And what are we to say of the supposed material emanation of radioactive 'elements' of their instability, of their decomposition by splitting off of helium and of the decomposition of the elements themselves? Until now there has not been furnished any demonstration whatever that elements of high atomic weight, to which gold and platinum certainly must be counted, are polymers of elements of lower atomic weights, and that they decompose into such. The idea of a chemical element in the old sense remains still unshaken, and it will require much more thorough chemical experimental research than those produced thus far, to disturb it. On the contrary, it appears from day to day more plainly, that radioactivity seems to be extremely widely distributed, and this observation leads us to the question whether radioactivity may not be simply a purely physical phenomenon, which may be exhibited by matter without in any way modifying its chemical nature, comparable to the magnetism of magnetic iron ore, which, like radioactivity, may be intensified, transferred, apparently destroyed and again called forth, and which, at the same time, also represents a mysterious manifestation of energy, without leading any one for a moment to imagine the existence of another element in magnetic ferro-ferric oxide not existing in the non-magnetic iron oxide. The idea of an elemental material difference was not thought of by any one, when Fr. Heusler succeeded in making magnetic alloys from unmagnetic metals such as manganese, tin, antimony and aluminum. Also in the case of radioactivity we should be free of material differences if the statement of F. Richarz and Rudolf Schenck should remain without valid objection, namely, that oxygen when ozonized becomes radioactive, so as to act upon the photographic plate, to make Sidot's blende (though only this kind of sphalerite) glow intensely and, like radium, to develop heat.
Considering the radium-craze now afflicting the world and affecting non-scientific circles especially, there is something humiliating to the chemist, after six years have elapsed since the discovery of radium, to say no more than that it resembles barium so closely that it can not be distinguished except by its higher atomic weight and its remarkable independent radiation. The chemical individuality of radium remains almost entirely unknown; nevertheless it is constantly sought, especially in those regions where pitchblende deposits occur, and where they already dream of developing radium ores and a future radium industry. So far as known, the occurrence of radioactive substances is tied to that of uranium. This is in the highest degree surprising and can not be understood if we are to assume the presence of special elements. Though the co-occurrence of certain elements is not uncommon and may be explained by their position in the system, their valence, the isomorphism of their compounds and other resemblances,
