INFERENCE / Vol. 6, No. 1 James Hutton A Theory of the Earth Mike Leeder ames hutton was a chemist, geologist, agricul- and there became a hands-on landlord who developed the turist, and prominent member of the Edinburgh land by applying the latest techniques in agriculture and intelligentsia during the height of the Scottish landscaping. JEnlightenment. His contemporaries and friends included From the mid-1760s, Hutton lived with his sisters in Robert Adam, David Hume, Adam Smith, Dugald Stewart, central Edinburgh and threw himself into the city’s scien- and James Watt. Hutton’s major work, Theory of the Earth, tific and philosophical life. Over the next twenty years, he published first in 1788 and expanded in 1794, describes gained enough field experience to have a detailed under- his geological observations and resulting theory for the standing of the basic geology of Scotland, England, and cycling of the earth.1 His conclusion was startling: “We Wales, and so established himself as the premier Scottish find no vestige of a beginning, no prospect of an end.”2 It geological philosopher. His practice of geology gained was a unique perspective among seventeenth- and eigh- breadth and substance through his love of chemistry, exten- teenth-century scientific efforts, expressed freely and sive surveys of the French scientific literature, and a close without regard for any scriptural constraints. Hutton’s friendship with the prolific chemist Joseph Black. It was ideas are easily recognizable in today’s understanding of Black who discovered the latent heat of steam, invented the deep time and the geodynamic cycling of the earth by plate eighteenth century’s most precise analytical balance, and tectonics. Like a Lazarus taxon, which disappears from discovered carbon dioxide, a product of animal respira- the fossil record and resurfaces later, his notion of a recy- tion and organic fermentation. He also produced aqueous cling earth was born from scientific endeavor in the Age of precipitates of calcium carbonate and investigated silica Enlightenment and resurrected in the nuclear age. precipitation from Icelandic geyser waters. he major sources for what is known of Hutton’s n initial version of Theory of the Earth was life and work come courtesy of his friend and read to the Royal Society of Edinburgh on two biographer James Playfair, as well as seventeen occasions in 1785, the first by Black when Hutton Tpreserved items of personal correspondence.3 Hutton was Awas ill, and the second by Hutton himself. Organized in born in 1726 in Edinburgh of prosperous merchant stock. four parts, the work was published three years later in the His father and elder brother died when he was young, debut volume of the Transactions of the Royal Society of and he and his sisters were raised by their mother. At the Edinburgh. University of Edinburgh, he followed the mathematics The intellectual method in Hutton’s magnum opus lectures of Isaac Newton’s protégé Colin Maclaurin and was influenced by his fieldwork, agricultural experience, studied humanities and medicine. Hutton never practiced and deism. He worked from a deductive hypothesis that the latter, but its study was the best route to pursue his the planet’s machinelike workings had been envisaged interest in chemistry. From 1747, he continued his stud- by a benevolent and canny creator who parried destruc- ies at the Universities of Paris and Leiden, and graduated tive mountain denudation by constructive processes of from Leiden with a medical degree in 1749. Returning renewal involving sedimentation, consolidation, and uplift. to Edinburgh, he set up with a friend in the profitable Hutton made detailed observations on the nature of rocks, manufacture of sal ammoniac, a salt used for dyeing and minerals, and fossils and their arrangement in the geolog- metalworking, using chimney soot as raw material. He ical record. But his observations on fossils were nugatory then made a radical change in life direction. In the early beyond their being indicative of former marine conditions 1750s, he took a two-year stint on a Norfolk farm where he during stratal deposition; nonetheless he became known learned advanced agricultural practices. He took charge of as “the famous fossil philosopher,” as Watt referred to him two family farms in Berwickshire in the Scottish Borders in a letter of 1774.4 1 / 6 BIOGRAPHIES In his view of the planet as machinelike—a word used His theory depended upon a number of assumptions: five times in his first nine paragraphs—Hutton estab- creation without scripture and myth; a benevolent and lished links with contemporary industrial steam-powered forward-looking creator; and linked, steady processes machines and particularly the role of heat to drive them. of destruction, consolidation, and replenishment.14 Of He posited that, like any machine, the planet must have course, some Christians rejected his theory out of hand on had a designer who knew how best to attain a certain pur- the basis of its first assumption. pose: in this case, the creation of a habitable and renewable Hutton proposed that eroded land is replenished by a surface world. “consolidating operation” that involves the hardening of Regarding the deeper earth, he claimed a general igno- loose sediment and fossil remains on and below the ocean rance: “We know little of the earth’s internal parts, or of floor: the materials which compose it at any considerable depth below the surface.”5 During Hutton’s time, a good deal more The loose materials that had subsided [deposited] from was known about the earth’s subsurface than he acknowl- water, should be formed into masses of the most perfect edged; Georges-Louis Leclerc, the comte de Buffon, solidity, having neither water nor vacuity between their devoted a whole appendix in his Les Époques de la Nature various constituent parts, nor in the pores of those constit- to measurements of ambient temperature in deep mines.6 uent parts themselves.15 Hutton focused instead upon the earth’s surface, where “the more inert matter [i.e., rock] is replenished with He considered two possible chemical reasons as to plants, and with animals and intellectual beings.”7 This why strata may become consolidated: “either by aqueous replenishment came courtesy of soil formed from the solution and crystallization, or by the effect of heat and breakdown of solid rock. But there was a problem, since fusion.”16 He regarded the former as impossible: “this soil is necessarily washed away, by the continual cir- culation of the water, running from the summits of the There must be made to pass through those porous masses, mountains towards the [ocean].”8 Hutton realized that the water impregnated with some other substances in a dis- end result would be the gradual elimination of global relief solved state; and the aqueous menstruum must be made to and the transfer of all land into the oceans. These observa- separate from the dissolved substances, and to deposit the tions on soil erosion were not new; they had been made as same in those cavities through which the solution moves.17 far back as Homer and Plato.9 Hutton invited readers But he found no reason to object to the efficacy of heat to examine the globe; to see if there be, in the constitution and fusion in consolidation. Soft sediment will compact by of the world, a reproductive operation, by which a ruined compression and constitution may be again repaired, and a duration or sta- bility thus procured to the machine.10 by the fusion of their substance; and foreign matter may be introduced into the open structure of strata, in form of He found evidence that the earth maintained a form of steam or exhalation, as well as in the fluid state of fusion stability. “In examining things present,” he wrote, [i.e., as melt].18 we have data from which to reason with regard to what has He ascribed various features to melting, notably sili- been; and, from what has actually been, we have data for ceous and clay ironstone concretions, the arrangement of concluding with regard to that which is to happen here- crystals in metallic ore veins, and concentrically arranged after … upon the supposition that the operations of nature stratification of rock salt. are equable and steady.11 Inductive logic was required to arrive at these conclu- sions, and while it served him well on some occasions, his Hutton believed that the traces of the past bear witness overzealous eliminative induction severely constrained to times “extremely remote” compared to the ancestry of him at others and left him with only a few possible mech- humanity recorded in the scriptures. His examination of anisms by which to explain matters.19 In this way, he ruled fossils indicated that the expanse of historical time was vast: out the real causa for aqueous precipitation: sediment pore waters were static and unmovable at and under the It is thus that, in finding the relics of sea-animals of every ocean floor. He also rejected the ability of water to either kind in the solid body of our earth, a natural history of those dissolve or precipitate natural crystalline substances that animals is formed, which includes a certain portion of time.12 might consolidate loose sediment by cementation, like calcareous, siliceous, bituminous, sulfidic, and ferrugi- For estimating this portion of time, Hutton recom- nous minerals. Likewise, he ignored the consequences of mended making “recourse to the regular operations of the mechanical compaction and Buffon’s observations that the world” and by calculations based on those.13 earth’s ambient temperature increases with depth.20 The 2 / 6 INFERENCE / Vol. 6, No. 1 huge influxes of water into many mines seem not to have processes worked so “that the destruction of one continent persuaded him of the efficacy of deep, warm, aqueous flow is not brought about without the renovation of the earth in through rock masses.