Obliquity of the Ectiptic. 16 
shadows give for the apparent distances of the sun’s centre 
from the zenith, after being corrected for the refraction and 
parallax, 
38° 50’ 27,4; 3394’ 0",5 5 32°. 55’ 48",5. 
Taking, ‘therefore, 39° 52’ 47’,1. for the apparent, di- 
stance of the equator from the zenith, we shall have the 
three north declinations of the sun following: 
1° 2'119",7; @ 48’ 46"6; 6° 56’ 58”.6); 
which gives for the apparent longitudes of the sun, 
2"36'S" 25 17° 16" 3057; 
These longitudes, calculated according to the new Tables, 
are, 
58 19° DMI" )3. 
2° 35! 10", 17°17' 24",1; 5* 12° 23’ 5”,0. 
The errors of the Tables are therefore, 
Lr 54",6, a 47",7 at y 3) shs 
which are within the limits of errors of observations. 
These observations are very fit to determine the equation 
of the sun’s centre at their epocha. They give that equa- 
tion greater by 122” than in 1800; and thereby confirm 
evidently its successive diminution, in the same manner, that 
the observations made about the solstices confirm the suc- 
cessive diminution of the ecliptic’s obliquity. 
- It remains for u3 to consider Cochcou-King’s observations 
Calculating from the new Tables the 
sun’s longitude at the moments of the solstices, we haye the 
of the -solstices. 
following results =: 
Longitude af the Sun. 
1277, 14th December, 
1278, 14th June, 3 
1278, 14th December, 8 
1279, 14th June, °° 3 
1270, 14th December, 9 
1280,'14th December, y 
5,8) wd 
Error of the Tables. 
— 18,2 
+2°14,2 
bib Weer Le 
2 D240 
+19;1 
+4-35,8 
The errors are very inconsjderable ; hut it ought ‘to’ be re- 
marked that they are ‘greater in the summer solstices, and 
almost nothing in the winter. 
=) 
This: difference:may be 
explained by observing that Cocheou-King determined thé 
moment of each solstice by means’ of a great many imeri- 
dian“ lengths, before’ and after the solstice. 
Supposing 
then that he has chosen some observations nearest: the 
equinoxes, a time when the daily variation of the declina® 
~tion is considerable, this astronomer supposed the great 
axis of the sun’s orb perpendicular to the jie of ¢quinoxes, 
as it is seen in the abridged History of Chinese Astronomy 5 
and in 1280 the 
ing to’the new Tables. 
nogw@um ‘was advanced’ 3% 64, aceords+ 
Cocheou: King was thus wrong an 
"BB? ixie 
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