30 March 1811{{efn|1=Sources disagree on Robert Bunsen's exact birth date. His parish register, as well as two curricula vitae handwritten by Bunsen himself, document 30 March 1811 as Bunsen's true birth date;{{cite journal|author=Martin Quack|title=Wann wurde Robert Wilhelm Bunsen geboren?|journal=Bunsen-Magazin|year=2011|volume=2|pages=56–57|publisher=Deutsche Bunsen-Gesellschaft für Physikalische Chemie}}Robert Wilhelm Bunsens Korrespondenz vor dem Antritt der Heidelberger Professur (1852): kritische Edition; Christine Stock, [ed.] Stuttgart: Wissenschaftliche Verlagsgesellschaft, 2007. {{ISBN|3-8047-2320-9}}[http://www.britannica.com/EBchecked/topic/84752/Robert-Wilhelm-Bunsen "Robert Wilhelm Bunsen"], Encyclopædia Britannica. Encyclopædia Britannica Online. Encyclopædia Britannica, 2011. Web. 3 April 2011Georg Lockemann: Robert Wilhelm Bunsen. Lebensbild eines deutschen Naturforschers, Wissenschaftliche Verlagsgesellschaft Stuttgart, 1949, p. 18 however, many later sources cite 31 March as the date.[http://www.rsc.org/Library/Collections/Historical/Archive/Bunsen.asp "Robert Bunsen's 200th Anniversary"], Royal Society of Chemistry[http://iopscience.iop.org/0031-9120/34/5/309 "Bunsen without his burner"], Colin A. Russell, Phys. Educ. 34(5) September 1999[http://www.encyclopedia.com/doc/1G2-2830900705.html "Bunsen, Robert Wilhelm Eberhard], Complete Dictionary of Scientific Biography (2008). Retrieved 31 March 2011 from Encyclopedia.com{{Cite journal | doi = 10.1038/086079b0| title = The Centenary of Bunsen's Birth| journal = Nature| volume = 86| issue = 2159| pages = 79| year = 1911| last1 = Jones | first1 = F. | last2 = Grossmann | first2 = J.| bibcode = 1911Natur..86...79J| s2cid = 3989053| url = https://zenodo.org/record/1429540| doi-access = free}}{{Cite journal | doi = 10.1111/j.1949-8594.1943.tb05846.x| title = Humanizing Science and Mathematics by Commemorating March Anniversaries| journal = School Science and Mathematics| volume = 43| issue = 3| pages = 234–250| year = 1943| last1 = Teller | first1 = J. D. }} According to his biographer Georg Lockemann, Bunsen himself celebrated his birthday on the 31st in his later years. Lockemann nevertheless regarded the 30th as the correct date.}}

– 16 August 1899) was a German chemist. He investigated emission spectra of heated elements, and discovered caesium (in 1860) and rubidium (in 1861) with the physicist Gustav Kirchhoff.{{cite book |last1=Weeks |first1=Mary Elvira |title=The discovery of the elements |date=1956 |publisher=Journal of Chemical Education |location=Easton, PA |url=https://archive.org/details/discoveryoftheel002045mbp |edition=6th }} The Bunsen–Kirchhoff Award for spectroscopy is named after Bunsen and Kirchhoff.

Bunsen also developed several gas-analytical methods, was a pioneer in photochemistry, and did early work in the field of organic arsenic chemistry. With his laboratory assistant Peter Desaga, he developed the Bunsen burner, an improvement on the laboratory burners then in use.

Early life and education

Bunsen was born in Göttingen, Germany, in 1811, in what is now the state of Lower Saxony in Germany. Bunsen was the youngest of four sons of the University of Göttingen's chief librarian and professor of modern philology, Christian Bunsen (1770–1837).{{cite journal|title=Professor Robert W. Bunsen|journal=Journal of the American Chemical Society|year=1900|volume=23|pages=89–107|url=https://books.google.com/books?id=u9oBAAAAYAAJ&pg=RA1-PA89|publisher=American Chemical Society|author1= American Chemical Society|issue=9|doi=10.1017/S0016756800174655|bibcode=1900GeoM....7R.431.|doi-access=free}}

After attending school in Holzminden, Bunsen matriculated at Göttingen in 1828 and studied chemistry with Friedrich Stromeyer, mineralogy with Johann Friedrich Ludwig Hausmann, and mathematics with Carl Friedrich Gauss. After obtaining a PhD in 1831, Bunsen spent 1832 and 1833 traveling in France, Germany, and Austria. During his journeys, Bunsen met the scientists Friedlieb Runge (who discovered aniline and in 1819 isolated caffeine), Justus von Liebig in Giessen, and Eilhard Mitscherlich in Bonn.

Academic career

In 1833, Bunsen became a lecturer at Göttingen and began experimental studies of the (in)solubility of metal salts of arsenous acid. His discovery of the use of iron oxide hydrate as a precipitating agent led to what is still today the most effective antidote against arsenic poisoning. This interdisciplinary research was carried on and published in conjunction with the physician Arnold Adolph Berthold.{{Cite web|title=Robert Wilhelm Bunsen|publisher=Encyclopedia.com|url=http://www.encyclopedia.com/topic/Robert_Wilhelm_Bunsen.aspx|access-date=16 September 2013}}{{Cite AmCyc|wstitle=Bunsen, Robert Wilhelm}} In 1836, Bunsen succeeded Friedrich Wöhler at the Polytechnic School of Kassel ({{langx|de|Baugewerkschule Kassel}}). Bunsen taught there for three years, and then accepted an associate professorship at the University of Marburg, where he continued his studies on cacodyl derivatives. He was promoted to full professorship in 1841. While at University of Marburg, Bunsen participated in the 1846 expedition for the investigation of Iceland's volcanoes.{{cite journal|last=Oesper|first=R.E.|title=Bunsen's Trip to Iceland as Recounted in Letters to His Mother|journal=J. Chem. Educ.|volume=18|issue=6|pages=253–260|year=1941|doi=10.1021/ed018p253 |bibcode=1941JChEd..18..253O}}

Bunsen's work brought him quick and wide acclaim, partly because cacodyl, which is extremely toxic and undergoes spontaneous combustion in dry air, is so difficult to work with. Bunsen almost died from arsenic poisoning, and an explosion with cacodyl cost him sight in his right eye. His work with Cadet's fuming liquid was an important step in the development of the radical theory of organic compounds.

In 1841,{{cite journal|last=Bunsen|first=R.|title=Ueber eine neue Construction der galvanischen Säule|journal=Justus Liebigs Annalen der Chemie|volume=38|issue=3|pages=311–313|year=1841|doi=10.1002/jlac.18410380307 |url=https://zenodo.org/record/1426963}} Bunsen created the Bunsen cell battery, using a carbon electrode instead of the expensive platinum electrode used in William Robert Grove's electrochemical cell. Early in 1851 he accepted a professorship at the University of Breslau, where he taught for three semesters. {{Citation needed|date=April 2011}}

File:Bunsen-Kirchhoff.jpg (left) and Robert Bunsen (right)|alt=Black-and-white image of two middle-aged men, either one leaning with one elbow on a wooden column in the middle. Both wear long jackets, and the shorter man on the left has a beard.]]

In late 1852, Bunsen became the successor of Leopold Gmelin at the University of Heidelberg. There he used electrolysis to produce pure metals, such as chromium, magnesium, aluminium, manganese, sodium, barium, calcium, and lithium. A long collaboration with Henry Enfield Roscoe began in 1852, in which they studied the photochemical formation of hydrogen chloride (HCl) from hydrogen and chlorine. From this work, the reciprocity law of Bunsen and Roscoe originated. He discontinued his work with Roscoe in 1859 and joined Gustav Kirchhoff to study emission spectra of heated elements, a research area called spectrum analysis. For this work, Bunsen and his laboratory assistant, Peter Desaga, had perfected a special gas burner by 1855, which was influenced by earlier models. The newer design of Bunsen and Desaga, which provided a very hot and clean flame, is now called simply the "Bunsen burner", a common laboratory equipment.{{cite journal|last=Jensen|first=William B.|title=The Origin of the Bunsen Burner|journal=Journal of Chemical Education|volume=82|issue=4|pages=518|year=2005|doi=10.1021/ed082p518 |bibcode=2005JChEd..82..518J}}[https://archive.org/details/chemicalmanipula00fararich "Chemical Manipulation, Being Instructions to Students in Chemistry"], Internet Archive Michael Faraday, 1827

There had been earlier studies of the characteristic colors of heated elements, but nothing systematic. In the summer of 1859, Kirchhoff suggested to Bunsen that he should try to form prismatic spectra of these colors. By October of that year, the two scientists had invented an appropriate instrument, a prototype spectroscope. Using it, they were able to identify the characteristic spectra of sodium, lithium, and potassium. After numerous laborious purifications, Bunsen proved that highly pure samples gave unique spectra. In the course of this work, Bunsen detected previously unknown new blue spectral emission lines in samples of mineral water from Dürkheim. He guessed that these lines indicated the existence of an undiscovered chemical element. After careful distillation of forty tons of this water, in the spring of 1860 he was able to isolate 17 grams of a new element. He named the element "caesium", after the Latin word for deep blue. The following year he discovered rubidium, by a similar process.{{cite journal |last1=Marshall |first1=James L. |last2=Marshall |first2=Virginia R. |title= Rediscovery of the Elements: Mineral Waters and Spectroscopy |journal=The Hexagon |date=2008 |pages=42–48 |url=http://www.chem.unt.edu/~jimm/REDISCOVERY%207-09-2018/Hexagon%20Articles/bunsen%20and%20spectroscopy.pdf |access-date=31 December 2019}}{{cite journal|last1=Lockemann|first1=G.|last2=Oesper|first2= R.|title=Bunsen's Transfer from Cassel to Marburg|journal=J. Chem. Educ.|volume=32|issue=9|pages=456–460|year=1955|doi=10.1021/ed032p456 |bibcode=1955JChEd..32..456L}}{{cite web|title=Robert Bunsen and Gustav Kirchhoff|url=https://www.sciencehistory.org/historical-profile/robert-bunsen-and-gustav-kirchhoff|website=Science History Institute|access-date=20 March 2018|date=June 2016}}

In 1860, Bunsen was elected a foreign member of the Royal Swedish Academy of Sciences.{{Citation needed|date=March 2011}}

He was elected as a member of the American Philosophical Society in 1862.{{Cite web|title=APS Member History|url=https://search.amphilsoc.org/memhist/search?year=1862;year-max=1862;smode=advanced;startDoc=1|access-date=20 April 2021|website=search.amphilsoc.org}}

File:Bunsen-Grabmal.jpg

In 1877, Robert Bunsen together with Gustav Robert Kirchhoff were the first recipients of the prestigious Davy Medal "for their researches and discoveries in spectrum analysis".{{Cite web |title=Davy Medal – Royal Society |url=https://royalsociety.org/grants-schemes-awards/awards/davy-medal/ |access-date=14 August 2020 |website=royalsociety.org |publisher=The Royal Society |language=en-gb}}

Personality

Bunsen was one of the most universally admired scientists of his generation. He was a master teacher, devoted to his students, and they were equally devoted to him. At a time of vigorous and often caustic scientific debates, Bunsen always conducted himself as a perfect gentleman, maintaining his distance from theoretical disputes. He much preferred to work quietly in his laboratory, continuing to enrich his science with useful discoveries. As a matter of principle he never took out a patent. He never married.{{cite book |first=G. |last=Lockemann |title=Robert Wilhelm Bunsen |publisher=Wissenschaftliche Verlagsgesellschaft |location=Stuttgart |year=1949 |pages=214–223 }}

Despite his lack of pretension, Bunsen was a vivid "chemical character", had a well-developed sense of humour, and is the subject of many amusing anecdotes.Jensen, William B. (2013) Chapter 2, pp. 7–31 in "Characters in Chemistry: A Celebration of the Humanity of Chemistry", {{doi|10.1021/bk-2013-1136.ch002}}, American Chemical Society Symposium Series, Vol. 1136. {{ISBN|9780841228016}}.

Retirement and death

When Bunsen retired in 1889 at the age of 78, he shifted his work solely to geology and mineralogy, interests which he had pursued throughout his career. He died in Heidelberg, Germany on 16 August 1899, at the age of 88.{{NDB|3|18|20|Bunsen, Robert|Lockemann, Georg|118664999}}{{cite journal |author1=Roscoe, Henry |author-link=Henry Roscoe (chemist) |title=Bunsen Memorial Lecture |journal=Journal of the Chemical Society, Transactions |date=1900 |volume=77 |pages=513 |doi=10.1039/CT9007700513|url=https://zenodo.org/record/1874777 }}

Notes

References

External links

{{Commons category-inline|Robert Bunsen}}
[https://web.archive.org/web/20070927224234/http://www.woodrow.org/teachers/ci/1992/Bunsen.html Robert Wilhelm Bunsen]
{{MathGenealogy|id=123967}}

Category:1811 births

Category:1899 deaths

Category:19th-century German chemists

Category:Battery inventors

Category:Caesium

Category:Corresponding members of the Saint Petersburg Academy of Sciences

Category:Foreign members of the Royal Society

Category:Foreign associates of the National Academy of Sciences

Category:19th-century German inventors

Category:Academic staff of Heidelberg University

Category:Members of the French Academy of Sciences

Category:Members of the Royal Swedish Academy of Sciences