A. Hinrichs on the Density, Rotation, and Age of the Planets. 45 
which numbers regularly decrease with the increasing age, con- 
h 
of the actual forms of the lunar systems of Jupiter, Saturn and 
Uranus shows that these latter are very irregular, whilst the 
bam world of Jupiter, the youngest of this group, is as yet very 
regular, 
Yet the distances of its moons is not quite regular; for they 
are, expressed in radii of the planet respectively 
6:0 9°623 15°350 26-998. 
As Jupiter is proved to be older than the interior planets, and 
as these exhibit sions of age in their mutual distances, the face 
of old Jove can neither be without wrinkles. Indeed, perceiy- 
ing that the same law of duplication is applicable to the above 
distances, and selecting as the primitive values 
7 7+3=> 0+6=16 16+12=—28, 
we get by the known dimensions of these moons the following 
relative ages: 
8 13 7 
which, as the third has as much mass as the other three taken 
together, by the reduction for masses, would become more regu- 
twice as great as the mean age of the first two. Therefore we 
Must likewise conclude that the age of Jupiter's satellites in- 
creases with their distance from the primary. 
f the masses and dimensions of the members of the more dis- 
tant worlds were known, we should certainly find this law of the 
age increasing with the distance from the central body to be 
Universal 
Sven by the diagram expressing the results of formula (12). 
_ We have already seen that the Jovial World indeed a pears 
Very regular, and that the smaller regularity of the more distant 
Worlds confirms our result as to their higher age. 
t what age will the configuration of the solar system corres- 
Pond to the present configuration of the world of Saturn? The 
lagram gives the fourth age as answer. For at that time we 
have the following similarity between the two systems: 
a For if in (12) ¢, @, A and x are multiplied by a constant n, 9 becomes n9, 
