Thus the one device is simply an extension of the principle of the other. A matter-transmitter is merely an enormously developed overdrive-field generator with a tuning device attached. But until this moment, apparently it had not happened that a matter-transmitter technician was in a predicament where the only way out was to put those facts together. Kim was such a technician, and on the _Starshine_ he had probably the only overdrive field generator of space-ship pattern still in working order in the Universe. "All I've got to do is to add two stages of coupling and rewind the exciter-secondary," he told her zestfully. "Doing it by hand may take a week. Then the _Starshine_ will be a matter-transmitter which will transmit itself! The toughest part of the whole job will be the distance-gauge. And I've got that." Worshipfully, Dona looked up at him. She probably hoped that he would kiss her again, but he mistook it for interest. He explained at length. There could be, of course, no measure of distance traveled in emptiness. Astrogation has always been a matter of dead reckoning plus direct observation. But at such immeasurably high speeds there could be no direct observation. At matter-transmitter speeds, no manual control could stop a ship in motion within any given galaxy! So Kim had planned a photo-gauge, which would throw off the transmitter-field when a specific amount of radiation had reached it. At thousands of light-speeds, the radiation impinging on the bow of a ship, would equal in seconds the normal reception of years. When a specific total of radiation had struck it, a relay would cut off the drive field. Among other features, such a control would make it impossible for a speeding ship to venture too close to a sun. Kim set joyously to work to make three changes in the overdrive circuit, and to build a radiation-operated relay. Outside the space-ship the sky turned deep-purple. Presently the dull-red sun arose, and the white hoarfrost melted and glistened wetly, and most of it evaporated in a thin white mist. The frozen waterfall dripped and dripped, and presently flowed freely. The lichenous plants rippled and stirred in the thin chill winds that blew over the small planet, and even animals appeared, stupid and sluggish things, which lived upon the lichens. Hours passed. The dull-red sun sank low and vanished. The little waterfall flowed more and more slowly, and at last ceased altogether. The sky became a deep dense black and multitudes of stars shone down on the grounded space-ship. It was a small, starved world, this planet, swinging in lonely isolation around a burned-out sun. About it lay the Galaxy in which were three hundred million inhabited worlds, circling brighter, hotter, much more splendid stars. But the starveling little planet was the only place in all the Galaxy, save one, where no Disciplinary Circuit held the human race in slavery.