Jan Ingenhousz

Jan Ingenhousz or Ingen-Housz (December 8, 1730 - September 7, 1799) was a Dutch-born British physiologist, botanist and physicist. He is best remembered for showing that light is essential to plant respiration, the first step in the discovery of photosynthesis.

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Ingenhousz discovered that, in the presence of light, plants give off bubbles from their green parts while, in the shade, the bubbles eventually stop. He identified the gas as oxygen. He also discovered that, in the dark, plants give off carbon dioxide. He realised as well that the amount of oxygen given off in the light is more than the amount of carbon dioxide given off in the dark. This demonstrated that some of the mass of plants comes from the air, and not only the soil.

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In 1785, he described the irregular movement of carbon dust on alcohol and therefore has a claim as discoverer of what came to be known as brownian motion.

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December 8: December 8 is the 342nd day (343rd in leap years) of the year in the Gregorian calendar. There are 23 days remaining....

September 7: September 7 is the 250th day of the year (251st in leap years). There are 115 days remaining....

1799: 1799 was a common year starting on Tuesday (see link for calendar)....

Jan Ingenhousz related Images and Photos (experimental)

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