1. Discontinuous Continuous 2. Limited Unlimited 3. Heterogeneous Homogeneous 4. Atomic Non-atomic 5. Definite structure Structureless 6. Gravitative Gravitationless 7. Frictionable Frictionless 8. Æolotropic Isotropic 9. Chemically selective ---- 10. Harmonically related ---- 11. Energy embodied Energy endowed 12. Energy transformer Non-transformer 13. Elastic Elastic? 14. Density Density? 15. Heatable Unheatable 16. Indestructible? Indestructible 17. Inertiative Inertiative conditionally 18. Magnetic ---- 19. Variable states ---- 20. Subject to shearing stress in solid Shearing stress maintained 21. Has Secondary qualities ---- 22. Sensation depends upon Insensible to nerves CHAPTER III Antecedents of Electricity--Nature of what is transformed--Series of transformations for the production of light--Positive and negative Electricity--Positive and negative twists--Rotations about a wire--Rotation of an arc--Ether a non-conductor--Electro-magnetic waves--Induction and inductive action--Ether stress and atomic position--Nature of an electric current--Electricity a condition, not an entity. So far as we have knowledge to-day, the only factors we have to consider in explaining physical phenomena are: (1) Ordinary matter, such as constitutes the substance of the earth, and the heavenly bodies; (2) the ether, which is omnipresent; and (3) the various forms of motion, which are mutually transformable in matter, and some of which, but not all, are transformable into ether forms. For instance, the translatory motion of a mass of matter can be imparted to another mass by simple impact, but translatory motion cannot be imparted to the ether, and, for that reason, a body moving in it is not subject to friction, and continues to move on with velocity undiminished for an indefinite time; but the vibratory motion which constitutes heat is transformable into wave-motion in the ether, and is transmitted away with the speed of light. The kind of motion which is thus transformed is not even a to-and-fro swing of an atom, or molecule, like the swing of a pendulum bob, but that due to a change of form of the atoms within the molecule, otherwise there could be no such thing as spectrum analysis. Vibratory motion of the matter becomes undulatory motion in the ether. The vibratory motion we call heat; the wave-motion we call sometimes radiant energy, sometimes light. Neither of these terms is a good one, but we now have no others.