And now, mental waves failing, they resorted to the purely physical. Hand rays of highest power blasted at that figure uselessly; fiercely driven bars, spears, axes, and all other weapons rebounded from it without leaving a mark upon it, rebounded bent, broken, and twisted. For that figure was in no sense matter as we understand the term. It was pure force--force made palpable and coherent by the incomprehensible power of disintegrating matter; force against which any possible application of mechanical power would be precisely as effective as would wafted thistledown against Gibraltar. Thus the struggle was brief. Paying no attention to anything, mental or physical, that the other monstrosities could bring to bear, Seaton compelled his victim to assume the shape of the heretofore-despised human being. Then, staring straight into that quivering brain through those hate-filled, flaming eyes, he spoke aloud, the better to drive home his thought: "Learn, so-called Great One, once and for all, that when you attack any race of humanity anywhere, you attack not only that one race, but all the massed humanity of all the planets of all the Galaxies! As you have already observed, I am not of the planet Valeron, nor of this Solar System, nor even of this Galaxy; but I and my fellows have come to the aid of this race of humanity whom you were bold enough to attack. "I have proved that we are your masters, mentally as well as scientifically and mechanically. Those of you who have been attacking Valeron have been destroyed, ships and crews alike. Those en route there have been destroyed in space. So also shall be destroyed any and all expeditions you may launch beyond the limits of your own foul atmosphere. "Since even such a repellent civilization as yours must have its place in the great scheme of things, we do not intend to destroy your planet nor such of your people as remain upon it or near it, unless such destruction shall become necessary for the welfare of the human race. While we are considering what we shall do about you, I advise you to heed well this warning!" XXI. The four Terrestrials had discussed at some length the subject of Chlora and her outlandish population. "It looks as though you were perched upon the horns of a first-class dilemma," Dorothy remarked at last. "If you let them alone there is no telling what harm they will do to these people here, and yet it would be a perfect shame to kill them all--they can't help being what they are. Do you suppose you can figure a way out of it, Dick?" "Maybe--I've got a kind of a hunch, but it hasn't jelled into a workable idea yet. It's tied in with the sixth-order projection that we'll have to have, anyway, to find our way back home with. Until we get that working I guess we'll just let the amœbuses stew in their own juice." "Well, and then what?" Dorothy prompted.