Once more, suppose that to one end of our iron bar we apply the negative “pole” of an electric battery, and to the other end the positive pole. We see that a current passes through the bar, whether hot or cold, which implies that it jumps across all the ether gaps, or rather is conveyed by them from one atom to another. The conclusion then is that ether is not merely omnipresent, penetrating all things, but the medium whereby heat, light, electricity, perhaps even thought itself, are transmitted from one point to another. In what manner is the transmission effected? We cannot imagine the ether behaving in a way void of all system. The answer is, by a wave motion. The ether must be regarded as a very elastic solid. The agitation of a portion of it by what we call heat, light, or electricity, sets in motion adjoining particles, until they are moving from side to side, but not forwards; the resultant movement resembling that of a snake tethered by the tail. These ether waves vary immensely in length. Their qualities and effects upon our bodies or sensitive instruments depend upon their length. By means of ingenious apparatus the lengths of various waves have been measured. When the waves number 500 billion per second, and are but the 40,000th of an inch long they affect our eyes and are named light--red light. At double the number and half the length, they give us the sensation of violet light. When the number increases and the waves shorten further, our bodies are “blind” to them; we have no sense to detect their presence. Similarly, a slower vibration than that of red light is imperceptible until we reach the comparatively slow pace of 100 vibrations per second, when we become aware of heat. Ether waves may be compared to the notes on a piano, of which we are acquainted with some octaves only. The gaps, the unknown octaves, are being discovered slowly but surely. Thus, for example, the famous X-rays have been assigned to the topmost octave; electric waves to the notes between light and heat. Forty years ago Professor Clerk Maxwell suggested that light and electricity were very closely connected, probably differing only in their wave-length. His theory has been justified by subsequent research. The velocity of light (185,000 miles per second) and that of electric currents have been proved identical. Hertz, a professor in the university of Bonn, also showed (1887-1889) that the phenomena of light--reflection, refraction, and concentration of rays--can be repeated with electric currents. We therefore take the word of scientists that the origin of the phenomena called light and electricity is the same--vibration of ether. It at once occurs to the reader that their behaviour is so different that they might as well be considered of altogether different natures.