Arnold Beckman

While a professor at California Institute of Technology, he founded Beckman Instruments based on his 1934 invention of the pH meter, a device for measuring acidity, later considered to have "revolutionized the study of chemistry and biology". He also developed the DU spectrophotometer, "probably the most important instrument ever developed towards the advancement of bioscience". Beckman funded the Shockley Semiconductor Laboratory, the first silicon transistor company in California, thus giving rise to Silicon Valley. In 1965, he retired as president of Beckman Instruments, instead becoming the chairman of its board of directors. On November 23, 1981, he agreed to sell the company, which was then merged with SmithKline to form SmithKline Beckman. After retirement, he and his wife Mabel (1900-1989) were numbered among the top philanthropists in the United States.