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this subject in his account of some fiery meteors, which appeared in 17831.

In

Of the aurora borealis I have one more observation to make of great importance to seamen. 1772, Mr. Winn presented a paper to the Royal Society, in which he says, that the appearance of an aurora borealis is a certain sign of a hard gale of wind from the south or southwest. This he never found to fail in twenty-three instances; and he even thinks, that from the splendour of the meteor, some judgment may be formed concerning the ensuing tempest. If the aurora be very bright, the gale will come on within twenty-four hours, but will be of no long duration: if the light be faint and dull, the gale will be less violent, and longer in coming on, but will also last longer. His observations were made in the English Channel, where such winds are very dangerous; and, by attending to the aurora, he says he often got easily out of it, when others narrowly escaped being wrecked.

There are other fiery meteors beside lightning and aurora borealis; such as fiery globes, moving at prodigious heights, with incredible velocity; the ignis fatuus, draco volans, falling stars, &c.

The Ignis Fatuus is a common meteor, chiefly seen in dark nights, frequenting meadows, marshes, and other moist places, and often seen in buryinggrounds, and near dunghills. It is known among the common people by the name of Will with a Wisp, and Jack with a Lanthorn. The form and size of these ignes fatui are very various. The late

1 Phil. Trans. vol. lxxiv. part i.

2 Phil. Trans. vol. Ixiv. part i. For M. Libes's new theory of the aurora borealis, see Gregory's translation of Hauy's Natural Philosophy, or the new edition of Dr. Hutton's Mathematical Dictionary.

3 For a description of these fiery globes, I must refer to Dr. Blagden's account above-mentioned.

experiments on air serve to furnish a rational explication of this phenomenon, to which the ignorant and superstitious have ascribed so many alarming purposes. Inflammable air has been found to be the most common of all the factitious airs in nature, and to be the usual product of the putrefaction and decomposition of vegetable substances in water; and Volta, in a letter to Priestley, informs him, that he fires inflammable air by the electric spark, even when the electricity is very moderate; and he supposes, that this experiment explains the inflammation of the ignis fatuus, provided it consists of inflammable air issuing from marshy ground by the help of the electricity of fogs, and by falling stars, which are very probably thought to have an electric origin. Dr. Shaw describes an ignis fatuus, which he saw in Palestine, that was sometimes globular, or in the form of the flame of a candle; and immediately after spread itself so much as to involve the whole company in a pale inoffensive light, and then contract itself again, and suddenly disappear. But in less than a minute it would become visible as before; or, running along from one place to another, with a swift progressive motion, would expand itself, at certain intervals, over more than two or three acres of the adjacent mountains. The atmosphere, at this time, had been thick and hazy, and the dew on their bridles was usually clammy and unctuous. In the same weather, he observed those luminous appearances, which, at sea, skip about the masts and yards of ships, and which the sailors call corpusanse, by a corruption of the Spanish word cuerposanto2.

The Draco volans is a fat, heterogeneous, earthy meteor, appearing long and sinuous, something in

Priestley's Observations on Air, vol. iii. page 382. 2 Shaw's Travels, p. 363.

the shape of a flying dragon. It is generally seen on the banks of rivers and in marshy places, and seldom rises very high from the ground, but plays and dances about the surface in an agreeable manner; and if people go up to it, it will adhere to their hands and clothes, without burning, or doing them any injury. They are more common in the summer months than in the winter, and are more frequently seen in thick weather than in clear.

A Falling Star is a meteor, the explication of which has puzzled all philosophers, till our modern discoveries in electricity have led to the most probable account of it. Beccaria makes it pretty evident that it is an electrical appearance': but many philosophers now regard falling stars as bodies actually projected from lunar volcanoes.

To the ignis fatuus, and other fiery meteors, which are visible near the earth, Thomson has thus alluded in his Autumn:

Now black, and deep, the night begins to fall,
A shade immense. Sunk in the quenching gloom,
Magnificent and vast, are heaven and earth.

Order confounded lies; all beauty void;
Distinction lost; and gay variety

One universal blot: such the fair power
Of light, to kindle and create the whole.
Drear is the state of the benighted wretch,

Who then, bewildered, wanders through the dark,
Full of pale fancies, and chimeras huge;
Nor visited by one directive ray,

From cottage streaming, or from airy hall.
Perhaps, impatient as he stumbles on,
Struck from the root of slimy rushes, blue,
The wild-fire scatters round, or gathered trails
A length of flame deceitful o'er the moss:
Whither decoyed by the fantastic blaze,
Now lost, and now renewed, he sinks absorpt,
Rider and horse, amid the miry gulf:

While still, from day to day, his pining wife

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And plaintive children his return await,
In wild conjecture lost. At other times,
Sent by the better Genius of the night,
Innoxious, gleaming on the horse's mane,
The meteor sits; and shows the narrow path,
That winding leads through pits of death, or else
Instructs him how to take the dangerous ford.

No. LII.

ON MAGNETISM AND THE MARINER'S COMPASS.

Almighty Cause! 'tis thy preserving care,
That keeps thy works for ever fresh and fair:
Hence life acknowledges its Glorious Cause,
And matter owns its Great Disposer's laws;
Hence flow the forms and properties of things;
Hence rises harmony, aud order springs.
Thy watchful providence o'er all intends;
Thy works obey their Great Creator's ends.
Thee, Infinite! what finite can explore?
Imagination sinks beneath thy power.
Yet present to all sense that power remains :
Revealed in Nature, Nature's Author reigns.

BOYSE.

ALTHOUGH the phenomena of the magnet have, for many ages, engaged the attention of natural philosophers, not only by their singularity and importance, but also by the obscurity in which they are involved; yet very few additions have been made to the discoveries of the first inquirers into the subject. The powers of genius which have been hitherto employed in investigating this subject, have not been able to frame a hypothesis, that will account, in an easy and satisfactory manner, for all

the various properties of the magnet, or to point out the links of the chain which connect it with the other phenomena of the universe. It is certain, indeed, that both natural and artificial electricity will give polarity, or a direction to the poles of the earth, to needles, and even reverse a given polarity; and hence it may be inferred, that there is a considerable affinity between the electric and magnetic fluid; but in what manner electricity acts in producing magnetism, is still utterly unknown.

From the works of Hippocrates, Plato, and Aristotle, who each flourished above three centuries before the christian era, it is certain that the ancients were acquainted with the attractive and repulsive powers of the magnet; but it does not appear, that they knew of its tendency to the pole, or of the mariner's compass. Lucretius, in his sixth book De Rerum Naturá, has given a poetical dissertation upon the attractive property of the magnet, but without the least intimation of its polarity. To him, however, we are indebted for the origin of the term magnet:

Quod superest, agere incipiam, quo fœdere fiat
Naturæ, lapis hic ut ferrum ducere possit.
Quem magneta vocant patrio nomine Graii,
Magnetum quia sit patriis in finibus ortus.

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That is, The magnet, of whose attractive virtues he intends to treat, is so called, by the Greeks, from Magnesia, a district of Lydia, in which it was first found.' Aristotle, by way of excellence, calls it only abos, the stone. Pliny calls it Heraclius lapis, from the city of Heraclea, in the country of the Magnetes abovementioned. By the Italians it is called calamita, and by the French aimant. Our English name, the loadstone, is of Saxon extraction. As the ancients were not acquainted with the true method of philosophising, and were content with ob

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