From cortisone to ultimate Frisbee

Five innovations with Princeton ties

By Brett Tomlinson
Published in the January 23, 2008, issue


Smithsonian Photograhic Services

The Electromagnet--Joseph Henry


Henry, a professor of natural philosophy, was Princeton's best-known scientist in the 19th century. Biographers argue that he discovered induction before Michael Faraday (Faraday published his finding first), created a working telegraph before Samuel Morse (sending signals to his wifef over a wire from his Princeton lab to his nearby home), and detected radio waves before Heinrich hertz. One achievement beyond dispute is Henry's work to build stronger electromagnets. Using wire carefully wrapped in silk and cotton threads for insulation, he created magnets that could life p to 3,500 pounds--a monumental improvement over those previously available--and enabled advances in mining and other industries. Scientists still employ the Princeton professor's surman, which serves as a unit for measuring induction. 

 
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