WCP3989

[1]

Parkstone, Dorset

Nov^r. 18th. 1894

My dear Meldola¹

I was very glad to hear of Prof. Perry's² discovery of Lord Kelvin's³ error — & to have the paper — though that is very unintelligible to me, except the point that the difference depends on assuming the interior of earth to be liquid instead of solid. But I am surprised that Perry makes no reference to Rev^d O. Fisher,⁴ who, in his Physics of the Earth's Crust,⁵ has gone into this whole question, both physically, ^geologically & [2] mathematically, & has arrived at the same conclusions. In his Chap. VI. he discusses L^d. Kelvin's views & shows that all the evidence, physical & geological is against solidity & in favour of a crust less than 20 miles thick, with a liquid energetic interior — that is a liquid subject to convection currents, which would bring about the "infinite conductivity" he ^Perry assumes. In the "Appendix" to last Edition Chap. XXVII — the same subject is reviewed, & the conclusions [3] shown to be in accordance with the "revelations of the Thermometer." -

Perry's calculations seem to me to be an independent confirmation of O. Fishers, and, as such of immense value; but before publishing them he should read Fisher's work & refer to it. It is most readable & interesting & discusses the whole subject from every point of view.

When your letter came I was suffering from an inflamed eye & had to leave off writing [4] or reading for nearly a month!

When I saw Mr. Fisher he told me that "mathematicians never read each other's work!" — at least nobody every seemed to read his — except geologists & naturalists — & this view seems to be confirmed by Perry's apparent ignorance of it, & by Lord Kelvin's taking no notice of it though it was first published thirteen years ago, & the 2nd. Ed. in 1889.

I have written a very severe criticism of Bateson⁶ & Galton⁷ — as to "Discontinuous Variation" — "Organic Stability" &c. — which I hope will be in next Fortnightly.

Yours very truly | Alfred R. Wallace [signature]