These phenomena show that whether the ether exhibits the quality called inertia depends upon the kind of motion it has. 18. MATTER IS MAGNETIC. The ordinary phenomenon of magnetism is shown by bringing a piece of iron into the neighbourhood of a so-called magnet, where it is attracted by the latter, and if free to move will go to and cling to the magnet. A delicately suspended magnetic needle will be affected appreciably by a strong magnet at the distance of several hundred feet. As the strength of such action varies inversely as the square of the distance from the magnet, it is evident there can be no absolute boundary to it. At a distance from an ordinary magnet it becomes too weak to be detected by our methods, not that there is a limit to it. It is customary to think of iron as being peculiarly endowed with magnetic quality, but all kinds of matter possess it in some degree. Wood, stone, paper, oats, sulphur, and all the rest, are attracted by a magnet, and will stick to it if the magnet be a strong one. Whether a piece of iron itself exhibits the property depends upon its temperature, for near 700 degrees it becomes as magnetically indifferent as a piece of copper at ordinary temperature. Oxygen, too, at 200 degrees below the zero of Centigrade adheres to a magnet like iron. In this as in so many other particulars, how a piece of matter behaves depends upon its temperature, not that the essential qualities are modified in any degree, but temperature interferes with atomic arrangement and aggregation, and so disguises their phenomena. As every kind of matter is thus affected by a magnet, the manifestations differing but in degree, it follows that all kinds of atoms--all the elements--are magnetic. An inherent property in them, as much so as gravitation or inertia; apparently a quality depending upon the structure of the atoms themselves, in the same sense as gravitation is thus dependent, as it is not a quality of the ether. An atom must, then, be thought of as having polarity, different qualities on the two sides, and possessing a magnetic field as extensive as space itself. The magnetic field is the stress or pressure in the ether produced by the magnetic body. This ether pressure produced by a magnet may be as great as a ton per square inch. It is this pressure that holds an armature to the magnet. As heat is a molecular condition of vibration, and radiant energy the result of it, so is magnetism a property of molecules, and the magnetic field the temporary condition in the ether, which depends upon the presence of a magnetic body. We no longer speak of the wave-motion in the ether which results from heat, as heat, but call it radiation, or ether waves, and for a like reason the magnetic field ought not to be called magnetism. THE ETHER IS NON-MAGNETIC.