Biografi Jan Ingenhousz

Jan Ingenhousz (8 Desember 1730 – 7 September 1799) adalah ilmuwan Britania Raya kelahiran Belanda yang membuktikan bahwaintensitas cahaya memengaruhi laju fotosintesis pada tumbuhan. Pada tahun 1778, ia mengulangi eksperimen Priestley. Ia menemukan bahwa cahaya matahari berpengaruh pada tumbuhan sehingga dapat "memulihkan" udara yang "rusak".

an Ingenhousz (1730-1799). Dutch-born physician, chemist, and plant physiologist. Showed light is essential to plantrespiration and that the gas plants produce in light is oxygen. He is therefore recognized as the discoverer ofphotosynthesis. 

Jan Ingenhousz was born in 1730 in the city of Breda in what is today the southern Netherlands. At 16, he began his study of medicine at the Catholic University of Louvain, the oldest and most prominent university in Belgium. There he received his MD in 1753. He then studied two additional years at the University of Leiden, where he attended lectures by Pieter van Musschenbroek, an experience that sparked his lifelong interest in electricity. 
 Discovery of photosynthesis 

In the experiment leading to his discovery, he placed plants underwater in a transparent container and saw that the undersides of their leaves made bubbles in sunlight. However, when the same plants were placed in darkness, the bubbles eventually stopped forming. He was also able to see that the leaves and other green (chlorophyll-containing) parts of the plants were the sites where the gas was produced. 
He collected this gas and conducted a series of tests to determine its identity. He eventually found that a smoldering candle would burst into flame when exposed to the unknown gas, which showed it was oxygen (Ingenhousz, 1779, see full citation below). He also found that in darkness plants release carbon dioxide (ibid). In recognition of these discoveries, Ingenhousz was elected to the Royal Society of London that same year. 

Brownian motion

In 1785, Ingenhousz reported that under a microscope he had observed irregular movement of coal dust on the surface of alcohol. He thus described Brownian motion at a much earlier date than did Robert Brown (1827), the English investigator for whom the phenomenon is named. 

Ingenhousz was taken ill during a visit to the Marquis at Bowood in 1799. He died there on September 7th and was buried nearby at Calne.
He collected this gas and conducted a series of tests to determine its identity. He eventually found that a smoldering candle would burst into flame when exposed to the unknown gas, which showed it was oxygen (Ingenhousz, 1779, see full citation below). He also found that in darkness plants release carbon dioxide (ibid). In recognition of these discoveries, Ingenhousz was elected to the Royal Society of London that same year. 
Brownian motion

In 1785, Ingenhousz reported that under a microscope he had observed irregular movement of coal dust on the surface of alcohol. He thus described Brownian motion at a much earlier date than did Robert Brown (1827), the English investigator for whom the phenomenon is named. 

Ingenhousz was taken ill during a visit to the Marquis at Bowood in 1799. He died there on September 7th and was buried nearby at Calne.
Brownian motion 
In 1785, Ingenhousz reported that under a microscope he had observed irregular movement of coal dust on the surface of alcohol. He thus described Brownian motion at a much earlier date than did Robert Brown (1827), the English investigator for whom the phenomenon is named. 

Ingenhousz was taken ill during a visit to the Marquis at Bowood in 1799. He died there on September 7th and was buried nearby at Calne.
In 1785, Ingenhousz reported that under a microscope he had observed irregular movement of coal dust on the surface of alcohol. He thus described Brownian motion at a much earlier date than did Robert Brown (1827), the English investigator for whom the phenomenon is named. 
Ingenhousz was taken ill during a visit to the Marquis at Bowood in 1799. He died there on September 7th and was buried nearby at Calne.
Ingenhousz was taken ill during a visit to the Marquis at Bowood in 1799. He died there on September 7th and was buried nearby at Calne.

The following year, the Austro-Hungarian empress, Maria Theresa read about the success of the English campaign against smallpox and decided to have both herself and her family vaccinated, though her own doctors were against it. She asked the English king, George III, to recommend a suitable physician and, on Pringle's recommendation, Ingenhousz was chosen. He traveled to Austria and successfully vaccinated several members of imperial family, including the empress, which gained him far more fame in his lifetime than did his discovery of photosynthesis. This feat also secured his professional career since he received as a result a pension for life and became body physician to Maria Theresa and her husband Joseph II. Ingenhousz lived the next ten years in Vienna, where in 1775 he married Agatha Maria Jacquin. 

In 1779, Ingenhousz returned to England and traveled to Calne, a small town in southwestern part of the country. There, at Bowood House, the country manor of the Marquis of Lansdowne, in the same laboratory where his colleague Joseph Priestley had discovered oxygen itself only a few years before, Ingenhousz carried out his research on photosynthesis.