76 
ASTRONOMY: //. N. RUSSELL 
7. Very's observations of the intensity of the earthshine^ indicate 
that the mean full earth, as seen from the moon, appears 40 times as 
bright as the mean full moon, seen from the earth, and that the stellar 
magnitude of the earth, as seen from the sun, would be about —3.5, 
with an uncertainty of at least 25%, or 0.20 mag. 
8. The intensity of sunlight from the zenith, according to H. H. 
Kimball, is 103,000 metre-candles. That of mean full moonlight, ac- 
cording to several observers, is 0.24 metre-candle. A standard candle, 
if of approximately the same color as the stars, would appear as bright 
as a star of the first magnitude if placed at a distance of 1.09 kilometres. 
9. Table 1 gives the values finally derived for the albedo of the various 
planets and satellites, and related quantities. 
TABLE 
I 
Object 
Mag. at 
Mean 
0pp. 
Mfg. at 
Unit 
Distance 
diameter 
p 
Albedo 
A 
Color- 
Index 
Photo- 
graphic 
Albedo 
Moon 
-12.55 
-1-0.40 
2f40 
0. 105 
0 
694 
0.073 
+ 1 
18 
0.051 
[- 2.94 
-0.88 
3.45 
0.164 
0 
42 
0.069 
2.12 
-0.06 
0.077 
0 
72 
0.055 
- 4.77 
-4.06 
8.55 
0.492 
1 
20 
0.59 
+0 
78 
0.60 
Mars 
- 1.85 
-1.36 
4.67 
0.139 
1 
1 
I 
0.154 
+ 1 
38 
0.090 
Jupiter 
- 2.29 
-8.99 
95.23 
0.375 
1 
5 
0.56 
+0 
50 
0.73: 
-1- 0.89 
-8.67 
77.95 
0.420 
1 
.5 
0.63 
+ 1 
12 
0.47: 
Uranus 
-h 5.74 
-6.98 
36.0 
0.42 
1 
5 
0.63 
+ 7.65 
-7.00 
34.5 
0.49 
1 
5 
0.73 
+ 7.15 
-f3.70 
0.53 
0.10 
0 
55: 
0.06 
Pallas 
+ 7.84 
4-4.38 
0.34 
0.13 
0 
55: 
0.07 
+ 8.95 
+5.74 
0.14 
0.22 
0 
55: 
0.12 
Vesta 
+ 6.04 
+3.50 
0.27 
0.48 
0 
55: 
0.26 
Jupiter 
Satellite I . , . . 
-h 5.54 
-1.16 
2.38 
0.46 
1 
5 
0.69 
II.. . 
. + 5.69 
-1.01 
2.08 
0.51 
1 
5 
0.76 
Ill . . 
. + 5.08 
-1.62 
3.62 
0.30 
1 
5 
0.45 
IV... 
. + 6.26 
-0.44 
3.49 
0.11 
1 
5 
0.16 
Titan 
+ 8.30 
-1.26 
2.9 
0.33 
1 
5 
0.50 
The Earth 
Lommel-Seeliger law 
-3.46 
8.79 
0.27 
1 
64 
0.45 
Lambert's law 
-3.52 
(( 
0.29 
1 
50 
0.43 
+0 
45? 
0.6? 
Observed law for 
Venus 
= 3.80 
i( 
0.37 
1 
20 
0.45 
-4.40 
(( 
0.65 
0 
70 
0.45 
Column 2 gives the stellar magnitude at mean opposition (in the case 
of Mercury and Venus, at full phase, unit distance from the earth, an'd 
mean distance from the sun) ; column 3 the magnitude for full phase and 
unit distance from the sun and the observer; column 4 the adopted 
mean angular semidiameter at unit distance; the next three columns, the 
values of py q, and A, defined as above; and the last two, the color- 
index and the photographic albedo (A) in the cases where these are 
