136 G. Hinrichs on nm Planetology. 
nebula; but as this nebula is a gaseous — 3 will be deter 
mined by 7 and gravity and, jus st as in the case of our 
come uniform in the successive homothetic ellipsoidal shells 
cluded between any two successive surfaces. e we Imi 
consider J as a function of the equatorial axis of ‘ie surface, 
and, as the density is increasing toward the center, we may, lt 
stead of the general law 
d=f(a), (ue 
take the law assumed by oe for the jniterioe of our earth, 
d—=A—ca. . ee a 
Plana has shown’ that this Jaw is ee cae probable in the. 
ease of theearth. Prof. Forchhammer of Copenhagen has lately. 
shown" how this law accounts for one of the principal circ 
stances relating to the succession of geological strata. 
Tt must finally be borne in mind that the nebula may hay 
various elements at the same place, because the laws of diffu 
of gases will apply to the gaseous nebula, Thus far the chem 
eal analyses of meteorites and the spectral analysis of the sul 
moon and planets have corroborated this conclusion; still we 
must not ~— consiade that some differences may not obtally 
pe | Ast 
Regi 1 190s, vol. xxv, No. 828. For the eneae at grt pate of the ah 
S$ 
Inlec ne ti en Rekk qr reemtnges Stoffernes Kredsléb i Naturen at 
creation the rina pie ure.) Nordisk Universitets- -Tidskrift, Ws 
ge . 68-81. : 
As an instance, Forchhammer describes the circulation of Lime: first the smal 
ological periods, put into circulation, especially by the inor st 
for these again 1 paetiants nence a new oye —wN No mA where id ti the oe at fir ‘ 
from? Forehhammer a. that as granitic rocks (s met gravity i g 
dense than oo dark trap-rocks, (on Bornholm, sp. gr. up to 2.93,) they woul, 
the first period of the i ‘ait earth, rote aps ca rapt thus the first on 
would be Tome of granitic rocks, rom. hes ep reecea unfit 10 " 
co tli fe, ossiliferous, By t sis ie sbek a at ns this rock was s disloc: 
“ae thr by the prea ian fr approcks catalog lime and iron as 
the being so rich in carbonie acid and be ing dis ee d in the th 
waters or decompose these silicates, rie thus bring lime inte circulation: 
period of rest, comm their eruption with emitting trachytic, i.e gm" . 
Masses aiehost free from I lime—whi ich are later succe sch a by Ate heavy black in 
nce ae hae th lime and iron, 
The > aban deposi of gypsum, the Triassic period, is succeeded by 
dinary limestone formation 1 of the Jurassic period, thus giving another li 
pair inductions, for sum, being more soluble, will more rapidly | 
lim 
si 
— eurlier it d the cause for 2° shit ti 
imestone during ¢ x Jurass ic period, ete. —in the simple cross ae = tht 
—t being lighter than trap, were exterior to the latter in 
