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17 April 2014 12:48 pm ,
Vol. 344 ,
Officials last week revealed that the U.S. contribution to ITER could cost $3.9 billion by 2034—roughly four times the...
An experimental hepatitis B drug that looked safe in animal trials tragically killed five of 15 patients in 1993. Now,...
Using the two high-quality genomes that exist for Neandertals and Denisovans, researchers find clues to gene activity...
A new report from the Intergovernmental Panel on Climate Change (IPCC) concludes that humanity has done little to slow...
Astronomers have discovered an Earth-sized planet in the habitable zone of a red dwarf—a star cooler than the sun—500...
Three years ago, Jennifer Francis of Rutgers University proposed that a warming Arctic was altering the behavior of the...
- 17 April 2014 12:48 pm , Vol. 344 , #6181
- About Us
17 September 1997 8:00 pm
Today is the 320th anniversary of the birth of Stephen Hales, an English clergyman known for his careful biological research, particularly on the physiology and growth of plants. Hales conducted a number of experiments between 1719 and 1725 in which he measured the pressure exerted by water moving through a plant. He attached a glass tube or a simple manometer filled with mercury to a cut stem surface and measured the change in height of the sap, which indicated root pressure. Hales made similar measurements of blood pressure in domestic animals, and by injecting chemicals, estimated blood-flow rates in organs. Hales also discovered the dangers of breathing "spent" air in enclosed spaces and invented a ventilator, which he introduced on ships and in hospitals and prisons.
[Source: Roy Porter, Ed., The Biographical Dictionary of Scientists (Oxford University Press, ed. 2, 1994).]