Prof. D. Kirkwood on the Nebular Hypothesis, 167 
the earth was in a melted and not improbably also in a gaseous 
state."* All this, it will be perceived, is in striking accordance 
with the Nebular Hypothesis. 
4. Whatever may be the nature of the elevating force, it is not 
confined to our globe. The lunarand planetary mountains afford 
evidence of its action in the other members of our system—a 
fact which seems indicative of their common origin. 
_5. The spheroidal figure of the planets points to a great and 
significant fact in regard to their primitive constitution—the fact 
that they have all, at former epochs in their history, been in a 
liquid, if not in a gaseous state. That the polar flattening of the 
earth is not conclusive evidence of its primitive fluidity, has been 
affirmed, we are aware, by more than one writer of scientific emi- 
nence. If we suppose our planet to have been originally solid 
and perfectly spherical—its surface being entirely covered with 
water—the effect of its axial revolution would be the accumula- 
_ fon of water in the equatorial region, and a consequent reces- 
sion from the poles. Sir John Herschel remarks,+ that the grad- 
ual abrasion of these polar continents and their slow deposition 
in the deep equatorial ocean would eventually reduce the solid 
earth itself to the form of an oblate spheroid. Recently, how- 
Supposed by Herschel, would be ;};, while that found by ac 
teal Measurement is ;1, to szs!5az-¢ The theory of primitive 
fluidity may therefore be regarded as fully established. is 
ther? of remark that the oblateness of Mars is much greater 
— they could assume the figure appertaining to their ve- 
ity of rotation.” 
"gies 
“ton of the phenomena of comets. Laplace supposed these bod- 
. to have had their origin in portions of nebulous matter which 
a np Our system from different quarters of the heavens. The 
* Religion of g . 
eology, p.22, + Outlines, Arts 226, 227. } Midler, p, 50, this vol. 
§ Humboldt’s Cosmos, vol, iv, (Bohn’s Edition,) p. 427. 
