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Helmont, Jan Baptista van

chemistry water tree matter

( c .1579–1644) Flemish alchemist, chemist and physiologist: made early studies of conservation of matter.

A member of a noble and wealthy family, Helmont studied the classics, theology and medicine before turning ‘for 7 years to chemistry and the relief of the poor’. He believed in alchemy, but his own work represents a transition to chemistry proper. He used a chemical balance and understood clearly the law of indestructibility of matter (eg that metals, dissolved in acid, can be recovered). He knew a fair range of inorganic salts and the acids H2SO4 and HNO3 . He believed that all matter was based on two elements or principles, air and water. In an experiment on this, he grew a willow tree for 5 years, when its weight increased from 5 to 169 lb (2.27 to 76.66 kg); the earth it had grown in had hardly lost weight, and he had given the tree only rainwater. So in his view the tree (and presumably all vegetation) was made of water. He was half-correct (willow is about 50% water); and he failed to realize that the plant had taken in CO2 from the air. He studied gases (he was the first to use the word ‘gas’, based on the Greek chaos ) but he had no method of collecting them; and better distinctions between different gases had to wait for work. He had rather confused ideas on animal digestion but, in directing thought to animal chemistry, his views were valuable.

Helmsley, Leona - Overview, Personal Life, Career Details, Chronology: Leona Helmsley, Social and Economic Impact [next] [back] Helmholtz, Hermann (Ludwig Ferdinand) von

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