Around her waist Tad adjusted a narrow black belt. It was a rope of interlaced, tiny black wires. A black curved box like a battery was fastened to the belt. Light in weight--all dead black. There were a dozen dangling black wires. Tad connected them at her shoulders, along her arms to the waist, down to the hem of the robe, and up to the crest of the hood. She stood, in the dim light of Tad’s room, a black grotesque blob of shape against the wall. Fantastic, hooded little figure merging with the shadows. But she was plainly to be seen--the outlines of her, blotting out the table and the wall behind her. An inky silhouette. [Illustration: _The fantastic hooded figure began merging with the shadows._] She said: “I’ll turn it on.” Her gloved hand fumbled with the battery. The current went into the robe. It glowed luminous for a moment. The shape of her was there, shimmering like a silver ghost. Misty--a fog dissolving--gone! The table and the wall behind her showed clearly; there was nothing to be seen in front of them. It was uncanny. Tad said sharply: “Nereid, you all right?” “Yes, Tad.” Her voice, calm, from the empty air. Tad reached out his hand and, fumbling, came upon her. The robe was vaguely vibrating. “It works, Nereid! I can’t see you! Stand back, close against the wall.” He could faintly make out the distorted blur of her shape as she backed nearer the table and wall; the table outlines were distorted; the wall seemed to have a shadow on it. “That’s too close, Nereid. We must remember that--keep away from things.” There is one of these robes now in the Anglo-American Museum of Science, in London. Apparently it cannot be duplicated. But the fundamental principle of its operation is simple. The electrification of the fabric--vibrations of an unknown current akin to what we call electricity--set up in the air surrounding the robe, a magnetic field. As Nereid stood in the center of Tad’s room, the light rays from the table and wall behind her were bent around this magnetic field so that their image was carried unbroken to Tad’s sight. It was only when she stood too close to the wall that its light rays were blocked by the solidity of her. The robe itself reflected no light rays. The color we call black is no color at all, but merely the absence of all colors--black, because it absorbs almost all the color-bearing light rays which strike it. There is, however, generally a glint, high lights and shadows. But this robe, with the current into it, reflected no light rays, no tiny glint from its folds. And with these two principles, for practical purposes it was invisible. Nothing really eerie or uncanny. Solid science, strange but rational. The bending of light rays for a century has been observed and understood by our astronomers. Our sun itself has a similar magnetic field about it, bending the light rays from the distant stars which in reality are behind the sun, but seem to be off to one side.