Penny Blood: Serial Sensation and Working-Class Entertainment — page 42: what you’re looking at

Machine-transcribed from the original scan — historical spelling and the odd misread are preserved.

CH, 11.) CONDITION OF INTERIOR. 25 fluidity would vary continuously from the solidity of the nucleus to the fluidity of the surface, where, at the mstant we are speaking of, it would be just such as not to admit of circula- tion ;... a change would take place in the process of solidification which it is important to remark. The superficial parts of the mass must in all cases cool the most rapidly, and now (in con- sequence of the imperfect fluidity) being no longer able to descend, a crust will be formed on the surface, from which the process of solidification will proceed far more rapidly down- wards, than upwards on the solid nucleus.” And in a note to the Report’, he’writes thus decidedly: “Supposing the earth once to have been fluid, it must be now, or have been at some antecedent epoch, in that state in which a solid exterior rests on an imperfectly fluid and incandescent mass beneath. It is important to know that this state of the earth, assuming its original fluidity, is one through which it must necessarily have passed in the course of its refrigeration, whatever might be the process of its solidification.” These remarks of Mr Hopkins deserve serious consideration, and are not lightly to be set aside. They are entirely indepen- dent of his subsequent calculations by which he considered he had proved (and was until very lately considered by the greatest mathematicians to have proved)* that this crust is not at the present time a thin one, but has grown to the thickness of at least not far short of a thousand miles; even if its downward growth has not already met the upward growth of the solid central nucleus, The reasoning by which Mr Hopkins concluded that a crust would be formed (and he clearly supposed it would be supported also), seems to be assailable only on the supposition that upon solidification a sudden considerable contraction, and consequent increase of density, would occur, which would enable the frag- ments to sink in a fluid, too viscous to admit of the sinking of portions cooled to the verge of solidification. But there is no reason whatever to suspect such a sudden considerable contrac- tion. Indeed the experiments above referred to, point in a contrary direction. 1 Page 48. 2 Vide supra, p. 22, GONG oOo SS (CO)