Mr. Goldingham on the geographical situation , &c. 409 
placed in the meridian, and the transits taken with the least 
possible error of observation ; as only a very small error in 
the Tables, or in the observed place of the moon, may pro- 
duce a considerable one in the result. But eclinses of the 
▲ 
satellites of Jupiter occur often, and correspondent ones with 
those taken at Greenwich, are not very unfrequent, even in 
this distant part of the globe. The observations taken at 
Greenwich also show the difference or error of the Tables, 
and consequently, the error of the longitude deduced from 
them. Errors also which may arise from a difference in the 
powers of the telescopes, and in the eyes of observers, as 
well as from a general difference in the state of the atmo- 
sphere, may be counterbalanced by taking a series of these 
eclipses, consisting of immersions as well as emersions. 
I shall, therefore, for the present at least, as regards the 
longitude of Madras, draw a conclusion from these eclipses ; 
a very long catalogue of which has been taken at the Madras 
Observatory. So numerous, indeed, are these observations, 
that the longitude of Madras, which I may give at a future 
time, by other methods, may perhaps be considered more as 
corroborating that now deduced, than as furnishing informa- 
tion for correcting it. 
We may now, however, notice a result obtained from lunar 
observations. Of these, about 800 have been taken at various 
times since the year 1787, with different sextants ; and re- 
duced to the Observatory, give its longitude 2' 55," 5 more 
than by the satellites. This will furnish us with a correction 
for numerous observations of this description taken at Bom- 
bay, when we come to treat of the longitude of that place. 
The first set of the following eclipses is composed of ob- 
mdcccxxii. 3 G 
