us the exact time at Greenwich. We know by our nautical almanac that, at a certain hour on a certain day, the sun will have attained at Greenwich a certain altitude. When on that day and that hour we find that the sun is so many minutes behind hand in attaining that altitude, we know we must be a certain distance further to the west, as, the world turning from west to east, the more westerly a place is the longer it will be before the sun appears there. If, on the contrary, we find the sun has gained a fixed altitude some time before it would have gained that altitude at Greenwich, we know that we must be to the east of Greenwich, or have met the sun sooner than the people at Greenwich have done. Thus, the further we sail east day after day, the sooner we see the sun; while the further we sail west, the longer the time which passes before he shines upon us.”

“I think I have an idea about it now, sir,” I exclaimed; “and I should be very much obliged if you will show me how to take an observation and to make use of the books, as well as to work out the calculations. Why, may I ask, do you cry Stop, sir, to the second officer or to Mr Thudicumb, who are watching the chronometer while you are taking an observation?”

“That they may mark the exact moment shown on the chronometer, while I mark the sun’s elevation as shown on the index of the sextant.”

“But then you take observations at night sometimes, sir, looking at the moon or the stars?”

“We do that to discover the distance which one star appears from another at a certain hour, or their elevation above the horizon. The object is the same as that for which we take an observation of the sun, though the calculation is rather more intricate.”

After this I set to work, and whenever the captain and his mates took an observation, I took one also, although I was, I must own, at first very far from correct. Sometimes my observation was imperfect; at other times I made mistakes in the calculation.

At length the ship, which had been favoured with a breeze more or less strong ever since she left England, was becalmed. Sometimes she got a little wind which lasted for an hour or two, and then died away; then light airs came, first from one quarter, then from another, and the crew were constantly employed in bracing up, or squaring away the yards.

“It is always like this in these Horse Latitudes,” said the boatswain as he walked the forecastle, where I had gone to have a talk with him.

“Why do you call them ‘Horse Latitudes?’” I asked, as I listened to his remarks.

“Why, I have heard say that they were so called by the Yankees, or the people of New England, before they were separated from Old England. They used to send out deckloads of horses to the West Indies, and they were very often kept becalmed so long in these latitudes that their water grew scarce, and to save the lives of some of the horses they were obliged to throw the others overboard; so that is how this part of the ocean came to be called the ‘Horse Latitudes.’”

I afterwards told Mr Hooker what Tarbox had said.

“A more scientific name would be the Tropic of Cancer,” he answered. “We had a good breeze before we entered it, but often the wind to the north of where we now are is very variable. After we have passed this belt of calm and light airs we shall get into the regions of the north-east trades, which will carry us along at a fine rate till we get into the very worst part of the ocean for trying a person’s temper, called the Doldrums. Remember to ask me more about it when we get there. You will remember, then, the Variables are to the north of the Tropic of Cancer. The ‘Horse Latitudes’ are on either side of the Tropic. Then we get into the north-east trade-winds, which carry us up to the Doldrums about the Equator; and passing through them with more or less trial of temper, we get into the south-east trade-winds, which we shall have to cross with our tacks aboard. Then we shall probably find calms about the Tropic of Capricorn; after which, without once sighting land, we may very likely find a breeze, more or less favourable, but seldom against us, which will carry us through the Straits of Sunda, between Java and Sumatra, to the west of the great island of Borneo, right away to the north, through the China sea, leaving the Philippine Islands on our right hand, up to Japan. I will have a talk with you another day about those East India Islands, for they are very curious, and are probably less generally known than most parts of the world.”

The events occurred very much as Mr Hooker had predicted. For nearly a whole week our ship lay with her head sometimes one way, sometimes another, the sails flapping against the masts. Then she got a breeze which carried her a few miles further to the south, and people’s spirits began to rise, soon again to fall when once more the sails would give a loud flap, and hang down without a particle of wind in them. At length, however, they once more bulged out. The yards were squared away. The captain walked the deck with a more elastic step than for the last week had been the case, and on the ship went hour after hour, the breeze rather increasing than lessening.

“We are in the north-east trades,” observed Mr Hooker. “Little fear now, for another two weeks or so we shall have a fine run of it.”

Three day after this, a seaman from aloft shouted out, “Land ahead!”

“Ay, ay,” answered Mr Thudicumb, who had charge of the deck. “It is land that will not hurt us, though;” and he continued to let the ship run on in the course she had been steering.

Curious to know what had attracted the man’s attention, I went aloft, and there I saw spread out on the surface of the calm ocean, what looked like a dark field, but little raised, however, above the water. On returning on deck, I told the first officer that I really thought there must be land ahead.

“No, Walter, no fear of that,” answered Mr Thudicumb; “we are crossing the Sargasso Sea. You will observe that it is merely sea-weed and drift-wood collected in this spot from all parts of the ocean. The currents and winds bring it, but why this place is selected I do not exactly know. In a calm it might bother us, but we shall only pass through a small portion of it, and there is wind enough to send us along in spite of the obstruction it may offer. We must get a bucket ready, for Mr Hooker will be anxious to have some of it up on deck, that he may examine the creatures who live upon it. In the Pacific there is a collection of the same sort, and people who could not otherwise for want of fuel inhabit some of the islands in that region, are enabled to do so in consequence of the supply of drift-wood it brings them.”

The ship, soon clear of the Sargasso Sea, glided on proudly, with all sail set below and aloft. The weather was delightful; the passengers constantly on deck. Emily and Grace were very happy together, for everything was new and interesting. They had plenty of employment; for Mrs Davenport, knowing what a sea voyage is, had brought work of all sorts. And then they had books; and they were not above running about the deck, and playing at ball occasionally, and Les Graces, and other games suitable for ship-board.

Thus day after day passed pleasantly by: the sea sparkling, the sky bright, or occasionally mottled with light clouds. One morning, however, when they came on deck expecting to see the blue sky above their heads, they saw only a thick canopy of clouds. The sails were flapping against the masts; the air was oppressive. There the ship lay, her head moving now in one direction, now in another. Those who had before been full of life and spirits began to complain of lassitude and weariness. The seamen no longer moved actively about the decks, but went sauntering along when called upon to perform any duty. The heat grew greater and greater. The iron about the ship was unpleasant to touch. The pitch bubbled in the seams of the deck