“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.