grees S. W. of Mira, is a star of the 3d magnitude n the heart, called Baten Kaitos, which makes a scalene triangle with two other stars of the same magnitude 70 and 100 W. of it; also, an equilateral triangle with Mira and the easternmost one in the square.

A great number of geometrical figures may be formed from the stars in this, and in most of the other constellations, merely by reference to the maps; but It is better that the student should exercise his own ingenuity in this way with reference to the stars themselves, for when once he has constructed a group into any letter or figure of his own invention, he never will forget it.

The teacher should therefore require his class to commit to writing the result of their own observations upon the relative position, magnitude and figures of the principal stars in each constellation. One evening's exercise in this way will disclose to the student a surprising multitude of crosses, squares, triangles, arcs and letters, by which he will be better able to identify and remember them, than by any instructions that could be given.

For example: Mira and Baten in the Whale, about 10° apart, make up the S. E. or shorter side of an irregular square, with El Rischa in the node of the riband, and another star in the Whale as far to the right of Baten, as El Rischa is above Mira. Again,

There are three stars of equal magnitude, forming a straight line W. of Baten; from which, to the middle star is 100, thence to the W. one 12; and 8° or 9° S. of this line, in a triangular direction, is a bright star of the second magnitude in the coil of the tail, called Diphda.

In a southerly direction, 25° below Diphda, is Alpha in the head of the Phenix, and about the same distance S. W. is Fomalhaut, in the mouth of the Southern Fish, forming together a large triangle. with Diphda in the vertex or top of it.

That fine cluster of small stars S. of the little square in the Whale, constitutes a part of a new constellation called the Chymical Furnace. The two stars N. E. and the three to the southward of the little square, are in the river Eridanus.

HISTORY.-This constellation is of very early antiquity; though most writers consider it the famous sea monster sent by Neptune to devour Andromeda because her mother Cassiopeia had boasted herself fairer than Juno or the Sea Nymphs; but slain by Perseus and placed among the stars in honour of his achievement.

"The winged hero now descends, now soars,

And at his pleasure the vast monster gores.
Deep in his back, swift stooping from above,
His crooked sabre to the hilt he drove."

It is quite certain, however, that this constellation had a place in the heavens long prior to the time of Perseus. When the equinoctial sun in Aries, which is right over the head of Cetus, opened the year, it was denominated the Preserver or Deliverer, by the idolaters of the East. On this account, according to Pausa. nias, the sun was worshipped, at Eleusis, under the name of the Preserver or Saviour

"With gills pulmonic breathes the enormous whale,

And sponts aquatic coluinns to the gale;

Sports on the shining wave at noontide hours,

And shifting rainbows crest the rising showers."-Darwin.

PERSEUS, ET CAPUT MEDUSÆ.

PERSEUS is represented with a sword in his right hand, the head of Medusa in his left, and wings at his feet. It is situ

How is Baten Kaitos situated? What is said of the various figures that different constellations exhibit? Give an example. Of what constellation does that fine cluster of stars of the little square in the Whale, constitute a part? How is the constellation Perseus represented?

ated directly N. of the Pleiades and the Fly, between Andromeda on the W. and Auriga on the E. Its mean declination is 49° N. It is on the meridian the 24th of December. It contains, including the head of Medusa, 59 stars, two of which are of the 2d magnitude, and four of the 3d. According to Eudosia, it contains, including the head of Medusa, 67 stars.

THE HEAD OF MEDUSA is not a separate constellation, but forms a part of Perseus.

It is represented as the trunkless head of a frightful Gorgon, crowned with coiling snakes, instead of hair, which the victor Perseus holds in his hand.

There are, in all, about a dozen stars in the Head of Medusa; three of the 4th magnitude, and one, varying alternately from the 2d to the 4th magnitude. This remarkable star is called Algol. It is situated 120 E. of Almaach, in the foot of Andromeda, and may be known by means of three stars of the 4th magnitude, lying a few degrees S. W. of it, and forming a small triangle.

It is on the meridian the 21st of December; but as it continues above the horizon 18 hours out of 24, it may be seen every evening from September to May. It varies from the 2d to the 4th magnitude in about 3 hours, and back again in the same time; after which it remains steadily brilliant for 24 days, when the same changes recur.

The periodical variation of Algol was determined in 1783, by John Goodricke of York (Eng.) to be 2 days, 20 hours, 48 minutes, and 56 seconds.

Dr. Herschel attributes the variable appearance of Algol to spots upon its surface, and thinks it has a motion on its axis similar to that of the sun. He also observes, of variable stars generally :-"The rotary motion of stars upon their axes is a capital feature in their resemblance to the sun. It appears to me now, that we cannot refuse to admit such a motion, and that indeed it may be as evidently proved as the diurnal mo

Where is it situated? What is its declination, and when is it on the meridian? What is the whole number of its stars? What is the magnitude of its principal ones? Or what constellation does Caput Medusæ form a par? How is it represented? What is the whole number of its stars? What is the magnitude of the principal ones? What are the name and position of the variable star in this constellation? When is it on the meridian, and how long may it be seen? In what time does it vary from the 2d to the 4th magnitude, and back again? How long is it steadily brilliant? When and by whom was its periodical variation determined? What is its exact period? To what does Dr erschel attribute its variable appearance?

tion of the earth. Dark spots, or large portions of the surface, Jess luminous than the rest, turned alternately in certain di :ections either towards, or from us, will account for all the phenomena of periodical changes in the lustre of the stars, so satisfactorily, that we certainly need not look out for any other cause."

It is said, that the famous astronomer Lalande, who died at Paris in 1807, was wont to remain whole nights, in his old age, upon the Pont Neuf, to exhibit to the curious the variations in the brilliancy of the star Algol.

Nine degrees E. by N. from Algol, is the bright star Algenib, of the 2d magnitude, in the side of Perseus, which with Almaack, makes a perfect right angle at Algol, with the open part towards Cassiopeia. By means of this strikingly perfect figure, the three stars last mentioned may always be recognised without the possibility of mistaking them. Algenib may otherwise be readily distinguished by its being the brightest and middle one of a number of stars lying four and five degrees apart, in a large semicircular form, curving to wards Ursa Major.

Algenib comes to the meridian on the 21st December, 15 minutes after Algol, at which time the latter is almost directly over head. When these two stars are on the meridian, that beautiful cluster, the Pleiades, is about half an hour E. of it; and in short, the most brilliant portion of the starry neavens is then visible in the eastern hemisphere. The glories of the scene are unspeakably magnificent; and the student who fixes his eye upon those lofty mansions of being, cannot fail to covet a knowledge of their order and relations, and to 66 reverence Him who made the Seven Stars and Orion."

The Milky-Way around Perseus is very vivid, being undoubtedly a rich stratum of fixed stars, presenting the most wonderful and sublime phenomenon of the Creator's power and greatness. Kohler, the astronomer, observed a beautiful nebula near the face of Perseus, besides eight other nebulous clusters in different parts of the constellation.

The head and sword of Perseus are exhibited on the circumpolar map. That very bright star 23° E. ut Algol, is Capella in the Charioteer.

HISTORY.-Perseus was the son of Jupiter and Danae. He was no sooner born than he was cast into the sea with his inother; but being driven on the coasts of one of the islands of the Cyclades, they were rescued by a fisherman, and carried to Polydectes, the king of the place, who treated them with great humanity, and intrusted them to the care of the priests of Minerva's Temple. His rising genius and manly courage soon made him a favourite of the gods. At a

How may Algenib be distinguished? When is it on the meridian? How long after Algol? When these two stars are on the meridian, what beautiful cluster is half an nour east of it? What is the general appearance of the eastern hemisphere at that time? What is the appearance of the Milky Way around Perseus? What nebulæ have been observed in this constellation?

great feast of Polydectes, all the nobles were expected to present the king with a superb and beautiful horse; but Perseus, who owed his benefactor much, not wishing to be thought less munificent than the rest, engaged to bring hini the head of Medusa, the only one of the three Gorgons who was subject to mortality. The names of the other two were Stheno and Euriale. They were re. "resented with serpents wreathing round their heads instead of hair, having yellow wings and brazen hands; their bodies which grew indissolubly together. were covered with impenetrable scales, and their very looks had the power of turning into stones all those on whom they fixed their eyes.

To equip Perseus for this perilous enterprise, Pluto, the god of the inferna! regions, lent him his helmet, which had the power of rendering the wearer invisible. Minerva the goddess of wisdem, furnished him with her buckler, which was as resplendent as a polished mirror; and he received from Mercury, wings for his feet, and a dagger made of diamonds. Thus equipped, he mounted into the air, conducted by Minerva, and came upon the monsters who, with the watchful snakes about their heads, were all asleep. He approached them, and with a courage which amazed and delighted Minerva, cut off with one blow Medusa's head. The noise awoke the two immortal sisters, but Pluto's helmet rendered Perseus invisible, and the vengeful pursuit of the Gorgons proved fruitless. "In the mirror of his polished shield Reflected, saw Medusa slumbers take,

And not one serpent by good chance awake;
Then backward an unerring blow he sped,
And from her body lopped at once her head."

Perseus then made his way through the air, with Medusa's head yet reeking in his hand, and from the blood which dropped from it as he flew, sprang al those innumerable serpents that have ever since infested the sandy deserts of Lybia.

The victor Perseus, with the Gorgon head,
O'er Lybian sands his airy journey sped,
The gory drops distilled, as swift he flew,

And from each drop envenomed serpents grew.'

The destruction of Medusa rendered the name of Perseus immortal, and he was changed into a constellation at his death, and placed among the stars, with the head of Medusa by his side.

CHAPTER III.

DIRECTIONS FOR TRACING THE CONSTELLATIONS WHICH ARE ON THE MERIDIAN IN JANUARY.

The constellations which pass our meridian in the months of January, February and March, present to us the most brilliant and interesting portion of the heavens; embracing an annual number of stars of the highest order and brightness, all so conspicuously situated, that the most inexperienced can easily trace them out.

TAURUS.

THE BULL is represented in an attitude of rage, as if about to plunge at Orion, who seems to invite the onset by provo cations of assault and defiance. Only the head and shoulders of the animal are to be seen; but these are so distinctly

What is the comparative brilliancy of the constellations which pass the meridian in January, February and March! How is Taurus represented? What parts of the animal are to be seen?

marked that they cannot be mistaken. Taurus is now the second sign and third constellation of the Zodiac; but anterior to the time of Abraham, or more than 4000 years ago, the vernal equinox took place, and the year opened when the sun was in Taurus; and the Bull, for the space of 2000 years, was the prince and leader of the celestial host. The Ram succeeded next, and now the Fishes lead the year. The head of Taurus sets with the sun about the last of May, when the opposite constellation. the Scorpion is seen to rise in the S. E. It is situated between Perseus and Auriga on the north, Gemini on the east, Orion and Eridanus on the south, and Aries on the west, having a mean declination of 16° N.

It contains 141 visible stars, including two remarkable clusters called the PLEIADES and HYADES. The first is now on the shoulder, and the latter in the face of the Bull.

The Pleiades, according to fable, were the seven daughters of Atlas and the nymph Pleione,* who were turned into stars, with their sisters the Hyades, on account of their amiable virtues and mutual affection.

Thus we every where find that the ancients, with all their barbarism and idolatry, entertained the belief that umblemished virtue and a meritorious life would meet their reward in the sky. Thus Virgil represents Magnus Apollo as bending from the sky to address the youth lulus :

"Macte nova virtute puer; sic itur ad astra;
Diis genite, et geniture Deos."

"Go on, spotless boy, in the paths of virtue; it is the way to the stars; offspring of the gods thyself-so shalt thou become the father of gods."

Our disgust at their superstitions may be in some measure mitigated, by seriously reflecting, that had some of these personages lived in our day, they had been ornaments in the Christian church, and models of social virtue.

The names of the Pleiades are Alcione, Merone, Maia, Electra, Tayeta, Sterope and Celeno. Merope was the only one who married a mortal, and on that account her star is dim among her sisters.

Although but six of these are visible to the naked eye, yet Dr. Hook informs us that, with a twelve feet telescope, he saw 78 stars; and Rheita affirms that he counted 200 stars in this small cluster.

The most ancient authors, such as Homer, Attalus, and Geminus, counted only siz Pleiades; but Simonides, Varro, Pliny, Aratus, Hipparchus, and Ptolemy, reckon them seven in number; and it was asserted, that the seventh had been seen before the burning of Troy; but this difference might arise from the dif ference in distinguishing them with the naked eye.

Dr. Hutton is of opinion that Atlas being the first astronomer who discovered these stars, called them by the names of the daughters of his wife Pleione.

What is the numerical order of Taurus among the signs and constellations of the Zodiac? What was its position in the Zodiac before the time of Abraham? How long did it continue to lead the celestial host? What constellation succeeded next? Where is Taurus now situated? How many stars does it contain? What remarkable clusters are in this constellation? Where are these placed? Mention the names of the Pleiades. Which of these seven stars is not seen, and why? Are these six all that can be seen through the telescope?