"Indeed but I have," said Helen. "Not wind my watch up! Why, if I was dying I should wind my watch up. See, it requires no key; a touch or two of the fingers and it is done. Oh, I am remarkably constant in all my habits; and this is an old friend I never neglect. Do you remember that terrible night in the boat, when neither of us expected to see the morning--oh, how good and brave you were!--well, I remember winding it up that night. I kissed it, and bade it good-by. But I never dreamed of not winding it up because I was going to be killed. What! am I not to be praised again, as I was on board ship? Stingy! can't afford to praise one twice for the same thing." "Praised!" cried Hazel excitedly; "worshiped, you mean. Why, we have got the longitude by means of your chronometer. It is wonderful! It is providential! It is the finger of Heaven! Pen and ink, and let me work it out." In his excitement he got up without assistance, and was soon busy calculating the longitude of Godsend Isle. CHAPTER XL. "THERE," said he. "Now the latitude I must guess at by certain combinations. In the first place, the slight variation in the length of the days. Then I must try and make a rough calculation of the sun's parallax. And then my botany will help me a little; spices furnish a clew; there are one or two that will not grow outside the tropic. It was the longitude that beat me, and now we have conquered it. Hurrah! Now I know what to diffuse, and in what direction; east, southeast; the ducks have shown me that much. So there's the first step toward the impossible problem." "Very well," said Helen; "and I am sure one step is enough for one day. I forbid you the topic for twelve hours at least. I detest it because it always makes your poor head so hot." "What on earth does that matter?" said Hazel, impetuously, and almost crossly. "Come, come, come, sir," said Helen authoritatively; "it matters to me." But when she saw that he could think of nothing else, and that opposition irritated him, she had the tact and good sense not to strain her authority, nor to irritate her subject. Hazel spliced a long, fine-pointed stick to the mast-head, and set a plank painted white with guano at right angles to the base of the mast; and so, whenever the sun attained his meridian altitude, went into a difficult and subtle calculation to arrive at the latitude, or as near it as he could without proper instruments. And he brooded and brooded over his discovery of the longitude, but unfortunately he could not advance. In some problems the first step once gained leads, or at least points, to the next; but to know whereabouts they were, and to let others know it, were two difficulties heterogeneous and distinct.