The reaction was practically instantaneous; so rapid that any ordinary mind could have perceived nothing at all; so rapid that even Kinnison's consciousness recorded only a confusedly blurred impression. But he did see something: in that fleeting millionth of a second he sensed a powerful, malignant mental force; a force backing multiplex scanners and subethereal stress-fields interlocked in peculiarly unidentifiable patterns. For that ball was, as Kinnison had more than suspected, a potent agency indeed. It was, as he had thought that it must be, a communicator; but it was far more than that. Ordinarily harmless enough, it could be so set as to become an infernal machine at the vibrations of any thought not in a certain coded sequence; and Helmuth had so set it. Therefore at the touch of the Patrolman's thought it exploded: liberating instantaneously the unimaginable forces with which it was charged. More, it sent out waves which, attuned to detonating receivers, touched off strategically placed stores of duodecaplylatomate. "Duodec," that concentrated essence of atomic violence than which science has even yet failed to develop a more devastating! "Hell's--jingling--bells!" Port Admiral Haynes grunted in stunned amazement, then subsided into silence, eyes riveted upon his plate; for to the human eye dome, fortress, and planet had disappeared in one cataclysmically incandescent sphere of flame. But the observers of the Galactic Patrol did not depend upon eyesight alone. Their scanners had been working at ultrafast speed; and, as soon as it became clear that none of the ships of the Fleet had been endangered, Kinnison asked that certain of the spools be run into a visitank at normal tempo. There, slowed to a speed at which the eye could clearly discern sequences of events, the two old Lensmen and the young one studied with care the three-dimensional pictures of what had happened; pictures taken from points of projection close to and even within the doomed structure itself. Deliberately, the ball of force opened up, followed an inappreciable instant later by the secondary centers of detonation; all expanding magically into spherical volumes of blindingly brilliant annihilation. There were as yet no flying fragments: no inert fragment _can_ fly from duodec in the first few instants of its detonation. For the detonation of duodec is propagated at the velocity of light, so that the entire mass disintegrates in a period of time to be measured only in fractional trillionths of a second. Its detonation pressure and temperature have never been measured save indirectly, since nothing will hold it except a Q-type helix of pure force. And even those helices, which perforce must be practically open at both ends, have to be designed and powered to withstand pressures and temperatures obtaining only in the cores of suns.