Now, as respects the interposed minus-pressure means or matter, which, by destroying the equilibrium, promote the approaching motion of two suspended magnets; there is nothing whatever to refer to, but the magnets themselves, that is, their polar atmospheres, which, together or facing one another, make a rare or minus-pressure medium between the proximate ends, into which both magnets are moved by the greater pressure on their remotest ends. It lies with the previously-instructed patient, while clairvoyant, through questioning by the mesmeriser, to make close observation, and report all circumstances respecting the magnetic lights; also, those attached to and proceeding from the mesmeriser, towards elucidating this most of all recondite subjects--magnetism, in the philosophy of physics. The mesmeriser should hold in mind, that, probably the air between the facing ends of two magnets is magnetically affected, that is, made a magnet in the series by the other two; which seems to be the case when the patient is magnetised at a distance from the mesmeriser by means of the pointed finger, and by the _effect_ of will at a much greater distance. NATURAL SLEEP. That sleep is not at the command of will is certain, or why undergo the tedium of a restless night? Before the state of sleep can obtain, the body has to experience an _electro-physico_ change, by which the extremities are left polarised and the body an animal or living magnet. That the extremities are polarised during sleep, is admitted by all physiologists; for the effecting of which there must be a pair of correlative elements concerned. While the elementary transfer, productive of the polarities, is taking place, so is drowsiness; when sleep has obtained, the natural magnetising procedure has terminated; hence from the degree of polarity, the mesmeriser can determine the stage to which the patient has been brought between the comatose and clairvoyant states, and know the capability of his patient for being made clairvoyant or not; this polar index should be well noticed.