It is simple, because it puts in the place of unknown chemical waves, a certain kind of aetherial waves with whose action we are definitely familiar, and whose origin and effect can be satisfactorily accounted for, as proved by Hertz. Chemical waves are not simple in conception, because we do not know exactly what they are, or how they are originated. Besides, as Newton points out, there is nothing superfluous in Nature. If one cause can effect the desired end, as electric waves, then another cause as chemical waves is superfluous and unnecessary. Further, in our hypothesis of the electric character of these chemical waves, we have a solution which satisfactorily fulfils the second Rule of our Philosophy. Experience and experiment teach us, that there are electric waves constantly being generated in a thousand ways. Indeed, it is an absolute impossibility to perform the simplest act of ordinary life, as brushing a hat, or wiping the boots on a mat, cutting an orange, or any other act of simple everyday life, but that these aetherial electric waves are generated. But as for these so-called chemical waves, experience has little to say about them, and experiment still less. If we decompose water, dividing it up into two gases, Oxygen and Hydrogen, we do it by passing a current of electricity through the water. If we want to decompose or split up a binary compound, as HCl, into its two elements, Hydrogen and Chlorine, then we can do it by electricity--that is, by the decomposing action of these electric waves. In all these experiments and results we know definitely what we are doing, and what the effect will be. There is no vagueness about the terms used. When we speak of chemical action we look to a definite source for that action, and we do not say that such action is produced by chemical waves, but rather by electricity. So that all experience teaches us, and all experiments made by such men as Faraday, Davy, Maxwell, and Hertz confirm the statement, that these aetherial electric currents can accomplish all that the so-called chemical waves accomplish, and that being so, the third Rule of our Philosophy is also fulfilled, as we have in the aetherial electric waves a satisfactory explanation for the fact which we seek to explain, viz. the character and origin of the chemical waves that exist in the violet end of the spectrum. Thus, we learn, that not only is the sun the source of all heat and light, in that it gives rise to the vibrations of the Aether which are propagated through it in waves, but that it is also the source of all electric waves in the solar system, in that electric currents are primarily due to the wave motion set up in the Aether, those electric waves also traversing space with the velocity of light. [Footnote 14: _Phil. Mag._, 1867.]