Lee De Forest (1873-1961), US inventor. De Forest made numerous inventions, but is remembered most for his invention of the Audion, a vacuum tube that could amplify signals. This photograph is courtesy of the DeForest Laboratories, New York. It was published in 'The March of Commerce' (1927), volume 4 of 'The Pageant of America: A Pictorial History of the United States'. This was a 15-volume series that commemorated 150 years since the founding of the USA in 1776.