Note 2 — APPENDIX I

One more isomeride, CH2CH(OH), is possible—that is, secondary vinyl alcohol, which is related to ethylene, CH2CH2, but derived by the principle of substitution from CH4. Other isomerides, of the composition C2H4O, such, for example, as CCH3(OH), are impossible, because it would correspond with the hydrocarbon CHCH3 = C2H4, which is isomeric with ethylene, and it cannot be derived from methane. If such an isomeride existed it would be derived from CH2, but such products are, up to the present, unknown. In such cases the insufficiency of the points of departure of the statical structural teaching is shown. It first admits constant atomicity and then rejects it, the facts serving to establish either one or the other view; and therefore it seems to me that we must come to the conclusion that the structural method of reasoning, having done a service to science, has outlived the age, and must be regenerated, as in their time was the teaching of the electro-chemists, the radicalists, and the adherents of the doctrine of types. As we cannot now lean on the views above stated, it is time to abandon the structural theory. They will all be united in chemical mechanics, and the principle of substitution must be looked on only as a preparation for the coming epoch in chemistry, where such cases as the isomerism of fumaric and maleic acids, when explained dynamically, as proposed by Le Bel and Van't Hoff, may yield points of departure.