“The igneous rock is largely silicates of magnesium, the stratiform layer next to it mostly calcium carbonate. The bubble is about fifteen feet in diameter, one side almost exactly tangent to the stratiform boundary. The boundary itself is parallel to the Void boundary a mile and a half away. The front edge of the sill was advancing at about six inches an hour, and the sill itself had a thickness of about—”
“All right; good so far. Taless, what else?” Another student took up the list; and the recent arrival forgot his news temporarily in the intensity of the resulting discussion. By the time he remembered it, a hypothesis had been developed.
“It seems possible,” Derrell summed the idea up, “that a force of unknown nature exists, which tends to drive liquids (at least) as far from the Void as they are free to travel. Our single observation is to that effect, anyway. It would seem desirable to find other, more accessible hollows in the deeper rocks, to determine how far from the Void boundary this force extends, and to learn if possible whether other things than liquids are affected.”
“I wonder what the existence of such a force—if it does exist—will do to the Pentong project,” remarked the newcomer, recalling his news suddenly.
“What is that? Another defense plan?”
“Not exactly.” The scientist described Pentong’s discovery of the Antarctic Continent, and his account of its covering of solid ocean. “His plan to melt this substance, and thus protect more of the world’s rock from the oxygen of the Void, has been favorably received by more than half the City Leaders of the continent, and parties are already under way to examine the Southern Continent more completely,” he concluded. A student cut in instantly.
“But if this force exists, and ocean is subject to it as magma is, won’t the freshly melted ocean simply spread flat over what is already there, and perhaps hardly protect any more land at all?”
“That seems probable,” replied Derrell. “Since such a project will involve a vast expenditure of effort, and very possibly interfere with defense on the frontiers, it now becomes imperative that we check the nature and existence of this force as quickly as possible.”
“However, if the available ocean surface is not too large,” put in another, “even spreading the new ocean over all of it might permit a considerable increase in the protected areas.”
“It might; but unless and until we have some idea of the size of the World inside the Void, and how much of the World is covered by ocean, we cannot afford to take a chance on that possibility. We must search for more bubbles; and this carbonate stratum is in contact with igneous rock over many thousands of square miles, it would seem. Break up into parties of three and start exploring; if you encounter savages, call—there are military personnel not too far behind us. This is important.” He turned back to the assistant who had brought the news. “I suppose they plan to do the melting by coaxing magma pools toward the Void boundary, and letting them flow out into contact with this solid ocean.”