Hutton's Geological Ideas Based on a Sample from His 1795 Theory (Volume I)
Authors: Galvin Cyril 
Published: April 2015

Sixty-two examples of Hutton's writing, collected at ten-page intervals from the first volume of his 1795 Theory of the Earth, are the basis of this study. James Hutton (1726-1797) described the planet which is the subject of geology primarily by three words: "earth," sometimes implying the earth of farmers, not the planet of Newton; "globe," often implying the outer spherical shell, rather than the sphere itself; and "world," usually described as the "living world." The most common technical phrase in the book is "bottom of the sea." The most common technical word is "stratum" (or strata).

Three axioms guide Hutton's thought: a theoretical axiom that grants validity to knowledge from a metaphysical analysis of causes; an empirical axiom that grants validity to observations of things as they are; and a theological axiom that (combined with his theoretical axiom) requires geology to produce a world designed for farmers. The theoretical and empirical axioms produce conflicts that Hutton resolves by selecting the result that eliminates the importance of low-temperature chemical action.

Hutton's empirical observations demonstrate a planet earth whose visible parts are dominated overwhelmingly by sedimentary rocks, but he mistakenly infers that most sedimentary rocks are produced in the deeps of the sea. Hutton emphasizes the process of consolidating sediments into rocks. His consolidation is the process of eliminating pore space from the sediments, primarily by heat and secondarily by pressure. Heat creates "fusion" of rock material, and the resulting liquid rock may be injected into the pore space of sediments. Heat also may soften the particles so that they deform under pressure. Neither consolidation process is valid to any significant extent, circa 2004.

Hutton's book yields a synthesized petrology with four classes of rocks: (1) rocks, including solidified lava and unstratified granite, that had been made entirely liquid by heat; (2) rocks, including flint, salt, ironstone, agate, jasper, and some forms of granite and coal, that had achieved their present state from "fusion"; (3) rocks, including most sedimentary and metamorphic rocks, that had been consolidated by heat and pressure; and (4) rocks that had been distilled by heat and pressure (primarily coal, possibly petroleum). Hutton included limestones in (3), correctly considering them to be clastic. The dominance of heat and, secondarily, pressure in Hutton's geophysics reduced the importance of chemical precipitation from aqueous solutions, which Hutton viewed as evidence in favor of the geology of Abraham Gottlob Werner (1749-1817).

Volume I of the 1795 Theory is unusually paginated in having five of eight chapters end with page numbers evenly divisible by ten, that is, their last digits are zero. Because there are ten possible last digits, having five out of eight be zero is a statistically rare event (one in 2500). Possibly, this rare event is the result of the publisher's actions. Hutton's 1785 Abstract, which does not bear his or a publisher's name, ends at page 30, and it is identical to both volumes of the 1795 Theory in beginning the text on page 3 and having the same typesetters' code at the base of pages 9, 17, and 25.