This strange race of people had built their own mechanical bodies, and by operation upon one another had removed their brains to the metal heads from which they directed the functions and movements of their inorganic anatomies. There had been no deaths due to worn-out bodies. When one part of the mechanical men wore out, it was replaced by a new part, and so the Zoromes continued living their immortal lives which saw few casualties. It was true that, since the innovation of the machines, there had been a few accidents which had seen the destruction of the metal heads with their brains. These were irreparable. Such cases had been few, however, and the population of Zor had decreased but little. The machine men of Zor had no use for atmosphere, and had it not been for the terrible coldness of space, could have just as well existed in the ether void as upon some planet. Their metal bodies, especially their metal-encased brains, did require a certain amount of heat even though they were able to exist comfortably in temperatures which would instantly have frozen to death a flesh-and-blood creature. The most popular pastime among the machine men of Zor was the exploration of the Universe. This afforded them a never ending source of interest in the discovery of the variegated inhabitants and conditions of the various planets on which they came to rest. Hundreds of space ships were sent out in all directions, many of them being upon their expeditions for hundreds of years before they returned once more to the home planet of far-off Zor. This particular space craft of the Zoromes had entered the solar system whose planets were gradually circling in closer to the dull red ball of the declining sun. Several of the machine men of the space craft's crew, which numbered some fifty individuals, were examining the various planets of this particular planetary system carefully through telescopes possessing immense power. These machine men had no names and were indexed according to letters and numbers. They conversed by means of thought impulses, and were neither capable of making a sound vocally nor of hearing one uttered. "Where shall we go?" queried one of the men at the controls questioning another who stood by his side examining a chart on the wall. "They all appear to be dead worlds, 4R-3579," replied the one addressed, "but the second planet from the sun appears to have an atmosphere which might sustain a few living creatures, and the third planet may also prove interesting for it has a satellite. We shall examine the inner planets first of all, and explore the outer ones later if we decide it is worth the time."