Lee de Forest was born on August 26, 1873, and died on June 30, 1961. He was an American inventor, electrical engineer, and an important early figure in the field of electronics. In 1908, he created the first practical electronic amplifier, a three-part vacuum tube called the Audion. This invention helped begin the Electronic Age and made it possible to develop electronic oscillators. These advancements allowed for radio broadcasting, long-distance telephone lines, and the creation of talking motion pictures, among many other uses.

Throughout his life, de Forest held over 300 patents worldwide. However, his career was challenging—he claimed he earned and lost four fortunes. He was involved in several major patent lawsuits, used a large part of his income to pay legal fees, and was tried (but found not guilty) for mail fraud.

For his pioneering work, he received the 1922 IEEE Medal of Honor, the 1923 Franklin Institute Elliott Cresson Medal, and the 1946 American Institute of Electrical Engineers Edison Medal.

Early life

Lee de Forest was born in 1873 in Council Bluffs, Iowa, to Anna Margaret (née Robbins) and Henry Swift DeForest. He was a descendant of Jessé de Forest, who led a group of Walloon Huguenots who left Europe in the 17th century because of religious persecution.

De Forest’s father was a minister in the Congregational Church and hoped his son would also become a pastor. In 1879, his father became president of Talladega College in Talladega, Alabama, which was part of the American Missionary Association. The school accepted students of all genders, races, and backgrounds, and focused on educating African Americans. Many white residents in the area disliked the school and its mission. As a result, Lee spent much of his childhood in Talladega, separated from the white community, and formed close friendships with Black children in the town.

To prepare for college, de Forest attended Mount Hermon Boys’ School in Gill, Massachusetts, for two years, starting in 1891. In 1893, he enrolled in a three-year program at Yale University’s Sheffield Scientific School in New Haven, Connecticut. He received a $300 annual scholarship created for relatives of David de Forest. Believing he would become a famous and wealthy inventor, de Forest tried to interest companies in his inventions and puzzles. He also entered prize competitions with essays, but had little success.

After finishing his undergraduate studies, de Forest began three years of postgraduate work in September 1896. His electrical experiments often caused power outages by blowing fuses. Despite warnings, he caused a blackout during an important lecture by Professor Charles S. Hastings. As a result, de Forest was expelled from Sheffield.

When the Spanish–American War began in 1898, de Forest joined the Connecticut Volunteer Militia Battery as a bugler. However, the war ended before he could leave the state, and he was released from service. He later completed his studies at Yale’s Sloane Physics Laboratory and earned a doctorate in 1899. His dissertation, titled “Reflection of Hertzian Waves from the Ends of Parallel Wires,” was supervised by physicist Willard Gibbs.

Early radio work

Lee de Forest is often called the "Father of Radio," a title he used in his 1950 autobiography. In the late 1800s, he believed radio communication, then called "wireless telegraphy," would become important. However, Italian inventor Guglielmo Marconi, who received a patent in 1896, was already making progress in Europe and the United States. One problem with Marconi’s system was his use of a coherer, a type of receiver that could record signals but was slow, unreliable, and required tapping to reset after each signal. De Forest aimed to create a better system, including a self-restoring detector that could receive weaker signals and allow faster Morse code transmission.

After trying to find work with Nikola Tesla and Marconi without success, de Forest began his own work. His first job after leaving Yale was at the Western Electric Company’s telephone lab in Chicago, where he developed his first receiver based on research by German scientists A. Neugschwender and Emil Aschkinass. Their design used a mirror with a narrow, moistened slit and a battery and telephone receiver to detect radio signals. With help from a coworker named Ed Smythe, de Forest improved the design, creating devices he called "responders."

De Forest held several short-term jobs, including three months at a company in Milwaukee and a position as an assistant editor for a publication in Chicago. Focused on radio research, he later took a night teaching job at the Lewis Institute, allowing him to experiment at the Armour Institute. By 1900, using a spark-coil transmitter and his responder receiver, de Forest increased his transmission range to about 7 kilometers (4 miles). Professor Clarence Freeman of the Armour Institute became interested in de Forest’s work and developed a new type of spark transmitter.

De Forest felt that Smythe and Freeman were slowing his progress, so in 1901, he moved to New York to compete with Marconi by transmitting race results for the International Yacht races. Marconi had already arranged to provide reports for the Associated Press, as he had done in 1900. De Forest signed a contract with the smaller Publishers’ Press Association to do the same.

The race effort was mostly unsuccessful. The Freeman transmitter failed, and de Forest threw it overboard before replacing it with a regular spark coil. Additionally, a company claiming ownership of a wireless communication patent operated a powerful transmitter, creating competition. None of the companies had effective tuning, so only one could transmit at a time without interference. A plan to rotate operations every five minutes failed, leading to chaotic overlapping signals. De Forest noted that the only successful communication was through visual semaphore flags. The 1903 race followed a similar pattern, with Marconi and de Forest competing again, while another company used a high-powered transmitter to overpower the others. Instead of receiving clear reports, listeners heard unclear messages mixed with unrelated words and phrases.

American De Forest Wireless Telegraph Company

Despite this challenge, de Forest stayed in the New York City area to share his ideas and raise money to support the small companies that had been created to help his work. In January 1902, he met Abraham White, who became de Forest's main supporter for the next five years. White had big plans that interested de Forest, but he was not honest. Much of the company’s work was based on exaggerated claims and dishonest business practices. To support de Forest, White created the American DeForest Wireless Telegraph Company, with White as president and de Forest as the scientific leader. The company aimed to develop "world-wide wireless" communication.

The original "responder" receiver, also called the "goo anti-coherer," was too simple to be used in real products. de Forest tried to create a new device that could receive radio signals without copying others’ patents. In 1903, Reginald Fessenden showed an electrolytic detector, and de Forest made a similar version called the "spade detector," claiming it did not copy Fessenden’s patents. Fessenden and the courts disagreed, and legal orders stopped de Forest from using the device.

At the same time, White promoted the company in many ways. "Wireless Auto No.1" was placed on Wall Street to send stock quotes using a loud transmitter to attract investors. In early 1904, two stations were built in Wei-hai-Wei, China, and on the ship SS Haimun, allowing a reporter from The Times of London to share news about the Russo-Japanese War. Later that year, a tower with the word "DEFOREST" in lights was built at the Louisiana Purchase Exposition in St. Louis, Missouri, where the company won a gold medal for its radio demonstrations. (Marconi left the event when he learned de Forest would be there.)

The company’s most important early contract was building five powerful radio stations for the U.S. Navy between 1905 and 1906, located in Panama, Pensacola, Key West, Florida, Guantanamo, Cuba, and Puerto Rico. It also built stations along the Atlantic Coast and Great Lakes and equipped ships with radio equipment. However, the company focused more on selling stock at increasingly high prices, driven by the construction of promotional stations. Most of these stations had no real use and were later abandoned.

De Forest later had disagreements with the company’s leaders. He felt he did not get enough support for research, while company officials were upset that he could not create a working receiver without copying patents. This problem was eventually solved when another employee, General Henry Harrison Chase Dunwoody, invented the carborundum crystal detector. On November 28, 1906, de Forest gave up his company stock and left in exchange for $1,000 (half of which went to an attorney) and rights to some early Audion patents. The company was then renamed the United Wireless Telegraph Company and remained a major U.S. radio firm until its collapse in 1912, supported by widespread stock fraud.

Radio Telephone Company

De Forest quickly worked to become an independent inventor again, using his own laboratory in the Parker Building in New York City. He formed the Radio Telephone Company to support his inventions. James Dunlop Smith, a former American salesperson for De Forest, became the company's president, and De Forest was vice president. De Forest preferred the term "radio" over "wireless," which had mostly been used in Europe.

At the 1904 Louisiana Purchase Exposition, Valdemar Poulsen presented a paper about an arc transmitter. Unlike spark transmitters, which sent broken signals, this device created steady signals that could carry sound. Although Poulsen had patented his invention, De Forest claimed he had a variation that avoided copying Poulsen's work. Using his "sparkless" arc transmitter, De Forest first sent sound across a lab room on December 31, 1906. By February 1907, he was testing transmissions, including music from Thaddeus Cahill's telharmonium, which could be heard throughout the city.

On July 18, 1907, De Forest made the first ship-to-shore radiotelephone transmissions. He sent race reports for the Annual Inter-Lakes Yachting Association Regatta on Lake Erie from the steam yacht Thelma to his assistant, Frank E. Butler, who was on South Bass Island. De Forest also interested the U.S. Navy in his radiotelephone, which ordered 26 arc sets for its Great White Fleet's around-the-world voyage in late 1907. However, after the trip, the Navy found the sets too unreliable and removed them.

The company built a network of radiotelephone stations along the Atlantic Coast and Great Lakes to help ships navigate. However, these installations were not profitable, and by 1911, the company and its subsidiaries were close to bankruptcy.

De Forest also used the arc transmitter for early radio broadcasts. In 1907, Eugenia Farrar sang "I Love You Truly" in a test from his laboratory. In 1908, during his honeymoon in Paris, music was broadcast from the Eiffel Tower to demonstrate the arc transmitter. In early 1909, De Forest's mother-in-law, Harriot Stanton Blatch, gave a radio speech supporting women's suffrage.

More tests followed. De Forest worked with the Metropolitan Opera House in New York City to see if opera performances could be broadcast live. On January 12, 1910, Tosca was performed, and the next day, Italian tenor Enrico Caruso participated in a test. On February 24, Mme. Mariette Mazarin sang "La Habanera" from Carmen and parts of Elektra from De Forest's lab. These tests showed the idea was not yet technically possible, and De Forest did not make more entertainment broadcasts until late 1916, when better vacuum-tube equipment became available.

De Forest's most famous invention was the "grid Audion," the first successful three-element vacuum tube, which could amplify electrical signals. He said the idea came to him in 1900, when he noticed a nearby gas flame flickering in response to loud sounds from a spark-gap transmitter. He later tested whether ionized gases in a glass tube could detect radio signals. In 1905 and 1906, he created various glass-tube devices he called "Audions." The first Audions had two electrodes, and on October 25, 1906, De Forest filed a patent for a diode vacuum tube detector, which was granted on January 15, 1907.

He later added a third electrode, originally placed outside the glass tube. These early designs did not work well. De Forest presented his work at a meeting of the American Institute of Electrical Engineers in 1906, and his findings were later published in Scientific American Supplement. He believed a small amount of gas was needed for the tubes to work but admitted he did not fully understand how the gas responded to radio signals.

In late 1906, De Forest moved the third electrode inside the tube, between the filament and the plate. He called this electrode a "grid," inspired by the "gridiron" lines on American football fields. Experiments with his assistant, John V. L. Hogan, showed the device could detect radio signals. He filed a patent on January 29, 1907, and received U.S. patent 879,532 on February 18, 1908. The grid Audion became the most valuable version, and the term "Audion" later referred only to this type, which became known as the triode.

The grid Audion was the first device to slightly amplify radio signals. However, many people thought De Forest had simply added a grid to the Fleming valve, a device that converted alternating current to direct current. De Forest disagreed, saying his invention amplified currents, while the Fleming valve only rectified them. U.S. courts ruled that the grid Audion did infringe on the Fleming valve patent, which was held by Marconi. Marconi agreed that the grid was a patentable improvement, and both sides licensed each other to manufacture three-electrode tubes in the United States. De Forest's European patents had expired because he could not afford to renew them.

The grid Audion was rarely used for five years after its invention because of its limited usefulness and inconsistent quality. In 1908, John V. L. Hogan noted, "The Audion could become a strong detector, but in its current form, it is unreliable and too complex for most wireless operators to handle."

Employment at Federal Telegraph

In May 1910, the Radio Telephone Company and its affiliated companies were restructured as the North American Wireless Corporation. However, financial problems caused the company's operations to nearly stop. De Forest moved to San Francisco, California, and in early 1911 began working as a researcher at the Federal Telegraph Company, which created long-distance radio telegraph systems using powerful Poulsen arcs.

At Federal Telegraph, de Forest focused on improving signal reception. He developed a method to strengthen audio signals by sending the output of a grid Audion into a second tube for extra amplification. He named this system a "cascade amplifier," which later included up to three connected Audions.

At the same time, the American Telephone and Telegraph Company (AT&T) was studying ways to improve telephone signals for long-distance calls. De Forest’s invention was seen as a possible tool to repeat telephone signals over long distances. In mid-1912, an associate named John Stone Stone contacted AT&T to arrange a demonstration of de Forest’s device. However, de Forest’s version of the Audion, which had a "gassy" design, could not handle the low voltages used by telephone lines. (Because of how he built the tubes, de Forest’s Audions stopped working if the vacuum inside was too strong.)

Through careful research, Dr. Harold D. Arnold and his team at AT&T’s Western Electric subsidiary discovered that improving the tube’s design would allow it to be more fully evacuated. The high vacuum enabled the Audion to operate at telephone-line voltages. With these changes, the Audion became a modern electron-discharge vacuum tube, using electron flows instead of ions. (Dr. Irving Langmuir at General Electric made similar discoveries, and both he and Arnold tried to patent the "high vacuum" design. However, the U.S. Supreme Court ruled in 1931 that this modification could not be patented.)

After a 10-month delay, in July 1913, AT&T, through a third party who hid his connection to the telephone company, bought the rights to use seven Audion patents for $50,000. De Forest had hoped for a higher payment but was in poor financial condition and could not negotiate more. In 1915, AT&T used this innovation to make the first transcontinental telephone calls during the Panama-Pacific International Exposition in San Francisco.

Reorganized Radio Telephone Company

In March 1912, officials from the Radio Telephone Company faced legal trouble for selling stocks in a way that broke the law, similar to actions taken by American DeForest. As part of a government effort to stop illegal stock trading, Lee de Forest and four other company leaders were arrested and charged with using the mail system to cheat people. Their trials happened in late 1913, and three of the people were found guilty, but de Forest was not. After these legal issues were resolved, de Forest reorganized his business as the DeForest Radio Telephone Company and opened a laboratory in the Bronx, New York. In October 1914, the company sold the rights to use a key radio patent called the Audion to AT&T for $90,000. De Forest kept the rights to sell the patent for use by amateurs and experimenters. In October 1915, AT&T tested radio signals from a Navy station in Virginia, and these signals were received as far as Paris and Hawaii.

The company later began selling "Oscillion" power tubes to radio hobbyists. To control the tube business, the company required customers to return old tubes before getting replacements. This policy encouraged others to make and sell unlicensed tubes without such rules. One competitor was Audio Tron Sales Company, started in 1915 by Elmer T. Cunningham in San Francisco. Audio Tron sold tubes that were cheaper and of equal or better quality than de Forest's. The de Forest company sued Audio Tron, but they eventually reached an agreement without going to court.

In April 1917, the company sold its remaining radio patents to AT&T's Western Electric division for $250,000. During World War I, the company earned money by selling radio equipment to the military, but its tubes were often criticized for being lower quality compared to those made by companies like General Electric and Western Electric.

Starting in 1912, inventors around the world studied vacuum tubes and discovered new uses for them. These discoveries led to legal battles over who had the right to claim the inventions first. One major dispute was between de Forest and Edwin Howard Armstrong over a discovery called "regeneration," also known as the "feedback circuit."

In 1913, Armstrong shared detailed information about how to use three-element vacuum tubes to amplify signals and create powerful radio signals. He applied for a patent for this invention, and on October 6, 1914, the patent was approved as U.S. Patent 1,113,149.

U.S. patent law allowed inventors to challenge patent grants if they could prove someone else had discovered the invention first. To increase the value of patents he planned to sell to Western Electric in 1917, de Forest filed multiple patent applications in 1915 that copied Armstrong's claims. He claimed he had discovered the feedback principle in 1912, using it to operate a low-powered radio transmitter. However, evidence showed de Forest did not understand the full importance of his discovery at the time.

The patent office identified four inventors who claimed to have discovered regeneration first: Armstrong, de Forest, General Electric's Irving Langmuir, and a German inventor, Alexander Meissner. Meissner's application was taken by the government during World War I.

Legal cases about the patents split into two groups. In 1920, Armstrong and Westinghouse sued the De Forest Company for using Armstrong's patent. A court ruled that de Forest had not fully understood his discovery and had not made further progress, so he could not claim to be the inventor.

A second set of cases focused on the patent office's decision. The interference board supported Armstrong, but de Forest appealed. In 1924, a court found that de Forest's 1912 notebook entry proved he had discovered the principle first. Armstrong tried to overturn this decision, but the U.S. Supreme Court rejected his efforts in 1928 and 1934.

This ruling legally recognized de Forest as the inventor of regeneration in the United States. However, many engineers believed Armstrong was the true developer, and de Forest was seen as someone who used the patent system to claim credit for an invention he did not fully develop. After the 1934 Supreme Court decision, Armstrong tried to return a medal he had been awarded in 1917, but the organization refused.

The outcome allowed de Forest's company to sell products using regeneration, as Armstrong had tried to block the company from using his patent during the dispute. De Forest often criticized Armstrong in articles, even after Armstrong's death in 1954. In 1956, de Forest wrote to an author who praised Armstrong, calling him "exceedingly arrogant" and defending the Supreme Court's decision.

Eventually, de Forest's patents were inherited by the Radio Corporation of America (RCA), which used the legal system to stop other companies from using patented technology. In 1938, Arthur A. Collins successfully defended his company against an RCA claim by showing that the vacuum tubes used in his radios were based on an earlier patent by Robert Goddard.

In the summer of 1915, the company received an experimental license to operate a radio station called 2XG at its Highbridge laboratory. In late 1916, de Forest restarted entertainment broadcasts that had been paused in 1910, using improved vacuum-tube equipment. The station's first program aired on October 26, 1916, as part of an arrangement.

Phonofilm sound-on-film process

In 1921, Lee de Forest stopped most of his radio research to focus on creating an optical sound-on-film process called Phonofilm. In 1919, he filed the first patent for this system, which improved on earlier work by Finnish inventor Eric Tigerstedt and the German company Tri-Ergon. Phonofilm recorded sound by capturing electrical waveforms from a microphone onto film using parallel lines of varying gray shades, a method called "variable density." This was different from "variable area" systems used by other processes, such as RCA Photophone. When movie film was shown, the recorded sound was converted back into audio, playing in sync with the picture.

From October 1921 to September 1922, de Forest lived in Berlin, Germany, where he met Tri-Ergon inventors Josef Engl (1893–1942), Hans Vogt (1890–1979), and Joseph Massolle (1889–1957), and studied other European sound film systems. In April 1922, he announced that he would soon have a working sound-on-film system. On March 12, 1923, he showed Phonofilm to the press. Later, on April 12, 1923, he gave a private demonstration to electrical engineers at the Engineering Society Building in New York City.

In November 1922, de Forest started the De Forest Phonofilm Company in New York City. However, Hollywood movie studios did not show interest in his invention, and since these studios controlled most theaters, de Forest could only show his films in independent theaters. The Phonofilm Company went bankrupt in September 1926.

After recording stage performances, speeches, and musical acts, de Forest premiered 18 Phonofilm short films at the independent Rivoli Theater in New York City on April 15, 1923. From May 1924, Max and Dave Fleischer used Phonofilm for their "Song Car-Tune" cartoons, which included the "Follow the Bouncing Ball" technique. However, de Forest’s focus on short vaudeville acts, rather than full-length movies, limited Phonofilm’s appeal to Hollywood studios.

De Forest also worked with Freeman Harrison Owens and Theodore Case to improve Phonofilm. However, he later had disagreements with both men. Because de Forest did not properly credit Theodore Case’s inventions, Case’s laboratory built its own camera. This camera was used by Case and his colleague Earl Sponable to record President Calvin Coolidge on August 11, 1924. De Forest claimed this film was his own work.

Believing de Forest prioritized his own fame over creating a functional sound film system, and because de Forest downplayed the contributions of Case’s laboratory, Case ended his partnership with de Forest in 1925. Case then negotiated an agreement with William Fox, owner of Fox Film Corporation, to use his patents. Fox marketed this innovation as Fox Movietone. Warner Bros. introduced a competing sound-on-disc system called Vitaphone, developed by Western Electric, with the release of the film Don Juan on August 6, 1926.

In 1927 and 1928, Hollywood expanded its use of sound-on-film systems, including Fox Movietone and RCA Photophone. Meanwhile, theater owner Isadore Schlesinger bought the UK rights to Phonofilm and released short films of British music hall performers from September 1926 to May 1929. Nearly 200 Phonofilm shorts were made, and many are preserved in collections at the Library of Congress and the British Film Institute.

Later years and death

In April 1923, the De Forest Radio Telephone & Telegraph Company, which made de Forest's Audions for use in businesses, was sold to a group led by Edward Jewett of Jewett-Paige Motors. This group expanded the company's factory to meet growing demand for radios. The sale also included hiring de Forest, who was working on new inventions. De Forest's money problems worsened after the 1929 stock market crash, and research into mechanical television did not earn money. In 1934, he started a small shop to make diathermy machines. In a 1942 interview, he still hoped to create at least one more major invention.

De Forest strongly criticized changes in the entertainment side of the radio industry. In 1940, he wrote an open letter to the National Association of Broadcasters, saying, "What have you done with my child, the radio broadcast? You have debased this child, dressed him in rags of ragtime, tatters of jive and boogie-woogie." That same year, de Forest and early TV engineer Ulises Armand Sanabria shared an idea for an early unmanned airplane that used a TV camera and a radio that was hard to interfere with in a Popular Mechanics article. In 1950, his autobiography, Father of Radio, was published, but it did not sell well.

De Forest was a guest on the May 22, 1957, episode of the television show This Is Your Life, where he was introduced as "the father of radio and the grandfather of television." He had a serious heart attack in 1958 and stayed mostly in bed afterward. He died in Hollywood on June 30, 1961, at age 87, and was buried in San Fernando Mission Cemetery in Los Angeles, California. He died with very little money, only $1,250 in his bank account.

Legacy

The grid Audion, which Lee de Forest called "my greatest invention," and the vacuum tubes that came from it were the main technology in electronics for 40 years. They made long-distance telephone service, radio broadcasting, television, and many other uses possible. The Audion could also act as an electronic switch and was later used in early digital electronics, including the first electronic computers. However, the invention of the transistor in 1948 led to microchips that eventually replaced vacuum-tube technology. Because of this, de Forest is often called one of the founders of the "electronic age."

According to Donald Beaver, de Forest's strong wish to improve his early life challenges helped him become independent, self-reliant, and inventive. He showed a strong desire to achieve goals, overcome difficulties, and focus on a career in invention. "He had the qualities of a traditional tinkerer-inventor: belief in the future, confidence, persistence, and the ability to work hard for a long time."

De Forest's collection of documents and items was given to the Perham Electronic Foundation by his wife. In 1973, the foundation opened the Foothills Electronics Museum at Foothill College in Los Altos Hills, California. In 1991, the college closed the museum, breaking its agreement. The foundation won a legal case and received $775,000. The items were stored for 12 years before being acquired in 2003 by History San José and displayed as the Perham Collection of Early Electronics.

Awards and recognition

• One of the first members, in 1912, of the Institute of Radio Engineers (IRE)
• Received the 1922 IRE Medal of Honor for creating the three-electrode amplifier and other work in radio technology
• Awarded the 1923 Franklin Institute Elliott Cresson Medal for inventions related to the Audion
• Received the 1946 American Institute of Electrical Engineers Edison Medal for the important effects on technology and society caused by the grid-controlled vacuum tube he introduced
• Honored with an Honorary Academy Award (Oscar) in 1960 by the Academy of Motion Picture Arts and Sciences for early work that added sound to movies
• Recognized on February 8, 1960, with a star on the Hollywood Walk of Fame
• DeVry University was originally called the De Forest Training School by its founder, Dr. Herman A. De Vry, who was a friend and colleague of de Forest.

Personal life

De Forest was married four times, with the first three marriages ending in divorce:

• He married Lucille Sheardown in February 1906, but they divorced before the end of the year.
• He married Nora Stanton Blatch Barney (1883–1971) on February 14, 1908. They had a daughter named Harriet, but they separated by 1909 and divorced in 1912.
• He married Mary Mayo White (1891–1957), who was also known as Mary Mayo, in December 1912. Records from 1920 show they lived with their infant daughter, Deena (born around 1919). They divorced on October 5, 1930, according to the Los Angeles Times. Mary Mayo died on December 30, 1957, in a fire in Los Angeles.
• He married Marie Mosquini (1899–1983) on October 10, 1930. Marie was a silent-film actress, and they remained married until his death in 1961.

De Forest was a conservative Republican and strongly opposed to communism and fascism. In 1932, during the Great Depression, he voted for Franklin Roosevelt. However, he later became upset with Roosevelt and called him "America's first Fascist president." In 1949, he wrote letters to all members of Congress, asking them to vote against socialized medicine, federally funded housing, and an excess profits tax. In 1952, he wrote to Vice President Richard Nixon, urging him to "prosecute with renewed vigor your valiant fight to put out Communism from every branch of our government." In December 1953, he canceled his subscription to The Nation, accusing it of being "lousy with Treason, crawling with Communism."

Although he was raised in a strongly religious Protestant household, De Forest later became an agnostic. In his autobiography, he wrote that during the summer of 1894, a significant change in his beliefs occurred: "Through that Freshman vacation at Yale, I became more of a philosopher than I have ever since. And thus, one by one, were my childhood's firm religious beliefs altered or reluctantly discarded."

Quotes

De Forest made many predictions, some of which did not happen, but he also correctly predicted things like microwave communication and cooking.

• "I discovered an Invisible Empire of the Air, intangible, yet solid as granite."
• "I foresee great improvements in short-pulse microwave signaling, where multiple programs can use the same channel in order, with very fast electronic communication. […] Short waves will be used in kitchens for roasting and baking, almost instantly." – 1952
• "So I repeat that while television may be possible technically, it is not practical or profitable. We should not spend time dreaming about it." – 1926
• "Putting a person in a multi-stage rocket to reach the moon, make scientific observations, and return to Earth is a wild dream, like those in Jules Verne’s stories. I believe such a journey will never happen, even with future advances." – 1957
• "I do not see spaceships traveling to the moon or Mars. Humans can only live on Earth or within its atmosphere." – 1952
• "The Bell Laboratories’ transistor, a small germanium crystal with three parts that can amplify sound, is becoming a competitor to the tube amplifier. However, its limits in frequency and power will prevent it from replacing the Audion amplifier widely." – 1952
• "I came, I saw, I invented—it’s that simple. No need to think deeply; it’s all in your imagination."

Patents

Patent images in TIFF format

• U.S. patent 748,597 "Wireless Signaling Device" (directional antenna), filed December 1902, issued January 1904;
• U.S. patent 824,637 "Oscillation Responsive Device" (vacuum tube detector diode), filed January 1906, issued June 1906;
• U.S. patent 827,523 "Wireless Telegraph System" (separate transmitting and receiving antennas), filed December 1905, issued July 1906;
• U.S. patent 827,524 "Wireless Telegraph System," filed January 1906, issued July 1906;
• U.S. patent 836,070 "Oscillation Responsive Device" (vacuum tube detector – no grid), filed May 1906, issued November 1906;
• U.S. patent 841,386 "Wireless Telegraphy" (tunable vacuum tube detector – no grid), filed August 1906, issued January 1907;
• U.S. patent 841,387 "Device for Amplifying Feeble Electrical Currents" (..), filed August 1906, issued January 1907;
• U.S. patent 876,165 "Wireless Telegraph Transmitting System" (antenna coupler), filed May 1904, issued January 1908;
• U.S. patent 879,532 "Space Telegraphy" (increased sensitivity detector – clearly shows grid), filed January 1907, issued February 18, 1908;
• U.S. patent 926,933 "Wireless Telegraphy";
• U.S. patent 926,934 "Wireless Telegraph Tuning Device";
• U.S. patent 926,935 "Wireless Telegraph Transmitter," filed February 1906, issued July 1909;
• U.S. patent 926,936 "Space Telegraphy";
• U.S. patent 926,937 "Space Telephony";
• U.S. patent 979,275 "Oscillation Responsive Device" (parallel plates in Bunsen flame), filed February 1905, issued December 1910;
• U.S. patent 1,025,908 "Transmission of Music by Electromagnetic Waves";
• U.S. patent 1,101,533 "Wireless Telegraphy" (directional antenna/direction finder), filed June 1906, issued June 1914;
• U.S. patent 1,214,283 "Wireless Telegraphy."