The man held the glowing, oblong brick within the shadowy steel. He released it, and it floated gently downward--wafted down like a feather very slowly. But it kept within the outlines of the girder. "You'd better follow it," said Brutar. "It will stop presently--and perhaps where you want it." Inside the building the Earth-people had seen us--we three hovering there. Men and soldiers were running from room to room, and up and down the staircases trying to get near us. There was a room and a portion of a hallway close to where we now hovered. They were soon thronged with men, crowding against the walls, within which our white shapes were visible. But the walls, solid to them, stopped their advance. They stood regarding us; and now I could see fear upon their faces as their glances followed the downward floating brick. And as it descended a story, many of them rushed down, scrambling against the walls, striving to reach into the place where they saw it. Did they divine its purpose? I thought so; for as presently it came to rest, lodged in the upright steel where cross girders were riveted, I saw men come rushing with crowbars and axes. Frantically they were tearing at the walls, ripping out the wood and plaster, striving to reach and perhaps to dislodge that shimmering thing lying there in the vitals of the building. Brutar laughed. "You see, Rob? They're beginning to understand now--and they're frightened. _It is materializing_--that brick, as you call it, is materializing!" Growing solid! In a surging torrent of horror complete realization rushed over me. I scarce heard Brutar's gloating words: "That inert matter, freed of physical contact with our Borderland bodies, tends slowly to change to the state of the thing nearest to it. As heat by contact communicates, so does the vibratory rate of all substances. That brick, lodged there, is materializing. Slowly now--but soon very fast. Presently it will be as solid as the steel girder itself--a brick resting there complete in your Earth-state--demanding space of its own, for its own existence!" * * * * * Space of its own! What diabolical force of Nature would this unleash! These molecules, atoms, electrons of the steel and brick thus intermingled! In a Space but half sufficient! A force created of unknown, unthinkable power--immeasurable as that proverbial irresistible force meeting an immovable body. Two solid bodies here, intermingled to their very essence, striving to occupy the same space at the same time! Brutar was drawing at me. "Look at them, Rob! Trying to get at it! And up there--and down below--see them?" The glowing bricks were lodged up and down the building--all seemingly on the one side. Down underground, lodged in the very foundations of the structure I could see three of them piled together. And frantic shapes of men digging for them through the walls of the cellars.