f (0,1 ! , t-/ r 1 The Invention of Television Albert Abramson elevision is the electrical transmission and came in 1843 when Samuel F. B. Morse developed reception of transient visual images, and is his telegraph (distant-record) machine. This was probably the first invention by committee, in a means of communication by which the letters the sense of resulting from the effort of hundreds of of the alphabet were converted into electrical equi- individuals widely separated in time and space, all valents (the Morse code) that could be either re- prompted by the urge to produce a system of seeing corded on paper tape or transcribed by trained over the horizon. operators. Since the code was transmitted over wires Whether with tom-toms. smoke signals, or sema- at almost the speed of light, it soon became the phore. human beings have always tried to com- quickest means of point-to-point communication. municate with neighbours beyond the horizon. The Before long, electric wires were strung on poles con- desire has been a matter of commerce, curiosity, or necting most of the major cities. These same wires most importantly, warfare. Written messages were were also run under the lakes and oceans of the sent by ships, horses, birds, and shanks mare. But world. these were slow, cumbersome, and subject to the About the same time, other inventors were seek- whims of weather, terrain, or the endurance of ing means to transmit more than dots and dashes animals. The first steps towards instant commun- over these same wires. One of the earliest was ications were really taken by seventeenth- and Alexander Bath in 1843. In Bains device, alphabetical eighteenth-century scientists such as Luigi Galvani, letters were formed by a number of lines, each being Allesandro Volta, Hans C. Oersted, Andre Ampere, connected by a separate wire. A comb like probe George S. Ohm, Michael Faraday, and James Clerk containing insulated metal points scanned the type Maxwell, who found that electrical currents could to he transmitted. At the receiver, a similar metallic flow through certain materials as well as interact comb reproduced the letters on chemically treated with magnetic forces. The first practical solution paper. Albert Abramson TIIE INVENTION OF TELEVISION the first mention in the literature of an all-electric The Transmission of Symbols By the end of t878, the combination of Bells tele- Experiments with electrical discharges inside phone and Edisons invention of the phonograph evacuated glass tubes started with the work of television system. Unknown to Campbell Swinton, both Professor A more advanced device was that of Frederick C. ( 1877) combined with progress being made in photo- Heinrich Geissler and Julius Plucker in 1858. Placket- Boris Rozing in Russia and Or Max Dieckmann in Bakewell in 1847 for transmitting handwriting, graphy led the magazine Punch to print a cartoon designed a sealed glass tube filled with gas, with an Germany were also experimenting with cathode which used a metal foil inscribed with insulating of a new Edison invention the telephonoscope. electrode inserted at each end. When a certain volt- ink wrapped around a cylinder. As the cylinder was Here was depicted a two-way visual system on a age was applied to the electrodes, the gas in the tube ray tubes as receivers. 1-lowever, no one before had suggested the use of a cathode ray tube as an image rotated by clockwork, a metal stylus was used to wide screen depicting parents in London speaking ionized (incandesced), current flowed, and the tube glide over the foil. A similar device at the receiver with their daughter in Ceylon by means of an elec- glowed with a characteristic colour. This became transmitter. Just one year later, in 1909, three different televi- provided means to shift the pens and to keep the tric camera obscure and telephone. Edison did not known as a Geissler tube. sion systems were actually built and operated. The devices in synchronism. apply for a patent on a motion picture system until Other scientists soon started to experiment with first (in order of publication) was that of Dr Max Another interesting device by Giovanni Caselli in 1889. It is ironic that Punch should have Edison invent these tubes. Wilhelm Hittorf discovered in 1869 that 1855 used the actions of pendulums. At the trans- an electric camera before he invented the motion a solid body would cast a shadow on the walls ofthe Dieckmann. His equipment consisted of a unique device at the transmitter with a cold cathode Braun mitter a stylus connected by a lever to a pendulum picture camera. But there were many schemes for tube. In 1876 Eugen Goldstein concluded that the tube for a receiver. The transmitter consisted of a would physically trace the object to be transmit- visual communication gadgets at the time. radiation came from the cathode and called them rotating wheel that was fitted with twenty wire ted and would be electrically turned on or off as In 188o Maurice LeBlanc detailed an ingenious cathode rays. William Crooks showed that the rays brushes. (It had no photo-cells or other light-trans- it scanned parts of the message. At the receiver, method of transmitting moving images over an elec- were projected at high velocities by electric forces ducing means.) The brushes actually touched the another stylus moved by a pendulum would be trical wire. He described a scanning device (at both near the surface of the cathode. Jean Perrin showed image to be transmitted, very much like the early turned on or off in sequence and would create a sender and receiver) consisting of two vibrating mir- that the charge was negative in 1895. In 1897, J. J. devices of Bain and Caselli. At the receiver, the Braun replica (on some form of recording medium) of the rors working together at two different rates of speed. Thompson proved that they could be deflected by an tube with four deflecting magnets scanned a pic- image being transmitted. The light from the image would be sent to a trans- electrostatic field, and finally in 1897 Karl Ferdinand ture approximately 1.25 inches square. The electron The scanning of simple figures was quite im- ducer (such as a selenium or Becquerel thermo- Braun developed the cold cathode ray tube that bears off as the rotating brushes portant as it involved two of the foundations of electric cell) to be converted into electricity. At the his name. beans was turned on or touched the object, thus creating a picture on the the later system of instant visual transmission. The receiver, he proposed that two pieces of mica (as a screen. This was not a true television system as the first was sequential scanning (dissecting) of the shutter) would be moved according to the signal to transmitter was actually a form of telegraph sender picture. The second was a means to synchronize control the light from a lamp. He suggested that The Cathode Ray Tube rattler than a transducer alight to electricity. (keep in step) the transmitter with the receiver. because of persistence of vision, it would be possible The second system was that of Ernst Ruhmer. It These primitive machines, while quite cumbersome, to build up a likeness of the transmitted image. An International Electricity Congress was held in consisted of a mosaic of twenty-live selenium cells in did work, and though of limited value at the time LeBlancs n88o fundamental paper contained in fact conjunction with the ono Paris Exhibition. On 25 rows of live each. Each cell when exposed to light led to more important devices in the future. These all the elements for a practical visual transmission August moo a paper was read by one Constantin sent an alternating systems were then called copy-telegraphs. Today system. Perskyi entitled "Television, in which he described was connected to a relay, which current over a line to a receiver. I fere, there was a they are known as photo-telegraphy or facsimile It was not long before the first practical solution an apparatus based on the magnetic properties of similar mosaic consisting of twenty-live incandes- (fax). appeared. In 1884, Paul Nipkow applied for a Ger- selenium. This new term slowly supplanted the .. • . cent lamps. At the receiver, there was one relay for The next step was the transmissioh of audio over man patent for an Elektrisches "feleskop. The heart of older names suds as the telephot or telectroscope these same wires. In 1876 the telephone pioneer Nipkows patent was a revolving apertured disc. The to describe the newly born art and science of seeing each cell that would operate its own incandescent could be shown. Alexander Graham Bell transmitted the sound of a disc had twenty-four holes in a spiral near the outer at a distance. lamp. Only simple geometric figures voice by means of an electric wire and thus three rim. Nipkow proposed that light from the subject The various theories of transmitting pictures by As it was a multi-wire (simultaneous) device, it was means of instant communications came into exis- would pass through the perforated disc on to a sele- wire had created much controversy in the scientific not a true television system. tence, the telegraph, the copy-telegraph, and the nium cell. At the receiver, a similar perforated disc community. A letter to Nature by Shelford Bidwell The third was a quite different television device telephone, and the time was ripe for the introduction would be illuminated by a polarized light source. in June 1908, reviewing the various methods being built and demonstrated by Georges Rignoux and of a visual transmission system.