The Bear revolving points his golden eye:
Who shines exalted on th’ ethereal plain,
Nor bathes his blazing forehead in the main.”
Fa. Very well; they are fine lines, indeed! You see, then, how long ago sailors thought it necessary to study astronomy. But as it frequently happens, especially in stormy weather, that the stars are not to be seen, this method was subject to great uncertainty, which rendered it dangerous to undertake distant voyages. At length, near 500 years since, a property was discovered in a mineral, called the magnet or loadstone, which removed the difficulty. This was, its polarity, or quality of always pointing to the poles of the earth, that is, due north and south. This it can communicate to any piece of iron; so that a needle well rubbed in a particular manner by a loadstone, and then balanced upon its centre so as to turn round freely, will always point to the north. With an instrument called a mariner’s compass, made of one of these needles, and a card marked with all the points—north, south, east, west, and the divisions between these, a ship may be steered to any part of the globe.
Ch. It is a very easy matter, then.
Fa. Not quite so easy, neither. In a long voyage, cross or contrary winds blow a ship out of her direct course, so that without nice calculations both of the straight track she has gone, and all the deviations from it, the sailors would not know where they were, nor to what point to steer. It is also frequently necessary to take observations, as they call it; that is, to observe with an instrument where the sun’s place in the sky is at noon, by which they can determine the latitude they are in. Other observations are necessary to determine their longitude. What these mean, I can show you upon the globe. It is enough now to say that, by means of both together, they can tell the exact spot they are on at any time; and then, by consulting their map, and setting their compass, they can steer right to the place they want. But all this requires a very exact knowledge of astronomy, the use of the globes, mathematics, and arithmetic, which you may suppose is not to be acquired without much study. A great number of curious instruments have been invented to assist in these operations; so that there is scarcely any matter in which so much art and science have been employed as in navigation; and none but a very learned and civilized nation can excel in it.
Ch. But how is Tom Hardy to do? for I am pretty sure he does not understand any of these things.
Fa. He must learn them, if he means to come to anything in his profession. He may, indeed, head a pressgang, or command a boat’s crew without them; but he will never be fit to take charge of a man-of-war, or even a merchant-ship.
Ch. However, he need not learn Latin and Greek.
Fa. I cannot say, indeed, that a sailor has occasion for those languages; but a knowledge of Latin makes it much easier to acquire all modern languages; and I hope you do not think them unnecessary to him.