and smooth. The substances of which they are composed have been pressed together by a tremendous force. It is as unlikely that anything should fall from them as that particles should drop from the inside of a rifle-barrel. “I admit, Margaret, that this proposed journey into the depths of the earth is a very peculiar one, but, after all, it is comparatively an easy and safe performance when compared to other things that men have done. The mountain-climbers of our fathers' time, who used to ascend the highest peaks with nothing but spiked shoes and sharpened poles, ran far more danger than would be met by one who would descend such a shaft as mine. “And then, Margaret, think of what our friends on board the Dipsey have been and are doing! Think of the hundreds of miles they have travelled through the unknown depths of the sea! Their expedition was fifty times as hazardous as the trip of a few hours which I propose.” Now Margaret spoke. “But I am not engaged to be married to Samuel Block, or to Mr. Gibbs, or to any of the rest of them.” He drew his chair closer to her, and he took both of her hands in his own. He held them as if they had been two lifeless things. “Margaret,” he said, “you know I love you, and--” “Yes,” she interrupted, “but I know that you love science more.” “Not at all,” said he, “and I am going to show you how greatly mistaken you are. Tell me not to go down that shaft, tell me to live on without ever knowing what it is I have discovered, tell me to explode bombs in that great hole until I have blocked it up, and I will obey you. That is how I love you, Margaret.” She gazed into his eyes, and her hands, from merely lifeless things, became infused with a gentle warmth; they moved as if they might return the clasp in which they were held. But she did not speak, she simply looked at him, and he patiently waited. Suddenly she rose to her feet, withdrawing her hands from his hold as if he had hurt her. “Roland,” she exclaimed, “you think you know all that is in my heart, but you do not. You know it is filled with dread, with horror, with a sickening fear, but it holds more than that. It holds a love for you which is stronger than any fear or horror or dread. Roland, you must go down that shaft, you must know the great discovery you have made--even if you should never be able to come back to earth again, you must die knowing what it is. That is how I love you!” Roland quickly made a step forward, but she moved back as if she were about to seat herself again, but suddenly her knees bent beneath her, and, before he could touch her, she had fallen over on her side and lay senseless on the floor. CHAPTER XXI. THE CAVE OF LIGHT