Let us consider the report of the Spectrum. Beginning with waves or vibrations far below the sensibility of Man, the scale shows an advance until the first "warm" vibration of iron was reached. This first indication of warmth comes when the vibrations reach the rate of 35,000,000,000,000 per second. Then gradually they increase until a dull red glow is noticed—the lowest visible light ray—when the vibrations are 450,000,000,000,000 per second. Then come the orange rays, then the golden yellow, then the pure yellow, then the greenish yellow, then the pure green, then the greenish blue, then the ocean blue, then the cyanic blue, then the indigo, then the violet—the latter evidencing when the vibrations reach the rate of 750,000,000,000,000 per second. Then come the Ultra-violet rays—invisible to human sight—but evidenced by chemical media. In this Ultra-violet region lies the X-Rays, etc., and also the "Actinic Rays," that produce photographs, sunburn one's face and blister the nose—that cause violent explosions in chemicals—that transform forms of Substance—that are employed to cure skin diseases, etc. These Actinic or Chemical Rays have an important role to play in plant-life, for they act upon the green leaves of the plant, causing a chemical change by which carbonic acid and water are transformed into sugar and starches.
Some of the rays of the Ultra-violet region of Light penetrate substances formerly considered solid and impenetrable. And some of them emitted from Radium, etc., would destroy organic life if applied in sufficient quantities. Some of them are practically waves of Electricity so that Light and Electricity are seen to be closely related.
To give one an idea of the differences produced by different rates of vibration, let us imagine a Mass of Iron, shaped like a great "Top," capable of being impelled to "spin" at a constantly increasing rate of speed, by some Mighty Will. At first it is seen as a slowly spinning Top, manifesting nothing but slow motion, to our senses.
Now, imagine our Top spinning at a rate doubling each second. The first second the Top spins at the rate of two revolutions per second. We notice no change, except that we can see the movement. The next second the revolutions are doubled to four per second. Then, doubling each second, we have, respectively, revolutions of eight per second, then sixteen, and then in the fifth second thirty-two per second. Then we begin to notice a change.
When the revolutions reach thirty-two per second the friction of the moving Top on the air causes it to give forth a very low, deep, bass note of sound. This note is like a low, deep "hum," and is the lowest possible of perception by the human hearing, although it is possible that some of the lower forms of life may be conscious of still lower vibrations.
The sixth second the revolutions reach sixty-four, and the low note has grown much higher in the scale. The seventh second records a rate of 128, and the note has correspondingly increased. Then, as the seconds pass, we have, successively, 256, 512, 1,024, 2,048, 4,096, 8,192, 16,384, 32,768, the latter in the fifteenth second, and representing the highest note recognizable by the human ear, although it is believed that some of the lower animals may recognize sounds too acute for our sense of hearing. During this increase in revolutions from the fifth second to the fifteenth, the sound-note has risen rapidly in the scale from the low sullen "hum," on through the notes of the musical scale, and beyond the range of instruments, until the shrillness becomes so intense as to be almost unbearable, and finally terminating in a shrill, piercing shriek like the "squeak" of the bat, only long-drawn out.
Then from the termination of the sound (by reason of the rate of vibration having become too high) silence reigns for thirty seconds—absolute silence, in spite of the rapidly increasing rate of vibrations, in fact, because of it.
When the forty-fifth second is reached, and the revolutions have reached the rate of 35,184,372,088,832 per second, our Top begins to emit heat-rays, increasing each second. Then a little later a dull, dim glow may be noticed. Then, as the seconds fly, the dull glow manifests a deep dark red color, such as one notices in the iron of the blacksmith's shop, soon after it begins to "glow." Then, on and on, as the seconds fly, the deep red grows lighter and brighter, gradually changing into orange, then into yellow, then into green, then into blue, then into indigo, then into violet, and then into the color of "white-heat." Then this "white-heat" changes into a still more dazzling white, and then a white impossible to describe appears, so bright, clear and brilliant that the eye cannot bear the sight. Then, suddenly, the intense brightness is succeeded by absolute darkness, and the moving Top cannot be seen by the eye—and yet it moves on. The highest recorded chemical rays of light are estimated to equal a rate of vibration of 1,875,000,000,000,000 per second. The vibration of the lowest shade of red light is estimated at 450,000,000,000,000, and the highest of violet at 750,000,000,000,000 per second, so we may imagine what the highest line on the spectrum is like.
Still vibrating, our Top, which has become now a Mass of Vaporized Iron, rapidly tending toward still more ethereal forms. It has passed out from the region of light-waves, into another "Unknown Region" of Vibrations, in which region, however, exist the vibrations known to us as the "X-Rays," etc. It is throwing off great quantities of Electrons. If we were to use a fluorescent screen we would be able to observe the phenomena of the Roentgen Rays, and similar manifestations of Radiant Energy.
On and on vibrates the Top of what we once called Iron—cold iron, warm iron, hot iron, melted iron, gaseous iron, etherealized iron, if you like. What it is like now, the imagination of Man cannot conceive. Still the revolutions continue, doubling each second. What is being produced? The imagination cannot conceive of what this state of Substance, now being reached, is like. By a scientific form of poetry we might think of it as melting into Energy—pure Energy, if there were such a thing. Long since it has been resolved into its original Particles—its Corpuscles, and perhaps into the "stuff" from which particles are made. But we must let the curtain drop—the wildest fancy cannot follow the Dance of Substance any further.