The Benson curve-light was similar to an ordinary white searchlight beam, except that its path, instead of being straight could be bent at will into various curves--hyperbola, parabola, and for its extreme curve, the segment of an ellipse--gradually straightening as it left its source. It was effective for police work, with hand torches for seeing around opaque obstructions. It had also another advantage, especially when used at long range: the enemy, when gazing back at its source, would under normal circumstances conceive it to be a straight beam and thus be misled as to the location of its source. Or even realizing it to be curved, one had no means of judging the angle of the curve. A narrow white stream of light, it flung through our window-oval, forward under the dome and through the bow dome bullseye, into space. I saw the men on the deck spring into sudden alertness with the realization we were using it. The bow lookout on the forward observation bridge crouched at his 'scope-finder to help us search. From the control turret came an audiphone buzz, and Drac's voice: "Am I headed right? The swing is almost completed." "Finish the job and don't bother me now." I bent over the field-mirror of the projector. On its glowing ten-inch grid the shifting image of my range was visible, a curving, brilliant limb of the Moon, with the sunlight on the jagged mountain peaks; everywhere else was the black firmament and the blazing dots of stars. Grantline crouched beside me. "I'll work the amplifiers. Going to spread it much, Gregg?" "Yes. A full spread first. We're in no mood for a detailed narrow search." I gradually widened the light. Three feet here at its source, it spread in a great widening arc. With the naked eye we could see its white radiance, fan-shaped as an edge of it fell upon the Moon. And though optically it was not apparent, the elliptical curve of it was rounding the Moon, disclosing the hidden starfield to our instruments. "Nothing yet?" I murmured. "No." "I'll try a narrower spread and less curve." Grantline was searching the magnified images on the series of amplifier grids. There was nothing. For an hour we worked; then suddenly Grantline cried: "Gregg! Wait! Hold it!" I tensed, stricken. I held the angle and the spread of light steady. "Two seconds of arc, east; try that. The damned thing is shifting." He gripped me. "It's at the eastern edge of the field; it shifts off. It must be in rapid motion." Then I saw it, a mere moving dot of black; but suddenly it clarified. I saw a dot which I could imagine was a shape with discs along its edge, moving with high velocity. Grantline was shifting our field to hold it. "Got it, Gregg. By God, that's it! Now we'll see." Then presently we saw that from its bow a very faint radiant beam was streaming. Beside me I heard Grantline gasp, "Gregg, am I crazy or is that bow beacon like the light-beam planted in Greater New York?"