rock covered with a volcanic tuff finer and lighter than sand. Though he could accelerate, he knew that the sensations experienced at full speed were hard to take for long, and he had a march of several hours ahead of him, in much more difficult terrain, before he reached the Depression. The flat, toothed contours on the horizon no longer looked like clouds. As he walked toward them, his shadow swept before him, misshapen. Because of the strider's great mass, the legs were only a third the length of the trunk. Pressed to increase its speed, it had to lengthen its steps, throwing each limb forward in turn with the hip. The hip could move because the circular mounting of the legs (more precisely, their undercarriage) was an enormous bearing plate into which the trunk fitted. The problem was that to the lateral tilting was then added the up-and-down motion of the giant, making the landscape reel before the operator like a drunkard. Such heavy machines were not built for running. Even a jump from a height of two meters was unwise on Titan. On lesser spheres, and on the Earth's Moon, there was more freedom of movement. But the constructors had not concerned themselves about the speed of these machines, whose walking was not to serve as a means of transportation but, rather, to perform heavy tasks. The ability to cover a distance was a plus, making the industrious colossi more self-sufficient.
For an hour or more, it seemed to Parvis alternately that 1) any second he would become stuck in a chaos of rock, and that 2) the azimuth line had been drawn by a genius, because each time Parvis approached a pile of rubble—slabs of stone balanced so precariously that it looked as if the least breeze would start a thundering avalanche—at the last moment there would always be a convenient way through, so he never needed to circle around or backtrack out of cul-de-sacs. Before long, he concluded that on Titan the best operator would be cross-eyed, since one had to watch the terrain in front of the machine, from a height, and at the same time the glowing directional indicator, which quivered like the needle of an ordinary compass on a semi-transparent map. Somehow he managed, doing not badly at all, relying on his eyes and on the needle. Cut off from the world by the roar of the power units and the overall rumble of resonance in the frame, he still could see Titan through the nonreflecting glass of his compartment. No matter where he turned his head—and he did so whenever more level terrain permitted—he saw, above a sea of mist, mountain ridges split by volcanoes that had been dead for centuries. Proceeding along the ragged ice, he noticed, sunken deep within it, the shadows of volcanic bombs and darker, unidentifiable shapes—as of starfish or octopuses set like insects in amber.
Then the land changed. It was still forbidding, but in a different way. The planet had gone through a period of bombardments and eruptions, sending blind bursts of lava and basalt skyward, to freeze in wild, alien immobility. He entered these volcanic defiles. The overhangs farther on were unbelievable. The nonliving dynamism of these seismic congealings—inexpressible in the language of beings raised on a tamer planet—was accentuated by a gravitation no greater than that of Mars. To a man lost in this labyrinth, his striding vehicle ceased to seem a giant. It dwindled, insignificant among the crags of lava, which once, in kilometer-long cascades of fire, had been transfixed by the cosmic cold. The cold cut short their flow, and before they froze, falling in the precipices, it drew them out into gigantic, vertical icicles—monstrous colonnades—a sight that was one of a kind. It made of the Digla a microscopic bug that inched past towering pillars—pillars of a building abandoned, after construction as careless as it was mighty, by the true giants of the planet. Or: a thick syrup flowing from the lip of some vessel and hardening into stalactites—as