“Yes, Princess, we’re all going.” “Into danger?” asked the girl. She had freed herself from Colton’s grasp, but now her eyes fell on his again. “No; just to clear up a little point. We shall all hang together.” “Don’t go to-night, Petit Père!” There was an imploring intonation in the girl’s flute-like voice. Haynes crossed over to her rapidly. “Princess, you’re tired out and nervous. Go to bed, won’t you?” “Yes; but promise me—father, you too, all of you—promise me you won’t any of you let yourselves be alone.” “My dear child,” said Professor Ravenden, “I’ll give you my word for the party, as I am the occasion of the expedition.” “I—I suppose I am foolish,” Helga said; “but I have dreamed so persistently of some terrible danger overhanging—floating down like a pall.” With a sudden gesture she caught Haynes’ hand to her cheek. “It hung over you, Petit Père!” she whispered. “I’ll throw a pebble at your window to let you know I’m back alive and well,” he said gaily. “I’ve never seen you so nervous before, Princess.” “You’ll hardly need the lantern,” said the girl, walking to the door, and looking up at the splendid moon, sailing in the unflecked sea of the Heavens. “When you’re looking for foot-prints on the sands of time,” observed Everard, “you need the light that never was on sea or land.” He dropped back as the exploring party filed out into the night, and fell into step with Professor Ravenden. “Isn’t it true,” he asked, “that all these flying monsters are extinct?” “Science has assumed that they were extinct,” said the Professor. “But a scientific assumption is a mere makeshift, useful only until it is overthrown by new facts. We have prehistoric survivals. The gar of our rivers is unchanged from its ancestors of fifteen million years ago. The creature of the water has endured; why not the creature of the air?” “But,” said Colton combatively, “where could it live and not have been discovered?” “Perhaps at the North or South Pole,” said the professor. “Perhaps in the depths of unexplored islands; or possibly inside the globe. Geographers are accustomed to say loosely that the earth is an open book. Setting aside the exceptions which I have noted, there still remains the interior, as unknown and mysterious as the planets. In its possible vast caverns there well may be reproduced the conditions in which the pteranodon and its terrific contemporaries found their suitable environment on the earth’s surface, ages ago.” “Then how would it get out?” “The recent violent volcanic disturbances might have opened an exit.” “Oh, that’s too much!” Haynes broke in. “I was at Martinique myself, and if you expect me to believe that anything came out of that welter of flame and boiling rocks alive-”