258 ON THE LIGHT OF THE MOON AND OF THE PLANET JUPITER. 
Earth, and having the phase corresponding to v — 11172, according to the foregoing 
observations, is equal to that of the lamp with the aperture Z, at a distance d' — 
41.40 feet. That received from Jupiter, if we omit the observation on April 2d, for 
the reason assigned in the notes, with a phase corresponding to v" = 169°.1, is equal to 
that of the lamp with the same aperture at a distance d" — 78.52 feet. We also have, 
for the distance from Z at which the Moon, similarly phased, is equally bright with 
the lamp, 
v = 1112 d = 1826 
os 1691 : d = 0.994 
Hence we shall have the following results: — 
For the Moon, at its mean distance from Earth and Sun, its phase corresponding to . woo. EB 111.2 
And for Venus at a distance from Earth of 1.000, and from the Sun of 0.7233, its phase cor- 
responding to . ^ $ i ; S à š S : > S s i v = 111.2 
(81) | : Light received from Venus d? . 1 
Light received from Moon d? ` 514. 
For the Moon at its mean distance from Earth and Sun, its phase corresponding to. 3 p 169.1 
And for Jupiter at a distance from Earth of 4.2028, and from the Sun of 5.2028, its phase 
corresponding to A e v = 169.1 
Light received from Jupiter 1 
32 ee? 
(82) Light received from Moon 6240 ` 
If the light of J upiter be increased by the correction of its phase to a complete illu- 
ee à . 1.018 
mination, or by the formula (30) in the ratio 309 and that of the Moon in the ratio 
1.050 . S E 
Er accordance with the curve representing the values of H. we shall have, 
ge Jupiter at mean opposition 1 
(33) Mean full Moon -. 6430" 
Seidel has compared the light of Venus and of J upiter with particular care, by 
means of a Steinheil photometer; correcting that of Venus to its epoch of greatest 
brightness, which he assumes to be when its distance from the Earth is 4 — 0.53944 
and v = 76° 135, he finds,* 3 
Venus at greatest brightness 
e 
' Jupiter at mean opposition = 
* Untersuchungen über die Lichtstärke der Planeten Venus, Mars, Jupiter, und Saturn, p. 34. 
