Essay on the Theory of the Earth

by baron Georges Cuvier

Notwithstanding all that is said to the contrary, the same opinion must be formed of the astronomical knowledge of the Chaldeans. It is natural enough to think, that a people who inhabited vast plains, under a sky perpetually serene, must have been led to observe the course of the stars, even at a period when they still led a wandering life, and when the stars alone could direct their courses during the night; but since what period were they astronomers, and to what perfection did they carry the science? Here rests the question. It is generally allowed that Callisthenes sent to Aristotle observations made by them, and which referred to a period of 2200 years before Christ; but this fact is related only by Simplicius[201], as stated upon the authority of Porphyry, and 600 years after Aristotle. Aristotle himself says nothing on the subject, nor has any creditable astronomer spoken of it. Ptolemy mentions and makes use of ten observations of eclipses really made by the Chaldeans; but they do not refer to an earlier period than that of Nabonassar (721 years before Christ); they are inaccurate also; the time is expressed only in hours and half-hours, and the shadow only in halves or fourths of the diameter. Notwithstanding, as they had fixed dates, the Chaldeans must have had some knowledge of the true length of the year, and some means of measuring time. They appear to have known the period of eighteen years, which brings back the eclipses of the moon in the same order; a piece of knowledge which the mere inspection of their registers would promptly afford them; but it is certain that they could neither explain nor predict eclipses of the sun.

It is from not having sufficiently understood a passage of Josephus, that Cassini, and after him Bailly, have imagined that they discovered in it a luni-solar period of 600 years, which had been known from the time of the first patriarchs[202].

Thus every thing leads us to believe that the great reputation of the Chaldeans was given them at a more recent period, by their unworthy successors, who, under the same name, sold their horoscopes and predictions throughout the whole Roman empire, and who, in order to procure themselves more credit, attributed to their rude ancestors the honour of the discoveries of the Greeks.

With regard to the Indians, every body knows that Bailly, believing that the epoch which is used as a period of departure in some of their astronomical tables had been actually observed, has attempted to draw from thence a proof of the great antiquity of the science among this people, or at least among the nation which had bequeathed them its knowledge. But the whole of this system, invented with so much labour, falls to the ground of itself, now that it is proved that this epoch has been adopted but of late, from calculations made backwards, and even false in their results.[203]

Mr Bentley has discovered that the tables of Tirvalour, on which the assertion of Bailley especially rested, must have been calculated about 1281 of the Christian era, or 540 years ago, and that the Surya-Siddhanta, which the Brahmins regard as their oldest scientific treatise on astronomy, and which they pretend to have been revealed upwards of 20,000,000 of years ago, could not have been composed at an earlier period than about 760 years from the present day[204].

Solstices and equinoxes indicated in the Pouranas, and calculated according to the positions which seem to be attributed to them by the signs of the Indian zodiac, such as they are supposed to be, have acquired the character of an enormous antiquity. A more attentive examination of these signs or nacchatras has lately convinced M. de Paravey that reference is only made to solstices of 1200 years before the Christian era. This author at the same time admits, that the place of the solstices is so inaccurately fixed, that this determination of their date must be received with a latitude of 200 or 300 years. They are in the same predicament as those of Eudoxus and of Tcheoukong[205].

It is ascertained that the Indians do not make observations, and that they are not in possession of any of the instruments necessary for that purpose. M. Delambre indeed admits, with Bailly and Legentil, that they have processes of calculation, which, without proving the antiquity of their astronomy, shew at least its originality[206]; and yet this conclusion can by no means be extended to their sphere; for, independently of their twenty-seven nacchatras or lunar houses, which strongly resemble those of the Arabians, they have the same twelve constellations in the zodiac as the Egyptians, Chaldeans, and Greeks[207]; and, if we refer to Mr Wilfort’s assertions, their extra-zodiacal constellations are also the same as those of the Greeks, and bear names which are merely slight alterations of their Greek names[208].

It is to Yao that the introduction of astronomy into China is attributed. He is represented, in the Chou-king, as sending astronomers toward the four cardinal points of his empire, to examine what stars presided over the four seasons, and to regulate the operations to be carried on at each period of the year[209], as if their dispersion was necessary for such an undertaking. About 200 years later, the Chou-king speaks of an eclipse of the sun, but accompanied with ridiculous circumstances, as in all the fables of this kind; for the whole Chinese army, headed by a general, is made to march against two astronomers, because they had not properly predicted it[210]; and it is well known that, more than 2000 years after, the Chinese astronomers possessed no means of accurately predicting the eclipses of the sun. In 1629 of our era, at the time of their dispute with the Jesuits, they did not even know how to calculate the shadows.

The real eclipses, recorded by Confucius in his Chronicle of the kingdom of Lou, commence only 1400 years after this, in the 776th before Christ, and scarcely half a century earlier than those of the Chaldeans related by Ptolemy. So true is it, that the nations which escaped at the same time from the general catastrophe, also arrived about the same period, when their circumstances have been similar, at the same degree of civilization. Now, it might be thought, from the identity of the names of the Chinese astronomers in different reigns (they appear, according to the Chou-king, to have all been named Hi and Ho), that, at this remote epoch, their profession was hereditary in China, as it was in India, Egypt, and Babylon.

The only Chinese observation of any antiquity, which has nothing in itself to prove its want of authenticity, is that of the shadow made by Tcheou-kong about 1100 years before Christ; and even it is far from being correct[211].