Penny Blood: Serial Sensation and Working-Class Entertainment — page 185: what you’re looking at

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

CHAPTER XIII. AMOUNT OF COMPRESSION. Our ideas respecting the sub-oceanic crust necessarily speculative.—Compression possibly confined to continental areas.—Compression might arise from extrava- sation of matter from beneath the crust, or from expansion of the crust.— Amount of compression needs to be estimated afresh.—Datum-lerel equation transformed to mean level.—Formula to express compression in terms of tnequalities.—Estimate of inequalities from Atlas—(1) on supposition that Oceans are due to compression, (2) that they are due to denser crust. THE great problem of the Physics of the Earth’s Crust 1s, how to account for the compression which geology shows to have affected, at one time or another, almost every portion of the area of the surface with which we are acquainted. And this latter expression itself suggests a large and difficult ques- tion. To what extent are we acquainted with: more than the land surfaces of the globe? It is hardly too much to affirm that our ideas respecting the nature of the earth's crust beneath the oceans are entirely derived by speculation from geology. We cannot explore it directly; but we know that most of the strata of the exposed portions of the surface have been deposited beneath seas, and from them we reason perhaps wrongly by analogy concerning the rocks at present composing the entire ocean floor. For it is the conviction of a large number of geologists’, whose judgment is of weight on such a point, that the continents have always occupied the positions which they now occupy: by which it must be understood, that 1 See a resumé of the history of this theory in a short letter by Dana, ‘¢ Nature,” vol. xx111., p. 410. COMmicsooks (CO) a a — ee ee