262 ON THE LIGHT OF THE MOON AND OF THE PLANET JUPITER. 
Light of Venus ES Po. 
Light of Moon ` 6080 © p’ 
(38) ; : 
Light of Jupiter = 1 0” y" 
Light of Moon ` 45610 © p ` 
But according to observation, we have in (31) and (32), 
Light of Venus at the phase v' = 1117.2 1 
Light of Moon at the phase v = 111°.2 c EIE 
Light of Jupiter at the phase o" — 169°.1 1 | 
Light of Moon at the phase v =169°.1 6240” 
and from (35), 
p 1 Ofrwv-11*3 
— me V dM 
(36) wc TERS ro a 
1 Hi 11 — pi 
E ww lom ue Sn Jupiter and Moon. 
p 71.31 O foto =169*.1 
If we suppose the surfaces of these bodies to absorb different proportions of the 
whole incident sunlight, while the light reflected by each is dispersed ee ally i in 
different directions, we should have, 
(87) 
This would apply for Lambert's or Eulers formula, or for any other of a general 
nature, when the special constitution of each reflecting body is not taken into account. 
The substitution of 
EN o" 
a — E e = 1, 
in (36), would thus give, 
Fou ls d aM — 111° 
"M La enus and Moon, v = 111°.2, 
(38) 
p 1 5 1 “ o 
P << 131 upiter e 1599.1, 
Owing to its situation in the solar system, Venus can afford reliable photometric 
observations only when near its position of greatest brightness, being then at a little 
less than the half-Moon phase, while that of Jupiter is always nearly full. If, how- 
ever, we suppose the light of the two planets to be distributed agreeably to Lamberts 
