Hal Clement - Mission of Gravity

Lackland had put down the photograph he was holding, and seemed immersed in-’thought. Much of the floor of the room was already covered with loosely fitted pictures; the region best known to Barlennan was already mapped fairly well. However, there was yet a long, long way to go before the area occupied by the human outpost would be included; and the man was already being troubled by the refusal of the photographs to fit together. Had they been of a spherical or nearly spherical world like Earth or Mars, he could have applied the proper projection correction almost automatically on the smaller map which he was constructing, and which covered a table at one side of the chamber; but Mesklin was not even approximately spherical. As Lackland had long ago recognized, the proportions of the Bowl on the Bree — Barlennan’s equivalent of a terrestrial globe — were approximately right. It was six inches across and one and a quarter deep, and its curvature was smooth but far from uniform.

To add to the difficulty of matching photographs, much of the planet’s surface was relatively smooth, without really distinctive topographic feature; and even where mountains and valleys existed, the different shadowing of adjacent photographs made comparison a hard job. The habit of the brighter sun of crossing from horizon to horizon in less than nine minutes had seriously disarranged normal photographic procedure; successive pictures in the same series were often illuminated from almost opposite directions.

„We’re not getting anywhere with this, Barl,” Lackland said wearily. „It was worth a try as long as there might be short cuts, but you say there are none. You’re a sailor, not a caravan master; that four thousand miles overland right where gravity is greatest is going to stump us.”

„The knowledge that enables you to fly, then, cannot change weight?”

„It cannot.” Lackland smiled. „The instruments which are on that rocket grounded at your south pole should have readings which might teach us just that, in time. That is why the rocket was sent, Barlennan; the poles of your world have the most terrific surface gravity of any spot in the Universe so far accessible to ib. ‘There are a number of other worlds even more massive than yours, and closer to home, but they don’t spin the way Mesklin does; they’re too nearly spherical. We wanted measures in that tremendous gravity field — all sorts of measures. The value of the instruments that were designed and sent on that trip cannot be expressed in numbers we both know; when the rocket failed to respond to its takeoff signal, it rocked the governments of ten planets. We must have that data, even if we have to dig a canal to get the Bree into the other ocean.”

„But what sort of devices were on board this rocket?” Barlennan asked. He regretted the question almost in the same instant; the Flyer might wonder at such specific curiosity, and come to suspect the captain’s true intentions. However, Lackland appeared to take the query as natural.

„I’m afraid I can’t tell you, Barl. You simply have no background which would give words like ‘electron’ and ‘neutrino’ and ‘magnetism’ and ‘quantum’ any meaning at all. The drive mechanism of the rocket might mean a little more to you, but I doubt it.” In spite of Lackland’s apparent freedom from suspicion, Barlennan decided not to pursue the subject.

„Would it not be well,” he said, „to seek the pictures that show the shore and inland regions east of here?”

Lackland replied, „There is still some chance, I suppose, that they do meet; I don’t pretend to have memorized the whole area. Maybe down next to the icecap — how much cold can you people stand?”

„We are uncomfortable when the sea freezes, but we can stand it — if it does not get too much colder. Why?”

„It’s just possible you may have to crowd the northern icecap pretty closely. We’ll see, though.” The Flyer riffled through the stack of prints, still taller than Barlennan was long, and eventually extracted a thin sheaf. „One of these. ” His voice trailed off for a few moments. „Here we are. This was taken from the inner edge of the ring, Barl, over six hundred miles up, with a narrow-angle telephoto lens. You can see the main shore line, and the big bay, and here, on the south side of the big one, the little bay where the Bree

is beached. This was taken before this station was built — though it wouldn’t show anyway.

„Now let’s start assembling again. The sheet east of this.” He trailed off again, and the Mesklinite watched in fascination as a readable map of the lands he had not yet reached took form below him. For a time it seemed they were to be disappointed, for the shore line gradually curved northward as Lackland had thought; indeed, some twelve hundred miles to the west and four or five hundred north, the ocean seemed to come to an end — the coast curved westward again. A vast river emptied into it at this point, and with some hope at first that this might be a strait leading to the eastern sea, Lackland began fitting the pictures that covered the upper reaches of the mighty stream. He was quickly disabused of this idea, by the discovery of an extensive series of rapids some two hundred and fifty miles upstream; east of these, the great river dwindled rapidly. Numerous smaller streams emptied into it; apparently it was the main artery for the drainage system of a vast area of the planet. Interested by the speed with which it broke up into smaller rivers, Lackland continued building the map eastward, watched with interest by Barlennan.

The main stream, as far as it could be distinguished, had shifted direction slightly, flowing from a more southerly direction. Carrying the mosaic of pictures in — this direction, they j found a range of very fair-sized mountains, and the Earthman looked up with a rueful shake of his head. Barlennan had come to understand the meaning of this gesture.

„Do not stop yet!” the captain expostulated. „There is a similar range along the center of my country, which is a fairly narrow peninsula. At least build the picture far enough to determine how the streams flow on the other side of the mountains.” Lackland, though not optimistic — he recalled the South American continent on his own planet too clearly to assume any symmetry of the sort the Mesklinite seemed to expect — complied with the native’s suggestion. The range proved to be fairly narrow, extending roughly east-northeast by west-southwest; and rather to the man’s surprise the numerous „water” courses on the opposite side began very quickly to show a tendency to come together in one vast river. This ran roughly parallel with the range for mile after mile, broadening as it went, and hope began to grow once more. It reached a climax five hundred miles downstream, when what was now a vast estuary merged indistinguishably with the „waters” of the eastern ocean. Working feverishly, scarcely stopping for food or even the rest he so badly needed in Mesklin’s savage gravity, Lackland worked on; and eventually the floor of the room was covered by a new map — a rectangle representing some two thousand miles in an east-west line and half as far in the other dimension. The great bay and tiny cove where the Bree was beached showed clearly at its western end; much pf the other was occupied by the featureless surface of the eastern sea. Between lay the land barrier.

It was narrow; at its narrowest, some five hundred miles north of the equator, it was a scant eight hundred miles from coast to coast, and this distance was lessened considerably if one measured from the highest usable points of the principal rivers. Perhaps three hundred miles, part of it over a mountain range, was all that lay between the Bree and a relatively easy path to the distant goal of the Earthmen’s efforts. Three hundred miles; a mere step, as distances on Mesklin went.