The autumnal equinox, or the point where the ecliptic crosses to the south of the equator, is in Virgo, and lies about fifteen degrees northeast of Spica. LIBRA Libra is the next zodiacal constellation, and it is a small one. The sun passes through it in about twenty-three days. It may be known by four fairly bright stars which form a more or less imperfect square. The ecliptic passes along the southern edge of this figure. During the summer and early autumn, Libra is best seen. It is then passing across the southern sky, drawing nearer the west each evening. A planet passing across this constellation would always be easy to identify, since it would always be so much brighter than any star in this region. The sun enters Libra about October 29th, and it is not visible in the evening during the rest of the year. SCORPIO It is a joy to know Scorpio, quite aside from its connection with the path of the planets. It is a brilliant constellation, best seen during the summer and autumn, as it passes across the southern sky. It is the most southerly of any of the constellations of the zodiac; but the ecliptic passes through only a very small portion of the northern part of it, so the sun does not reach the most southerly point in its path while it is in this constellation. Scorpio may be best identified by its brilliant deep-red star Antares,[5] which is supposed to lie in the heart of the Scorpion. The whole figure makes a splendid serpent-like sweep toward the southern horizon, and is one of the most conspicuous objects just west of the Milky Way in the south in summer. [5] See “Antares” in _The Friendly Stars_. The line of the ecliptic runs about three degrees north of Antares; hence the planets in their course sometimes pass very near it. Jupiter has been in that region all this year (1912), and will not be far from there the early part of 1913. Mercury and Mars both have something the color of Antares; but this is not likely to result in any confusion. The star is always there, and in the same relative situation with reference to the other stars. When Mars is there, it will always be above the star. Mercury can seldom be seen when he is in Scorpio. If he is in greatest elongation while there, he will still be near the sun, and the sun, as seen from the middle latitudes, is so far south and so near the horizon when in that part of the ecliptic that the situation will not be favorable for seeing the planet. Farther south, and particularly in high altitudes, Mercury could be well seen in Scorpio, but if the position of Antares is kept in mind, Mercury will easily be recognized as a stranger in the constellation. The sun enters Scorpio about November 21st, and the constellation then ceases to be visible in the evening sky until the following May. It is in its greatest glory during the summer and early autumn. SAGITTARIUS