Lee De Forest Research Articles

Wireless: From Marconi’s Black Box to the Audion

By 1897 Guglielmo Marconi had transformed James Clerk Maxwell's theory of electromagnetic waves into a workable wireless telegraphy system, and by 1907 Lee de Forest had invented the audion, a feedback amplifier and oscillator that opened the way to practical radio transmission. Fifteen years after Marconi's invention, wireless had become an essential means of communication, as well as a hobby for many.This book offers a new perspective on the early days of wireless communication. Drawing on previously untapped archival evidence and recent work in the history and sociology of science and technology, it examines the substance and context of both experimental and theoretical aspects of engineering and scientific practices in the first years of this technology. It offers new insights into the relationship between Marconi and his scientific advisor, the physicist John Ambrose Fleming (inventor of the vacuum tube). It includes the full story of the infamous 1903 incident in which Marconi's opponent Nevil Maskelyne interfered with Fleming's public demonstration of Marconi's syntonic (tuning) system at the Royal Institution by sending derogatory messages from his own transmitter. The analysis of the Maskelyne affair highlights the struggle between Marconi and his opponents, the efficacy of early syntonic devices, Fleming's role as a public witness to Marconi's private experiments, and the nature of Marconi's shows. It also provides a rare case study of how the credibility of an engineer can be created, consumed, and suddenly destroyed. The book concludes with a discussion of de Forest's audion and the shift from wireless telegraphy to radio.

De forest and the first electrosurgical unit.

In the United States, Lee De Forest, who patented the first triode vacuum tube (audion) in 1907 and 1908, was experimenting with a high-frequency spark-gap generator for use in surgery and filed a U.S. patent application describing his work on 10 February 1907, which was issued on 17 December 1907. This device was the first electrosurgical unit, and there are no better words than his own in his patent for describing it; he stated: Be it known that I, Lee De Forest, a citizen of the United States, and a resident of New York, in the county of New York and State of New York, have invented a new and useful improvement in Cauteries, of which the following is a specification. My invention relates to devices for producing burning effects by means of high-frequency electrical currents, and more particularly to cauteries employed in surgery. (A cautery is a heated rod used to cut and coagulate living tissue.) I have discovered that when a conductor is attached to any part of a high-frequency oscillating circuit, the high-frequency electrical current passing into a body, for example, a human body, will produce a heating or burning effect at the point of contact of the electrode conveying such currents to said body, and that the intensity of said heating or burning effect is inversely proportional to the terminal area of said electrode. If therefore the electrode ends in a fine point or cutting edge, or relatively small area of other shape, an extremely intense burning effect may be obtained.

The Irwin handbook of telecommunications

The Irwin handbook of telecommunications

Marconi and the Maxwellians: The Origins of Wireless Telegraphy Revisited

Marconi and the Maxwellians: The Origins of Wireless Telegraphy Revisited SUNGOOK HONG The point is which of the two was the first to send a wireless telegram? Was it Lodge in 1894 or Marconi in 1896? [Silvanus P. Thompson, London Times,July 15,1902] We live in a world where technological priority disputes and patent litigation are so commonplace that only a spectacular case, such as Kodak versus Polaroid over the instant camera, attracts our attention. In the past two hundred years, such disputes have become increasingly frequent. Notable examples include those over the invention of spin­ ning machines (John Hargreaves vs. Richard Arkwright), steelmaking (Henry Bessemer vs. William Kelly), the incandescent lamp (Thomas Edison vs. Joseph Swan), the telephone (Alexander Graham Bell vs. Elisha Gray), the airplane (the Wright brothers vs. Samuel Langley), and amplifiers and the heterodyne principle in radio (Lee De Forest vs. Edwin Howard Armstrong). Historians of technology, however, have generally paid little attention to the conflicting priority claims themselves, except when priority and patent disputes can be used as a window through which the character­ istics of the evolution of technology are analyzed.1 There are two well-grounded reasons for this neglect. First, unlike scientific discoverDr . Hong received his Ph.D. from Seoul National University with the dissertation “Forging the Scientist-Engineer: A Professional Career ofJohn Ambrose Fleming” and is working on the science-technology relationship in power and early radio engineering. He thanksJed Buchwald, Bert Hall, Bruce Hunt,Janis Langins, and the Technology and Culture referees for their valuable comments. He is indebted to Professor Thad Trenn of the University of Toronto and Roy Rodwell of the Marconi Company Archives for their help with the archives quoted here, and he thanks Youngran Jo, Shinkyu Yang, Jane Jenkins, André Leblanc, and Ben Olshin for their assistance, as well as the Institute of Electrical and Electronics Engineers Fellowship in Electrical History for facilitating the research. ‘See, e.g., the important research of David E. Hounshell, “Elisha Gray and the Telephone: On the Disadvantage of Being an Expert,” Technology and Culture 16 (1975): 133-61; Robert C. Post, “Stray Sparks from the Induction Coil: The Volta Prize and the Page Patent,” Proceedings ofthe Institute ofElectrical and Electronics Engineers (IEEE) 64 (1976): 1279-86; James E. Brittain, “The Introduction of the Loading Coil: George A. Campbell© 1994 by the Society for the History of Technology. All rights reserved. 0040-165X/94/3504-0004$01.00 717 718 Sungook Hong ies, priority disputes in technology often develop into patent litigation, which ultimately involves judicial decisions or interferences by the Patent Office. These court decisions act like a forcedjudgment on the question of priority. “Closure” of the controversy (to use the social constructivist’s term) is not brought about by negotiation among the engineers involved, but rather by external, compulsory forces. These court judgments, which historians cannot overrule and which funda­ mentally determine future histories, sometimes differ from those based on detailed historical analysis. Historians therefore treat historical assessments of inventions as a sphere separate from legal decisions about patents and avoid entering into the latter realm.2 Second, and more important, historians of technology have usually considered invention as a long-term, social process, which includes not only the creative activity of an inventor but also historically accumulated tradi­ tions in which the work of many people is merged.3 The priority dispute is itselfinterpreted as evidence for regarding the invention as something socially conditioned. The question, for example, of who first invented wireless telegraphy is hardly meaningful from such a perspective, because “wireless telegraphy” itself did not burst into being as a result of a single genius’s efforts, but was gradually shaped as several different technological traditions converged. Recent historical studies on the origin of radio reflect such a shift of emphases in the interpretation of technological inventions. In a highly influential monograph, Syntony and Spark: The Origins of Radio, Hugh G.J. Aitken argues that wireless telegraphy cannot be said to have been and Michael I. Pupin,” Technology and Culture 11 (1970): 36-57. Hounshell contrasts the amateurish style of invention (Alexander Graham Bell) with the professional style (Elisha Gray), arguing for the former’s...

Lee de Forest and the Fatherhood of Radio.

Lee de Forest and the Fatherhood of Radio.

Legends in their own time: a century of American physical scientists

America's scientific giants of the 20th century have transformed the world in terms of scientific understanding, military preparedness, and the quality and comfort of our daily lives. In this exquisitely written book, Anthony Serafini - a respected historian and philosopher of science - regales the reader with vivid descriptions of the lives and contributions of the men and women who explored the depth of molecular structure, relativity, astronomy, quantum mechanics, nuclear research, and much, much more. These evocative and stunning portrayals of some of the greatest scientists who ever lived delve into the personalities and opinions of these pioneers. Furthermore, Serafini makes their significant discoveries accessible and meaningful to everyone. You will meet the indefatigable Lee De Forest, whose passion for wireless telegraphy resulted in the Audion Radio Tube, which broadcasted radio to thousands of America's living rooms. The roster of distinguished scientists continues with Ernest Lawrence, who began his academic career with the hope of becoming a physician. He later succumbed to the enticement of physics, becoming the first to discover how to unleash the unimaginable power within the nucleus. This discovery ultimately led to the creation of the atomic bomb. In addition, Robert Millikan astounded the scientific community by measuring the charge of an electron and convincing even the most hardened skeptics of the validity of the atomic theory of matter. Legends in Their Own Time recounts the most exciting events that took place during the Manhattan Project. It also explores the ongoing search for a Unified Field Theory of the cosmos - a goal that eluded even Albert Einstein.Serafini traces the evolution of scientists in America from a group of lackluster journeymen to world-renowned professionals, rivaling the scientific titans of Europe. This perceptive author portrays how the combination of politics and war has ironically contributed to the advancemen

Empire of the Air: The Men Who Made Radio by Tom Lewis

TECHNOLOGY AND CULTURE Book Reviews 701 history of the Steinmetz myth” (p. x). The reader therefore must not expect a connected narrative of Steinmetz’s private life. Kline might have observed, however, that Steinmetz’s vision of technological and economic transformation did not, apparently, include speculation on possible concomitant change in the relations of men and women. Of the various works on Steinmetz, many represent superficial research or, though scholarly, focus on certain aspects of his thought. Kline’s biography is solidly based on several manuscript and archive collections, on relevant technical literature, and on recent interpreta­ tions of intellectual and cultural history. Throughout, he takes pains to sift reality from legend. The tone is balanced, critical, but essen­ tially understanding of its subject in his time. Jean Christie Dr. Christie is professor of history emerita, Fairleigh Dickinson University, author of Morris Llewellyn Cooke: Progressive Engineer (New York, 1983), and coeditor of Decisions and Revisions: Interpretations of Twentieth-Century American History (New York, 1975). Empire ofthe Air: The Men Who Made Radio. By Tom Lewis. New York: HarperCollins, 1991. Pp. vii + 421; illustrations, notes, bibliogra­ phy, index. $25.00 (cloth); $13.00 (paper). In Empire of the Air: The Men Who Made Radio, Tom Lewis (an English professor at Skidmore College) tells the story of radio broad­ casting through the interactions of two inventors (Lee deForest and Edwin Howard Armstrong) and one business entrepreneur (David Sarnoff). The book, on which Ken Burns based his television docu­ mentary of the same name, is a collective biography that seeks to explore the technology and institutions of American radio through the intersecting lives. Writing in an engaging prose style, Lewis does a goodjob ofincluding the kind of telling details that also make a narrative interesting. Moreover, the book contains useful descriptions of how radio broad­ cast technology developed and works. Lewis’s explanations of Arm­ strong’s inventions, including the superheterodyne and frequency modulation, are particularly good. In fact, the material on Armstrong and his contributions provides the most interesting, and the only new, material in the book. Lewis relies throughout both on primary sources and on the important work of historians Hugh Aitken, Erik Barnouw, and Susan Douglas. Telling the story of radio through an examination of the personal and work lives of three men brings with it a host of problems that the author ignores. By the middle of the book, the shifting from one character to another becomes distracting, as does the fact that some of the stories needed for symmetry do not work very well (deForest did little in World War II, but Lewis feels he must describe his nonrole 702 Book Reviews TECHNOLOGY AND CULTURE because Armstrong and Sarnoff were so busy). Additionally, none of the main characters are particularly appealing, and while reading about one nasty person can be fun, three proved dreary. The book is primarily descriptive, giving psychological answers to the few questions it does raise. The lack of analysis leads to lengthy accounts of quite boring patent battles. To make any patent case (let alone one as absurd as that between deForest and Armstrong) interesting enough to be the center of a work, the author must explain why patents are important. Although the book is about inventors and inventing, Lewis never ties the stories of invention and patents together. Why do deForest, Armstrong, and Sarnoff care so deeply about who receives the patent for certain inventions? Lewis focuses on what might be thought of as a second generation of “heroic” inventors, given that deForest and Armstrong self-consciously, and from child­ hood, modeled themselves on their 19th-century predecessors. Sar­ noff, who needed the new inventions to consolidate his power, defined himself as a protégé of Marconi and as a businessman who understood technology. Thus, the patent cases represent personal crusades to preserve the heroic inventor and symbols of the disjuncture between the heroic ideal and the reality of invention in the corporate age. Not only do the patent battles bring the three main characters into direct conflict (and thus hold Lewis’s narrative to­ gether), but they also illuminate 20th-century changes in the context for technology. In addition, patent struggles show...

Inventing American Broadcasting 1899–1922 by Susan J. Douglas

484 Book Reviews TECHNOLOGY AND CULTURE legraphers felt uncomfortable with unions, which they associated with manual laborers; accordingly, they never fully closed ranks with their supposed ally, the Knights of Labor, depriving themselves of a po­ tentially valuable resource during the strike. Also, segmentation within the craft (by location, status, function, and age) weakened solidarity. Contributing this volume to a series on class and culture, Gabler probably regarded historians of technology as a secondary audience. Indeed, observations about technology per se are rare, though Gabler does note that, with the advent of multiplex telegraphy, “pressure for increased productivity shifted from capital to labor” (p. 53) and that “all operators had a shared work culture that grew out of the nature of the medium itself” (p. 79). Gabler opens the book with a straightforward sketch of the 1883 strike and returns to it in the last chapter as the basis for a more detailed examination of unionism and telegraphy. In between, he devotes chapters to the industry’s structure, the work and social cul­ ture of telegraphers, and women in the field. Although this organi­ zational scheme has much to commend, splitting discussion of the strike introduces some redundancy. Gabler draws his inferences care­ fully—for example, by adjusting salaries for deflation and dealing with telegraphers’ perceptions of well-being as well as the reality. The book is exceptionally well written, enlivened by selective use of vi­ gnettes and vivid characterizations of individuals. Richard B. Kielbowicz Dr. Kielbowicz. an assistant professor of communications at the University of Wash­ ington, is currently studying the effects of the telegraph on news and the news business. Inventing American Broadcasting 1899—1922. By Susan J. Douglas. Bal­ timore: Johns Hopkins University Press, 1987. Pp. xxix + 363; il­ lustrations, notes, index. $45.00 (cloth); $14.95 (paper). Little more than ten years ago, the student seeking a good book on the early history of radio technology was out of luck. The best work on the subject was W. Rupert Maclaurin’s Invention and Innovation in the Radio Industry—first published in 1949 and skimpy in its technical explanations. This situation began to change in 1976 with the pub­ lication of Hugh G. J. Aitken’s Syntony and Spark, which afforded a concise and thoughtful look at radio’s transition from curious labo­ ratory phenomenon to realistic technical possibility. The second vol­ ume of Aitken’s researches, The Continuous Wave, appeared in 1985, providing a thorough investigation of the technical history of radio’s development in the first decades of this century. Now, with Susan Douglas’s treatment of economic, social, and political aspects of the same period—what she terms “the social construction of radio” (p. technology and culture Book Reviews 485 xvii)—it is fair to say that there are few technologies better covered by recent scholarship. Douglas’s contribution to this fine state of affairs is a well-written and well-organized study of the key inventors, companies, and gov­ ernment agencies that collectively shaped radio in its first two decades in the United States. Her survey of this period is subdivided into three phases. The first of these, from 1899 to 1906, was characterized by Guglielmo Marconi’s successful transfer of his early wireless enter­ prise to American shores and the responses to this by three inventors: Reginald Fessenden, Lee De Forest, and John S. Stone. As Douglas makes clear, our understanding of the first American efforts in radio requires sorting out not only different technical contributions but also the entrepreneurial strategies of the various players. In addition, the American experience was shaped from the beginning by the changing attitudes of the press and the U.S. Navy toward the emerging tech­ nology. Douglas sets out her cast of characters carefully and clearly, which greatly assists her subsequent analysis. The second phase of this story is the period 1906—12, when the independent inventors become increasingly entangled with the large corporations that are such a prominent part of American technology and business at the turn of the century. None of the early American inventors turns out to be a successful entrepreneur, so Douglas’s story here is largely one of Marconi’s success...

DeForest's “Diffraction Microphone”—Optical Detection of Sound in Air

A theoretical analysis of a microphone which optically detects the changes in air density or index of refraction due to sound waves [Lee DeForest, U. S. Patent 1,726,289 (1924)]. A light ray penetrates a thermal gradient in the air, and predicted deflection of the ray is approximately 3 × 10−5 cm per microbar sound pressure for a 300°K temperature change in a centimeter of path length.

Hoover, Edison featured speakers at dinner honoring Lee de Forest

Hoover, Edison featured speakers at dinner honoring Lee de Forest

Father of Radio: The Autobiography of Lee De Forest

Father of Radio: The Autobiography of Lee De Forest

Dr. H. J. van der Bijl, F.R.S

DR. HENDRIK JOHANNES VAN DER BIJL, whose death occurred on December 2, was born in 1887. From early children he showed that he was of stern stuff and would be different from others. A successful stay at the University of Stellenbosch concluded with a B.Sc. honours degree. He proceeded to Germany, where, at the University of Halle, he obtained the degree of M.A., to be followed later on by the Ph.D. of the University of Leipzig. It was while he was instructor in physics at the Royal School of Technology at Dresden that he came in contact with Prof. R. A. Millikan, who had gone to Germany to deliver a lecture on an aspect of physics with which van der Bijl was also dealing at the time ; this meeting laid the foundation for van der Bijl's meteoric career. So impressed was Prof. Millikan that on his return to the United States he advised the Western Electric Company, New York, to employ the serious young South African to pursue research on the triode, which had recently been invented by Lee de Forest, and was just being applied in the fast-developing art of radio.

Lee de Forest, Pioneer and Benefactor of Radio

Lee de Forest, Pioneer and Benefactor of Radio

1946 Edison medal presentation: Lee de Forest

PRESENTATION of the 1946 Edison Medal to Lee de Forest (F '18) “for pioneering achievements in radio and for the invention of a grid-controlled vacuum tube with its profound technical and social consequences” was made by AIEE President J. Elmer Housley on Tuesday, January 27, at a general session of the 1947 AIEE winter meeting. David Sarnoff (M '23) introduced the medalist. The history of the medal itself was given in ELECTRICAL ENGINEERING for February 1947, page 122.

Inaugural Address of Dr. Lee De Forest

Inaugural Address of Dr. Lee De Forest

The Radio Year-Book 1926 (Fourth Year): a Book of Reference for all Interested in Broadcast Receiving

THIS book will prove of value to all who listen to broadcasting. Photographs are given of many of the eminent men and of many of the popular artistes who have spoken or performed before the microphone during the past year. So far as British broadcasting is concerned, this year will be a momentous one, as the Government will have to come to a decision regarding the future of the British Broadcasting Company. The book is not a mere record of past achievements; many of the contributions look into the future and make conjectures as to new developments. Mr. Thorne Baker discusses the problem of the radio transmission of visual images. He shows that theoretically it is possible to have a screen in one's home on which, for example, the progress of the yachts at a regatta, possibly hundreds of miles away, could be watched. He points out the difficulties in the way, but says that they have nearly all been overcome by Mr. Baird. The technical section of the book gives many useful hints on the management of receiving sets and aerials. A chapter has been included on “speaking” films by Mr. Elwell; the reason being that the three-electrode valve has proved of the greatest value in this connexion. Dr. Lee de Forest is rightly given the credit of being the pioneer of perfectly synchronised talking motion pictures, which are called “phonofilms” in America. We learn that the talking motion picture in a commercially perfect form will shortly be introduced into Great Britain. A chapter is also devoted to loudspeaker extensions, and a system of wiring the various rooms of a house so that each room can have its own loud speaker or head-phones if so desired is described. A drawback to the method, however, is that if one is speaking in a room with a loud speaker, a listener on the phones in another room hears most of what is said.