One of the things I love about the Eighteenth Century was that ‘there walked giants’ – everywhere you turn there are people who were prepared to turn known ideas on the head, and to usher in new concepts. This was certainly true of a man I had never heard of until I realized that it is the anniversary of his death in 1797 – one James Hutton.
To set the scene: it had previously been taken as a universal truth that the Bible was an accurate historical narrative showing that the world was formed on a specific date in history. As recently as the sixteenth century Archbishop James Ussher of Ireland had totted up the days and calculated that that Day, the Big One when the earth was formed, was 22nd October 4004 B.C. All done and dusted on a single day, no evolution, no geology, no changes (apart from the Flood).
This background makes it all the more remarkable that James Hutton was able to formulate his ideas on the formation of the Earth. In doing so he established himself as the ‘Father of Modern Geology’ and in my view his works deserve to share an equal place with those of Charles Darwin, who arguably was influenced to no small degree by Hutton’s ideas and thoughts.
He had an interesting past for a geologist: born in Edinburgh in 1726 he trained briefly as a lawyer, then travelled to Paris and Leyden to study as a doctor, qualifying after writing a thesis on the circulation of the blood. He moved on to chemistry, and jointly with a colleague James Davie he devised a cheap and efficient way of making sal ammoniac from soot. This crystalline substance was widely used in dyeing, metalworking and as smelling salts. Previously it had been available only from natural sources and had to be imported from Egypt.
With commercial success came the ability to buy farmland and for twenty years or more he was a ‘gentleman farmer’. He still studied in Edinburgh, falling in with a number of first-class scientific minds including John Playfair and Joseph Black. He was also a close friend of the philosopher David Hume and the economist Adam Smith, all pillars of the new Scottish Enlightenment.
Hutton turned his attention to selective breeding of cattle and experimenting with crop yields, ending up with writing an unpublished work entitled The Elements of Agriculture. Above all he looked and speculated at what lay beneath the surface of the land. He thought long and hard about the jagged outcrops which marked the Scottish landscape, about the streams cutting into the rocks, about each hill and incline.
In a 1753 letter he wrote that 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.” Eventually he came up with a theory, and it was one which blew away the biblical explanation of the world’s creation in the first Chapter of Genesis. According to his friends he was in no hurry to publish his theory – it took him 25 years to come out with it. John Playfair stated that Hutton “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”. But finally, in March and April 1785 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 Edinburgh Royal Society. He called his theory uniformitarianism: it was based on the idea that the geological process was ongoing and immensely slow, with incredibly long cycles of erosion, deposition, sedimentation and volcanic up-thrust. He came up with the idea of ‘deep time’ measured in tens of thousands of years. Yes, he may have been way out from modern ideas of the Earth being billions of years old, but he was on the right track in appreciating that yesterday’s sea beds have, through volcanic activity became today’s mountains. Revolutionary stuff!
The man and his hammer.
Hutton proposed that at its core the Earth was hot, and that this heat caused new rock to be created: land was eroded by air and water and deposited as layers in the sea; heat then consolidated the sediment and then drove it upwards to create new landscapes. The theory was known also as ‘Plutonism’ in contrast to the earlier flood orientated ideas. He demonstrated that igneous rocks were once molten. He studied Salisbury Crags, an igneous intrusion (sill) in Edinburgh from the Carboniferous Period, and concluded that molten rock had forced its way between layers of sandstone before cooling to form rock. He also studied the rock formations at Siccar Point in Berwickshire where rocks of very different ages are found one on top of the other, often at different angles and in unequal layers. It was unconformities like these which lay at the heart of his ideas of deep time.
He studied eroded rock, concluding that rocks are made up of “materials furnished from the ruins of former continents.” It was an ongoing process – new rocks being exposed to the atmosphere and then being eroded away. He called this alternating destruction and renewal the “great geological cycle,” and realized that it had been completed innumerable times.
Hutton Unconformity at Jedburgh, Scotland, illustrated by John Clerk in 1787.
For good measure his Theory of the Earth also contained a section on the Theory of Rain: he looked at data about rainfall and climate throughout different regions of the world and realized that rainfall levels are regulated by humidity on the one hand and the mixing of air currents in the higher atmosphere of the other.
Not content with establishing geology, and dabbling in meteorology he also laid the foundation stones for Darwin’s theory of Evolution. His treatise on Elements of Agriculture may not have been published but the underlying ideas would certainly have been prevalent in Edinburgh at the time Charles Darwin was studying medicine there in 1825. Hutton applied his theory of uniformitarianism to living creatures and came up with the idea of ‘principles of variation’ to explain different varieties of flora and fauna. He distinguished between ‘heritable variation’ which came about as a result of breeding, and ‘non-heritable variations’ caused by environmental differences such as soil and climate. Sounds close to Darwinism and the ideas of natural selection to me!
James Hutton died in Edinburgh on 26th March 1797. I have him down as a hero of his Age, without a doubt. And finally – the only way I could add colour to this post, since let’s face it, Hutton was not exactly flamboyant or colourful – a satellite image of Edinburgh and the Firth of Forth.