266 — ON THE LIGHT OF THE MOON AND OF THE PLANET JUPITER, 
makes the Sun about five hundred and fifty thousand times brighter than the full Moon,* 
in which case 
1 
n= 31" 
If the whole quantity of sunlight reflected by the Moon, which is ut, were dispersed 
from it as if it were a polished sphere, —that is, equally in all directions, — the 
amount of moonlight incident upon d e would be 
pide e? i de 2 
de Ai Ag AP 
but the actual amount incident upon d e is 
HW. de 
Aa A? 
(47) 
3 
and therefore, since, from the definition on p. 233, @ is the ratio of these two quantities, 
f 
(48) oc Hr 
vg 1 
Hence, using from (41) s = 9335 for the Moon, 
ai = 2.67 Hy for Venus, 
6" = 2.67 H" for Jupiter, 
o = 431 H forthe Moon, 
(49) 
and for the two latter assuming, as in (15), 
Ri = Rs Se nhe 
T 
(50) A 2:8 sin. v — v cos. v 
3 T z 
we shall have, from (39), 
ai qi 
dën EE O, 1.616 ' 
EE ae p 1 
y o Tor Ww TAT" 
which are, perhaps, the most reliable values which the data in our possession will 
furnish. : 
* For a new determination of this ratio, giving S 
= 470980 and p= 22 the reader is referred to a me- 
moir in a subsequent part of this volume. i 
