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But could she partial Fortune blame,
At length from all her honours cast,
She now of this or that, inquires;
"And pray what's this, and this, dear sir?” "A Needle," says the interpreter.
She knew the name; and thus the fool
"A needle with that filthy stone, Quite idle, all with rust o'ergrown! You better might employ your parts, And aid the sempstress in her arts; But tell me how the friendship grew Between that paltry flint and you ?" "Friend," says the Needle, "
I follow real worth and fame.
cease to blame;
Know'st thou the loadstone's power and art,
That virtue, virtues can impart?
Of all his talents I partake,
Who then can such a friend forsake?
'Tis I direct the pilot's hand
To shun the rocks and treacherous sand:
By me the distant world is known,
And either India is our own.
Had I with milliners been bred,
AN ELEGY ON THE DEATH OF A MAD DOG.
GOOD people all, of every sort,
Give ear unto my song,
And if you find it wondrous short,
In Islington there was a man,
A kind and gentle heart he had,
And in that town a dog was found,
Both mongrel, puppy, whelps, and hound,
And curs of low degree.
This dog and man at first were friends;
But when a pique began,
The dog, to gain his private ends,
Went mad and bit the man.
Around from all the neighbouring streets,
The wondering neighbours ran,
To bite so good a man.
The wound it seem'd both sore and sad
To ev'ry Christian eye;
And while they swore the dog was mad,
But soon a wonder came to light,
That show'd the rogues they lied;
The man recover'd of the bite,
WHY THE EARTH MOVES ROUND THE SUN.
EVENINGS AT HOME.
P. You remember, Lucy, that I explained to you, some time ago, what was the cause that things fell to the ground.
L. Oh yes—it was because the ground drew them to it. P. True. That is a consequence of the universal law that bodies attract each other in proportion to their bulk. So a very small thing in the neighbourhood of a very large one always tends to go to it, if not prevented by some other power. Well—you know I told you that the sun was a ball, a vast many times bigger than the ball we inhabit, called the earth; upon which you properly asked, how, then, it happened that the earth did not fall into the sun. L. And why does it not?
P. That I am going to explain to you. You have seen your brother whirl round an ivory ball, tied to the end of a string which
he held in his hand.
L. Yes; and I have done it myself, too.
P. Well, then—you felt that the ball was continually pulling, as though it tried to make its escape.
L. Yes; and one my brother was swinging did make its escape, and flew through the sash.
P. It did so. That was a lesson in the centrifugal motion, or that power by which a body thus whirled continually endeavours to fly off from the centre round which it moves. This is owing to the force or impulse you give it at setting out, as though you were going to throw it away from you. The string by which you hold it, on the contrary, is the power which keeps the ball towards the centre, called the centripetal power. Thus, you see, there are two powers acting upon the ball at the same time; one to make it fly off, the other to hold it in; and the consequence is, that it moves directly according to neither, but between both; that is, round and round. This it continues to do while you swing it properly; but should the string break or slip off, away flies the ball; on the other hand, if you cease to give it the whirling force, it falls towards your hand.
L. I understand all this.
P. I will give you another instance of this double force acting at the same time. Do not you remember seeing some curious feats of horsemanship?
P. One of them was, that a man standing with one leg upon the saddle and riding full speed, threw up balls into the air and catched them as they fell.
L. I remember it very well.
P. Perhaps you would have expected these balls to have fallen behind him, as he was going at such a rate.
L. So I did.
P. But you saw that they fell into his hand as directly as if he had been standing quite still. That was because at the instant he threw them up, they received the motion of the horse straight forward, as well as the upright motion that he gave them, so that they made a slanting line through the air, and came down in the same place they would have reached if he had held them in his hand all the while.
L. That is very curious, indeed!
P. In the same manner, you may have observed, in riding in a carriage, that if you throw anything out of the window, it falls directly opposite, just as though the carriage were standing still, and is not left behind you.
I. I will try that, the next time I ride in one.
P. You are then to imagine the sun to be a mighty mass of matter, many thousand times larger than our earth, placed in the centre, quiet and unmoved. You are to conceive our earth, as soon as created, launched with vast force in a straight line, as though it were a bowl on a green. It would have flown off in this line for ever, through the boundless regions of space, had it not, at the same instant, received a pull from the sun, by its attraction. By the wonderful skill of the Creator, these two forces were made exactly to counterbalance each other; so that just as much as the earth, from the original motion given it, tends to fly forwards, just so much the sun draws it to the centre; and the consequence is, that it takes a course between the two, which is a circle round and round the sun.
L. But if the earth were set a-rolling, like a bowl upon a green, I should think it would stop of itself, as the bowl does.
P. The bowl stops because it is continually rubbing against the ground, which checks its motion; but the ball of the earth moves in empty space, where there is nothing to stop it.
L. But if I throw a ball through the air, it will not go on for ever, but it will come down to the ground.
P. That is because the force with which you can throw it is much less than the force by which it is drawn to the earth. But there is
another reason, too, which is the resistance of the air. This space all around us and over us is not empty space; it is quite full of a thin, transparent liquid, called air.
L. Is it?
P. Yes. If you move your hand quickly through it, you will find something resisting you, though in a slight degree. And the wind, you well know, is capable of pressing against anything with almost irresistible force; and yet wind is nothing but a quantity of air put into violent motion. Everything, then, that moves through the air is continually obliged to push some of this fluid out of the way, by which means it is constantly losing part of its motion.
L. Then the earth would do the same.
P. No; for it moves in empty space.
L. What! does not it move through the air?
P. The earth does not move through the air, but carries the air along with it. All the air is contained in what is called the atmosphere, which you may compare to a sort of mist or fog clinging all around to the ball of the earth, and reaching a certain distance above it, which has been calculated at about forty-five or fifty miles. L. That is above the clouds, then.
P. Yes; all the clouds are within the atmosphere, for they are supported by the air. Well-this atmosphere rolls about along with the earth, as though it were a part of it, and moves with it through the sky, which is a vast field of empty space. In this immense space are all the stars and planets, which have also their several motions. There is nothing to stop them, but they continually go on, by means of the force that the Creator has originally impressed upon them.
L. Do not some of the stars move round the sun, as well as our earth?
P. Yes; those that are called planets. These are all subject to the same laws of motion with our earth. They are attracted by the sun as their centre, and form, along with the earth, that assemblage of worlds, which is called the solar system. L. Is the moon one of them?
P. The moon is called a secondary planet, because its immediate connexion is with our earth, around which it rolls, as we do around the sun. It, however, accompanies our earth in its journey round But I will tell you more about its motion, and about the other planets and stars, another time. It is enough at present, if you thoroughly understand what I have been describing.
L. I think I do.