which numbers regularly decrease with the increasing age, confirming the law.

Third Law. The regularity and symmetry disappears more and more with increasing age.-A single glance at the representation of the actual forms of the lunar systems of Jupiter, Saturn and Uranus shows that these latter are very irregular, whilst the lunar 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

As Jupiter is proved to be older than the interior planets, and as these exhibit signs of age in their mutual distances, the face of old Jove can neither be without wrinkles. Indeed, perceiving that the same law of duplication is applicable to the above distances, and selecting as the primitive values

7

7+3=10

10+6 16

16+12=28, we get by the known dimensions of these moons the following relative ages:

1

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 regular; yet we see that the mean age of the last two satellites is twice as great as the mean age of the first_two. Therefore we must likewise conclude that the age of Jupiter's satellites increases with their distance from the primary.

If the masses and dimensions of the members of the more distant worlds were known, we should certainly find this law of the age increasing with the distance from the central body to be

universal.

Fourth Law. Similar systems must represent the same configuration at corresponding ages."-Having found the more distant planets to be the older members of the solar system, and consequently that they are in a state of configuration which the solar system as a whole can first exhibit only at a future time, we are enabled to put the theory of resistance to another test by comparing the present configuration of the lunar worlds of the superior planets to different future epochs of the solar world as given by the diagram expressing the results of formula (12).

We have already seen that the Jovial World indeed appears very regular, and that the smaller regularity of the more distant worlds confirms our result as to their higher age.

At what age will the configuration of the solar system correspond to the present configuration of the world of Saturn? The diagram gives the fourth age as answer. For at that time we have the following similarity between the two systems:

" For if in (12) s, a, ▲ and x are multiplied by a constant n, 9 becomes n 9.

The Rings of Saturn are represented by the hosts of asteroids, which already in the first age intersect the orbit of our earth, but in the fourth age will closely encroach the sun, and (perhaps together with those meteorites which are not intercepted by any of the planets) may form continuous rings around the fiery sun, either on account of their number, or because they probably will become melted; they will form not one ring, but rings, because they will approach the sun according to the amount of their factor, just as detritus is deposited in horizontal layers of variable fineness.

The four inner moons of Saturn, being very close to each other and to the primary, will be represented by the four interior planets, for these also are at the fourth age very close together and very near the sun, being altogether within the present distance of Mercury. The distances are, then, for the planets [see results of (12) ]:

for the Moons of Saturn, now,

Mimas 3.36, Enceladus 4:31, Tethys 5.34, Dione 6.84

or whilst the planetary distances will be ast

1 : 4: 5: 7,

the corresponding lunar distances are now as

3:45: 7,

or only differing in the first number.

The four outer moons of Saturn, now, correspond in configuration to the four exterior planets at age four; for the first three of each are about equidistant, the fourth far above the rest. The distances of the planets then are

Jupiter 360, Saturn 454, Uranus 596, Neptune 1504,

and of the moons are now

Rhea 955, Titan 22:14, Hyperion 28.00, Japetus 64.35, or the relative distances are,

for the Planets as
for the Moons as

again a very close harmony.

7: 9: 12:30,
4: 9 : 12: 26,

A complete correspondence would demand a complete similarity of masses at the commencement, which perhaps is not to be expected. Comparing the better known superior bodies more in particular, we must from the smaller distance (4 instead of 7) of Rhea conclude, that its mass is not correspondingly as great as that of Jupiter; and for Japetus that its mass is not as great as the corresponding one of Neptune, or perhaps Hyperion must be comparatively of small mass, so as to leave Japetus far behind; this latter circumstance appears to be actually the case.