continue it. I have deposited copper in the magnetic field and outside the magnetic field, and have endeavored to ascertain the thermo-electric relations of these layers of copper, and have apparently discovered—I say apparently, for such experiments require a large number of trials, and I have made thus far only a limited number—that there is a difference of superficial energy between the surface in which the molecules of copper have been subjected to a strong attractive force while they were being deposited, and those molecules which have been only under the influence of ordinary gravitation force.
The experiments which I have tried have continually deepened in me the belief that any change in the state of aggregation of particles—in other words, any change which results in a modification of attracting force—whether gravitative or the commonly called chemical attracting forces, results in an electrical potential; and, conversely, that the passage of electricity through any medium produces a change of aggregation of the molecules and atoms. Professor Schuster, in a late number of "Nature" (July 3, 1884, page 230), gives some of the results of his recent investigation of gases subjected to electrical discharges, and believes himself justified in making the following hypothesis: "In a gas the passage of electricity from one molecule to another is always accompanied by an interchange of the atoms composing the molecule; the molecules are always broken up at the negative pole," and in his comments upon this law he remarks that a molecule of mercury consists of a single atom; but mercury has a very brilliant spectrum: this would seem to militate against the hypothesis. On the other hand, if an essential part of the glow discharge is due to the breaking up of the molecules, we might expect mercury-vapor to present other and much simpler phenomena than other vapors. This is the case, for if mercury-vapor is sufficiently free from air, the electrical discharge through it shows no negative glow, no dark spaces, and no stratifications. In reflecting upon experiments of this nature, can not we believe that, if we could systematically break up the arrangement of the atoms in the molecules of any substance, we could produce a difference of electrical potential? Our instrumental means are probably too coarse to enable us to follow the track of such splitting of the molecules. We are like blind men in a great field of energy striving to ascertain the configuration about us with only three senses—the galvanometer sense, the electrometer sense, and the voltameter sense. Suppose you add to the equipment of such blind men a magnetic sense, or an attractive-force sense. Suppose such a blind man could perceive the equivalence of our thoughts in electrical and magnetic relations, as we now see a manifestation of equivalence of mechanical work when a lighthouse lamp bursts upon our sight. Suppose such a person could become sensible of every change among atoms and molecules. Suppose that the quick passing of what we call life from the body into another shape or state of existence should be sensible as a reaction in
