Though we felt that we were being watched, nothing came to interrupt our hard work. At last we won our fight with materials when we arrived at the microscopic size-level limit of the workability of metals. We now had three true micro-robots. They were like their half-inch creators, except that they had two coordinated sets of eyes--a lensed pair to see by ordinary light, and another pair, fitted with magnetic focusing rings, to see by the rebounding of electrons from objects at close range, where detail was less than the span of a single light-wave. Step two, down into The Small, was made like step one. We used the same control hoods, adjusted slightly, while we sat at our work table in the shop aboard the ship. "To the bottom of the pit!" were Jan's final words as a woman. We put on our hoods and plunged. It seemed infinite, this time. The gleaming walls and girders of the shop appeared as distant as planets. The surface on which we sprawled became pitted and scored from our new viewpoint. Polish was gone with magnification. An eerie, elfin ringing--perhaps the finer overtones of normal sounds--reached our tiny, tympanic ears. We arose unsteadily. Our mechanical fingers joined, till we were a chain of three, moving toward the door of the box as a group. Then we were out on the undulating porcelain expanse of the table top. An air current, magnified to a hurricane by our minuteness, lifted us up till we floated free, still clutching each other's hands. One peculiar thing about difference in size, is that the smaller an object is, the larger is its exposed surface in proportion to volume and mass. That greater surface in relation to weight, allows the bombardment of passing air molecules to lift anything of dust-grain dimensions and density into wingless flight. It also can give a sense of helplessness, as if the atmosphere has become a treacherous medium full of irresistible currents. We tumbled, we laughed, and would have been panic stricken except for knowing that our real selves were in normal circumstances. Nearby, the air seemed to shimmer. A gnarled thing floated close--floss, looking like a twisted tree-stump, to which clear ovoids clung--some common form of microscopic life. A chunk of mineral dust came drifting nearer, its sheared-off side glinting like quartz strata. Our two pairs of eyes still were not developed to distinguish colors. Yet Jan had reasons when she exclaimed in tinkling tones: "Beautiful, truly beautiful! We came--we got here! In a sense, it's farther than the stars! But now what happens? Where are--_they_?" "I don't believe they'll be long in coming," Dr. Lanvin said at last. "To write, to make tools, and to get into our sealed ship requires a capacity to think and plan. So, about us, they must be following a set purpose." IV