Observing that Servadac was completely absorbed in his own thoughts, Lieutenant Procope had leisure to contemplate some of the present perplexing problems, and to ponder over the true astronomical position. The last of the three mysterious documents had represented that Gallia, in conformity with Kepler’s second law, had traveled along her orbit during the month of March twenty millions of leagues less than she had done in the previous month; yet, in the same time, her distance from the sun had nevertheless been increased by thirty-two millions of leagues. She was now, therefore, in the center of the zone of telescopic planets that revolve between the orbits of Mars and Jupiter, and had captured for herself a satellite which, according to the document, was Nerina, one of the asteroids most recently identified. If thus, then, it was within the power of the unknown writer to estimate with such apparent certainty Gallia’s exact position, was it not likely that his mathematical calculations would enable him to arrive at some definite conclusion as to the date at which she would begin again to approach the sun? Nay, was it not to be expected that he had already estimated, with sufficient approximation to truth, what was to be the true length of the Gallian year? So intently had they each separately been following their own train of thought, that daylight reappeared almost before the travelers were aware of it. On consulting their instruments, they found that they must have traveled close upon a hundred leagues since they started, and they resolved to slacken their speed. The sails were accordingly taken in a little, and in spite of the intensity of the cold, the explorers ventured out of their shelter, in order that they might reconnoiter the plain, which was apparently as boundless as ever. It was completely desert; not so much as a single point of rock relieved the bare uniformity of its surface. “Are we not considerably to the west of Formentera?” asked Servadac, after examining the chart. “Most likely,” replied Procope. “I have taken the same course as I should have done at sea, and I have kept some distance to windward of the island; we can bear straight down upon it whenever we like.” “Bear down then, now; and as quickly as you can.” The yawl was at once put with her head to the northeast and Captain Servadac, in defiance of the icy blast, remained standing at the bow, his gaze fixed on the horizon. All at once his eye brightened. “Look! look!” he exclaimed, pointing to a faint outline that broke the monotony of the circle that divided the plain from the sky. In an instant the lieutenant had seized his telescope. “I see what you mean,” said he; “it is a pylone that has been used for some geodesic survey.”