Robert Bunsen Ka Chirag

photo credits: www.pinterest.co.uk & www.trip advisor. com.au

Spell binding or lab shattering, practical escapades or examinations, mundane or mind blowing; the Bunsen burner brings back times when we threw everything into a test tube and watched the mixture transmute or explode. Its single non luminous flame turning calcium brick red, sodium yellow or copper sulphate bluish green initiated each one of us into the secrets of alchemy. It was fire power captured in a 15 cm metallic cylinder when coal gas was replacing candle power in the late 1700s and early 1800s for heating and lighting. The burner was named after Robert Wilhelm Eberhard Bunsen, a genie whose life spanned the “science mad” 19th century in his lifetime. He was famous in 19th century chemistry for the legacy of discoveries, inventions and famous students he gave to posterity. Born in 1811, to the University of Gottingen’s chief librarian and professor of modern philology; Robert Bunsen studied and began his working life as a lecturer in 1833 in this university ( its website lists 25 Nobel laureates today).

In true genie fashion, he arrived with a bang! His first explosive encounter while trying to distil arsenic with potassium acetate, associated his name with product of this reaction; a poisonous compound called cacodyl that becomes a smelly, poisonous gas exploding on contact with air. It provided Bunsen with proof to confirm the new theory of organic radicals proposed by Friedrich Wohler, his contemporary. It also possibly gave him the damaged right eye we see in his photograph on the Wikipedia page. At this time, when arsenic poisoning was not only commonplace but a prized weapon of murder; Robert Bunsen’s six year work on arsenic related compounds established the first clear antidote to arsenic poisoning and is still in use 200 years later! His meticulous laboratory work drew respect and recognition from Jons Jacob Berzelius, one of the founders & god fathers of modern chemistry.

But, our genie has now been working for 18 years and we still have not come to his eponymous chirag! Well, in1852, he moved to the oldest German university, the University of Heidelberg as a professor where he would spend the rest of his active working life. It was at Heidelberg that Bunsen teamed up with Peter Desaga an instrument maker to improve Michael Faraday’s laboratory burner: adjustable slits were put at the base to control the air and gas mixture and by 1855 the Bunsen burner was finalized. About this time the streets of Heidelberg were just beginning to be lit by coal gas and it enabled the use of the same resource to fire Bunsen’s fifty new burners and light up his laboratory. Bunsen’s fame as a teacher and his fine experimental laboratory would draw collaborators like Dimitri Mendeleev from Russia; Edward Frankland, John Tyndall and Henry Roscoe from England; in Germany at least two Nobel laureates Adolf von Baeyer and Fritz Haber would be his students among many others; the light of the our genie’s chirag was now attaining its true luminosity. In a century where almost half the elements on the periodic table were discovered, Bunsen’s modified battery with the cheaper carbon rods and then the prototype spectroscope in collaboration with Gustav Kirchhoff contributed to the technology that helped to purify elements. So progressing from the simple flame test on the Bunsen burner to flame spectroscopy Bunsen and Kirchhoff would discover two elements Caesium and Rubidium in 1860 and in 1877 they became the first recipients of the Davy Medal in 1887 for contributions to spectral analysis. Bunsen was also honoured with Copley Medal of the Royal Society of London in 1860, and the Albert Medal in 1898, a year before his death and the close of the century.

For all his original work and inventions, Bunsen never took out a patent; a singular exception in the professional work German culture! Thus in contribution, recognition and respect the light from his chirag throw its light far and wide among the pathfinders in chemistry in the 19th century. Yet, I till clicked on the web pages or opened the books, my only connect with Bunsen was the laboratory burner of the same name. How much had remained hidden only because I had not explored the “who, when, where, what, how and why” of the history of science!

Main resources:

1. Wikipedia
2. Encyclopedia Britannica
3. https://www.uni-heidelberg.de
4. Henry Roscoe, “Bunsen Memorial Lecture”, J.Chem.Soc.,Trans.,1900,77,513-554.
5. Ernst Mayr, “The Growth of Biological Thought”, Belknap Press, ISBN 0674364465