Jan Ingenhousz

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Monument to Jan Ingenhousz in the arcade courtyard of the University of Vienna

Jan Ingenhousz (born December 8, 1730 in Breda , † September 7, 1799 in Bowood Park) was a Dutch doctor and botanist . He is considered the founder of photosynthesis research .

resume

Ingenhousz came from a merchant family, studied medicine at the universities in Leuven and Leiden and, after graduating in 1753, settled as a doctor in his hometown of Breda. The English doctor John Pringle (then President of the Royal Society ) invited him to come to London in 1765. There Ingenhousz met personalities like Benjamin Franklin and Joseph Priestley . In 1769 he became a member of the Royal Society. In 1786 he was elected a member of the American Philosophical Society .

Scientific work

Smallpox vaccination

Ingenhousz was an advocate of - already by Lady Mary Wortley Montagu propagated - smallpox vaccination ; he took patients who were suffering from a mild form of smallpox, serum (with still-living viruses ), and "inoculated" that's not ill persons ( " Variolation "). Ingenhousz vaccinated the Georgs III family . of Great Britain and the family of Empress Maria Theresa and from 1768 worked as court doctor in Vienna with an annual salary of 5000 guilders .

photosynthesis

In 1774 Priestley had isolated the element oxygen ( dephlogistic air ) as part of the air and found that "putrid air" could be refreshed by plants. It was a mystery, however, under what conditions this happened. This contradicted the observations made by chemist Carl Wilhelm Scheele , who stated that plants can degrade the air.

In order to clarify these different observations, Ingenhousz carried out extensive series of tests after his return from Vienna in 1779. He published the results in the text Experiments "upon ..." In which he explained that plants release carbon dioxide ( fixed air ) in the dark , absorb it when exposed to light - depending on the intensity - and release oxygen. He also showed that the carbon that plants need to grow is not extracted from the soil (as previously assumed), but comes from the ambient air. He had discovered that light is necessary for the growth and air purification (of animal breath) of plants; this was the beginning of photosynthesis research . His research also influenced Antoine de Lavoisier .

physics

Ingenhousz also made a number of experiments on the electrical conductivity of different materials and on magnetism . In 1766 he had constructed a generator for static electricity. In 1775 he reported on his investigations on the electric ray ( English torpedo ). Occasionally he has been portrayed as the true discoverer of Brownian molecular motion with a paper from the 1780s , but this is very dubious (see the article Brownian molecular motion ). In 1789 he carried out the first reliable experiments on the thermal conductivity of metal rods. “As an aside” he constructed a hydrogen- working lighter (to make the annoying ignition sponge unnecessary) and experimented with an electrically ignited ether gun, also known as the electric gun .

Awards

In 1910, Ingen-Housz-Gasse was named after him in Vienna- Alsergrund (9th district) .

Publications

  • Experiments upon Vegetables: Discovering their Great Power of Purifying the Common Air in the Sunshine and of Injuring it in the Shade at Night (1779)
  • An Essay on the Food of Plants and the Renovation of Soils (1796).
  • Experiments on the Torpedo (1775)

Quotes

Alexander von Humboldt in “Introduction to some objects of plant physiology”, the German edition of the “Essay on the food of plants and the renovation of the soil” (1798, translated by Johann Gotthelf Fischer von Waldheim ):

“Mr. Ingenhouszen is one of the small number of working physicists who have the fruitful talent not only to pursue individual objects with admirable effort, but also to combine each new phenomenon (instead of presenting it in isolation) harmoniously with the older ones. His writings teach that he never loses sight of the great purpose of all natural research, the interaction of forces, ... "

literature

Individual evidence

  1. ^ Member History: Jan Ingenhousz. American Philosophical Society, accessed October 9, 2018 .
  2. ^ Robert Rosner: Chemistry in Austria 1740-1914. Teaching - Research - Industry. Böhlau publishing house. ISBN 3-205-77309-8 ; P. 36
  3. ↑ gun, electrical, blast air gun, electricum Sclopetum, Pistolet électrique. ( Memento of the original from February 1, 2014 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. , accessed January 20, 2014 @1@ 2Template: Webachiv / IABot / archimedes.mpiwg-berlin.mpg.de

Web links

personal data
SURNAME Ingenhousz, Jan
BRIEF DESCRIPTION Dutch doctor and botanist
DATE OF BIRTH December 8, 1730
PLACE OF BIRTH Breda ( Netherlands )
DATE OF DEATH September 7, 1799
Place of death Bowood Park ( England )