VIII.—Problems connected with a Cooling Earth

Extract

In the Geological Magazine for June and July of this year, I stated a new theory to account for the inequalities of the earth's surface, and, at the same time, offered a criticism of Mr. Eeade's theory, as epitomised by him in the May Number of the game Journal. in a short reply, contributed by Mr. Eeade to the September Number, he shows so clearly that he has totally misunderstood the physical reasoning upon which my theory is based, that some rejoinder is absolutely demanded.

In criticising my theory, he asks: “How then could the underlayers, by shrinking, exert such a huge pressure on the interior as to actually compress the materials of the earth into a smaller volume?” and, a few lines further on, he proposes that we should “work out the decrease of volume which would result from a given contraction of a shell of steel, 30 miles thick, acting on a sphere of the size and composition of our earth.”

Did I rely upon actual decrease of volume due to pressure, my theory would, of course, be absurdly untenable; but my reasoning is based upon the transference of material from beneath a surface of great pressure to below a surface upon which the pressure is much less. This I have so frequently reiteratedinmy paper that I could quote from almost any page; perhaps the following extract, taken from my first paper, will suffice: “The underlying material will be, so to speak, squeezed out, and this will cause a real transfer from under the sinking area to beneath the surrounding regions.”