Thus, a de-electronired metal was found to produce black. Not black as habitually we meet it—a "shiny" black, a "dull" black; but a true black—a real absence of light-ray reflection—a "nothingness to see"; in effect, an invisibility.
A word of explanation is necessary regarding the other property of the de-electronired field—the bending of distant light rays into a curve, yet leaving their spectrum unchanged. It was Albert Einstein who first made the statement—in the years following the turn of the century at 1900—that it was a normal, natural thing for a ray of light to be slightly deflected from its straight path when passing through a magnetic field. The claim caused world-wide interest, for upon its truth or falsity the whole fabric of the Einstein Theory of Relativity was woven.
An eclipse of the sun in the 1920's established that light is actually bent in the manner Einstein had calculated. A magnetic field surrounds the sun. In those days they did not know that it is a field of subnormal electronic balance—in effect, the result of de-electroniration. It was found, nevertheless, that stars close to the limb of the sun appeared, not in their true positions, but shifted in just the directions and with the amount of shift Einstein predicted. The light rays coming from them to the eye of the observer on Earth were curved in passing so close to the sun. But the color-bands of their spectrums were unaltered.
And some of the stars actually were behind the sun, yet because of the curved path of the light, were visible. I mention this because it is an important aspect of the subject of mechanical invisibility.
With the foregoing factors, the secret of mechanical invisibility is constructed. Gracely, an American—following a long series of world-wide experiments, tests of current strength, frequencies of oscillation, suitable metals, etc., which I cannot detail here—in 1955 was the final developer of the mechanisms subsequently used in the X-flyers.
Gracely produced what he christened "aluminoid-spectrite"—a light-weight alloy which, when carrying an oscillating electronic current of the proper frequency, produced the effects I have described. It absorbed from the light rays coming from the metal, all the colors of the solar spectrum, well beyond the range of the human eye at both ends of the scale. The result was a "visible nothingness."
A moment's thought will make clear that term. A visible nothingness is not invisibility. The fact that something was there but could not be seen was obvious. A black hat with a light on it and placed against an average background is almost as easy to see as a white hat. Gracely's first crude experiments were made with an aluminoid-spectrite cube—a small brick a foot in each dimension. The cube glowed, turned, dark, then black, then was gone. He had it resting on a white table, with a white background. And the fact that the cube was still there, was perfectly obvious. It was as though a hole of nothingness were set against the white table. It outlined the cube; reconstructed it so that for practical purposes the eye saw not a white, aluminoid brick, but a dead black one.
And this is very much what a man sees when he stares at his black hat on a table. The hat occults its background, and thus reconstructs itself.
But when Gracely determined the proper vibrations of his oscillating current to coincide with all the other material factors he was using, the final result was before him-real invisibility. He used a patterned background—a symmetrically checkered surface, most difficult of all. The light rays coming from this background passed through the magnetic field surrounding the invisible colorless cube, and were bent into a curved path. But their own color-spectrum—in actuality the color, shape, all the visible characteristics of the background—was not greatly altered. The observer saw what actually was behind the invisible cube: the checkered background, sometimes slightly distorted, but nevertheless sufficiently clear for its abnormality to escape notice. Thus the cube's outlines were not reconstructed; and, in effect, it had vanished.
In practical workings with the X-flyers, no such difficult test as Gracely's cube and rectangular, symmetrically patterned background is ever met. The varying background behind a plane—at rest or flying, and particularly at night—demands less perfection of background than Gracely's laboratory conditions. I am informed that an X-flyer can vaguely be seen—or sensed, rather—from some angles and under certain and unfavorable conditions of light, and depending on its line of movement relative to the angle of observation, and the type and color-lighting of its background. But under most conditions it represents a very nearly perfect mechanical invisibility.