Experimental investigation of the spirit manifestations, [electronic ...

OF MATTER, MIND, AND SPllllT. 3831871. In the next place, if wc procure a horsc-shoc magnet, lay it on atable, cover it with a sheet of paper, and then sift over it iron filings, weshall sec the shape of the magnet delineated upon the paper, by the filingsarranginii; themselves above its corners in preference. JJut as the siftingproceeds, the filings will be seen to extend themselves in filaments, so asvery much to resemble the electrified hair above described. A tuft of theferruginous filaments will be formed upon each pole of the magnet, eachfilament avoiding its neighbours, as far as possible. Eut while each filament,in cither tuft, avoids every other in its appropriate tuft, the wholeof the filaments in one, are attracted by those in the other. Thus, thecharges of polarity which cause each similarly polarized filament to avoidthose in the same state, induce those polarized by one of the poles ofthe magnet, to attract such as arc polarized by the other pole of themagnet.1872. Here is, so far, a great analogy between the phenomena of thepolarization of filings and the polarization of the hair, above described.But then there is this difference : excepting iron, cobalt, and nickel, thereis no metal which can, by contact with the poles of a magnet, neutralizethe polarity by which the iron filings are affected; and even these metalsproduce this result by a process, the inverse of that by which charges ofstatical electricity are neutralized. In fact, the magnetic metal, far fromacting as a discharger, acts as a keeper ; and a piece of iron, of a suitableshape, applied to the terminations of a horse-shoe magnet, prevents thegradual diminution of the magnetism, which otherwise ensues. Hencethe name keeper is applied to it, as well as armature, derived from theFrench.1873. It will be perceived that, in a steel magnet, the charges are sustainedat the terminations of a conductor, which, as estimated by Cavendish,conducts electricity with a velocity two hundred thousand times asgreat as water.1874. The charge of the conductor of the machine is superficial, a giltglobe of glass holding as good a charge as a solid globe of metal ; and,moreover, in this superficial charge, the ether and the air participate, undergoinga polar affection, analogous to that of the filings exposed to theinfluence of the magnet.1875. On the other hand, in the use of the steel magnet, the chargeis internal, and, other things being equal, increases with the quantity ofiron charged ; neither the air nor the ether participate in this magneticcharge. There is no mode in which the charges of the poles of a magnetcan be made to pass from one to the other, through any interposed conductingmass.1876. The retention of the charge seems to be dependent upon a stateof the particles in which they are capable of being deranged from theirnormal position with a certain degree of extraneous influence, and can only