Bernard Courtois (), also spelled Barnard Courtois, (8 February 1777 – 27 September 1838) was a French

chemist A chemist (from Greek ''chēm(ía)'' alchemy; replacing ''chymist'' from Medieval Latin ''alchemist'') is a graduated scientist trained in the study of chemistry, or an officially enrolled student in the field. Chemists study the composition of ...

credited with first isolating

iodine Iodine is a chemical element; it has symbol I and atomic number 53. The heaviest of the stable halogens, it exists at standard conditions as a semi-lustrous, non-metallic solid that melts to form a deep violet liquid at , and boils to a vi ...

, making early photography possible. By 1811 the

Napoleonic Wars {{Infobox military conflict , conflict = Napoleonic Wars , partof = the French Revolutionary and Napoleonic Wars , image = Napoleonic Wars (revision).jpg , caption = Left to right, top to bottom:Battl ...

had made the government-controlled

saltpeter Potassium nitrate is a chemical compound with a sharp, salty, bitter taste and the chemical formula . It is a potassium salt of nitric acid. This salt consists of potassium cations and nitrate anions , and is therefore an alkali metal nitrate ...

business taper off since there was by then a shortage of wood ashes with which potassium nitrate was made. As an alternative, the needed potassium nitrate was derived from seaweed that was abundant on the

Normandy Normandy (; or ) is a geographical and cultural region in northwestern Europe, roughly coextensive with the historical Duchy of Normandy. Normandy comprises Normandy (administrative region), mainland Normandy (a part of France) and insular N ...

and

Brittany Brittany ( ) is a peninsula, historical country and cultural area in the north-west of modern France, covering the western part of what was known as Armorica in Roman Gaul. It became an Kingdom of Brittany, independent kingdom and then a Duch ...

shores. The seaweed also had another, yet undiscovered, important chemical. One day towards the end of 1811 while Courtois was isolating

sodium Sodium is a chemical element; it has Symbol (chemistry), symbol Na (from Neo-Latin ) and atomic number 11. It is a soft, silvery-white, highly reactive metal. Sodium is an alkali metal, being in group 1 element, group 1 of the peri ...

and

potassium Potassium is a chemical element; it has Symbol (chemistry), symbol K (from Neo-Latin ) and atomic number19. It is a silvery white metal that is soft enough to easily cut with a knife. Potassium metal reacts rapidly with atmospheric oxygen to ...

compounds from seaweed ash, he discovered

after he added

sulfuric acid Sulfuric acid (American spelling and the preferred IUPAC name) or sulphuric acid (English in the Commonwealth of Nations, Commonwealth spelling), known in antiquity as oil of vitriol, is a mineral acid composed of the elements sulfur, oxygen, ...

to the seaweed ash. He was investigating corrosion of his copper vessels when he noticed a vapor given off. It was in the form of an unusual purple vapor.

Humphry Davy Sir Humphry Davy, 1st Baronet (17 December 177829 May 1829) was a British chemist and inventor who invented the Davy lamp and a very early form of arc lamp. He is also remembered for isolating, by using electricity, several Chemical element, e ...

later records

Later life

Courtois was acknowledged by Humphry Davy and

Joseph Louis Gay-Lussac Joseph Louis Gay-Lussac ( , ; ; 6 December 1778 – 9 May 1850) was a French chemist and physicist. He is known mostly for his discovery that water is made of two parts hydrogen and one part oxygen by volume (with Alexander von Humboldt), f ...

as the true discoverer of iodine. In 1822, he began manufacturing high-quality iodine and its salts. In 1831, he was awarded 6,000 francs as part of the Montyon Prize by ''L'Academie royale des sciences'', for the medicinal value of the element. He struggled financially for the rest of his life and died 27 September 1838. He was 61 years old and had no assets to leave to his widow or son. In the year of his death, under the heading

Obituary An obituary (wikt:obit#Etymology 2, obit for short) is an Article (publishing), article about a recently death, deceased person. Newspapers often publish obituaries as Article (publishing), news articles. Although obituaries tend to focus on p ...

, the ''Journal de chimie médicale'' drily noted his passing with:

"Bernard Courtois, the discoverer of iodine, died at Paris the 27th of September, 1838, leaving his widow without fortune. If, on making this discovery, Courtois had taken out a certificate of invention, he would have realized a large estate." as translated by

Notes

References

* Toraude, L. G., ''Bernard Courtois (1777–1838) et la découverte de l'iode (1811)'', Vigot Frères, Paris, 1921 * Smeaton, W. A., ''Guyton de Morveau's Course of Chemistry in the Dijon Academy'', Ambix 1961, 9, 53–69 {{DEFAULTSORT:Courtois, Bernard 19th-century French chemists 1777 births 1838 deaths Discoverers of chemical elements Scientists from Dijon 19th-century French photographers Iodine École Polytechnique alumni 18th-century French chemists