Penny Blood: Serial Sensation and Working-Class Entertainment — page 184: what you’re looking at

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

CH. x11] THE THERMOMETER. 167 how well it agrees with the others previously made, in which those considerations are involved. Neither can p’ be less than p (or as assumed than 2°68). It must therefore have some value betweert this and o (or as assumed. 2°96). Now if we suppose the sub-oceanic crust to consist of basic crystalline rocks, their density approaches very nearly to that of the basic eruptive rocks, and the probability is that o—p’ is very small, and consequently & need not be small. But we have reason to believe it to be smaller than c, because at the locality A, which is continental, the crust has been probably thickened by compression. Let us then assume c= 25 miles and k = 20 miles. | We then obtain p’ =2°953, a value which would admit of the sub-oceanic crust floating. This result is not unsatisfactory considering that we are dealing with densities about which we have no certain knowledge. It is probable that the absolute values of all the densities have been taken somewhat too high. It 1s impossible to attain accuracy in such estimates as we have been engaged in making, but we may conclude as the result of our inquiries, that the crust of the earth at a place near the sea-level is about 25 miles thick; that beneath the central parts of the ocean it 1s about 20 miles thick, or perhaps less, and that it 1s more dense in those regions; and that it is by such increased density of the crust itself that the collection of water is to be explained, and not by increased density in the more deeply seated matter. COLA @ NOO (CO)