Cobb viewed for a moment the brilliant light, which was apparently gently swaying to right and left just beneath him, and then his eyes passed along the line made by the others. The second light was quite bright also, but the third seemed faint. The fourth light appeared as a star lying just on the edge of the ocean. Indeed, were it not for the fact that the Orion lay exactly in the line of the stations, and for the further fact that no stars were visible so low down toward the horizon, the light might not have been noticed at all. "How far apart are these stations?" he asked. "They are placed at intervals of fifty miles," returned the other. "Then, that light away down near the horizon is nearly 150 miles from us?" "Yes." "And our elevation now is 10,000 feet, you say?" "So I observed it, as I told you, some fifteen or twenty minutes ago." Then, after a moment's silence, Cobb exclaimed: "We are rising. We cannot be less than 12,500 feet above the ocean." "How do you make that out, Junius?" asked Hugh. "I don't think we have ascended 2,500 feet since my last observation." "It is easily answered," said the other. "The curvature of the earth and the refraction of light necessitate an elevation of 1,430 feet for one to see an object on the surface at a distance of fifty miles. To see this light, distant 150 miles, our altitude must be at least 11,500 feet." "Yes?" "Yes. Let us go inside, and see if I am not correct, and then I want you to tell me about these stations," touching the other on the arm, and then moving aft. Once in the cabin, the barometer was consulted, and found to read 19.29 inches, or an elevation of 11,581 feet. Cobb again asked his friend to enlighten him concerning this new invention, the lights of which he had seen twinkling and scintillating away toward the east. "I cannot tell you much, Junius, for I am not well posted on the subject. These transatlantic life-stations are set on a line extending from St. John's, Newfoundland, to Land's End, England, or nearly on the fiftieth parallel of north latitude. Perhaps there may be something relating to the subject among the books in the chart-room. Excuse me but a moment, and I will look." Saying which, he arose and passed out to the pilot's house. A moment later he returned, bearing a pamphlet in his hand. "Here we are, my boy," he exclaimed, as he shut the door behind him. "Here's quite a history of these stations. I found it among the nautical almanacs and charts in the pilot's room."