Critical Factor

by Clement Hal

“That is the general idea. However, they plan to do it not only on the Southern Continent. It was felt that there might be much of this solid ocean on our own continent, which we had never discovered because we cannot venture near enough to the Void boundary; so every pool we can reach is to be brought into use. The places where light rocks project into the Void probably cannot be reached, but it seems to the planners who investigated the data that all the other regions—more than three quarters of the continent—can easily be coated with melted rock, if it clings to the surface reasonably well.”

Derrell glanced back at the bubble. “It should do that, all right,” he said, “if our force applies out in the Void as well as in the rock next to it. But that means an even more vast expenditure of effort than I had supposed; they’ll be pulling the defenders away from the frontiers until the savages from Asia are fighting the ones from Europe—around our dead bodies. Let’s find those bubbles.” He joined one of the search teams, worried more about the possible waste of work on an inefficient and probably unproductive effort than about the results of covering most of the American continents with lava. After all, he had never heard of the human race, and probably never would.

There was probably not another spot on the North American continent where his team could have found what they sought so quickly; if other regions existed where a lava flow had extended into a shallow sea, hardened, been buried with such speed under calcareous detritus, and then carried down rapidly enough and steadily enough to develop a thick limestone cap over the hardened lava, they had either been lifted back to the surface where they were unapproachable to Derrell’s kind or carried so far down as to be altered completely beyond recognition. Here, however, there were cavities; many of them filled by the limy material that had settled into them and hardened into rock and many just too deep in impenetrable regions of the lava to be attained although they were easily visible, but a fair number both empty and attainable. The water that had once filled them had long since gone into hydrates in the overlying rock, and been replaced by gases from the lava—usually oxides of carbon and sometimes even sulfur. These did not bother the investigators, and it was not long before one of the search teams reported an ideal site for investigation. The group congregated at the spot as quickly as possible, and plans were rapidly made.

There was no magma pool near enough to be “tickled” into action this time; but that did not bother Derrell. He had already seen what molten rock would do in this situation. He rapidly gave orders, and the group of liquid bodies gathered in the limestone just above the bubble and began to—eat. The eating was done in a very careful manner; and gradually a large fragment of limestone was separated from the rest of the formation. It was located directly above the bubble, and when freed from its original matrix rested on the thin silicate layer that formed the roof of the cavity. That layer was seamed with cracks, microscopic in size, but adequate to the needs of the scientists; their fluid bodies worked inside those cracks, loosening particle after particle, gradually weakening the flimsy roof. The actual force that any one of the beings could exert was minute, lifting a grain of sand would have been impossible for one of the big, but fluid, bodies; but bit by bit the lava moved, as it was dissolved along the tiny zones of weakness the brief exposure to the sea had left.

Toward the end the workers very carefully stayed away from the thin layer, extending only narrow pseudopods to do the remainder of the job. Most of them, in fact, withdrew even farther in order to observe, and two of the assistants completed the final task. Derrell was ready when the lava roof suddenly collapsed, permitting the great block of limestone they had previously freed to drop into the cavern.

No one was very surprised. It behaved, within its limitations, as the magma had done, hurtling against the wall farthest from the Void, and sending a few fragments of its’ mass flying off at angles. The fragments also returned to that part of the vast cavity farthest from the broken roof. The force evidently existed; and it appeared to work on solids as well as liquids. Bits of the lava roof had also obeyed the invisible urge; and as far as any one could tell, not a single fragment that was free to move away from the Void had failed to do so.

Without a word, Derrell flowed through the limestone to a point just above the opening. Here he pulled himself into the smallest possible volume, and deliberately began to dissolve the rock about him. He had tried to get to the portion of the bubble where the rocks had come to rest, and found it impossible; the tiny cracks that would have furnished access extended only a foot or two from the surface of the lava. Now he was going to get there—and incidentally, see what effect the new force had on living matter. He learned!

The rock in which he lay broke free as its predecessor had done; and Derrell became the first member of his race to experience the acceleration of gravity. He also was the first to discover that the most noticeable thing about a fall is the sudden stop. The shock did not hurt him—after all, he was accustomed to traveling in regions of seismic strain, and seeing by the resultant shock waves—but the whole thing was slightly surprising. For one thing, the rock had turned over as it fell, and no member of his race had ever had a sudden change of orientation with respect to his surroundings. It took several seconds for him to realize that it was he who had moved, not the surrounding universe.

Once convinced of that, he started to emerge from the rock which he had ridden; and in doing so he learned the most painful lesson of all about gravity.

Derrell’s body was liquid. It was less dense than water, being composed mainly of hydrocarbons; it had no more rigidity than water. All its support was normally furnished by the rock in which it happened to be “soaked” at the moment; he moved by controlling the liquid’s surface tension, as an amoeba moves—or, for that matter, as a man moves a muscle. Outside the supporting rock, however, he was just a puddle of oil—and once he started out, he was completely unable to stop. The block of limestone he had ridden was not quite at the bottom of the huge cavity; as a portion of his mass emerged, it tended to flow downhill toward the lowest available point; he had the choice of following it or being torn apart, and he liked the latter alternative no better than a more solid organism would. He followed. Five seconds later he was a completely helpless pool of living liquid, in the bottom of a bowl of glassy, impenetrable lava. He could not even raise a ripple on his own surface.