ORIGINAL SITE OF THE LABORATORY AND FACTORY OF FEDERAL TELEGRAPH COMPANY, FOUNDED IN 1909 BY CYRIL F. ELWELL. HERE, WITH TWO ASSISTANTS, DR. LEE DE FOREST, INVENTOR OF THE THREE-ELEMENT RADIO VACUUM TUBE, DEVISED IN 1911-13 THE FIRST VACUUM TUBE AMPLIFIER AND OSCILLATOR. WORLD-WIDE DEVELOPMENTS BASED ON THIS RESEARCH LED TO MODERN RADIO COMMUNICATION, TELEVISION AND THE ELECTRONICS AGE.