I >92 ] 
r,at the Royal Obfervatory at Greenwich. The im- 
,• merfions and emerfions obferved there, proper to 
i compare with the preceding obfervations, are thefe ; 
all obferved with a fix-feet reflector, which, I reckon, 
fhews an immerfion of the firft fatellite zo" later* 
. and an emerfion of the fame as much fooner, than 
a two-feet reflecting telefcope. 
1767 
Obferved at Greenwich. 
Apparent time. 
h / n 
App. time per 
Naut. Almanac, 
h / " 
Corre&ion of Naut. 
Almanac. 
/ // 
Jam 12. 
Ini. 11 41 41 
II 42 8 
— O 27 
Feb. 27. 
Im. 11 57 7 
II 58 6 
— 0 59 
Mar. 22. 
Em. 14 28 48 
[4 28 50 
— 0 2 
April 9. 
Em. 7 20 1 
7 20 23 
— 0 24 
14* 
Em. 14 47 52 
14 47 48 
-f- ° 4 
16. 
Em. 916 13 
9 16 55 
— 0 42 
3 °* 
Em. 13 9 10 
'3 8 59 
■fon 
May 9. 
Em. 9 32 26 
9 33 1 2 
— 0 46 
The correction of the Nautical Almanac for a 
fix feet refleCtor, by the mean of the two immer- 
fions, is — 43", which applied to 4 h 15' 19k", the 
longitude of Jupiter’s inlet found from immer- 
fions, by the help of the Nautical Almanac, gives 
4 h 14' 361", the difference of longitude deduced 
from the immerfions. The correction of the Nau- 
tical Almanac, by the mean of the fix emerfion s, 
is — 16%", which applied to 4 h 14' 45!", the lon- 
gitude of Jupiter’s inlet found by the emerfions, by 
the help of the Nautical Almanac, gives 4 h 14 29", 
the longitude deduced from the emerfions. The 
mean of thefe two refults, found from the immer- 
sions and emerfions feparately, is 4 h 14' 33", the 
proper difference of longitude of jupiter’s inlet 
west 
