You have no doubt wondered how Robinson could work in his cave, especially at night without a light. The truth is, it was a great source of discomfort to him. At sunset he was in total darkness in his cave. During the day light enough streamed in from the open doorway. To be alone in total darkness is not pleasant. "If I only had fire!" he said again and again. He watched the many large beetles and fire-flies flash their light in the dark of the evening as he sat in front of his shelter. The thought came to him that if he only had some way of keeping together a number of them, they would serve very well for a candle in his cave at night. How he longed for a glass bottle such as he had so often wantonly broken when at home! Back of his shelter there was a hill where the rock layers jutted out. He had noticed here several times the thin transparent rock that he had seen in his father's store. It is called isinglass. "I will make a living lantern," he said aloud in his eagerness. He soon had a suitable piece pried loose. He cut a part of a cocoanut shell away and in its place he put a sheet of isinglass. That evening at dark he gathered several handfuls of the great fire beetles and put them in his lantern. What joy their glow gave him in his cave at night. It was almost as much comfort as a companion. But while it lighted up the deep dark of the cave and enabled him to move about, he was unable after all to write in his diary at night. Every morning he set his captives free. In the evening he would go out and capture his light. XXIII ROBINSON IS SICK One evening Robinson went to bed sound and well. The next morning he was sick. Before he had only the heat of the day to complain of. To-day he was freezing. He wanted to go to work to get warm, but even this did not break his chill. It increased till his teeth chattered with the cold. "Perhaps," thought he, "if I can sleep a little I will get better." But he could not sleep. He was burning with fever and then shaking with cold by turns. He felt a strong thirst, but he was so weak that he could scarcely get the goat's milk. He had no sooner drunk the milk than his tongue was as dry as before. He felt better after a night of sleep, but the next day his fever and chills were worse than before. Then he bethought him of his parents. How kindly his mother had taken care of him! Now no one was near that could assist him. "Ah," he sighed, "must I die here? Who would bury me? There is no one to miss me." At this the tears came to his eyes. His sickness increased with each day. Occasionally the fever would go down sufficiently to allow him to get something to eat. Then it would be worse than before. In his dire need he wanted to pray, but he was so weak that he could only stammer, "Dear God, help me, or I shall die!"