ON THE LIGHT OF THE MOON AND OF THE PLANET JUPITER. 273 
This will explain the reason why the relative albedo of Jupiter, obtained after the 
above corrections have been applied, viz. 
? 979 143 | 
— ig se 60% = 158 
e sl im , 
the Moon being 61? from opposition (v = 119°), is larger than that given in (51). 
The latter is certainly to be preferred, because it is a result depending on the average 
of the whole illuminated surface of the Moon, seen under various phases, while the 
former relates to but one or two isolated points of a single phase. 
Perhaps the most probable correction which we can adopt, to refer the partial and 
incomplete result derived from any single phase to the more general condition, is to 
apply the coefficient z = Um. taken from the table on page 257, L, being the value 
of H, according to Lambert’s formula. We then have, 
t . y D 1.43 H, 
ee UN vee 0j e ok 
4.5 I 182 de 
Or 
Es = zi for the brightest parts of the Moon; 
y-3 
and in the same way, 
‘= R for the darker regions having the Sun at high altitude. 
II 
p 
The corrections due to the phase of Jupiter aiid to the difference of extinction are 
not appreciable. Proceeding in a similar manner, we may reduce the observations on 
other dates, noticing the changes required when the light from the whole disc of the 
planet has been admitted. 
On March 30th, we have, for the logarithm of the ratio of the brightness of the 
focal image of Jupiter compared with the lamp, taking the mean of the observations, 
Jupiter `` 
Log. es 8.227, 
and for the portion of the bright. parts of the Moon admitted by the aperture in the 
focus diaphragm, 
Log. i = 8.540. 
Lamp 
The coefficients for the several corrections will be 
