The first zodiac of which we have written record is a lunar one of 28 constellations, which is referred to in the “Canon of the Emperor Yaou,” a Chinese emperor who began to reign in B.C. 2356. “Yaou commanded He and Ho, in reverend accordance with their observation of the wide heavens, to calculate and delineate the movements and appearances of the sun, the moon, the stars, and the zodiacal spaces, and so to deliver respectfully the seasons to the people.” That these astronomers studied “the movements and appearances” of the sun by means of the gnomon as well as observations of the stars is plain from what follows, where directions are given for determining the solstices. One astronomer was commanded by the Emperor to “reside at Nankeaou and arrange the transformations of the summer, and respectfully to observe the extreme limit of the shadow. The day, he said, is at its longest, and the star is _Ho_: you may thus exactly determine midsummer.” _Ho_ (= fire) is the fiery red Antares in Scorpio. The star of the winter solstice, when “the day is at its shortest” was Maou, which is the Pleiades. Directions are also given for observing the spring and autumn equinoxes, when day and night are of medium length, and certain other stars are to be observed.[7] ------------------------------------------------------------------------ [7] Journal of the British Astronomical Association, June 24, 1909, report of a lecture on Chinese astronomy by E. B. Knobel, F.R.A.S. ------------------------------------------------------------------------ The Hindus had also a lunar Zodiac, but with only 27 constellations, and the Arabs had their 28 “Mansions of the Moon.” These 27 or 28 asterisms were evidently suggested by the moon’s sidereal period of 27¼ days. But her synodical period, _i.e._ her revolution with regard to the sun, in which she runs through her phases, is much more convenient for marking a period of time for general uses, and this month of about 30 days has been almost universally adopted by primitive peoples, the first day being counted when the crescent new moon begins to be seen after sunset. From this custom arose another, that of counting the beginning of the day from sunset, but in various times and places other starting-points have been chosen—sunrise, midday, or midnight. Twelve of these synodical lunar months are nearly equal to one solar year, and this doubtless suggested the solar zodiac of twelve constellations, each constellation marking the portion of sky passed over by the sun in a month. The Chinese “Yellow Path of the Sun” contained twelve animals, the Mouse, Cow, Tiger, Rabbit, Dragon, Serpent, Horse, Ram, Ape, Hen, Dog, and Pig. These animals were widely adopted by other nations—the Koreans and the Japanese, the Mongols of Tibet, the Tartars, and the Turks.