Penny Blood: Serial Sensation and Working-Class Entertainment — page 37: what you’re looking at

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

20 CONDITION OF INTERIOR. [cH. 11, Whole earth. Surface rock. Maskelyne............ 50 Cavendish ............ 5°448 Reich ...........cee eee 5°44 Baily............ee00e. 5°67 Airy and Miller .... 6°566 2°56 JAMES 0. ..cccceccceces 5°316 2°75 Mallet ............... 2°69 Waltershausen....... 2°66 If we select Col. James’ determination for the density of surface rock, viz. 2°75, and double it, we get 5°50, which 1s a fair representation of the mean value of the density of the whole earth ; being somewhat greater than the mean 5°375 if Airy’s determination is omitted, and somewhat less than the mean 5°573 if it be included. - These are the values used by Archdeacon Pratt in his “Figure of the Earth.” The increase of density in approaching the centre will depend partly upon the pressure, and partly upon the nature of the materials. We do not know enough about the ultimate constitution of matter to reason satisfactorily about the effect of pressure. It has been thought that by that means the density of a substance can be increased up to a certain limit, but no further. If this be so, 1t renders it probable that the high density of the central parts of the globe is due to the intrinsic nature of the materials there, and that a large proportion of the heavy metals occupy that position. The assumption of a law of density for the purpose of deter- mining the forms of the strata of equal pressure and density within the earth will also give a corresponding form for the - outer surface. And it is found that a law (due to Laplace and suggested by analytical necessity) which, using the mean values for the surface and mean densities indicated above, leads to an ellipticity of 54, for the outer surface, is consistent with the sup- position that the density, if it depended on pressure alone (without asserting ‘that it does so, which has been shown above to be highly improbable), would be such, that the increase of the square commiclsoolkks (CO)