Practical genius has often gone unrewarded

There is a compelling fascination in the magic moment at which an original idea crystallizes in someone's head and a new invention is born. Sometimes the moment comes after months or years spent searching for a solution to a clearly-defined problem; in other cases a need is perceived and in answer provided for it almost simultaneously. But a flash of inspiration does not necessarily bring a happy or a prosperous future. For many gifted inventors, legal wrangles over patents have soured the original joy of their discoveries; others, as employees of large corporations, never saw any of the profits made from the commercial exploitation of their ideas. Still others made large fortunes from their inventions, yet have continued to live their lives much as before.

Wired up

The creator of the first wire coat-hanger received not a cent for his ingenious invention. In 1903, Albert J. Parkhouse (Left) was working for a company in Jackson, Michigan, manufacturing wire lampshade frames. The firm was too mean to provide enough hooks for its employees to hang up their coats, so one day, rather than throw his coat on the floor, Parkhouse twisted a piece of wire into the now familiar shape of a hanger. His employer noticed what he had done, immediately grasped its potential and patented the idea. Parkhouse just went on working on the shop floor of the factory.

Keeping time

In the early 19th century, many inventors were competing to produce a practical and reliable metronome - a device that helps musicians learn to play in a steady rhythm. Dietrich Nikolaus Winkel (Left), a German organ-builder living in Amsterdam, finally solved the problem in 1814. He placed two weights on a clockwork-driven pendulum, one fixed and one sliding, on opposite sides of a pivot. Each time the pendulum swings, it produces a clicking noise. The position of the sliding weight affects the speed of the pendulum, so musicians can adjust the metronome to produce a series of clicks at the speed they wish to play. Unfortunately for Winkel, he demonstrated his invention to Johann Nepomuk Maelzel, a German rival in the same field. Maelzel unscrupulously patented the metronome in his own name and began mass production. The gadget, which still uses the principle devised by Winkel, has been known as the Maelzel Metronome ever since.

Seeing in the dark

One dark and foggy night in 1933, Percy Shaw (Left), a road-repairer from Yorkshire, England, was struck by the sight of a cat's eyes gleaming brightly in the light of his headlamps. This everyday experience inspired him to develop a revolutionary form of road-marking for night driving - a convex lens backed by an aluminium mirror. These are embedded in a rubber pad, which is mounted in a cast-iron housing set into the road. The lens and mirror are positioned so as to direct reflected light from car headlamps back to the driver. A year after he first had the idea, Shaw was ready to patent his invention. He opened a factory to manufacture his 'catseyes' in 1935. Although the invention made him rich and famous, his style of life was completely unaltered. He continued to lead a simple existence in a small house in his native Halifax, and spent only a faction of his vast accumulated wealth.

Riding on air

The pneumatic rubber tyre was first invented by a London engineer, Robert W. Thomson (Left), in 1845, for use on the wheels of carriages. The invention failed to catch on at first - rubber was expensive at the time, so Thomson's idea was not marketable. In 1887, the pneumatic tyre was re-invented by John Boyd Dunlop, a Scottish-born veterinarian, who had a flourishing practice in Ireland. Dunlop noticed how his son's tricycle jarred its rider as the solid rubber tyres bumped over the unevenly paved streets of Belfast. He substituted rubber tyres filled with air and patented his invention the following year. Dunlop's pneumatic tyres were an immediate success with bone-shaken cyclists and should have made him a millionaire. But he sold his interest in the business in 1896, and gained nothing from any of the subsequent developments of his invention, such as the automobile tyre - a multi-million-dollar business that made his name famous throughout the world.