Stephen Hales

author

Stephen Hales

1677–1761

An English clergyman and scientist, he helped open up the study of plant physiology and made some of the first direct measurements of blood pressure. His curiosity ranged widely, from how sap moves in plants to practical inventions for ventilating ships, prisons, and public buildings.

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An account of a useful discovery to distill double the usual quantity of sea-water, by blowing showers of air up through the distilling liquor : $b and an account of the great benefit of ventilators in many instances, in preserving the health and lives of people, in slave and other transport ships ... also an account of the good effect of blowing showers of air up through milk, thereby to cure the ill taste which is occasioned by some kinds of food of cows.

An account of a useful discovery to distill double the usual quantity of sea-water, by blowing showers of air up through the distilling liquor : $b and an account of the great benefit of ventilators in many instances, in preserving the health and lives of people, in slave and other transport ships ... also an account of the good effect of blowing showers of air up through milk, thereby to cure the ill taste which is occasioned by some kinds of food of cows.

by Stephen Hales

About the author

Born in 1677, Stephen Hales was an English clergyman whose scientific work crossed the boundaries between biology, medicine, and practical engineering. He studied at Cambridge and later served for many years as parish priest of Teddington, while carrying out experiments that earned him a place among the leading natural philosophers of his time.

Hales is best remembered for pioneering experiments on plants and animals. In Vegetable Staticks, he investigated how water moves through plants and how they exchange air, work that helped lay foundations for plant physiology. He also became known for measuring blood pressure directly in animals, a striking and influential step in the history of physiology.

His interests were not only theoretical. Hales designed ventilating systems intended to improve air in ships, prisons, and other crowded places, showing a strong practical concern for public health. He died in 1761, leaving behind a reputation as an inventive and wide-ranging investigator whose work connected careful experiment with everyday human needs.