and particularly in the book of Job; to which some critics have assigned a date even earlier than the time of Moses.*

The portion, or zone, of the heavens within whose limits the paths of the sun and planets were found to be confined, received the name of the Zodiac, and included twelve remarkable constellations, called signs, by a reference to which the positions of the movable bodies were determined. It is on all hands agreed that the origin of astronomical observation is to be traced to the East; but the particular people among whom it commenced, as well as the date, are lost in obscurity. It is most probable that its rise was simultaneous among various early nations, and its progress must have been so gradual that it would be impossible to fix any precise period for its commencement, even were our knowledge of remote antiquity far more complete than it is. Meanwhile, it is not an uninteresting topic of reflection to notice the probable circumstances which attended the early cultivation of these sciences. The fine climate and clear atmosphere of the oriental regions render the heavens an object of far more striking and attractive splendour than they appear to us. The habits of pastoral life were such as to lead the people of those regions to the nightly contemplation of the glorious spectacle thus placed before their view. The dullest apprehension could scarcely fail to be impressed with admiration and curiosity, and to recognise some of the more obvious changes which would soon be found going on among the brilliant objects before them. When these changes were found closely connected with those of the seasons, other reasons of practical utility would mix themselves up with the spirit of contemplation; and the importance of celestial phenomena, in connection with the institutions of civil society, and with the labours of agriculture, would by degrees lead to more extended and precise observations. Other motives would not be wanting from the natural influence of those feelings of religious awe with which

*See Hales's Chronology, ii, 57.

those most glorious portions of the visible universe would be contemplated; and while their real nature was unknown, and no approach as yet made to an apprehension of the laws and causes of their motions, it was far from unnatural that that adoration which can properly originate only out of a perception of causation and design, and rise to the great origin of that design, should have been degraded to the character of a grovelling superstition, and have been transferred to the heavenly bodies themselves.

In immediate connection, too, with these last motives, was the application of a knowledge of the stars to the purposes of astrology. The desire to penetrate the future, one of the most deeply seated in ignorant minds, was really gratified as soon as astronomical observation had reached far enough to notice those periods called cycles, in which the celestial motions and configurations recurred. The prediction of the future appearances of the sky, and, above all, of eclipses, led the ignorant to expect, and the learned too frequently to keep up the expectation, that other events also might be predicted. Hence the combination of motives which tended to foster the cultivation of astronomy, and to impart to it a sacred character in the early periods of human society. The appearances of eclipses and of comets were regarded as prognostics of misfortune and public calamities. The conjunctions and configurations of the planets were considered as influencing the fortunes of states and individuals; and thus their motions came to be studied, though often with worthier motives, yet very generally with the view of being made subservient to the prediction of future events, and not unfrequently as giving to the initiated a command over the multitude, and as furnishing an engine of priestcraft. It is also far from improbable that in many cases pretences accordant with popular superstition were held out merely as an excuse and protection to the real enquirer after knowledge; whose pursuits, if openly avowed, might have met but with reproach and ridicule, or even with opposition and

persecution, at the hands either of people or rulers, equally incapable of appreciating their value. If, however, some motive were assigned more level to the apprehensions of the vulgar, and especially one connected with their superstitions, this would at once secure their respect and enhance their reverence for the individual engaged with such lofty objects.

Several ancient nations have laid claim to considerable advances in astronomy at periods of antiquity far beyond reasonable probability. Thus the Chinese and the Indians each refer to a date of about 3000 years before the Christian era, as that to which their astronomical records reach, and the Chaldeans to more than 2000 years. But though these extravagant claims are unsupported by evidence, and at variance with all probability, we have still good grounds for considering the science to have made some progress among these nations upwards of 1000 years before our era.

The Chaldeans.

The antiquity of the Chaldean astronomy rests upon the authority of Porphyry, who says that Callisthenes transmitted to Aristotle a series of observations made at Babylon, during a period of 1903 years preceding the capture of that city by Alexander, or reaching back to about 2234 B. c. Ptolemy, however, who afterwards made great use of them, quotes none prior to 720 B. c. This certainly is not conclusive against the existence of any of earlier date, though it doubtless furnishes a strong presumption.

These early observations, though probably but of a rude description, yet possess a peculiar interest as having furnished the first materials for those comparisons of the state of the heavens at distant periods, by which the great progressive changes in our system have been brought to light.

The Chaldeans appear to have found, with considerable accuracy, the length of the remarkable cycle of 6585 days or about 18 years, in which the series of

the moon's revolutions under the same conditions as compared with those of the sun come round again, so that very nearly the same series of eclipses will recur. By these means they were able to predict eclipses with tolerable accuracy. They observed, with great care, the motions of the planets *; and according to some testimonies (though contradicted by others), they would appear to have formed just notions of the nature of comets. Herodotus ascribes to them the duodecimal division of the day, and the use of the gnomon.

The Chinese.

Our knowledge of the Chinese astronomy is entirely derived from the laborious researches of the Jesuit missionaries stationed in that country, and in particular from the works of father Gaubil. The Chinese records refer to the date of 2461 B. c., at which they assert a remarkable conjunction of five planets took place. This point has been much discussed; and it seems, on the whole, most probable, that it was a purely fictitious epoch obtained by reckoning backwards. They also mention a solar eclipse in the reign of the emperor Tchong Kang, for neglecting to predict which the two chief astronomers were put to death. To this, dates are assigned, varying between B. c. 2159 and 2128. By calculating backwards, on modern data, Gaubil and others find an eclipse in the last-mentioned year; but the data are so completely uncertain that little weight can be attached to the statement. No eclipses are mentioned for many centuries after this.

More importance may fairly belong to the recorded observation of the length of the shadow of a gnomon, compared at the summer and winter solstices, about B.c. 1100. The obliquity of the ecliptic deduced is found to agree very closely with what would result from the modern calculation of the diminution of the obliquity founded on the theory of gravitation: this

See History of Astronomy, Lib. Useful Knowledge, p. 2. et seq.

agreement is the more remarkable, as the diminution was unknown to Gaubil. Observations of about the same period, on the position of the winter solstice, compared with others of about the date B. c. 600, have been found, in like manner, to agree with deductions from the law of the precession of equinoxes. During the period B. c. 720-481 observations of many eclipses are recorded, several of which have beer verified by calculating backwards; appearances of many comets also are described. The regulation of the calendar and the prediction of eclipses, were regarded in China as matters of national importance, and a mathematical tribunal was established for the superintendence of astronomy; but the obstinate attachment of the Chinese to whatever had become established extended itself to their astronomy, and repressed all improvement in science.

Such is the view of the Chinese astronomy, derived from authorities of considerable weight. A different opinion, however, has been maintained by Mr. Davis*, who has contended, from an elaborate examination, that nothing really original in astronomical science can be attributed to the Chinese, who, he conceives, were entirely ignorant of its objects and principles before its introduction among them by the Arabians in the middle ages.

On this one subject, he says, "That singular nation has deviated from its established prejudices and maxims against introducing what is foreign, they have even adopted the errors of European astronomy;" for he discovered, in a Chinese book, the exact representation of the Ptolemaic system. He adds, "It is indeed im possible not to smile at the idea of attributing any science to a people whose learned books are filled with such trumpery as the diagrams of Fo-hi, and a hundred other puerilities of the same kind."

Mr. Davis offers several other proofs of the propensity of the Chinese to appropriate to themselves the

Phil. Trans. 1823.