Note 1 — APPENDIX I

Because more than four atoms of hydrogen never unite with one atom of the elements, and because the hydrogen compounds (e.g. HCl, H2S, H3P, H4Si) always form their highest oxides with four atoms of oxygen, and as the highest forms of oxides (OsO4, RuO4) also contain four of oxygen, and eight groups of the periodic system, corresponding to the highest basic oxides R2O, RO, R2O3, RO2, R2O5, RO3, R2O7, and RO4, imply the above relationship, and because of the nearest analogues among the elements—such as Mg, Zn, Cd, and Hg; or Cr, Mo, W, and U; or Si, Ge, Sn, and Pt; or F, Cl, Br, and I, and so forth—not more than four are known, it seems to me that in these relationships there lies a deep interest and meaning with regard to chemical mechanics. But because, to my imagination, the idea of unity of design in Nature, either acting in complex celestial systems or among chemical molecules, is very attractive, especially because the atomic teaching at once acquires its true meaning, I will recall the following facts relating to the solar system. There are eight major planets, of which the four inner ones are not only separated from the four outer by asteroids, but differ from them in many respects, as, for example, in the smallness of their diameters and their greater density. Saturn with his ring has eight satellites, Jupiter and Uranus have each four. It is evident that in the solar systems also we meet with these higher numbers four and eight which appear in the combination of chemical molecules.