To the southeast of Orion, on the line of the Three Kings, shines the most magnificent of all the stars, _Sirius_, or _Alpha_ of the constellation of the Great Dog. This constellation rises in the evening at the end of November, passes the meridian at midnight at the end of January, and sets at the end of March. It played the greatest part in Egyptian astronomy, for it regulated the ancient calendar. It was the famous Dog Star; it predicted the inundation of the Nile, the summer solstice, great heats and fevers; but the precession of the equinoxes has in three thousand years moved back the time of its appearance by a month and a half; and now this fine star announces nothing, either to the Egyptians who are dead or to their successors. But we shall see farther on what it teaches us of the grandeur of the sidereal universe. The _Little Dog_, or Procyon, is found above the Great Dog and below the Twins (Castor and Pollux), to the east of Orion. With the exception of Alpha Procyon, no brilliant star distinguishes it. The two double-stars, 61 Cygni and Alpha Centauri, are formed each of two orange suns. In the Southern Cross there is a wonderful group of stars, consisting of about one hundred and ten suns, nearly all invisible to the naked eye. Among the principal stars of this group, which Sir John Herschel described as being, when viewed through a powerful telescope, like “a casket of variously-colored precious stones,” are two red stars, two bright green, three pale green, and one of a greenish blue. The splendor of these natural illuminations can hardly be conceived by our terrestrial imagination. The tints which we admire in these stars from here can give but a distant idea of the real value of their colors. Already, in passing from our foggy latitudes to the limpid regions of the tropics, the colors of the stars are accentuated, and the sky becomes a veritable casket of brilliant gems. What would it be if we could transport ourselves beyond the limits of our atmosphere? Seen from the moon, these colors would be splendid. Antares, Alpha Herculis, Pollux, Aldebaran, Betelgeuse, Mars, shine like rubies; the Polar Star, Capella, Castor, Arcturus, Procyon, are veritable celestial topazes; while Sirius, Vega, and Altair are diamonds, eclipsing all by their dazzling whiteness. How would it be if we could approach the stars so as to perceive their luminous disks, instead of merely seeing brilliant points destitute of all diameter? Blue days, violet days, dazzling red days, livid green days! Could the imagination of poets, could the caprice of painters, picture on the palette of fancy a world of light more astounding than this? Could the mad hand of the chimera, throwing on the receptive canvas the strange lights of its fancy, erect by chance a more astonishing edifice? CHAPTER XXV. GROUPS AND CLUSTERS OF SUNS.