in the Dippers which never disappear below your horizon? If the reader is not sure about the answer to any of these queries, he should watch the heavens until doubt gives way to certainty. The definition sphere. The expression "celestial sphere," which we have used so freely, has a technical meaning among astrono- of the celestial mers. They define it as a sphere whose radius is infinite, so that the remotest stars lie far within it. The apparent position of any object on this sphere is the point where a line drawn from the observer's eye through the object, and extended to an infinite distance, pierces the sphere. Our first and most difficult lesson in astronomy is at an end. CHAPTER III. THE CONSTELLATIONS IN GENERAL. 66 Look how the floor of heaven Is thick inlaid with patines of bright gold; There's not the smallest orb which thou behold'st, Still quiring to the young-eyed cherubins." -Shakespeare. MEN of the earliest ages were quick to perceive that there were certain striking groups of stars, some of The menagerie. which rudely resembled men and animals. To these they gave names, according to their fancy. Even the most savage nations have not failed to name certain groups. A celestial globe of the present day is covered with a veritable menagerie of monsters, the names of which are largely taken from Greek mythology. We cannot trace the origin of these names satisfactorily ; some of them occur in the most ancient writings. Many of the groupings are highly artificial, and were apparently devised to immortalize the heroes and heroines of mythological tales. Andromeda. She was Her The story of Andromeda is a case in point. a daughter of Cepheus, a king of the Ethiopians. mother, Cassiopeia, imprudently boasted that the beauty of Andromeda excelled that of the Nereids, who were lovely divinities inhabiting the depths of the Mediterranean. Incensed at this, the Nereids betook themselves to Poseidon, the chief divinity of that sea, and prevailed upon him to visit Libya by an inundation, and further to send a sea-monster to ravage the unhappy land. An oracle promised deliverance if Andromeda were given up to the rapacious maw of the leviathan. The clamor of his people obliged Cepheus to yield, and Andromeda was chained to a rock. It so happened that a brave youth, Perseus by name, had just accomplished the daring feat of slaying Medusa, one of the Gorgons. Her snaky head, which turned the beholder to stone, was borne aloft by Perseus in triumph. From her blood sprang Pegasus, the winged horse. As Perseus journeyed homeward through the air, with his horrid trophy, he spied Andromeda. Everybody will admit that the only proper thing for this prehistoric knight to do was to kill Cetus, the seamonster, break the chains of Andromeda, and marry her. He proved equal to all these demands, though her color did not match his. Among the stars we now find Andromeda, Cassiopeia, Cepheus, Cetus, Perseus with Medusa's head still in his hand, and Pegasus. The Great Dipper, to which we paid so much attention in the last chapter, is a portion of the constellation of the Great Bear. One of the Greek legends is that Jupiter, who had a penchant for falling in love with fair women, wooed the nymph Callisto, and metamorphosed her into a bear, lest Juno should enliven his domestic affairs unduly. But Juno was not deceived by this ruse, and persuaded Diana to slay the bear. Jupiter then gave Juno a standing lesson about meddling with his royal prerogatives by placing Callisto among the stars, under the name of Arctos, the Greek word for bear. The Iroquois Indians, when America was discovered, are said to have called this star-group Okouari, which signifies bear. Perseus. The Great Bear. The Iroquois. The Greeks also applied the designation "The "The Chariot." Chariot" to the Great Dipper. The bowl may be considered as the body of the chariot, and the handle as the pole. This conceit survives in England, where the appellation "King Charles' Wain" is used, and in France, where it is often called "David's Chariot." The ancient constellations. Christian heavens. Heraldic constellations. The zodiac. Ptolemy, who did so much in systematizing the astronomy of his day, has transmitted to us forty-eight constellations, which are now called the "ancient constellations," and are accepted and retained largely on account of their historic interest. Their names are thoroughly woven into astronomical literature, both popular and scientific. Some attempts have been made to dispossess the ancient heroes of their happy hunting grounds. Early in the eighth century the Venerable Bede advocated a plan for Christianizing the heavens. Henceforth the apostles were to have conspicuous places in the sky. Peter was to take the place of the Ram, as was fitting, and the other disciples were to be distributed around the zodiac after him. In the seventeenth century Professor Weigel, of the University of Jena, proposed that a series of heraldic constellations be formed, the zodiac being composed of the arms of the twelve foremost families in Europe. But this attempt to displace the old scheme, as well as all others, failed. The zodiac, or zone of animals, is a belt sixteen degrees wide, which extends around the sky like the stripe on a croquet ball. From antiquity onward much attention has been paid to the constellations in it. Imagine that a line from the center of the sun to the earth's center is prolonged through the earth, and extended till it meets the celestial sphere. While the earth travels round the sun in its annual journey, the extremity of this line traces a circle on the celestial sphere. The name of the circle is "the ecliptic." The ecliptic. To an eye situated at the sun's center the earth would To an eye placed similarly appear to appear to travel around the ecliptic. The ancients gave to certain small and conspicuous groups special names, such as the Pleiades and the Hyades. Individual stars of pronounced brightness were also named. We glance for a moment at some interesting facts concerning the Pleiades. The Pleiades were often used in connection with the calendar by ancient peoples, and are still employed thus by some savage tribes. This group of stars is situated near the ecliptic. The sun, therefore, in his annual journey, gets so near them at one time of the year that they cannot be seen for several days. Six months after this time, when the sun has gone half way round the heavens, it is opposite the Pleiades, so that they rise when it sets, and vice versâ. From Hesiod we learn that the Greeks in his day accounted the winter season as commencing when the Pleiades were seen low down in the east soon after sunset, and the summer season when they set soon after the sun. Other names. The Pleiades. Islanders. The Society Islanders are said to have divided the The Society year into two parts, according to the position of the Pleiades. That half of the year during which they could be seen early in the evening was called “the |