Albert Einstein once said that if at first an idea is not absurd "then there is no hope for it". Indeed, some of the maddest notions of their time are now essential to modern living. But for every ingenious invention that changes the world there are hundreds of equally imaginative ones that quietly fizzle out.
History is littered with these heroically daft ideas, from a plan to put a roof over New York City, to giving London its own Eiffel Tower and a scheme for a house that cleans itself.
James Moore, co-author of Pigeon Guided Missiles And 49 Other Ideas That Never Took Off, published next week says: "Behind all these ideas is one person that keeps going and going. If you look at successful entrepreneurs, they do the same thing. These ideas have ended up on the scrapheap of history, yet at the time they seemed like they could really happen."
Here are 20 wacky notions that, thankfully, play no part in life as we know it.
1. Pigeon-guided missiles
In 1941, the American scientist B F Skinner believed pigeons were the answer to defeating Adolf Hitler. He showed that our feathered friends could steer a missile towards a model ship by pecking at a target on a screen which moved its rudders. His pigeons continued to peck accurately even in rapid descent and with explosions going on, often making more than 10,000 pecks in 45 minutes. He planned to load three inside missile cones, but mass production was cancelled in 1944 because officials didn't want to put weapons in the hands - or claws - of birds.
2. The international 'hot air' airline
Long before the jet engine carried millions around the world, William Henson and John Stringfellow decided steam power could fly a plane. Dubbed the Aeriel Steam Carriage, the 1841 invention was expected to carry a dozen passengers 1,000 miles. Grand posters picturing it in flight over the pyramids and China piqued people's interest, but the furthest this heavy beast ever flew was 30 feet - or what others described as a "short hop".
3. The diabolical death ray
Following H G Wells's fictional description of an all-powerful death-ray in The War of the Worlds, inventors scrambled to create the real thing. Gloucestershire-born inventor Harry Grindell Matthews claimed to have made one in 1923, managing to con the British and French governments into a bidding war over it. Despite the media frenzy, his prototype only appeared to turn on a lightbulb and stop a small motor. A full-size version was never made.
4. Edison's concrete furniture
While the light bulb, the telegraph and the X-ray saw Thomas Edison hailed as a genius inventor, not all his ideas were winners. After buying a concrete factory he became convinced that furniture made from the hefty grey stuff was the answer to affordable living. Despite his faith that his idea was inspired, few concrete sofas and pianos were sold.
5. London's Eiffel Tower
When the Eiffel Tower was completed in 1889, Londoners got size envy. Patriotic Briton Sir Edward Watkin vowed "Anything Paris can do, we can do bigger". The first level of his tower was completed and opened after being dubbed an "unfinished ugliness" by Building News, but the costly exercise made Watkin's company go bust and the construction was never finished. In 1907, the rusting stump was blown up.
6. Nelson's pyramid
Trafalgar Square might have looked very different if the front-runner had been chosen in a competition staged to commemorate Britain's seafaring hero Admiral Lord Horatio Nelson. A pyramid representing victory over the Nile was planned to stand in the Square on a scale that would dwarf St Paul's Cathedral. Its grotesque size and £1m price tag - then a fortune - meant that building work instead started on Nelson's Column in 1840.
7. A roof over New York
In an attempt to avoid snow-clogged New York winters in the 1950s, inventor Richard Buckminster Fuller designed a geodesic dome to cover a two-mile wide stretch of central Manhattan. It would be pulled into place a mile above the city using 16 helicopters, creating an energy efficient microclimate. In the end, New Yorkers could not be persuaded that it was worth $200m to be kept inside all day. The barmy idea did not stop Fuller later becoming president of Mensa.
8. Exploding traffic lights
When John Peake Knight invented the world's first traffic lights in 1868 he proved it was possible to be too far ahead of your time. The gas-fired device exploded two weeks into a trial outside the Houses of Parliament in London, leaving the police officer operating it badly burned and putting off the use of traffic lights for another half century.
9. The Flying car
In 1940 Henry Ford was convinced that airborne automobiles were the future. "Mark my word", he said, "a combination airplane and motor car is coming. You may smile. But it will come." In 1949, Waldo Dean Waterman even made a prototype "Aerocar" with removable wings. It did fly, but thanks to production costs it never took off.
10. The atomic car
The Ford Nucleon - the world's first nuclear powered car - promised to go 5,000 miles without ever needing to refuel. In 1958, scientists were convinced that atomic-powered automobiles carrying their own nuclear reactors would be a brilliant transport solution. Fortunately, someone realised a simple car accident could nuke a whole town, and the plan was dropped.
11. The X-ray shoe-fitting machine
In the 1920s, when X-rays were thought to be a safe and exciting novelty, the pedescope became the accessory of choice in every shoe shop. Children would look forward to looking through its viewfinder and see an X-ray image of their bones wiggling inside new shoes to check that they fitted. In the 1940s, reports of bone, skin, marrow and growth damage emerged, but it wasn't until the 1970s that these devices fell out of use because of radiation fears.
12. Is it a train or a plane?
When the railway lines became congested in the 1920s, George Bennie decided to create a lightning speed passenger alternative. The Bennie Railplane looked a bit like a modern monorail with airplane-like cars driven along by propellers at either end. Sadly, his costly invention coincided with the Great Depression and never got further than a prototype and test run.
13. British Rail's flying saucer and the 'great space elevator'
In 1969, British Rail was the unlikely applicant for a spacecraft patent. The flying-saucer-shaped craft was the brainchild of scientist Charles Osmond Frederick, who worked in British Rail's research department. His drawings detailed a 120ft vehicle that would ferry passengers into space in a compartment above engines powered by "a controlled thermonuclear fusion reaction ignited by laser beams".
14. The perpetual machine
In the 17th century, scientists wasted decades of research attempting to design perpetual motion machines. Ideas such as self-propelling mills in which buckets on a rope redeliver water on a wheel worked perfectly well on paper but never in practice. The natural laws of thermodynamics, still almost 200 years away from being defined, prevented any such machines from ever working.
15. Bessemer's anti-seasickness ship
Victorian inventor Sir Henry Bessemer suffered so seriously from seasickness that he decided to look for a scientific cure. His "swinging saloon" was designed to sit in a ship on pivoted supports. The idea was that the weighted structure would move independently of the ship's hull and stop sickness. After pouring his money into the project, however, a test at sea ended in disaster because the ship was impossible to steer and crashed into a pier at Calais.
16. Escape coffins for the mistakenly interred
The horror of being buried alive has captured the imaginations of generations. In 1868, Franz Vester invented the "improved burial case", complete with escape ladder and a pull cord that rang a bell around the graveyard. It was never manufactured.
17. Bentham's all-seeing panopticon
More than 150 years before George Orwell, Jeremy Bentham designed the all-seeing panopticon, a building in which people would feel watched at all times and be compelled to behave. The circular or semi-circular design with a surveillance tower in the centre would mean every single room could be watched every day, making it ideal for school or prisons. No such buildings were ever built - though CCTV has created a modern version.
18. The self-cleaning house
American housewife Frances Gabe hated housework so much that in the 1960s she created a home that was in effect a giant washing machine. At the touch of a button, small ceiling-mounted devices in every room in her house in Newberg, Oregon, would run through an entire cleaning and drying cycle. Even the bookshelves dusted themselves, but as all fixtures, fittings and fabrics had to be waterproofed, only one such house was ever made.
19. The jaw-dropping diet
Early American dieting guru Horace Fletcher earned the nickname "The Great Masticator" for his strange dieting techniques in the 1890s. He calculated the ideal number of chews per food type to lose weight. Followers of his diet had to chew food until it was completely liquidised. Bread, for example, required 70 chews and a shallot might require 700. He believed his technique would also allow the body to absorb more goodness from food.
20. Why Smell-O-Vision stank
The 1960 movie Scent of Mystery was designed to open up a fourth dimension in film. According to producer Michael Todd Jr, Smell-O-Vision would be a "scentsation", as 30 different odours - from tobacco to garlic - were pumped into cinemas through tubes beneath the seats. Test audiences didn't agree, complaining of lingering smells and hissing noises.