A  The possibility of seeing events without being present at them was a dream of humanity for countless centuries. When the telephone emerged as a practical device in the late 1870s, the idea of also 'seeing by electricity' caught the public imagination, and as early as 1878 a cartoonist conceived of the 'telephonoscope', a wildly accurate prediction of global video communication. Various experiments were conducted, and two forms of television were invented almost simultaneously: the electronic and the mechanical.

B  In 1897 a German physicist, Ferdinand Braun, developed a method of displaying electronic traces on a fluorescent screen coated inside an evacuated glass bulb. He called this the cathode-ray oscilloscope. A few years later a British scientist, A. A. Campbell Swinton, realized that Braun's device could be used to display pictures transmitted electronically. Campbell Swinton wrote about the possibility of a television system in a scientific journal, Nature, in 1911. However, at that time it could not be built, as the components were not available.

C  The real pioneer of electronic television was Vladimir Zworykin. His interest in the field developed when he worked on a cathode-ray tube receiver in St. Petersburg. In 1918 he left Russia for the United States, and in 1923 he patented the principles of the Iconoscope, a camera tube, and in 1924 the Kinescope, or television receiver. The Radio Corporation of America (RCA) recognized the potential of Zworykin's ideas, and in 1929 funded a laboratory for him to continue his research. The work was conducted in secret and Zworykin did not publish his paper describing the Iconoscope in detail until 1933. This was the breakthrough that made electronic television a practical possibility. For the first time, a pick-up device could televise studio and outdoor scenes at a standard of definition that would bear comparison with the cinema.

D  Meanwhile, in Britain, public interest in television was stimulated by a Scotsman, John L. Baird. He loved experimenting and, in 1922, found the cause to which he was to devote his life — to invent mechanical television. As he lacked a real understanding of electronics, and would probably have been unaware of Zworykin's work, he began his research using very simple mechanical equipment. Baird successfully transmitted his first crude pictures in April 1925, and gave the first public demonstration of television in 1926. But it was not until 1929 that the government accepted that the technical quality of his pictures had improved sufficiently to allow broadcasting. Transmissions began on frequencies available when normal radio programs had finished for the day. Baird used the late transmission time to his advantage — it became an opportunity to encourage performers from top London shows to the medium. They dropped into his nearby studio after finishing on stage and performed a song or a dance for one of his shows. He developed a large amount of material, and in 1931 he televised the Epsom Derby horse race live.

E  However, at the beginning of the 1930s, interest in television in Britain was spreading beyond Baird. The research departments of Britain's two largest record companies came together and formed Electric and Musical Industries Ltd. (EMI) in 1931. The new department of brilliant scientists was led by Isaac Schoenberg, who, like Zworykin, had once worked in Russia. The group first looked to develop cathode-ray receivers, retaining mechanical scanning for generating the picture. However, work on an electronic camera tube started in 1933, after Zworykin's paper was published.

F  The EMI team made a successful electronic tube in January 1934 and they called the design the Emitron. This was fundamentally the same as Zworykin's Iconoscope, though there were manufacturing differences that gave it a superior performance. EMI did not immediately give up mechanical scanning, but they now joined forces with the Marconi Company to design the components and circuits of an all-electronic system of television. Very soon the technical superiority of the Marconi-EMI system was so obvious that, on 30 January 1937, the BBC ended transmissions using Baird's television equipment.

G  In 1936 television receiving sets were very expensive, possibly costing as much as a small car. Fewer than 500 were in use when the broadcasting service started, and growth was slower than had been hoped for. The signals could only be received clearly within a radius of about 30 miles from the television studio. Gradually the cost of sets came down, and just under 19,000 had been sold by 1939, when television in Britain abruptly came to an end for security reasons. War was about to be declared. The screens were to be dark for nearly seven years until, in 1946, the British government decided to restart television.

H  Transmissions restarted with a broadcast of the Victory Parade in London. Television remained confined to the London region until 1949 when studios in Birmingham opened. From then on, coverage gradually spread across Britain. Many people had their first experience of television watching Queen Elizabeth's 1953 coronation ceremony. Households with television receivers opened up their homes to friends and neighbors. As the better-off purchased their new sets, so their old ones were sold on, which enlarged the audience still further. With quality entertainment now cheaply available at home, people went out far less often. Many cinemas and theatres closed down, and town centers became much emptier at night. The television age had finally arrived.

Maps codify the miracle of existence. And the man who wrote the codes for the maps we use today was Gerard Mercator, a cobbler's son born 500 years ago on a muddy floodplain in northern Europe.

Mercator was a humble man with a universal vision. In his own time he was 'the prince of modern geographers', his depictions of the planet and its regions unsurpassed in accuracy, clarity and consistency. More recently, he was crowned by the American scholar Robert W. Karrow as 'the first modern, scientific cartographer'. Where his predecessors had adopted a piecemeal approach to cartography, Mercator sought to wrap the world in systematic overlapping maps. Along the way he erected a number of historic milestones. He participated in the naming and mapping of 'America', he constructed the two most important globes of the 16th century, and the title of his pioneering 'modern geography', the Atlas, became the standard term for a volume of maps. Mercator also devised a new method — 'a projection' — of converting the spherical world into a two-dimensional map.

Mercator was born in 1512 and died in 1594. His world was one of military conflict, social upheaval, religious revolution — and geographical discovery. He was ten years old when the survivors of the world's first circumnavigation returned to Spain in their leaking caravel. No better example is required of genius arising from turmoil. He knew poverty, plague, war and persecution. He was imprisoned for his ideas yet patronised by an emperor. His life was one of brilliant breakthroughs and abrupt reversals. In its telling, his is the story of the poor boy made good: the pauper who embraced the world, found fame, faced death, yet triumphed through fortitude. Variously described by his peers as honest, calm, candid, sincere and peaceable, Mercator wore an aura of calm in troubled times. His attitude to his geographical calling was described by his friend and neighbour, William Ghim, as 'indefatigable'. Some 40 or so of Mercator's letters have survived, together with examples of virtually all of his printed maps and globes.

Mercator's most significant work was a project of cosmic proportions. A multi-part cosmography, the work would include a section on astronomy, a chronology of world events and a modern geography, which would eventually contain over 100 maps. Before he commenced the great work, Mercator produced in 1569 an enormous world map on a new projection. His method for converting the spherical globe into a two-dimensional map helped to solve the greatest cartographic riddle of the day: how could the course of a ship following a constant compass bearing be represented as a straight line on a map which had been constructed on a grid of latitude and longitude?

Mercator's solution was to progressively increase the space between his lines of latitude, away from the equator. The effect was to straighten the lines of constant compass bearing (also known as rhumbs or loxodromes). Unfortunately, straightening the rhumbs caused areal* distortion: at the map's northern and southern extremities, the polar regions occupied the full width of the map, while North America appeared to fill half the circumference of the world.

Few of Mercator's contemporaries understood what he was up to, despite the map's title explaining that it was intended 'for use in navigation'. Mercator knew that his projection was unsuitable as an areal description of the world, but it would be several decades before the map's true navigational value would be recognised.

Meanwhile, Mercator was marshalling and editing all the geographical data he needed for his modern regional maps of the world. His sources were wide-ranging and multitudinous, including an imperial physician in Vienna and his competitor, the Viceroy of Holstein. He was still working on these maps when he died. The great cosmography that Mercator had already titled 'Atlas' would never be finished.

In the Atlas, Mercator had embodied the principles of future mapmaking: his italic lettering, his identical map overlaps, his complete coverage of regions at more than one scale, his consistent use of grids of latitude and longitude, his singular editorial control, were all adopted as cartographic standards. 'Atlas', the cosmography, became 'atlas', the (Oxford English Dictionary) term for 'a collection of maps in a volume.'

The projection assumed a life of its own. So powerful a cartographic tool did it become that Mercator the man became subsumed by his own device. By the 20th century, Mercator's Projection had been adopted by state cartographers to map the land that he had named 'North America'. In 1938, Mercator's Projection was selected by the Ordnance Survey to map Britain anew. And in 1974, the American cartographer Alden P. Colvocoresses used the Space Oblique Mercator Projection for the first satellite map of the USA. When the Jet Propulsion Laboratory sent Mariner 8 and Mariner 9 to map Mars, they undertook their Martian cartography on a standard Mercator Projection. One by one, the mappable orbs of our solar system are appearing on the worldwide web, flattened for our screens according to Mercator's cartographic principles.

Mercator's Projection succeeded in reconciling the sphere and the plane, while his Atlas enveloped the world with an integrated system of maps.

* areal: of an area