CHAPTER XVI.

THE ANCIENT ASTRONOMY OF CHINA.

A conjunction of the planets taken as an epoch by the Chinese.--The commencement of the Chinese year at one time coincided with that of the Hindus. A regulation of the seasons by the Emperor Yao.--Ancient observations made in China with the gnomon.-Destruction of the Chinese writings. The Chinese histories contain catalogues of celestial phenomena. Alleged resemblances of the Chinese sphere and those of the Hindus and Egyptians.-Divisions of time in use among the Peruvians and Mexicans.

THE astronomy of China may vie with that of India in the remoteness and obscurity of its origin; and, like the latter, it is supposed to have commenced with a primitive epoch at which the sun, moon, and several planets were in conjunction. In a Chinese work alleged to have been composed about the year 204 Before Christ, this conjunction is said to have been observed or predicted by the Emperor Tchuen-hi, and to have taken place in the constellation Xi; and the writer asserts that 143,127 years had elapsed between the time of the conjunction and that in which he lived; now M. Bailly disregarding that pretended interval of time, has found by computation that Mars, Jupiter, Saturn and Mercury were together, on the morning of February 28, Julian reckoning, in the year 2449 B. c. in a part of the heavens situated, in longitude, between the eighth and twenty-fifth degree of the sign Pisces, a space which must have been, then, comprehended between the star a Arietis and the Pleiades: and hence it is inferred that this portion of the zodiac must have coincided with the Chinese constellation Xi. The same astronomer found, also, that a conjunction of the sun and moon took place on the same day, in the nineteenth degree of the sign Aquarius, or near the star Piscium; these he conceives, therefore, to have been the phenomena alluded to, which is not improbable since historians have placed in the Astr. Ind. Chap. IX. sect. 2.

Martini Historia Sinica, Tom. I.

same age the reign of the above mentioned monarch. According to Père De Mailla, who translated the Annals of the Empire, Tchuen-hi collected all the ancient observations which had been made in the country and gave precepts for computing the motions of the sun, moon, and planets; and it appears from the expression in the original work that, during the reign of this prince, and in the year which was distinguished by the abovementioned conjunction of the planets, the first day of the spring quarter, by which we are to understand the commencement of the year, occurred previously to the first day of the first moon. Mailla, who finds by computation that the conjunction took place in 2461 B. c. makes the time of new moon two days later than the arrival of the sun at a point in the ecliptic whose longitude was 10° 15°, which, then, nearly coincided with the star ? Piscium, that is with the first point in the fixed zodiac of the Hindus: now the ancient Chinese always made their spring commence when the sun had that longitude, or was 45 degrees westward of the equinoctial point; it follows therefore that, in the time of Tchuen-hi, the place of the sun at the beginning of the Chinese year, and the origin of the Hindu zodiac were identical; and Bailly thence infers that the coincidence was the result of design on the part of the prince; no other reason, he observes, can be given why the year should be made to begin when the sun was in a part of the heavens which is not distinguished by any remarkable star, nor coincided with either of the equinoctial or solstitial points; and the circumstance may be considered favourable to the opinion that the astronomy of China was derived, at some period, from that of India; or that the people of both countries drew their knowledge of the science from a common source. The origin of the Chinese fixed zodiac, or the commencement of their constellation Hiu, is not however the same as that of the Hindus; it is supposed by Père Glaubil to have coincided, in the time of the Emperor Yao, with the place of the winter solstice; and, if we adopt Bailly's opinion of the age in which this prince lived, that place must have been about the middle of the constellation Aquarius.

a Hist. Gen. de la Chine, Tom. I.

From the abstract of the Chinese History given by M. de Guignes we learn that the emperor Yao, along with the other measures adopted for the improvement of his people, promoted among them the study of astronomy, and he particularly applied himself to the correction of the calendar; he directed that the length of the year should be 365 days and, to determine the seasons, he appointed the use of an intercalary moon; probably signifying that an additional month, or 30 days, was to be introduced every 120 years. From the means he proposed for distinguishing the commencements of the seasons an effort has been made to ascertain the age in which he lived; according to Pere Souciet, he prescribed that the equality of the days and nights and the constellations Niao and Hiu should indicate the vernal and autumnal seasons respectively; and the longest and shortest days with the constellations Ho and Mao should mark, respectively, the summer and winter. Now, of these constellations, it is known that Mao designates the Pleiades; and, as all the four should be in or near the cardinal points of the ecliptic, it will follow that Ho must coincide with the beginning of Scorpio, Niao with the beginning of Leo, and Hiu with that of Aquarius; but it is doubtful in what sense these constellations were to indicate the seasons; for, if we suppose that their heliacal risings or settings took place on the respective days of the equinoxes or solstices, the epoch would be so remote as to be beyond the bounds of probability: it has, therefore, been considered that those days were indicated by the arrival of the constellations on the meridian soon after sunset; and if, agreeably to this supposition, we place on the meridian a point of the ecliptic whose longitude is 100 degrees, in which case the vernal equinox would be about 10 degrees below the horizon towards the West, the time at which the constellation Niao, or the first stars of Leo (whose longitudes are now about 150 degrees) occupied the point on the meridian, would be about the year 1800 Before Christ; hence the reign of Yao may be placed at that period, and M. Bailly by a similar supposition places it about 500 years earlier; but it must be owned that, since the

Observations Mathematiques Astronomiques, etc., tirées des livres Chinois.

supposition may be varied considerably, the result obtained from this kind of estimate is extremely uncertain.

If what has been above ascribed to Yao be correct we may conclude with La Place that, in the time of this prince, the astronomers of China must have observed the arrival of the sun at the equinoxes or solstices and the transits, or passages, of stars over the meridian; but it should also be remarked that in such observations no great precision was necessary nor, probably, attempted. Before the time of Yao, a representation of the heavens on the surface of a sphere is said to have been made by one of the sovereigns of the country; but modern writers have ascertained that the word formerly translated sphere is the same as that used to signify the cover of a vessel; and the most that can be inferred from the account is that, in some remote age, there had been formed, in China, a sort of planisphere exhibiting rudely, like those of Egypt, a view of the constellations, or some of the principal stars.

From a Chinese MS. sent by Père Glaubil to M. Delisle, it appears that the regent Tcheou-Kong, who is said to have lived between the years 1104 and 1098 Before Christ, caused a number of observations to be made; and three, on the lengths of the meridional shadows cast at the times of the winter and summer solstices by a gnomon which was set up at Loyang in the province of Honan, have, fortunately, been preserved. From these, La Place, after making the necessary corrections for the sun's semidiameter, for refraction and parallax, has determined the latitude of the place of observation to be 34° 47′ 10", north, and the obliquity of the ecliptic, 23° 54′ 3′′; and, supposing the observations to have been made in the year 1100 Before Christ, the value of this element exceeds that which is found, for the same period, from the formulæ in the Mecanique Celeste, by 2′ 4′′ only, a difference which is inconsiderable: but nothing is more uncertain from the dubious light afforded by the Chinese histories, than the age in which that prince is supposed to have lived, and the rude nature of the observations renders the evidence resulting from the near coincidence of the values of the obliquity any thing but conclusive.

The use of the gnomon must, however, be admitted to have

been very ancient among the Chinese, but the first notice obtained concerning it, from any of their written works, is that given in the Tcheou-li, which is said to have been composed two hundred years before Christ; it is there stated that the length of the shadow, at noon, is less than at any other time, on a given day; that the meridional shadow becomes longer as we proceed towards the north, and that, in proceeding towards the east, the shadow arrives earlier at the minimum. The particular gnomon alluded to is said to have been 8 feet high and to have consisted of a vertical pillar with a graduated horizontal bar, at its lower extremity, by which the angular distance of the celestial body from the zenith might be computed; and Cocheou Kong, who lived in the year 1280 of our era, erected one whose height was 40 feet and by which the obliquity of the ecliptic was found, in his days, to be 23° 33′ 40": between the ages of Tcheou Kong and of the last mentioned prince three other observations of the obliquity of the ecliptic appear to have been made; the first in the year 50 Before Christ, and the others in the years 460 and 630 since the commencement of our era; all in the same manner, and, which is the best proof of the reality of the observations, all agreeing in the indication of a progressive diminution of that element. The Jesuit missionaries from whom so much information has been obtained concerning the state of the sciences in China, allege that Clepsydra were used at a period as remote as the age of Yao for measuring time and the divisions of the zodiac, and they describe a machine having some resemblance to an armillary sphere with which it is pretended that astronomical observations were then made: but it is very certain that, if such a machine existed in that country, it was at a much later age than that of Yao, when the people were only beginning to form written characters and when, consequently, they cannot be supposed to have constructed such instruments as armillary spheres for the purpose of determining the places of stars.

The possibility that the ancient Chinese may have acquired some knowledge of the retrogradation of the equinoctial or solstitial points has been inferred from the positions assigned to the winter solstice by means of two recorded observations; of