"What was it?" I contrived to articulate at last.
The old man stood erect in the opening, with a hand upon his thoughtful brow. "I don't know," he said. "I didn't think they could come. They must have mastered secrets of time and space that we know nothing of. They have conquered our limitations of distance. They must be ages ahead of us!"
"But the house—it just melted away!"
"As for that, the emanations of the green cloud must have disrupted the atoms, allowing the electrons to fall together to make neutrons (formed of united protons and electrons) so small that they fell through the ground, toward the center of the earth. That is easy enough to understand—in fact, I could probably have developed a similar ray myself, as a result of my work on the hydrodyne. The strange thing is how they got here!"
"The thing just seemed to appear and vanish!"
"Possibly we could see it only when it was lit with the radiation of the green. It may have just slipped up and away in the darkness. But it is more likely—judging from the etheric disturbance it created—that it did not come through our space at all, but moved by the distortion of hyper-space—came through the fourth dimension, in effect!"
"And they seemed to know just where to strike!"
"Yes. They must have found that by triangulation on my interference waves I was doing the same trick for them when the apparatus warned me."
"You were what?"
"I have been working a long time to get the direction of that mysterious force."