In the star-maps, the Centaur is shown halting at the edge of the star stream and aiming across its mist of light at the great red star which flutters on the heart of the Scorpion. The Scorpion, however, is pictured as observing with interest the nearby tail of the many-headed watersnake although he is almost crushed by the mighty foot of the giant Ophiuchus whose head lies high up in the sky against that of Hercules. The Centaur's group of stars, the constellation of Sagittarius, is a zodiacal constellation, with the arrow and part of the bow for its symbol. ♐︎ There is also another centaur in the sky but no part of him can be seen in these latitudes. This constellation contains two famous stars, Alpha and Beta Centauri, sometimes called the "Southern Pointers" because they point to the figure of the Southern Cross. [Figure 85] These two stars are on the Centaur's forefeet. Alpha Centauri is the nearest star to the earth, lying at a distance of only 25,000,000,000,000 miles. Unthinkable as this number of miles may seem, it is such a short distance across the fields of the heavens that Alpha Centauri and our sun would appear to be very close together as seen from the planets of other stars. Thus our kingdom of the sun is not an isolated isle among the dim star-lights of space, but shines as one of the stars in a community of such kingdoms. The tiny star 61 Cygni is the nearest star to the earth as seen from the northern hemisphere. HYDRA, THE WATER-SNAKE [Figure 86] Hydra, the Water-snake, first rears a venomous head above the eastern horizon on January 5th about 9 P. M. He slowly squirms along the southern horizon, his length being so appalling that it takes him four months to completely pass any one point in the sky. Along the body of this Water-snake are scattered a few 4th magnitude stars. The twinkling lights of these stars may be followed far to the south and then east, almost to the boundary of Scorpio. Indeed, when the Watersnake is completely above the horizon, as he is in April, these stars show that his long length stretches over nearly a quarter of the sky! Some poets state that this creature had one hundred heads, others claim that he had only nine. However this may be, there is only one that is easily traced and this lies, triangle-shaped, just below Leo, the Lion. The only noticeably bright marking on the Water-snake is the orange-hued star of the second magnitude which lies upon the reptile's heart. This star is called Cor Hydræ after its location, but it also has the name of Alphard, the Solitary. Since the naming of the star, science has discovered the latter name to be rather a misnomer for it has a telescopic companion of a pale shade of green. Cor Hydræ rises in the early evening on the 21st of February, and passes the meridian about 9 o'clock during the middle of March.