BY D. W. BELISLE.

ARGO NAVIS.—This beautiful constellation occupies a large space in the southern hemisphere, though few of its stars are seen in our latitude. It is situated south-east of Canis Major, and may be known by three stars forming a small triangle in the prow and deck of the ship. Sixteen degrees south of this triangle is a very brilliant star in the row-lock, called Naos. This star is the south-east corner of the Egyptian X, and comes to the meridian on the 3d of March, when, for a few hours only, it is visible in our latitude. It is then eight degrees above the horizon. Seven degrees south of Naos, on the 7th of March, may be seen Gamma, a brilliant star which, for a few moments, skims the horizon, and then disappears. It is never in our latitude more than one degree above the horizon, and is rarely visible. Thirty-six degrees south of Sirius is Canopus, a star of great brilliancy and beauty. It is of the first magnitude; but, having a south declination of fifty-three degrees, it cannot be seen in the United States. Twenty-five degrees east of Canopus is Miaplacidus, a star of the first magnitude in the oars of the ship. This is also invisible to us. This constellation contains sixty-four stars, which, seen from the southern hemisphere, are of singular beauty and brilliancy.

According to Greek mythology, the ship was placed in the heavens to perpetuate the expedition of Jason into Colchis to recover the Golden Fleece. Hebrew mythology also claims the origin of it, and with them it perpetuates Noah's Ark, in which a remnant of every living thing was saved during the deluge. There is good foundation for the supposition that the Argonautic expedition is founded on certain Egyptian traditions relating to Noah's Ark, and that the Greeks located them within their territory, and claimed them as a triumph of Neptune, the god of the sea.

CANCER.—This constellation is situated directly east of the Twins, and occupies considerable space in the heavens. Its stars are small and scattered, yet it may readily be distinguished by three small stars in the centre, which form a triangle, and nearly in the centre of this triangle is a nebula, sufficiently luminous to be distinguished with the naked eye. The appearance of this nebula to the unassisted eye is not unlike the nucleus of a comet, and it was repeatedly mistaken for the comet of 1832, which passed in its neighborhood. On being viewed through a telescope, it resolves into distinct stars, and we thus catch a glimpse of an interminable range of systems upon systems, and firmaments upon firmaments; and, in contemplating the immensity of space that encircles them, the imagination becomes bewildered and lost. Who can trace the boundless depths of air?

These minute stars have the appearance of planets with oval disks, somewhat mottled, but approaching in vividness to actual planets. This constellation is on the meridian the 3d of March.

The Greeks assert that Cancer received its origin through the favor of Juno, who sent a sea-crab to annoy Hercules during his famous contest with the Lernean monster. The Chaldeans, however, represented the cluster by the figure of an ass, whose name, in the Chaldaic, is muddiness. It is supposed to allude to the discoloring of the Nile, which began to rise when the sun was entering Cancer.

VIA LACTEA.—

There is a luminous zone, varying from four to twenty degrees in width, which passes quite round the heavens, called by the Greeks Galaxy, by the Latins Via Lactea, which, in our tongue, is Milky Way. "Of all the constellations which the heavens exhibit to our view, this fills the mind with the most indescribable grandeur and amazement. When we consider what unnumbered millions of mighty suns compose this cluster, whose distance is so vast that the strongest telescope can hardly separate their mingled twilight into distinct specks, and that the most contiguous of any two of them may be as far asunder as our sun is from them, we fall as far short of adequate language to express our ideas of such immensity as we do of instruments to measure its boundaries."

All the stars in the universe have been arranged into groups, which are called nebulÆ or starry systems. The fixed star which we call our sun belongs to that extensive nebula the Milky Way, and, though evidently of such immeasurable distance from its fellows, it is probably no farther from them than they are from each other. We know very little of the number and economy of the stars that compose this group. Herschel counted five hundred and eighty-eight in a single spot, without moving his telescope. He found the stars unequally dispersed in all parts of the constellation, and apparently arranged into separate systems or clusters. In a small space in Cygni, the stars seem to be clustered into two distinct divisions, and in each division he counted upwards of one hundred and sixty-five thousand stars.

Various changes are constantly taking place among the nebulÆ. Several new ones are being formed by the dissolution of larger ones, and it has been ascertained beyond a doubt that many nebulÆ of this kind are detaching themselves from the Milky Way at the present time. In the body of Scorpio there is a large opening, four degrees broad, entirely destitute of stars, through which we get a glimpse of regions of space beyond.

Already nearly three thousand nebulÆ have been observed, and if each contains as many stars as the Milky Way in that portion of the heavens which lies open to our observation, there must be several hundred millions of stars. How vast and unfathomable to mortal mind must be the ways and attributes of that intelligence that creates and guides in unison these starry worlds!

This nebula may be traced in the heaven, beginning at the polar star, through the constellations Cassiopeia, Perseus, Auriga, part of Orion, and the feet of Gemini, where it crosses the Zodiac, thence over the equinoctial into the southern hemisphere, through Monoceros and Argo Navis, St. Charles's Oak, the Cross, the Altar, and the feet of the Centaur. Here it passes over the Zodiac into the northern hemisphere, divides itself, one branch running through the tail of Scorpio, the bow of Sagittarius, the shield of Sobieski, the feet of Antonius, Aquila Delphinus, the Arrow, and the Swan. The other branch passes through the upper part of the tail of Scorpio, the side of Serpentarius, Taurus Poniatowski, Goose, neck of the Swan, head of Cepheus to the polar star, where it again unites to the place of its beginning.

Anciently, the Milky Way was supposed to be the sun's track, and its luminous appearance was caused by the scattered beams left visible in the heavens. The Pagans maintained it was a path their deities used in the heavens, which led directly to the throne of Jupiter.