Patents and Inventions When an invention is made, the inventor has three possible courses of action open to him: first, he can give the invention to the world by publishing it; keep the idea secret or patent it. Secrecy obviously evaporates once the invention is sold or used, and there is always the risk that in the meantime another inventor, working quite independently will make and patent the same discovery. A granted patent is the result of a bargain struck between an inventor and the state, whereby, in return for a limited period of monopoly(16 years in the UK), the inventor publishes full details of his invention to the public. Once the monopoly period expires, all those details of the invention pass into the public domain.(A) Only in the most exceptional circumstances is the life-span of a patent extended to alter this normal process of events.(B) The longest extension ever granted was to Georges Valensi: his 1939 patent for color TV receiver circuitry was extended until 1971.(C) Because for most of the patents normal life there was no color TV to receive and thus no hope of reward for the invention.(D) George Valensi was more fortunate than most of other inventors. Because a patent remains perpetually published after it has expired, the shelves of the library attached to the British Patent Office contain details of literally millions of ideas that are free for anyone to use and, if older than half a century, sometimes even re-patent. Indeed, patent experts often advise anyone wishing to avoid the high cost of conducting a search through live patents, that the one sure way of avoiding infringement of any other inventors rights is to plagiarize a dead patent. Likewise, because publication of an idea in any other form. permanently invalidates future patents on that idea, it is traditionally safe to cull ideas from other areas of print. Much modern technological advance is based on these presumptions of legal security. Anyone closely involved in patents and inventions soon learns that most 'new' ideas are, in fact, as old as the hills. It is their reduction to commercial practice, either through necessity, dedication or the availability of new technology, that makes news and money. The basic patents for the manufacture of margarine and the theory of magnetic recording date back to 1869 and 1886 respectively. Many of the original ideas behind television stem from the late 19th and early 20th century, well before Baird aroused public interest. Every stereo gramophone sold today owes its existence to the theory patented by Blumlein in 1931, and even the Volkswagen rear engine car was anticipated by a 1904 patent for a cart with the horse at the rear. Such anticipations can have surprising significance. The German chemical giant, BASF, was recently refused a patent for the clever idea of pumping expanded plastics into a submerged ship and thereby floating it to the surface. The grounds of the refusal were that the German Examiner had once seen a Walt Disney cartoon in which Donald Duck had performed a similar trick on a sunken boat with table-tennis balls. If the BASF scheme proves successful in practice and enables valuable wrecks to be salvaged it is likely that Walt Disney will be credited as the inventor. Even the apparently safe history of the telephone and gramophone contains some surprises. US legal case law details how an American called Drawbaugh had ideas for a telephone which anticipated Bells patents of 1875 —1876 by five years, but it was Alexander Graham Bell who made the system practical on a commercial level and was acknowledged and rewarded as inventor. The future will produce many similar situations. Patents are daily being granted for ideas from inventors for schemes that cannot yet work~-but that one day, following massive investment by industry, will become a reality. It is remarkably easy to sit in the comfort of an armchair and patent pipe dreams which are nothing more than prophecies of the future and problems for others to solve. The word evaporate in Paragraph 1 is closest in meaning to______.