Lecturer
He started out as aide to his uncle, Henry Moyes, an itinerent lecturer in Natural Philosophy whose blindness necessitated assistance for his chemistry and optics demonstrations. Nicol, having himself become a popular lecturer on that subject at the University of Edinburgh, settled in Edinburgh to live a very retired life. He conducted extensive studies of fluid inclusions in crystals and the microscopic structure of fossil wood. He did not publish any of his research findings until 1826.
Nicol made his prism by bisecting a parallelepiped of Iceland spar (a naturally occurring, transparent crystalline form of calcium carbonate) along its shortest diagonal, then cementing the two halves together with Canada balsam. Light entering the prism is refracted into two rays, one of which emerges as plane-polarized light. Nicol prisms greatly facilitated the study of refraction and polarization, and were later used to investigate molecular structures and optical activity of organic compounds.
In 1815, Nicol developed a method of preparing extremely thin sections of crystals and rocks for microscopical study. His technique (which involved cementing the specimen to a glass slide and then carefully grinding until it was extremely thin) made it possible to view mineral samples by transmitted rather than reflected light and therefore enabled the minerals' internal structures to be seen.
He died at Edinburgh on the 2 September 1851, and was buried in Warriston Cemetery. His burial site is now marked by a plaque on the north wall.
Dorsum Nicol on the Moon is named after him.
Read more about this topic: William Nicol (geologist)