James Hutton MD (Edinburgh, 3 June 1726 OS (14 June 1726 NS)  – 26 March 1797) was a Scottish geologist, physician, naturalist, chemist and experimental farmer. He is considered the father of modern geology.[1][2] His theories of geology and geologic time,[3] also called deep time,[4] came to be included in theories which were called plutonism and uniformitarianism. James Hutton was born in Edinburgh on 3 June 1726 OS as one of five children of a merchant who was Edinburgh City Treasurer, but died when James was still young. Hutton's mother had him educated at the High School of Edinburgh where he was particularly interested in mathematics and chemistry, then when he was 14 he attended the University of Edinburgh as a "student of humanity". He was apprenticed to a lawyer when he was 17, but took more interest in chemical experiments than legal work and at the age of 18 became a physician's assistant as well as attending lectures in medicine at the University of Edinburgh. After three years he studied the subject in Paris, then in 1749 took the degree of Doctor of Medicine at Leyden with a thesis on blood circulation.[5] Around 1747 he had a son by a Miss Edington, and though he gave his child James Smeaton Hutton financial assistance, he had little to do with the boy who went on to become a post-office clerk in London.[6] After his degree Hutton returned to London, then in mid-1750 went back to Edinburgh and resumed chemical experiments with close friend, James Davie. Their work on production of sal ammoniac from soot led to their partnership in a profitable chemical works,[7] manufacturing the crystalline salt which was used for dyeing, metalworking and as smelling salts and previously was available only from natural sources and had to be imported from Egypt. Hutton owned and rented out properties in Edinburgh, employing a factor to manage this business.[8] Hutton inherited from his father the Berwickshire farms of Slighhouses, a lowland farm which had been in the family since 1713, and the hill farm of Nether Monynut.[9] In the early 1750s he moved to Slighhouses and set about making improvements, introducing farming practices from other parts of Britain and experimenting with plant and animal husbandry.[10] He recorded his ideas and innovations in an unpublished treatise on The Elements of Agriculture.[11] This developed his interest in meteorology and geology,[10] and by 1753 he had "become very fond of studying the surface of the earth, and was looking with anxious curiosity into every pit or ditch or bed of a river that fell in his way”. Clearing and draining his farm provided ample opportunities, and Hutton noticed that “a vast proportion of the present rocks are composed of materials afforded by the destruction of bodies, animal, vegetable and mineral, of more ancient formation”. His theoretical ideas began to come together in 1760. While his farming activities continued, in 1764 he went on a geological tour of the north of Scotland with George Clerk Maxwell.[12] In 1768 Hutton returned to Edinburgh, letting his farms to tenants but continuing to take an interest in farm improvements and research which included experiments carried out at Slighhouses. He developed a red dye made from the roots of the madder plant.[13] He had a house built in 1770 at St John’s Hill, Edinburgh, overlooking Salisbury Crags.[13] He was one of the most influential participants in the Scottish Enlightenment, and fell in with numerous first-class minds in the sciences including John Playfair, philosopher David Hume and economist Adam Smith.[14] He was a particularly close friend of Joseph Black, and the two of them together with Adam Smith founded the Oyster Club for weekly meetings, with Hutton and Black finding a venue which turned out to have rather disreputable associations.[14] Between 1767 and 1774 Hutton had considerable close involvement with the construction of the Forth and Clyde canal, making full use of his geological knowledge, both as a shareholder and as a member of the committee of management, and attended meetings including extended site inspections of all the works. In 1777 he published a pamphlet on Considerations on the Nature, Quality and Distinctions of Coal and Culm which successfully helped to obtain relief from excise duty on carrying small coal.[15] Hutton hit on a variety of ideas to explain the rock formations he saw around him, but according to Playfair he "was in no haste to publish his theory; for he was one of those who are much more delighted with the contemplation of truth, than with the praise of having discovered it”. After some 25 years of work,[16] his Theory of the Earth; or an Investigation of the Laws observable in the Composition, Dissolution, and Restoration of Land upon the Globe was read to meetings of the Royal Society of Edinburgh in two parts, the first by his friend Joseph Black on 7 March 1785, and the second by himself on 4 April 1785. Hutton subsequently read an abstract of his dissertation Concerning the System of the Earth, its Duration and Stability to Society meeting on 4 July 1785,[17] which he had printed and circulated privately.[18] In it, he outlined his theory as follows; At Glen Tilt in the Cairngorm mountains in the Scottish Highlands, Hutton found granite penetrating metamorphic schists, in a way which indicated that the granite had been molten at the time. This showed to him that granite formed from cooling of molten rock, not precipitation out of water as others at the time believed, and that the granite must be younger than the schists.[19][20] He went on to find a similar penetration of volcanic rock through sedimentary rock near the centre of Edinburgh, at Salisbury Crags,[2] adjoining Arthur's Seat: this is now known as Hutton's Section.[21][22] He found other examples in Galloway in 1786, and on the Isle of Arran in 1787. The existence of angular unconformities had been noted by Nicolas Steno and by French geologists including Horace-Bénédict de Saussure, who interpreted them in terms of Neptunism as "primary formations". Hutton wanted to examine such formations himself to see “particular marks” of the relationship between the rock layers. On the 1787 trip to Arran he found his first example of Hutton's Unconformity to the north of Newton Point near Lochranza,[23][24] but the limited view meant that the condition of the underlying strata was not clear enough for him,[25] and he incorrectly thought that the strata were conformable at a depth below the exposed outcrop.[26] Later in 1787 Hutton noted what is now known as the Hutton Unconformity at Inchbonny,[3] Jedburgh, in layers of sedimentary rock.[27] As shown in the illustrations to the right, layers of greywacke in the lower layers of the cliff face are tilted almost vertically, and above an intervening layer of conglomerate lie horizontal layers of Old Red Sandstone. He later wrote of how he "rejoiced at my good fortune in stumbling upon an object so interesting in the natural history of the earth, and which I had been long looking for in vain." That year, he found the same sequence in Teviotdale.[25] In the Spring of 1788 he set off with John Playfair to the Berwickshire coast and found more examples of this sequence in the valleys of the Tour and Pease Burns near Cockburnspath.[25] They then took a boat trip from Dunglass Burn east along the coast with the geologist Sir James Hall of Dunglass. They found the sequence in the cliff below St. Helens, then just to the east at Siccar Point found what Hutton called "a beautiful picture of this junction washed bare by the sea".[28][29] Playfair later commented about the experience, "the mind seemed to grow giddy by looking so far into the abyss of time".[30] Continuing along the coast, they made more discoveries including sections of the vertical beds showing strong ripple marks which gave Hutton "great satisfaction" as a confirmation of his supposition that these beds had been laid horizontally in water. He also found conglomerate at altitudes that demonstrated the extent of erosion of the strata, and said of this that "we never should have dreamed of meeting with what we now perceived”.[25] Hutton reasoned that there must have been several cycles, each involving deposition on the seabed, uplift with tilting and erosion then undersea again for further layers to be deposited, and there could have been many cycles before over an extremely long history. In a 1788 paper he presented at the Royal Society of Edinburgh,[3] Hutton remarked, "we find no vestige of a beginning, no prospect of an end." (This memorable line[3][31] was quoted in the 1989 song “No Control” by songwriter and professor Greg Graffin.[32]) Though Hutton circulated privately a printed version of the abstract of his Theory (Concerning the System of the Earth, its Duration, and Stability) which he read at a meeting of the Royal Society of Edinburgh on 4 July 1785;[18] the theory as read at the 7 March 1785 and 4 April 1785 meetings did not appear in print until 1788. It was titled Theory of the Earth; or an Investigation of the Laws observable in the Composition, Dissolution, and Restoration of Land upon the Globe and appeared in Transactions of the Royal Society of Edinburgh, vol. I, Part II, pp.209-304, plates I and II, published 1788.[17] Following criticism, especially Richard Kirwan's, who thought him atheist and not logical, among other things,[17] Hutton published a two volume version of his theory in 1795,[33][34] consisting of the 1788 version of his theory (with slight additions) along with a lot of material drawn from shorter papers Hutton already had to hand on various subjects such as the origin of granite. It included a review of alternative theories, such as those of Thomas Burnet and Georges-Louis Leclerc, Comte de Buffon. The whole was entitled An Investigation of the Principles of Knowledge and of the Progress of Reason, from Sense to Science and Philosophy when the third volume was completed in 1794.[35] Its 2,138 pages prompted Playfair to remark that “The great size of the book, and the obscurity which may justly be objected to many parts of it, have probably prevented it from being received as it deserves.”