John MacCulloch FRS (6 October 1773 – 21 August 1835) was a Scottish geologist. He was the first geologist to be employed by the government in Britain and is best known for his pioneering texts on geology and for producing the first geological maps of Scotland. He introduced the word "malaria" into the English language. Biography MacCulloch, descended from the MacCullochs of Nether Ardwell in Galloway, was born in Guernsey, his mother being a native of that island. He was born at the home of his mother's parents, grandfather James being a magistrate. John's father, James, worked in France as wine merchant and returned to Britain after the French Revolution. Having displayed remarkable powers as a boy, demonstrating skills with fireworks at Lostwithiel, he was sent after finishing grammar school to study medicine at the university of Edinburgh. Here he was inspired by the chemist Joseph Black. He qualified as MD in 1793, and then entered the army as assistant surgeon. Attaching himself to the artillery, he became chemist to the board of ordnance (1803). He still continued, however, to practice for a time as a physician, and during the years 1807–1811 he resided at Blackheath and joined the newly founded Geological Society of London. He assisted ordnance chemist Cruickshank who taught at the Royal Military Academy and when Cruickshank was declared insane in 1804 took over his teaching position. He also taught cadets at Addiscombe from 1814 and made use of his textbook A Geological Classification of Rocks (1811). In 1811 he communicated his first papers to the Geological Society of London. They were devoted to an elucidation of the geological structure of Guernsey, of the Channel Islands, and of Heligoland. The evidence they afforded of his capacity, and the fact that he already had received a scientific appointment, probably led to his being selected in the same year to make some geological and mineralogical investigations in Scotland. He was in 1809 to identify limestone suitable for use in gunpowder making. He was also consulted on the suitability of the chief Scottish mountains for a repetition of the pendulum experiments previously conducted by Nevil Maskelyne and John Playfair at Schiehallion, and on the deviations of the plumb-line along the meridian of the Trigonometrical Survey. In the course of the explorations necessary for the purposes of these reports he made extensive observations on the geology and mineralogy of Scotland. He