Robert Bunsen

Who Gave the Flame a Collar · Chemist · 1811–1899

Who measured the gases going up an ironworks chimney, found that more than half the fuel was escaping unburned, and then built the burner whose collar of air decides whether a flame is clean or sooty.

Who was Bunsen?

Bunsen was born in Göttingen in 1811, the son of a professor of linguistics, and spent almost his whole career at Heidelberg, where he built one of the great teaching laboratories of the century. His early work was on the cacodyl compounds of arsenic, which are foul, spontaneously inflammable and lethal; one of them exploded and cost him the sight of his right eye, and he twice nearly died of arsenic poisoning. He also found the antidote — hydrated iron oxide, which is still the treatment — and then abandoned the field, on the ground that no result was worth what it was costing him. In 1838 he turned to something more useful. The blast furnaces of Germany and England were burning enormous quantities of fuel, and nobody had measured what came out of the top of them. Bunsen developed methods of gas analysis good enough to answer the question, worked at the ironworks with Lyon Playfair, and showed that more than half of the heating value of the charge was going up the chimney as unburned gas — chiefly carbon monoxide, which is a fuel in its own right and was simply being thrown away. That work required flames he could control, and in 1855, with the university's mechanic Peter Desaga, he arrived at the burner. Its whole principle is that the gas is mixed with air BEFORE it burns: an adjustable collar at the base lets air in, and the flame changes from a large yellow luminous one that deposits soot to a small blue one hot enough to melt platinum wire. Neither Bunsen nor Desaga patented it. He made electrochemical work practical with a cheap zinc–carbon cell, prepared magnesium and other metals by electrolysis in quantity, invented the ice calorimeter and the grease-spot photometer, and — with his Heidelberg colleague Gustav Kirchhoff — did the work on the light emitted by flames that is his other monument. He refused chairs at Breslau and Berlin, never married, and by all accounts spent every day of his working life at the bench with his students. He died at Heidelberg in 1899.

Major achievements

• Analysed the gases leaving blast furnaces and showed more than half the fuel was escaping unburned
• Developed the methods of gas analysis the work required
• Designed, with Peter Desaga, the burner that pre-mixes gas with air and can be adjusted from a sooty yellow flame to a clean blue one
• Found hydrated iron oxide as the antidote to arsenic poisoning, still in use
• Devised a cheap zinc–carbon cell and used it to prepare metals by electrolysis

Life in brief

• 1811 — Born in Göttingen: Son of a professor of linguistics.
• 1836 — The arsenic compounds: An explosion costs him the sight of an eye.
• 1838 — The furnace gases: More than half the fuel going up the chimney unburned.
• 1852 — Professor at Heidelberg: The laboratory that trained a generation.
• 1855 — The burner: Gas mixed with air before it burns, with a collar to choose how much.
• 1899 — Dies at Heidelberg: Having refused chairs at Breslau and Berlin.

Explore the life of Bunsen — five chapters

1. The Compounds That Cost Him an Eye — Cacodyl, and knowing when to stop
2. More Than Half of It Going Up the Chimney — Measuring what a blast furnace throws away
3. The Collar at the Base — The burner, 1855
4. Reading the Flame — Spectroscopy with Kirchhoff, and two new elements
5. Every Day at the Bench — Refusing Berlin, and a laboratory full of students

Read the five-chapter life of Robert Bunsen →

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