rs 
2 
216 Agassiz’s Contributions to the Natural History, &c. 
way of ascent along the spiral, are identical, as far as their meaning is 
concerned, with the fractions expressing these same positions, by the long 
way, namely, 4, 3, 3, 3, fs, 23, 34, ete. 
“ Let us, therefore, repeat our diagram in another form, the third column 
giving the theoretical time of revolution. 
eptune, 4 62,000 60,129 
“ 4 62,000 — 
Uranus, 3 31,000 30,687 
“ 15,500 a 
Saturn, Z 10,333 10,759. 
“ 2 6,889 — 
Jupiter, a 4,133 4,333 
“ 2.480 —_ 
Asteroids, ’ 1,550 1,200 
~ 3 96 es ee 
Mars, #3 596 687 
Earth, ae 366 365 
Venus, 33 227 225 
es Pa 140 —— 
Mercury, 24 88 
3 j 
“Tt appears from this table, that two intervals usually elapse between 
two successive planets, so that the normal order of actual fractions 18 4, 
relatively to Uranus, and Jupiter relatively to Saturn, and the planets 
thus formed engross too large a proportionate share of material, and this 
is especially the case with Jupiter. Hence, when we come to the Aste- 
ids, the disposition is so stro e end of a single interval, that “* 
outer Asteroid is but just within this interval, and the whole material " 
the Asteroids is ispersed in separate masses over a wide space, inst ais 
being concentrated into a single planet. A consequence of acs 
persion of the forming agents is, that a small proportionate materia’ ™ 
exterior to its true place, that when the next interval elapses the residual 
force becomes strong enough to form the Earth, after which the n° a 
law is resumed without any further disturbance. Under this ‘law, 
can be no planet exterior to Neptune, but there may be one interior 
Mercury.”—pp. 128, 129. 
The subjects to which we have thus far alluded in our noes 
of Professor Agassiz’s work are, as before said, incidental to os 
author’s main purpose, the illustration of the relations of pce 
with reference to principles of classification and the fundamen 
ideas of system in nature. To this topic we now turn. 
(Zo be continued.) ‘ 
Dei igo ee 
