On June 3, 1726, Scottish geologist, physician, chemical manufacturer, naturalist, and experimental agriculturalist James Hutton was born. He originated the theory of uniformitarianism, a fundamental principle of geology, which explains the features of the Earth’s crust by means of natural processes over geologic time. Hutton’s work established geology as a proper science, and thus he is often referred to as the “Father of Modern Geology“.
“The past history of our globe must be explained by what can be seen to be happening now. No powers are to be employed that are not natural to the globe, no action to be admitted except those of which we know the principle.”
— James Hutton, Theory of the Earth (Paper, published in Transactions of the Royal Society of Edinburgh in 1785)
James Hutton was born into a rather wealthy family and entered Edinburgh High School at the age of 10. In 1740, Hutton entered the University of Edinburgh, where he was taught mathematics, as well as logic and metaphysics. In 1747, Hutton went to Paris and continued his studies in medicine, which he completed in Leiden later on. It is believed that he never really intended to practice medicine. He moved to London after graduating and visited James Davie in Edinburgh to set up a chemical works. The works was a great success and provided Hutton with a decent income.
In this period, his interest in geology evolved, and especially the works Discourse on earthquakes by Hooke, New theory of the Earth by Whiston, Protogaea by Leibniz  and Histoire naturelle by Buffon, as well as Steno’s  treatise Dissertation concerning a solid body enclosed by the process of nature within a solid caught his attention. He moved to his father’s farm in 1754 where he began farming and working on his theories of geology. It is further believed that in 1767, he returned to live in Edinburgh and set up his laboratory in order to pursue his theories of the history of the Earth. When realizing that soil is caused by erosion of rocks, James Hutton also understood that there is another mechanism creating rocks beneath the surface, which then form new land. As he knew that this process was extremely slow, Hutton concluded that the Earth had to be really old. Unfortunately, he could not successful figure out how to quantify this.
The Royal Society of Edinburgh invited James Hutton to give two lectures on his theory. The first lecture took place in March 1785 and since Hutton was ill, his friend Joseph Black took over, talking about the system of the Earth. The second lecture was delivered by Hutton himself one month later. As the church highly criticized Hutton’s findings, he sailed down the North Sea coast of Scotland viewing the exposed rock formations in the cliffs to gain further evidence for his theory. As Hutton’s writing style was difficult for some people and the notes from his famous two lectures at the Royal Society were only published years later, John Playfair published Illustrations of the Huttonian Theory of the Earth in 1802. He presented Hutton’s theories in a different style from that of The theory of the earth. Playfair managed to explain Huttons ideas in a more simple and clear way and gave facts to support and arguments against it. He spent almost five years, from Hutton’s death in 1797 until 1802, writing the Illustrations.
At yovisto academic video search you can learn more about ‘Earth History in the Broadest Possible Context‘ in a lecture by Walter Alvarez at Berkeley University.
References and Further Reading:
-  MacTutor History of Mathematics archive
-  James Hutton at Famous Scientists
-  James Hutton at the American Museum of Natural Science
-  Robert Hooke and his Micrographia, SciHi Blog
-  Let Us Calculate – the Last Universal Academic Gottfried Wilhelm Leibniz, SciHi Blog
-  Comte de Buffon and his Histoire Naturelle, SciHi Blog
-  Nicolas Steno and the Principles of Modern Geology, SciHi Blog
-  James Hutton at Wikidata