Christobel smiled, and gently unbent, allowing the kindly expression of appreciation and regret to reach her with comfort in these moments of dream-like isolation. A friendly hand seemed to have been outstretched across the chasm which divides the passionately regretted past, from the scarcely appreciated present. She could see her father's tall scholarly figure, as he stood lovingly fingering a book, engaged in earnest conversation with Mr. Taylor, regardless of the passing of time; until she was obliged to lay her hand on his arm, and hurry him through the crowded streets, down the steep incline, to the platform from which the Cambridge express was on the point of starting. And when safely seated, with barely a minute to spare, he would turn to her, with a smile of gentle reproof, saying: "But, my dear child, we had not concluded our conversation." And she would laugh and say: "But we had to get home to-night, Papa." Whereupon he would lean back, contentedly, replying: "Quite right, my dear. So we had." Ah, happy those whose fathers and mothers still walk the earth beside them. Youth remains, notwithstanding the passing of years, while there is still a voice to say, in reproof or approbation: "My child." But the bookseller, not yet connecting her with the Professor, still waited her pleasure; and suddenly a thought struck Christobel. An eager wish awoke within her. "Mr. Taylor," she said, hurriedly; "can you supply me with the very newest thing on the subject of aviation? I want to learn all there is to know about propellers, steering-gear, cross-currents, and how to avoid the dangers----" She stopped short. The Professor had found what he wanted, and was fumbling for his purse. The bookseller turned quickly to a pile at his elbow, took up a paper-covered book, and placed it in her hands. "The very latest," he said. "Published yesterday. You will find in it all you want to know." Then, as he handed the Professor his change, "Allow me to place it to your account, Miss Charteris," he said.