MATHEMATICAL PAPERS. tat 
‘The apparent time of the true ecliptic conjunction, by the ex- 
ternal contacts, being 11% 16' 512", and by the internal onés 11> 
10' 50%", let us call the time 11" 10’ 51", when Mercury's 
latitude, by the former, muft have been 15/ 58”, 257, and by 
the latter, 15’ 56", 752, the mean of which, 15* 57", 504, 
may be called Mercury's true latitude by obfervation, at the 
time of the ecliptic conjunction. By M. de la Lande’s tables 
it was 15^ 51", 524; fo that the error in the tables, by this 
mean, is — 5", 98, 
For Mercury’s heliocentric latitude, according to the obferved 
geocentric latitude. 
Mercury’s diftance from the fun, 31198: Mercury's diitance 
from the earth 67681 :: Mercury’s geocentric latitude at the 
ecliptic conjunction, by obfervation, 15'57”, 504=9 57" 2504: 
"Mercury's heliocent. lat. by obfervation, 2077", 2 — 34! 37", 2. 
For the place of the afcending node by obfervation. 
Let 2 E, in Plate II. Fig. IV. be a portion of the ecliptic ; 
the point & the place of $'s afcending node ; & ¥ a portion of 
g's heliocentric orbit ; the point at $ his heliocentric place in 
his orbit, at the time of the ecliptic conjunction, and E his 
place reduced to the ecliptic ; Ex his heliocentric latitude ; 
the isle Ea y the inclination of his orbit, by modern Aftro- 
nomers generally determined to be 7° o'o”. In the right-an- 
gled fpheric triangle E y, right-angled at E, there are given ; 
the angle Es ¥, and the perpendicular or fide Ey, to find the 
bafe or fide 2 E. 
: Tang. Et or ¥’s heliocentric lat. 34” 37",2 8 0030458 
:: Tang. Ge-inclination y’s orbit, 83° o o 10 9108562 . 
: Sinebafe LE org'sdift.fromaíc.node,4 42 16 8 9139020 
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