to attend even an ordinary table-sitting. And they occasionally rally the human personalities with whom they are communicating upon the dullness of apprehension which has hitherto stood in the way of a broad induction from the myriad everyday facts of weight, coiled springs, drawn bows, artificial jumping frogs, jacks-in-boxes, closely touching billiard-balls in a row, projectiles at the moment of terminating their upward flight, cricket-balls at the moment of meeting the stroke of the bat, and all other examples of latent and sensible Motion. These views entertained by spirits who have been spoken to on the subject have of late been borne out very markedly by Dr. Crawford’s experiments, referred to in Chapter I of the present book. Dr. Crawford himself seems to be regarding his tests from the point of view of Mass alone and to be thinking that he is on the track of a new kind of Matter; but his results fit in still better with the long-established facts of levitation and with the new doctrine of Motion that is fast being accepted in Progressive Circles. It is difficult to believe that a living woman can be deprived of a considerable portion of her Mass without sustaining serious physiological injury. It is also difficult to believe that the removed Mass when laid on the floor or on the drawing-board can be invisible. But there is not any difficulty at all in supposing Motion to have been removed from the medium, the chair, the drawing-board and the platform, without any change of either visibility or appearance in any of the entities concerned. When water at 70° Fahr. is cooled down to 50° Fahr. it loses a something we call heat, but the human eye cannot detect any difference in the liquid. When a bowled cricket ball is arrested by the bat it loses a something we call sensible motion, but its outward appearance remains unvaried. We need not therefore expect a human body or a chair to look otherwise than as usual simply because it loses some or all of its latent Motion.