Page:Popular Science Monthly Volume 79.djvu/530

526 stream in that direction to render possible a closer approach to the Pole.

Another graduate of the ancient system in Canton offered the following as an explanation of why he thought it was hotter in Peking than in Canton:

"At Peking the earth is thicker than at Canton, and so a person living on top of the earth is nearer the sun at Peking than at Canton and hence gets more heat, and we know that the earth is thicker at Peking than at Canton because in Peking you have to dig many tens of feet to get water, whereas in Canton you can readily strike water at ten to twenty feet."

4. Astronomy—Astrology.—The precise attainments of the ancient Chinese in astronomy are not easily understood from the scanty records. To the burning of all native scientific books, except those on agriculture, medicine and astrology, by imperial order in 221 the Chinese attribute the loss of a mass of astronomical learning. Wylie furnishes a list of 925 solar and 574 lunar eclipses, extracted from Chinese works, observed between 2150 and A.D. 1785. The earliest known record of an eclipse occurs, though imperfectly, in the ancient "Shu-King," or "Book of History." Retrospective calculation shows that it may have occurred as early as the autumn of 2158 B.C. Simple methods for predicting solar eclipses seem to have been in use in China before 2000 but this eclipse of 2158  is said to have appeared unexpectedly and to have so disturbed the emperor that he at once executed the two court astronomers for failing to predict it!

In the Chinese canonical books thirty-eight solar eclipses are mentioned, eighteen of which agree with modern lists, but the others seem in error in either month or year, though the day is-always correct. This suggests that the records are reliable and that the non-agreement is probably due to an imperfect knowledge of the ancient calendar, particularly with reference to intercalation and the beginning of the year, which are probably irregular. Intercalations were probably introduced by Yao about 2637 B.C., but it is hardly likely that they have continued without variation to this day. Romish missionaries rectified the calendar about 1700 and have aided in its preparation until recently. A cycle of sixty years was adopted in very early times, but there is no record of when or why this number was selected. The Chinese year is lunar, but its commencement is regulated by the sun. New Year falls on the first new moon after the sun enters Aquarius, which makes it come not before January 21 nor after February 19.

Comets, whose brilliancy enabled them to be seen, have been carefully noted by the Chinese, because their course among the stars is thought to determine their influence as portents. A list of 373 comets mentioned in Chinese records has been published, extending from 611