on the Atmosphere of the Moon . 
357 
Immersions. 
The western, preceding, first satellite disappeared behind 
the sharp bright limb of the moon, at io h 43' 12.* 
N. B. There may here have been an error of two or three 
seconds, as the satellite became indistinct at the limb. 
The second satellite disappeared, without becoming at all 
indistinct, exactly at io h 45' 19". 
The western limb of Jupiter came in contact, most distinctly, 
with the eastern limb of the moon, at io h 46' 32", 5. 
Jupiter's eastern limb disappeared, as distinctly, at io h 48' 
20", 5. 
N. B. This immersion took place, as represented in fig. 3, 
to the eastward of Aristarchus, at about the 24th degree of 
N. lat. 
The third satellite disappeared, after having been for about 
one or two seconds faint and indistinct, at io h 58' 57", 5. 
The fourth satellite, which appeared the least of them all, 
became undiscernible near the limb, and vanished at about 
n h 2' 16". 
N. B. There may have been an error of four or five seconds. 
Emersions. 
The two preceding first and second satellites were here like- 
wise of use in determining precisely the emersion of both the 
limbs of Jupiter, from the dark hemisphere of the moon. 
* True time, determined by equal altitudes, taken on the 12 th and 8th of April, 
and 2d and 27th of March, and by the known rate of the clocks ; but as no altitudes 
could be taken on the 7th, there may be an error of two or three seconds. 
3 A 
MDCCXCII. 
