"Because the rate of vibration of the etheric atoms in the bar is now about 412 trillions per second, and this rate of vibration having been imparted to the ether of the air, has in turn been imparted to the ether of your eye, and this rate of vibration in the ether of the nerves of your eye your brain recognizes and calls 'red.' "The heat still continues and increases. You now have both heat and light. So you see that the ether is not vibrating in a single note, but in two chording notes, producing light and heat. There are two kinds of ether around the iron atom. There is sound also, but the note is too high for one's ears. It is a chord of three notes. "Professor Silliman, of Yale, discovered over twenty years ago, that the ether could be differentiated into the luminiferous, or light ether, and the sonoriferous, or sound ether. "Other great scientists since then have found a third ether--the heat ether. "Their discoveries show that the atmospheric etheric envelope of each etheric atom is made up of etheric atoms of different vibratory powers. As the atmosphere of the earth is made up of atoms of oxygen and nitrogen and argon, so that of an atom is made up of three kinds of ethers, corresponding to three of our senses. That it consists of five ethers, corresponding to our five senses, as the ancient Hindus assert--who can say? "I mention this subject of the differentiation of the ether merely that you may not suppose that the ether is a simple substance. For the present we will treat it as a simple substance, but next year we will take it up as a compound one. "This steel bar before you is not one bar, but two bars. There is a visible bar and an invisible bar, the visible bar being made of physical atoms, and the invisible bar of etheric atoms. The etheric bar is invisible, but it is made of matter, the same as the visible bar, and it is just as real, just as truly a bar as the one we see. "More than this. The etheric, invisible bar is the source and cause of all phenomena connected with the bar. It is the real bar, and the one we see is merely the shadow in physical matter of a real bar. In shape, strength, color, in short, in everything, it depends on the invisible one. The invisible dominates, governs, disposes. The visible is merely its attendant shadow, changing as the invisible, etheric bar changes, and recording for our senses these invisible changes. "The invisible change always comes first; the invisible phenomena invariably precede the visible. "In all this physical world--in all this universe--there is nothing, not even a grain of sand or an atom of hydrogen, that is not as this bar of iron is--the shadow cast on a visible world by the unknown and mysterious work of an invisible world.