ADDEESS. 9 



perties which he accurately specified. Since that time these gaps have 

 actually been stopped by the discovery of Gallium by Lecoq de Boisbau- 

 dron, of Scandium by Nilson, and of Germanium by Winkler, and their 

 properties, both physical and chemical, as determined by their discoverers, 

 agree absolutely with those predicted by the Russian chemist. Nay, 

 more than this, we not unfrequently have had to deal with chemical 

 foundlings, elements whose parentage is quite unknown to us. A careful 

 examination of the personality of such waifs has enabled us to restore them 

 to the family from which they have been separated by an unkind fate, and 

 to give them that position in chemical society to which they are entitled. 



These remarkable results, though they by no means furnish a proof of 

 the supposition already referred to, viz., that the elements are derived 

 from a common source, clearly point in this direction, and lend some 

 degree of colour to the speculations of those whose scientific imagination, 

 wearying of dry facts, revels in picturing to itself an elemental Bathybius, 

 and in applying to the inanimate, laws of evolution similar to those which 

 rule the animate world. Nor is there wanting other evidence regarding 

 this inquiry, for here heat, the great analyser, is brought into court. The 

 main portion of the evidence consists in the fact that distinct chemical in- 

 dividuals capable of existence at low temperatures are incapable of exist- 

 ence at high ones, but split up into new materials possessing a less com- 

 plicated structure than the original. And here it may be well to empha- 

 sise the distinction which tlie chemist draws between the atom and the 

 molecule, the latter being a more or less complicated aggregation of 

 atoms, and especially to point out the fundamental difference between the 

 question of separating^ the atoms in the molecule and that of splitting 

 up the atom itself. The decompositions above referred to are, in fact, not 

 confined to compound bodies, for Victor Meyer has proved in the case of 

 iodine that the molecule at high temperatures is broken to atoms, and 

 J. J. Thomson has added to our knowledge by showing that this breaking 

 up of the molecule may be effected not only by heat vibrations, but 

 likewise by the electrical discharge at a comparatively low temperature. 



How far, now, has this process of simplification been carried ? Have 

 the atoms of our present elements been made to yield ? To this a negative 

 answer must undoubtedly be given, for even the highest of terrestrial 

 temperatures, that of the electric spark, has failed to shake any one of these 

 atoms in two. That this is the case has been shown by the results 

 with which spectrum analysis, that new and fascinating branch of science, 

 has enriched our knowledge, for that spectrum analysis does give 

 us most valuable aid in determining the varying molecular conditions of 

 matter is admitted by all. Let us see how this bears on the question of 

 the decomposition of the elements, and let us suppose for a moment that 

 certain of our present elements, instead of being distinct substances, were 

 made up of common ingredients, and that these compound elements, if 

 I may be allowed to use so incongruous a term, are split up at the 

 temperature of the electric spark into less complicated molecules. Then 



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