A luminous blur became visible in the nearer sky--moving blobs of silver luminosity in the mud-brown light of the Zed-ray. A hundred or more moving silver blobs. They were taking form. The silvery phosphorescent look faded, became grey-white. Took definite shape. Waving arms and legs! Bones bereft of flesh. Human skeletons! Limbs waving rhythmically. Bony arms, with fingers clutching metal weapons. Assailants coming at us through the air, stripped by the Zed-ray of clothing, skin, flesh, organs, to the naked bone. Skeletons with skulls of empty eye-sockets and set jaw-bones to make the travesty of human faces grim with menace! CHAPTER XXXV _Attack on the Power House_ Stricken with surprise and awe, Elza and I sat there motionless. Our encampment was in a turmoil of confusion--chaos, out of which very soon order came. The skeleton figures in the air--I saw now that there were nearer two hundred than one hundred--were perhaps two thousand feet away, and at an altitude of about the cliff-ledge where Elza and I were sitting. They swept forward, bathed in the Zed-ray with all our other search-beams darkened to give it full sway. Momentarily I saw them clearer; metallic cylinders in bony fingers, and a metal mechanism of flight encasing, yet not touching the ribs. "Jac! Why don't our rays--" As though to answer Elza's unfinished question, one of our towers turned a disintegrating ray upon them. A narrow pencil-point of light, barely visible in this flat daylight. It swung up into our Zed-ray, searched and clung to one of the skeleton figures. Had it penetrated, the man would have been dissipated like a puff of vapor. But it did not; and then I knew that for that distance at least, this enemy's isolation power--individual barrage--was too great. Yet the assailed figure wavered! Our amplifier gave out his shout--half fear, half admonition. The line of skeletons swung upward. Came on, but mounted so that I saw that they were making for the summit of the cliff above us--above our power house. Their defense--invisibility, and a mere isolation barrage so that we could not harm them with our tower rays while they kept beyond range. But what was their means of attack? Why would Tarrano.... "The power house," Elza answered; and I realized then that she had read my thoughts. The power house, if they could demolish it.... Our thoughts, questions and answers unspoken, flew fast; but the drama before us unfolded faster. With the knowledge that we could see them, these invaders cast aside a portion of their equipment to give them greater freedom. We could see the metal portions of the trappings falling like plummets. The skeleton images faded; and then as our tower withdrew the Zed-ray and our search-beams picked them up, we saw our enemies as they really were. Men clothed in a casing of cylindrical garments with the flying mechanisms strapped to their chests; some with visors and headpieces, nearly all with small weapons in their hands.