A D V E N T U R E S in C Y B E R S O U N DMichael (Mihailo Idvorsky) Pupin : 1858 - 1935
Michael (Mihailo Idvorsky) Pupin was born in Idvor, Banat, October 9, 1854. Received his academic education at Columbia College, New York, and his scientific education at the universities of Cambridge, England,and Berlin, Germany. Obtained his Ph.D. degree at the University of Berlin, and returned to Columbia University in 1889, to take a position as instructor in theoretical electrical engineering. Has been professor at Columbia University since 1892, lecturing on mathematical physics. His earliest interest, when still as a student in Berlin, was in physical chemistry, and his doctor' s dissertation "Osmotic Pressure and its Relation to Free Energy" related to this subject. His position as instructor in the electrical theory gradually directed his interest to the study of electromagnetic phenomena. The subject of electrical resonance engaged his attention between 1892 and 1895, and resulted in the electrical tuning which is now universally applied in all radio work.
In April, 1896, he discovered the Secondary X-ray Radiation and is today credited with this discovery. Considering that secondary X-ray radiation is universally employed in the study of X-ray spectra, it is obvious that Pupin' s discovery is a very important contribution to electron physics. In February, 1896, he discovered a rapid method of X-ray photography which consisted in the interposition of a fluorescent screen between the object to be photographed and the photographic plate. This shortened the time of exposure from about an hour to a few seconds. This method of X-ray photography, originated by Pupin, is now in universal use. For reasons which need not be mentioned here, Pupin was compelled in 1896 to give up X-ray work and he then devoted himself to the theory of telegraphic and telephonic transmission over conducting wires, and particularly over telephone cables. Transmission over telephone cables became a very important problem thirty years ago, because American cities had passed an ordinance demanding that all telephone conductors within city limits be placed underground. Pupin solved this problem completely by proving mathematically and experimentally, that inductance coils placed in a cable at definite intervals, determined by the wave lengths which were to be transmitted, made the cable equivalent to overhead conductors of high inductance, and this diminished both distortion and attenuation. In this connection Pupin developed the toroidal form of inductance coil without which the theoretical results would have had small practical value, because otherwise coils belonging to different telephonic circuits would have mutual inductance, and this would result in cross-talk. A toroidal inductance coil has no external circuits. This type of telephone cable was developed by the Western Electric Co., in New York, and by Siemens-Halske of Berlin, and it revolutionised telephonic transmission. Fourteen years ago the American Telephone and Telegraph Company, established telephinic communication between Boston - New York - Washington. Over a cable of this kind, and at that time this was the longest telephonic cable transmission in the world. It was 500 miles, or 800 kilometers long. Today the distance has been indefinitely increas by the interposition of vacuum tube amplifiers. But it is admitted that without the inductance coils introduces according to Pupin' s theory the vacuum tube amplifiers alone would make transmission over telephone cables impossible. The coils eliminate distortion, not only that due to enerqual reduction of amplitude of different frequencies, but also that due to different velcoties of propagation for different frequencies.
 Michael Pupin with Albert Einstein
In the development of the inductance coils during the last twenty five years, Pupin was consulted by both the Western Electric Company and Siemens-Halske of Berlin. During the World War Pupin and his scientific committee were doing research work for the purpose of developing a system of submarine detection and a system of telephonic communication between aeroplanes. This work earned him a recognition from the late President Harding, which was expressed in Mr. Harding's letter appering on page 386, of Pupin' s autobiography, "From Immigrant toInventor". This autobiography enumerates at some length Pupin's work, described by the writer briefly in the foregoing sketch; its correctness has never been questioned. It should be mentioned here that in his essay of 1899, entitled "Transmission Over Non-Uniform Conductors", Pupin gave the first mathematical treatment of electrical transmission over the so-called artificial lines and this theory is the foundation of the modern electrical filters used so much in telephonic, telegraphic and radio transmission. During the last six years Pupin has been studying theoretically, as well as experimentally, electrical transmission over submarine cables, and has succeeded to extend Lord Kelvin' s mathematical treatment of this subject. The result of this study is a new type of artificial line to be used in duplex working of submarine cables. The theory and the experimental results have not yet been published, but will be published in the near future. A preliminary announcement was sent to the editorial committee in charge of the Volta Commemoration which took place at Como, Italy, in September 1927.
John Kayganovich, C.E.,
Mihailo Pupin was born in Idvor, little Serbian village. He watched at night with other village boys to keep the oxes from straying beyond their pasture into the fields of tall corn and falling prey to the cattle-thieves who lay there in hiding.
"My life as a scientist began with the questions I asked myself in the blackness of midnight when I lay with my ear pressed to the ground listening to the secret code of our little band of village boys."The young herdsmen were trained by their leader to send signals through the ground to each other in time of danger. With their long wooden-handled knives plunged deep in the earth, they made a sound by rapping on the stout handles. This, their comrades, listening with ears pressed close to the ground, could hear at a considerable distance. The boys discovered that the rap-rap of their signals could not be carried through the air, nor could it be heard over the soft plowed land of the corn-fields. But they became expert in sending warnings to each other through the hard earth of the open fields, knowing that the Rumanian thieves who might be lurking among the corn could not overheard the sound and locate the watchers. When he asked his teacher why the sound was lost in the air, he shook his head in a puzzled faction "There are many things we can not explain." Through many years he never stopped trying to find an answer to that question, pressing on through many adventures with science which brought that best reward of hard work in which all people have a share. Through the careful experiments he arrived at his invention of loading a telephone wire with inductance coils also known as Pupin's coils. AT&T bought the rights to use the patent for half a million dollars. It was estimated that in first twenty two years this invention had saved over a hundred million dollars."Where are those one hundred million dollars which the invention has saved?" Pupin asks. "I know that not even a microscopic part of them is in the pockets of the inventor. I have figured out also, with the same accuracy with which I once figured out the invention, that those hundred million dollars are not in the pockets of the telephone company. They must be, therefore, in the pockets of the American public. The invention made it possible to provide the telephone service, which is now being given, at a lower rate than would otherwise have been possible."
The List of Pupin's Patents Published in U.S.A.
 Michael Pupin in his laboratory
Michael Pupin (b. Oct. 4, 1858, Idvor, Hung.--d. March 12, 1935, New York, N.Y., U.S.), American physicist who devised a means of greatly extending the range of long-distance telephone communication by placing loading coils (of wire) at predetermined intervals along the transmitting wire. The son of illiterate parents who encouraged his education, Pupin in 1890 became an instructor in mathematical physics at Columbia University, New York City. Six years later he discovered that atoms struck by X rays emit secondary X-ray radiation. He also invented a means for taking short-exposure X-ray photographs. In 1901 the Bell Telephone Company and some German telephone interests acquired the patent for his invention of long-distance telephony. Pupin received the 1924 Pulitzer Prize in biography for his autobiographical work From Immigrant to Inventor (1923).
Michael Pupin, physicist and inventor, born in Idvor, Hungary. A penniless immigrant, he studied at Columbia University, and became professor of electromechanics there (1901-31). He devised a system of multiplex telegraphy, the fluoroscope, and the Pupin inductance coil, which made long-distance telephony practical by amplifying the signal at intervals along the line without distortion. His autobiography, From Immigrant to Inventor (1923), won the Pulitzer Prize.
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