The American physicist and inventor Michael Idvorsky Pupin (1858-1935) is recognized for his contributions to telephony and telegraphy, his invention of electrical tuning, and his discovery of secondary x-ray radiation.

Michael Pupin was born on Oct. 4, 1858, at Idvor in Banat Province, a part of Austria (now of Yugoslavia) settled by Serbs in 1690. The son of illiterate but highly intelligent parents who sacrificed to give their son an education, Pupin soon left the village school to study at Pancevo and then at Prague. Following the death of his father, Pupin sailed to the United States in 1874. Arriving without funds or friends, he held farm and factory jobs, learned English, and in 1879 entered Columbia College.

Pupin subsequently became the first holder of Columbia's Tyndall fellowship in physics. By then he was pursuing his studies abroad, at Cambridge and Berlin, studying mathematical physics and physical chemistry. Receiving his doctorate in 1889, he returned to Columbia as an instructor in its new department of electrical engineering. Pupin combined effective teaching with a program of experimental research. His preliminary work and first publications dealt with electrical charges passing through gases and then with distortions in alternating currents and a general theory of wave propagation. This work led to his development of the electrical resonator (1893), later used in radio tuning, and then to the Pupin coils, inductance coils which when spaced properly along telephone circuits reinforced the vibrations and permitted long-distance calls (1894). Subsequently Pupin expanded upon this work, developing multiplex telegraphy and means to overcome static in wireless communications.

When Wilhelm Roentgen announced his discovery of x-rays in December 1895, Pupin made an x-ray tube and, within 2 weeks, discovered secondary x-radiation; he used this discovery to make short-exposure x-ray photographs, a procedure of obvious medical importance later. The Bell Telephone Company acquired the rights to his line-loading coils in 1901, as did the Siemens and Halske Company in Germany, and long-distance telephony soon became a reality.

Concern over the people in his native land led Pupin to an increasingly active role in public affairs during the Balkan War and World War I, and he headed many philanthropic and humanitarian efforts on behalf of other Serbs. He was a popular and eloquent platform speaker and a skillful interpreter of scientific learning to laymen. Pupin published approximately 70 technical articles and reports during his lifetime, obtained 34 patents, and received many awards and distinctions. He died in New York City on March 12, 1935.

Further Reading

• The best source on Pupin's life remains his charming and inspiring autobiography, From Immigrant to Inventor (1923), for which he received the Pulitzer Prize. His other major writings are The New Reformation: From Physical to Spiritual Realities (1927) and Romance of the Machine (1930). There is a short sketch of Pupin's work in Orrin E. Dunlap, Jr., Radio's 100 Men of Science: Biographical Narratives of Pathfinders in Electronics and Television (1944).
• Pupin, Michael Idvorsky, From immigrant to inventor, New York: Arno Press, 1980.