ON THE LIGHT OF THE MOON AND OF THE PLANET JUPITER. 261 
Taking the mean, we have 
lx temm Mi 
a Lyre 
Hence, from Herschel’s observations of the Moon, according to the above reduction, 
Jupiter at mean opposition ` e Centauri _ Jupiter siye H 
Mean full Moon Moon a Lyre ` a Centauri ` 6620" 
Considering the number of intermediate steps required in effecting the comparison 
of the original data, this confirmation of the value before given in (33), viz. : 
Jupiter at mean opposition E 1 
Mean full Moon 6430 ' 
is entirely satisfactory. 
If we make in (13), 
P — sin. 15 34.67 = sin. Moon’s semidiameter at its mean distance from the Earth, 
E = sin. 0 8.67 = sin. Venus's semidiameter at the distance 1.0000 “ & 
fe — sin. 0 22.77 = sin. Jupiter's " * 42028 * " 
e = edendi for the Moon, 
T 1.0000 
= = mee for Venus, 
r 0.7233 
dE = Lp , for Jupiter, 
p. 5.2028 
the amount of light received at the Earth, compared with sunlight, will be, 
r di Op _ Light of Moon 
dL 194810 Light of Sun’ 
9! y! Light of Ven 
99 “ = 1184400000 Light of Sun 
k 9" y" ... Light of Jupiter 
L = 3884600000 Light of Sun ` 
Hence at the Earth, 
VOL. VIII. 34 
