Archdeacon Pratt on Chinese Astronomical Epochs. 

 Table V. 





Their differences of Right Ascension. 



Nos. of mansions 





compared. 





235/ B.C. 



1/29 B.C. 



1100 B.C. 



1 and 15 



182 8 



182 32 



182 36 



2 „ 16 



176 45 



178 24 



176 53 



3 „ 17 



16) 45 



161 53 



162 37 



4 „ 18 



176 51 



178 27 



179 11 



5 „ 19 



183 7 



183 24 



183 45 



6 „ 20 



179 1 



177 42 



178 27 



7 „ 21 



180 47 



181 7 



181 22 



8 „ 22 



175 37 



176 33 



177 26 



9 „ 23 



178 8 



179 9 



180 4 



10 „ 24 



180 16 



180 27 



180 38 



11 „ 25 



179 



179 6 



179 11 



12 „ 26 



172 1 



171 29 



171 5 



13 „ 27 



175 20 



175 3 



174 42 



14 „ 28 



177 10 



176 58 



176 55 



M. Biot attempts to illustrate the correctness of his list of 

 stars, though so irregularly distributed and in many instances so 

 inferior in importance, by stating that there is evidently a law in 

 their selection, and that a narrow mansion in one part of the 

 heavens corresponds to a narrow mansion in the opposite part ; 

 so also with the wider mansions ; so that the stars, at the epoch, 

 were situated in pairs on the same meridian. 



5. It is by the application of this test, which is to some extent 

 approximately true, that I think I can detect a flaw which destroys 

 the necessity of passing so far back into past time as the twenty- 

 fourth century B.C. In the first of the three columns in Table 

 V., I have given the differences of M, for 2357 B.C. gathered 

 from M. Biotas results in Table I. It will there be seen that the 

 pairs of stars deviate from being on the same meridian by an 

 average = about 3°, if we except the third pair in which the 

 deviation is as much as 18° 15'. There must be some reason 

 for this exception. The fact is, both the limiting stars of that 

 mansion are exceptional ; No. 3 being so near Nos. 2 and 4 (as I 

 have already pointed out), and No. 17 having so large a declina- 

 tion. (No. 6 has as large a declination, see Table I. ; but that star 

 is close upon the ecliptic, which No. 17 is not, which may be 

 some reason for its use, there being no nearer star.) These two 

 stars, moreover, are both small, being only of the fourth order of 

 magnitude. I conclude, therefore, for these reasons that they 

 have been wrongly determined. If X Orion is rejected, the 

 necessity for pushing back the epoch so far is removed. 



6. In Tables III., IV., V. I have given the results of calcula- 

 tions I have made for two other epochs, viz. 1100 B.C. and 1729 

 B.C. (halfway between 1100 b.c and 2357 B.C.), in order to see 



