8 Archdeacon Pratt on Chinese Astronomical Epochs, 



astronomy, as being at the equinoxes and solstices in the time of" 

 Yao. As one of the points (sec Table II.) is wrong by 6° 46', 

 this commits the Chou-king to an error of 487 years. Moreover, 

 these traditions are not to be relied upon as facts. We have in 

 Indian astronomy an instance of an ancient conjunction of sun, 

 moon, and planets stated as if an observed phenomenon, whereas 

 it is dear that the idea (which is false in fact) was come at by 

 calculating backwards, and that upon defective data. (5) An- 

 other thing which M. Biot appears to think confirmatory of his 

 epoch is this. He states that the Chinese used to observe with 

 care the motion of the circum polar stars in the Dragon, the 

 Great Bear, and the Lesser Bear, and two in Lyra ; and conjec- 

 tures that the position of the declination-circles passing through 

 them at that epoch influenced the astronomers in the choice of 

 the stars which define the twenty-eight mansions. Eleven, how- 

 ever, of the mansions have none of these circles passing through 

 them, and the angular distances of the others from the nearest 

 stars vary through all degrees of magnitude between 0° 8' and 

 7° 26'; of these approximate conjunctions on the same meridian 

 twelve take place at the inferior passage of the circumpolar star. 

 There does not appear to be anything at all remarkable in these 

 approximate relations. Other positions of the pole and other 

 epochs may be no doubt found where even a nearer approxima- 

 tion of the kind exists. (6) Another argument of M. Biot in 

 favour of his epoch is, that a star is spoken of by Chinese 

 astronomers as the " Unity of the Heaven^/' which name is sup- 

 posed to indicate that it was at the pole of the equator when first 

 so designated : and the Trench chronologist Freret thinks the 

 star must be « in the Dragon, though M. Biot thinks it may be 

 another star close to it. It is very easy to show that, as the 

 longitude of this star was in 1750 a.d. 153° 54', it must have 

 been 63-9x72 = 4601 years before that epoch (that is, 2850 

 B.C.) when it was at the pole, or at its nearest point only a few 

 minutes from it. This is 500 years before M. Biot's epoch. In 

 this time, however, it would not have moved away more than 

 about 2° 46', and therefore might still be regarded as the pole- 

 star. But this shows the uncertainty of such means of fixing 

 dates, even by the best astronomical means, if the data are not 

 precise. The star would continue within a distance of 2° 46', 

 taking both sides of the pole, for no less a period than 1000 

 years. The fact, therefore, of its being regarded as the pole- 

 star, if such errors are allowed (and we see larger errors allowed 

 in this approximation to a system), would not fix the date within 

 1000 years. There is a tradition that the Chaldee astronomers 

 had observed a Draconis in the pole. It is quite possible that 

 such a circumstance might be handed down, one so easily observed, 



