Guglielmo Marconi, 1st Marquis of Marconi was an Italian inventor and electrical engineer, known for his pioneering work on long-distance radio transmission, development of Marconi's law, a radio telegraph system. He is credited as the inventor of radio, he shared the 1909 Nobel Prize in Physics with Karl Ferdinand Braun "in recognition of their contributions to the development of wireless telegraphy". Marconi was an entrepreneur and founder of The Wireless Telegraph & Signal Company in the United Kingdom in 1897, he succeeded in making an engineering and commercial success of radio by innovating and building on the work of previous experimenters and physicists. In 1929, Marconi was ennobled as a Marchese by King Victor Emmanuel III of Italy, and, in 1931, he set up the Vatican Radio for Pope Pius XI. Marconi was born into the Italian nobility as Guglielmo Giovanni Maria Marconi in Bologna on 25 April 1874, the second son of Giuseppe Marconi and his Irish/Scot wife Annie Jameson. Marconi had a brother, a stepbrother, Luigi.
Between the ages of two and six and his elder brother Alfonso lived with their mother in the English town of Bedford. Marconi did not go on to formal higher education. Instead, he learned chemistry and physics at home from a series of private tutors hired by his parents, his family hired additional tutors for Guglielmo in the winter when they would leave Bologna for the warmer climate of Tuscany or Florence. Marconi noted an important mentor was professor Vincenzo Rosa, a high school physics teacher in Livorno. Rosa taught the 17-year-old Marconi the basics of physical phenomena as well as new theories on electricity. At the age of 18 back in Bologna Marconi became acquainted with University of Bologna physicist Augusto Righi, who had done research on Heinrich Hertz's work. Righi permitted Marconi to attend lectures at the university and to use the University's laboratory and library. From youth, Marconi was interested in electricity. In the early 1890s, he began working on the idea of "wireless telegraphy"—i.e. the transmission of telegraph messages without connecting wires as used by the electric telegraph.
This was not a new idea. A new development came from Heinrich Hertz, who, in 1888, demonstrated that one could produce and detect electromagnetic radiation. At the time, this radiation was called "Hertzian" waves, is now referred to as radio waves. There was a great deal of interest in radio waves in the physics community, but this interest was in the scientific phenomenon, not in its potential as a communication method. Physicists looked on radio waves as an invisible form of light that could only travel along a line of sight path, limiting its range to the visual horizon like existing forms of visual signaling. Hertz's death in 1894 brought published reviews of his earlier discoveries including a demonstration on the transmission and detection of radio waves by the British physicist Oliver Lodge and an article about Hertz's work by Augusto Righi. Righi's article renewed Marconi's interest in developing a wireless telegraphy system based on radio waves, a line of inquiry that Marconi noted that other inventors did not seem to be pursuing.
At the age of 20, Marconi began to conduct experiments in radio waves, building much of his own equipment in the attic of his home at the Villa Griffone in Pontecchio, Italy with the help of his butler Mignani. Marconi built on Hertz's original experiments and, at the suggestion of Righi, began using a coherer, an early detector based on the 1890 findings of French physicist Edouard Branly and used in Lodge's experiments, that changed resistance when exposed to radio waves. In the summer of 1894, he built a storm alarm made up of a battery, a coherer, an electric bell, which went off when it picked up the radio waves generated by lightning. Late one night, in December 1894, Marconi demonstrated a radio transmitter and receiver to his mother, a set-up that made a bell ring on the other side of the room by pushing a telegraphic button on a bench. Supported by his father, Marconi continued to read through the literature and picked up on the ideas of physicists who were experimenting with radio waves.
He developed devices, such as portable transmitters and receiver systems, that could work over long distances, turning what was a laboratory experiment into a useful communication system. Marconi came up with a functional system with many components: A simple oscillator or spark-producing radio transmitter. In the summer of 1895, Marconi moved his experiments outdoors on his father's estate in Bologna, he tried different arrangements and shapes of antenna bu
History of videotelephony
The history of videotelephony covers the historical development of several technologies which enable the use of live video in addition to voice telecommunications. The concept of videotelephony was first popularized in the late 1870s in both the United States and Europe, although the basic sciences to permit its earliest trials would take nearly a half century to be discovered; this was first embodied in the device which came to be known as the video telephone, or videophone, it evolved from intensive research and experimentation in several telecommunication fields, notably electrical telegraphy, telephony and television. The development of the crucial video technology first started in the latter half of the 1920s in the United Kingdom and the United States, spurred notably by John Logie Baird and AT&T's Bell Labs; this occurred in part, at least with AT&T, to serve as an adjunct supplementing the use of the telephone. A number of organizations believed that videotelephony would be superior to plain voice communications.
However video technology was to be deployed in analog television broadcasting long before it could become practical—or popular—for videophones. Videotelephony developed in parallel with conventional voice telephone systems from the mid-to-late 20th century. Expensive videoconferencing systems evolved throughout the 1980s and 1990s from proprietary equipment and network requirements to standards-based technologies that were available to the general public at a reasonable cost. Only in the late 20th century with the advent of powerful video codecs combined with high-speed Internet broadband and ISDN service did videotelephony become a practical technology for regular use. With the rapid improvements and popularity of the Internet, videotelephony has become widespread through the deployment of video-enabled mobile phones, plus videoconferencing and computer webcams which utilize Internet telephony. In the upper echelons of government and commerce, telepresence technology, an advanced form of videoconferencing, has helped reduce the need to travel.
Two years after the telephone was first patented in the United States in 1876 by Dr. Alexander Graham Bell, an early concept of a combined videophone and wide-screen television called a telephonoscope was conceptualized in the popular periodicals of the day, it was mentioned in various early science fiction works such as Le Vingtième siècle. La vie électrique and other works written by Albert Robida, was sketched in various cartoons by George du Maurier as a fictional invention of Thomas Edison. One such sketch was published on December 1878 in Punch magazine; the term'telectroscope' was used in 1878 by French writer and publisher Louis Figuier, to popularize an invention wrongly interpreted as real and incorrectly ascribed to Dr. Bell after his Volta Laboratory discreetly deposited a sealed container of a Graphophone phonograph at the Smithsonian Institution for safekeeping. Written under the pseudonym "Electrician", one article earlier claimed that "an eminent scientist" had invented a device whereby objects or people anywhere in the world "....could be seen anywhere by anybody".
The device, among other functions, would allow merchants to transmit pictures of their wares to their customers, the contents of museum collections to be made available to scholars in distant cities...." In the era prior to the advent of broadcasting, electrical "seeing" devices were conceived as adjuncts to the telephone, thus creating the concept of a videophone. Fraudulent reports of'amazing' advances in video telephones would be publicized as early as 1880 and would reoccur every few years, such as the episode of'Dr. Sylvestre' of Paris who claimed in 1902 to have invented a powerful video telephone, termed a'spectograph', the intellectual property rights he believed were worth $5,000,000. After reviewing his claim Dr. Bell denounced the supposed invention as a "fairy tale", publicly commented on the charlatans promoting bogus inventions for financial gain or self-promotion; however Dr. Alexander Graham Bell thought that videotelephony was achievable though his contributions to its advancement were incidental.
In April 1891, Dr. Bell did record conceptual notes on an'electrical radiophone', which discussed the possibility of "seeing by electricity" using devices that employed tellurium or selenium imaging components. Bell wrote, decades prior to the invention of the image dissector: Should it be found... is illuminated an apparatus might be constructed in which each piece of selenium is a mere speck, like the head of a small pin, the smaller the better. The darkened selenium should be placed in a cup-like receiver which can fit over the eye... When the first selenium speck is presented to an illuminated object, it may be possible that the eye in the darkened receiver, should perceive, not light, but an image of the object... Bell went on to predict that: "...the day would come when the man at the telephone would be able to see the distant person to whom he was speaking." The discoveries in physics and materials science underlying video technology would not be in place until the mid-1920s, first being utilized in electromechanical television.
More practical'all-electronic' video and television would not emerge until 1939, but would suffer several more years of delays before gaining popularity due to the onset and effects of World War II. The compound name'videophone' entered into general usage after 1950, although'video telephone' entered the lexicon earlier after video was coined in 1935. Prior to that time there appeared to be no standard terms for'video telephone', with exp
The photophone is a telecommunications device that allows transmission of speech on a beam of light. It was invented jointly by Alexander Graham Bell and his assistant Charles Sumner Tainter on February 19, 1880, at Bell's laboratory at 1325 L Street in Washington, D. C. Both were to become full associates in the Volta Laboratory Association and financed by Bell. On June 3, 1880, Bell's assistant transmitted a wireless voice telephone message from the roof of the Franklin School to the window of Bell's laboratory, some 213 meters away. Bell believed. Of the 18 patents granted in Bell's name alone, the 12 he shared with his collaborators, four were for the photophone, which Bell referred to as his "greatest achievement", telling a reporter shortly before his death that the photophone was "the greatest invention made, greater than the telephone"; the photophone was a precursor to the fiber-optic communication systems that achieved worldwide popular usage starting in the 1980s. The master patent for the photophone was issued in December 1880, many decades before its principles came to have practical applications.
The photophone was similar to a contemporary telephone, except that it used modulated light as a means of wireless transmission while the telephone relied on modulated electricity carried over a conductive wire circuit. Bell's own description of the light modulator: We have found that the simplest form of apparatus for producing the effect consists of a plane mirror of flexible material against the back of which the speaker's voice is directed. Under the action of the voice the mirror becomes alternately convex and concave and thus alternately scatters and condenses the light; the brightness of a reflected beam of light, as observed from the location of the receiver, therefore varied in accordance with the audio-frequency variations in air pressure—the sound waves—which acted upon the mirror. In its initial form, the photophone receiver was non-electronic, using the photoacoustic effect. Bell found. Lampblack proved to be outstanding. Using a modulated beam of sunlight as a test signal, one experimental receiver design, employing only a deposit of lampblack, produced a tone that Bell described as "painfully loud" to an ear pressed close to the device.
In its ultimate electronic form, the photophone receiver used a simple selenium cell photodetector at the focus of a parabolic mirror. The cell's electrical resistance varied inversely with the light falling upon it, i.e. its resistance was higher when dimly lit, lower when brightly lit. The selenium cell took the place of a carbon microphone—also a variable-resistance device—in the circuit of what was otherwise an ordinary telephone, consisting of a battery, an electromagnetic earphone, the variable resistance, all connected in series; the selenium modulated the current flowing through the circuit, the current was converted back into variations of air pressure—sound—by the earphone. In his speech to the American Association for the Advancement of Science in August 1880, Bell gave credit for the first demonstration of speech transmission by light to Mr. A. C. Brown of London in the Fall of 1878; because the device used radiant energy, the French scientist Ernest Mercadier suggested that the invention should not be named'photophone', but'radiophone', as its mirrors reflected the Sun's radiant energy in multiple bands including the invisible infrared band.
Bell used the name for a while but it should not be confused with the invention "radiophone" which used radio waves. While honeymooning in Europe with his bride Mabel Hubbard, Bell read of the newly discovered property of selenium having a variable resistance when acted upon by light, in a paper by Robert Sabine as published in Nature on 25 April 1878. In his experiments, Sabine used a meter to see the effects of light acting on selenium connected in a circuit to a battery; however Bell reasoned that by adding a telephone receiver to the same circuit he would be able to hear what Sabine could only see. As Bell's former associate, Thomas Watson, was occupied as the superintendent of manufacturing for the nascent Bell Telephone Company back in Boston, Bell hired Charles Sumner Tainter, an instrument maker, assigned to the U. S. 1874 Transit of Venus Commission, for his new'L' Street laboratory in Washington, at the rate of $15 per week. On February 19, 1880 the pair had managed to make a functional photophone in their new laboratory by attaching a set of metallic gratings to a diaphragm, with a beam of light being interrupted by the gratings movement in response to spoken sounds.
When the modulated light beam fell upon their selenium receiver Bell, on his headphones, was able to hear Tainter singing Auld Lang Syne. In an April 1, 1880 Washington, D. C. experiment and Tainter communicated some 79 metres along an alleyway to the laboratory's rear window. A few months on June 21 they succeeded in communicating over a distance of some 213 meters, using plain sunlight as their light source, practical electrical lighting having only just been introduced to the U. S. by Edison. The transmitter in their latter experiments had sunlight reflected off the surface of a thin mirror positioned at the end of a speaking tube. Tainter, on the roof of the Franklin School, spoke to Bell, in his laboratory listeni
Hedy Lamarr, born Hedwig Eva Maria Kiesler. After a brief early film career in Czechoslovakia, including the controversial Ecstasy, she fled from her husband, a wealthy Austrian ammunition manufacturer, secretly moved to Paris. Traveling to London, she met Metro-Goldwyn-Mayer studio head Louis B. Mayer, who offered her a movie contract in Hollywood, she became a film star with her performance in Algiers. Her MGM films include Lady of the Tropics, Boom Town, H. M. Pulham, Esq. and White Cargo. Her greatest success was as Delilah in Cecil B. DeMille's Delilah, she acted on television before the release of her final film, The Female Animal. She was honored with a star on the Hollywood Walk of Fame in 1960. At the beginning of World War II, she and composer George Antheil developed a radio guidance system for Allied torpedoes that used spread spectrum and frequency hopping technology to defeat the threat of jamming by the Axis powers. Although the US Navy did not adopt the technology until the 1960s, the principles of their work are incorporated into Bluetooth technology and are similar to methods used in legacy versions of CDMA and Wi-Fi.
This work led to their induction into the National Inventors Hall of Fame in 2014. Lamarr was born Hedwig Eva Maria Kiesler in 1914 in Vienna, Austria-Hungary, the only child of Gertrud "Trude" Kiesler and Emil Kiesler, her father was a successful bank director. Trude, her mother, a pianist and Budapest native, had come from an upper-class Hungarian Jewish family, she had converted to Catholicism and was described as a "practicing Christian" who raised her daughter as a Christian. Lamarr helped get her mother out of Austria after it had been absorbed by the Third Reich and to the United States, where Gertrude became an American citizen, she put "Hebrew" as her race on her petition for naturalization, a term used in Europe. As a child, Lamarr was fascinated by theatre and film. At the age of 12, she won a beauty contest in Vienna. Lamarr was taking acting classes in Vienna when one day, she forged a note from her mother and went to Sascha-Film and was able to get herself hired as a script girl. While there, she was able to get a role as an extra in Money on the Street, a small speaking part in Storm in a Water Glass.
Producer Max Reinhardt cast her in a play entitled The Weaker Sex, performed at the Theater in der Josefstadt. Reinhardt was so impressed with her. However, she never trained with Reinhardt or appeared in any of his Berlin productions. Instead, she met the Russian theatre producer Alexis Granowsky, who cast her in his film directorial debut, The Trunks of Mr. O. F. starring Walter Abel and Peter Lorre. Granowsky soon moved to Paris, but Lamarr stayed in Berlin and was given the lead role in No Money Needed, a comedy directed by Carl Boese. Lamarr starred in the film which made her internationally famous. In early 1933, at age 18, Lamarr working under the name Hedy Kiesler, was given the lead in Gustav Machatý's film Ecstasy, she played the neglected young wife of an indifferent older man. The film became both celebrated and notorious for showing Lamarr's face in the throes of orgasm as well as close-up and brief nude scenes, a result of her being "duped" by the director and producer, who used high-power telephoto lenses.
Although she was dismayed and now disillusioned about taking other roles, the film gained world recognition after winning an award in Rome. Throughout Europe, it was regarded an artistic work. In America it was considered overly sexual and received negative publicity among women's groups, it was banned there and in Germany. Lamarr had played a number of stage roles, including a starring one in Sissy, a play about Empress Elisabeth of Austria produced in Vienna, it won accolades from critics. Admirers tried to get backstage to meet her, she sent most of them away, including a man, more insistent, Friedrich Mandl. He became obsessed with getting to know her. Mandl was an Austrian military arms merchant and munitions manufacturer, reputedly the third-richest man in Austria, she fell for his charming and fascinating personality due to his immense financial wealth. Her parents, both of Jewish descent, did not approve, due to Mandl's ties to Italian fascist leader Benito Mussolini, German Führer Adolf Hitler, but they could not stop the headstrong Lamarr.
On August 10, 1933, Lamarr married Mandl. She was 18 years old and he was 33. In her autobiography Ecstasy and Me, she described Mandl as an controlling husband who objected to her simulated orgasm scene in Ecstasy and prevented her from pursuing her acting career, she claimed she was kept a virtual prisoner in their castle home, Castle Schwarzenau in the remote Waldviertel near the Czech border. Mandl had close social and business ties to the Italian government, selling munitions to the country, had ties to the Nazi regime of Germany; this despite his own father being Jewish, just like Lamarr's. Lamarr wrote that both Hitler attended lavish parties at the Mandl home. Lamarr accompanied Mandl to business meetings, where he conferred with scientists and other professionals involved in military technology; these conferences were her introduction to the field of applied science and nurtured her latent talent in science. Lamarr's marriage to Mandl even
History of mobile phones
The history of mobile phones covers mobile communication devices that connect wirelessly to the public switched telephone network. While the transmission of speech by radio has a long history, the first devices that were wireless and capable of connecting to the standard telephone network are much more recent; the first such devices were portable compared to today's compact hand-held devices, their use was clumsy. Along with the process of developing a more portable technology, a better interconnections system, drastic changes have taken place in both the networking of wireless communication and the prevalence of its use, with smartphones becoming common globally and a growing proportion of Internet access now done via mobile broadband. Before the devices existed that are now referred to as mobile phones or cell phones, there were some precursors. In 1908, a Professor Albert Jahnke and the Oakland Transcontinental Aerial Telephone and Power Company claimed to have developed a wireless telephone.
They were accused of fraud and the charge was dropped, but they do not seem to have proceeded with production. Beginning in 1918, the German railroad system tested wireless telephony on military trains between Berlin and Zossen. In 1924, public trials started with telephone connection on trains between Hamburg. In 1925, the company Zugtelephonie AG was founded to supply train telephony equipment and, in 1926, telephone service in trains of the Deutsche Reichsbahn and the German mail service on the route between Hamburg and Berlin was approved and offered to first-class travelers. Fiction anticipated the development of real world mobile telephones. In 1906, the English caricaturist Lewis Baumer published a cartoon in Punch magazine entitled "Forecasts for 1907" in which he showed a man and a woman in London's Hyde Park each separately engaged in gambling and dating on wireless telephony equipment. In 1926, the artist Karl Arnold created a visionary cartoon about the use of mobile phones in the street, in the picture "wireless telephony", published in the German satirical magazine Simplicissimus.
The Second World War made military use of radio telephony links. Hand-held radio transceivers have been available since the 1940s. Mobile telephones for automobiles became available from some telephone companies in the 1940s. Early devices were bulky, consumed large amounts of power, the network supported only a few simultaneous conversations. Modern cellular networks allow automatic and pervasive use of mobile phones for voice and data communications. In the United States, engineers from Bell Labs began work on a system to allow mobile users to place and receive telephone calls from automobiles, leading to the inauguration of mobile service on June 17th 1946 in St. Louis, Missouri. Shortly after, AT&T offered Mobile Telephone Service. A wide range of incompatible mobile telephone services offered limited coverage area and only a few available channels in urban areas; the introduction of cellular technology, which allowed re-use of frequencies many times in small adjacent areas covered by low powered transmitters, made widespread adoption of mobile telephones economically feasible.
In the USSR, Leonid Kupriyanovich, an engineer from Moscow, in 1957-1961 developed and presented a number of experimental pocket-sized communications radio. The weight of one model, presented in 1961, could fit on a palm. However, in the USSR the decision at first to develop the system of the automobile "Altai" phone was made. In 1965, the Bulgarian company "Radioelektronika" presented a mobile automatic phone combined with a base station at the Inforga-65 international exhibition in Moscow. Solutions of this phone were based on a system developed by Leonid Kupriyanovich. One base station, connected to one telephone wire line, could serve up to 15 customers; the advances in mobile telephony can be traced in successive generations from the early "0G" services like MTS and its successor Improved Mobile Telephone Service, to first-generation analog cellular network, second-generation digital cellular networks, third-generation broadband data services to the state-of-the-art, fourth-generation native-IP networks.
In 1949, AT&T commercialized Mobile Telephone Service. From its start in St. Louis, Missouri, in 1946, AT&T introduced Mobile Telephone Service to one hundred towns and highway corridors by 1948. Mobile Telephone Service was a rarity with only 5,000 customers placing about 30,000 calls each week. Calls were set up manually by an operator and the user had to depress a button on the handset to talk and release the button to listen; the call subscriber equipment weighed about 80 pounds Subscriber growth and revenue generation were hampered by the constraints of the technology. Because only three radio channels were available, only three customers in any given city could make mobile telephone calls at one time. Mobile Telephone Service was expensive, costing US$15 per month, plus $0.30–0.40 per local call, equivalent to about $176 per month and $3.50–4.75 per call. In the UK, there was a vehicle-based system called "Post Office Radiophone Service,", launched around the city of Manchester in 1959, although it required callers to speak to an operator, it was possible to be put through to any subscriber in Great Britain.
The service was extended to London in 1965 and other major cities in 1972. AT&T introduced the first major improvement to mobile telephony in 1965, giving the improved service the obvious name of Improved Mobile Telephone Service. IMTS used additional radio channels, allowing more simultaneous calls in a given geographic area, introduced customer dialing, eliminating manual call setup by an operator, reduced the size and weight of the subscriber equipment. Desp
Sir Timothy John Berners-Lee known as TimBL, is an English engineer and computer scientist, best known as the inventor of the World Wide Web. He is a professor of computer science at the University of Oxford and the Massachusetts Institute of Technology, he made a proposal for an information management system on March 12, 1989, he implemented the first successful communication between a Hypertext Transfer Protocol client and server via the internet in mid-November the same year. Berners-Lee is the director of the World Wide Web Consortium, which oversees the continued development of the Web, he is the founder of the World Wide Web Foundation and is a senior researcher and holder of the 3Com founders chair at the MIT Computer Science and Artificial Intelligence Laboratory. He is a director of the Web Science Research Initiative, a member of the advisory board of the MIT Center for Collective Intelligence. In 2011, he was named as a member of the board of trustees of the Ford Foundation, he is a founder and president of the Open Data Institute, is an advisor at social network MeWe.
In 2004, Berners-Lee was knighted by Queen Elizabeth II for his pioneering work. In April 2009, he was elected a foreign associate of the United States National Academy of Sciences. Named in Time magazine's list of the 100 Most Important People of the 20th century, Berners-Lee has received a number of other accolades for his invention, he was honoured as the "Inventor of the World Wide Web" during the 2012 Summer Olympics opening ceremony, in which he appeared in person, working with a vintage NeXT Computer at the London Olympic Stadium. He tweeted "This is for everyone", spelled out in LCD lights attached to the chairs of the 80,000 people in the audience. Berners-Lee received the 2016 Turing Award "for inventing the World Wide Web, the first web browser, the fundamental protocols and algorithms allowing the Web to scale". Berners-Lee was born in London, United Kingdom, one of four children born to Mary Lee Woods and Conway Berners-Lee, his parents worked on the first commercially built computer, the Ferranti Mark 1.
He attended Sheen Mount Primary School, went on to attend south west London's Emanuel School from 1969 to 1973, at the time a direct grant grammar school, which became an independent school in 1975. A keen trainspotter as a child, he learnt about electronics from tinkering with a model railway, he studied at The Queen's College, from 1973 to 1976, where he received a first-class bachelor of arts degree in physics. While he was at university, Berners-Lee made a computer out of an old television set, which he bought from a repair shop. After graduation, Berners-Lee worked as an engineer at the telecommunications company Plessey in Poole, Dorset. In 1978, he joined D. G. Nash in Ferndown, where he helped create type-setting software for printers. Berners-Lee worked as an independent contractor at CERN from June to December 1980. While in Geneva, he proposed a project based on the concept of hypertext, to facilitate sharing and updating information among researchers. To demonstrate it, he built a prototype system named ENQUIRE.
After leaving CERN in late 1980, he went to work at John Poole's Image Computer Systems, Ltd, in Bournemouth, Dorset. He ran the company's technical side for three years; the project he worked on was a "real-time remote procedure call" which gave him experience in computer networking. In 1984, he returned to CERN as a fellow. In 1989, CERN was the largest internet node in Europe, Berners-Lee saw an opportunity to join hypertext with the internet: I just had to take the hypertext idea and connect it to the Transmission Control Protocol and domain name system ideas and—ta-da!—the World Wide Web... Creating the web was an act of desperation, because the situation without it was difficult when I was working at CERN later. Most of the technology involved in the web, like the hypertext, like the internet, multifont text objects, had all been designed already. I just had to put them together, it was a step of generalising, going to a higher level of abstraction, thinking about all the documentation systems out there as being part of a larger imaginary documentation system.
Berners-Lee wrote his proposal in March 1989 and, in 1990, redistributed it. It was accepted by his manager, Mike Sendall, who called his proposals'vague, but exciting', he used similar ideas to those underlying the ENQUIRE system to create the World Wide Web, for which he designed and built the first Web browser. His software functioned as an editor, the first Web server, CERN HTTPd. Mike Sendall buys a NeXT cube for evaluation, gives it to Tim. Tim's prototype implementation on NeXTStep is made in the space of a few months, thanks to the qualities of the NeXTStep software development system; this prototype offers WYSIWYG browsing/authoring! Current Web browsers used in'surfing the internet' are mere passive windows, depriving the user of the possibility to contribute. During some sessions in the CERN cafeteria, Tim and I try to find a catching name for the system. I was determined that the name should not yet again be taken from Greek mythology..... Tim proposes'World-Wide Web'. I like this much, except that it is difficult to pronounce in French... by Robert Cailliau, 2 November 1995.
The first website was built at CERN. Despite this being an international organisation hosted by Switzerland, the office that Berners-Lee used was just across the border in France; the website was put online on 6 August 1991 for the first time: info.cern.ch was th
A heliograph is a wireless telegraph that signals by flashes of sunlight reflected by a mirror. The flashes are produced by momentarily pivoting the mirror, or by interrupting the beam with a shutter; the heliograph was a simple but effective instrument for instantaneous optical communication over long distances during the late 19th and early 20th century. Its main uses were military and forest protection work. Heliographs were standard issue in the British and Australian armies until the 1960s, were used by the Pakistani army as late as 1975. There were many heliograph types. Most heliographs were variants of the British Army Mance Mark V version, it used a mirror with a small unsilvered spot in the centre. The sender aligned the heliograph to the target by looking at the reflected target in the mirror and moving their head until the target was hidden by the unsilvered spot. Keeping their head still, they adjusted the aiming rod so its cross wires bisected the target, they turned up the sighting vane, which covered the cross wires with a diagram of a cross, aligned the mirror with the tangent and elevation screws so the small shadow, the reflection of the unsilvered spot hole was on the cross target.
This indicated. The flashes were produced by a keying mechanism that tilted the mirror up a few degrees at the push of a lever at the back of the instrument. If the sun was in front of the sender, its rays were reflected directly from this mirror to the receiving station. If the sun was behind the sender, the sighting rod was replaced by a second mirror, to capture the sunlight from the main mirror and reflect it to the receiving station; the U. S. Signal Corps heliograph mirror did not tilt; this type produced flashes by a shutter mounted on a second tripod. The heliograph had some great advantages, it allowed long distance communication without a fixed infrastructure, though it could be linked to make a fixed network extending for hundreds of miles, as in the fort-to-fort network used for the Geronimo campaign. It was portable, did not require any power source, was secure since it was invisible to those not near the axis of operation, the beam was narrow, spreading only 50 feet per mile of range.
However, anyone in the beam with the correct knowledge could intercept signals without being detected. In the Boer War, where both sides used heliographs, tubes were sometimes used to decrease the dispersion of the beam. In some other circumstances, though, a narrow beam made it difficult to stay aligned with a moving target, as when communicating from shore to a moving ship, so the British issued a dispersing lens to broaden the heliograph beam from its natural diameter of 0.5 degrees to 15 degrees. The distance that heliograph signals could be seen depended on the clarity of the sky and the size of the mirrors used. A clear line of sight was required, since the Earth's surface is curved, the highest convenient points were used. Under ordinary conditions, a flash could be seen 30 miles with the naked eye, much farther with a telescope; the maximum range was considered to be 10 miles for each inch of mirror diameter. Mirrors ranged from 1.5 inches to 12 inches or more. The record distance was established by a detachment of U.
S. signal sergeants by the inter-operation of stations on Mount Ellen and Mount Uncompahgre, Colorado, 183 miles apart on September 17, 1894, with Signal Corps heliographs carrying mirrors only 8 inches square. The German professor Carl Friedrich Gauss of the University of Göttingen developed and used a predecessor of the heliograph in 1821, his device directed a controlled beam of sunlight to a distant station to be used as a marker for geodetic survey work, was suggested as a means of telegraphic communications. This is the first reliably documented heliographic device, despite much speculation about possible ancient incidents of sun-flash signalling, the documented existence of other forms of ancient optical telegraphy. For example, one author in 1919 chose to "hazard the theory" that the mainland signals Roman emperor Tiberius watched for from Capri were mirror flashes, but admitted "there are no references in ancient writings to the use of signaling by mirrors", that the documented means of ancient long-range visual telecommunications was by beacon fires and beacon smoke, not mirrors.
The story that a shield was used as a heliograph at the Battle of Marathon is a modern myth, originating in the 1800s. Herodotus never mentioned any flash. What Herodotus did write was that someone was accused of having arranged to "hold up a shield as a signal". Suspicion grew in the 1900s; the conclusion after testing the theory was "Nobody flashed a shield at the Battle of Marathon". In a letter dated 3 June 1778, John Norris, High Sheriff of Buckinghamshire, notes: "Did this day heliograph intelligence from Dr Franklin in Paris to Wycombe". However, there is little evidence that "heliograph" here is other than a misspelling of "holograph"; the term "heliograph" for solar telegraphy did not enter the English language until the 1870s—even the word "telegraphy" was not coined until the 1790s. Henry Christopher Mance, of the British Government Persian Gulf Telegraph Department, developed the first accepted heliograph about 1869 while stationed at Karachi, in the Bombay Presidency in British India.
Mance was familiar with heliotropes by their use for the Great India Survey. The Mance Heliograph was operated by one man, since it weighed about seven pounds, the operator could carry the devi