ONE MAN AND HIS WIDGET

Scientist, thinker and writer James Lovelock, whose ground-breaking device sparked off modern-day environmentalism, talks exclusively to Fred Pearce about his inventions and the $20m which eluded him

It is 40 years since James Lovelock invented a super-sensitive pollution "sniffer" the size of a film cassette. The device opened the way to modern environmentalism by revealing the global perils from pesticides and ozone-eating CFCs. But other people got the Nobel prizes, and Lovelock reveals here for the first time that he was swindled out of his patent royalties on the device by the US government.

Lovelock is part string-and-sealing-wax inventor, part New Age visionary. He is best known as the author of the Gaia hypothesis, which holds that our planet operates as a single "superorganism". But his roots, and perhaps his reputation, go back to the laboratory where in 1957 he invented the electron-capture detector, a modest-looking device that can identify concentrations of some gases down to a part in a trillion or less. If a few litres of a rare chemical evaporated into the air somewhere in Japan, his device could detect the chemical in air masses passing over Europe a few weeks later, and anywhere on Earth within a couple of years.

The device can sniff out anything from seaweed's breath to explosives on an airport carousel. But its greatest speciality is detecting pollutants and cancer-causing chemicals in air or water, food or soil. Without it, we might not know that pesticides kill our wildlife and poison our food. But for Lovelock's invention, we might never have heard of the hole in the ozone layer.

Taxi drivers are wary of going near Lovelock's house. Guarded by peacocks and a Hazchem sign, the scientist, a white-haired boffin in his 78th year, lives in a remote cottage down a long lane in the West Country. In the front room each morning, Lovelock the thinker and author works on his autobiography. In the garage every afternoon, Lovelock the inventor works away at his bench surrounded by an Aladdin's cave of home-built equipment. After more than 30 years as one of the few full-time practising independent scientists in the world, he is still creating refined versions of his great invention, the electron-capture detector.

To many Greens, enthused by his almost religious notions of Gaia, he is a guru. But they would be horrified by his laboratory. In the safe are various items of radioactive material. Close by are a cylinder of explosive fluorine and shelves of often unmarked bottles of chemicals. "I really don't know what I've got here any more," he says. "It's going to be a hell of a mess for someone to sort out when I'm gone. I'm sure nobody would let me keep these things if I employed anyone, but as it is I just notify the fire brigade once a year."

He has always worked like this - even when he had a proper job, at the government's National Institute for Medical Research in north London back in the Fifties. "It was one of the leading laboratories in the world. But we made most of our own equipment." Indeed, they even invented much of it.

At the time, they were pioneering methods of freezing mice and other small animals and bringing them back to life. It was gruesome work, and in the process of finding a more humane way to warm up animals quickly, Lovelock invented the first microwave oven. "I published a paper on the invention. I even used to heat my lunch in it. But not being an entrepreneur, I didn't realise its great commercial potential. And nobody thought of patenting such things in those days."

During the same work, Lovelock found that the bits of the animals most likely to be damaged by freezing were cell membranes, but that much depended on the precise make-up of the membranes. To analyse them, he wanted to separate out the chemical components using the new technique of gas chromatography invented in a laboratory upstairs by the Nobel prize-winner Archer Martin. "But Martin's detector wasn't sensitive enough, and he challenged me to invent a better one." So Lovelock did just that.

The device, sometimes called a "radioactive nose", behaves a little like an old television vacuum tube. A normal gas chromatograph uses absorbent material, such as paper, to separate out the different components of a chemical for analysis. Lovelock replaced this with a chamber containing electrical terminals and a radioactive source that would ionise any gases put into it. The denser the gas, the greater the number of ions produced and the larger the flow of current between the terminals. The work involved using radioactive material, often radium scraped from the luminous dials of old aircraft.

The device has two huge benefits. The first is that it is extraordinarily sensitive. Overnight it increased the power of the gas chromatograph to detect certain chemicals a million-fold. Moreover, the chemicals it spotted the best included many substances that have worried the world most in the 40 years since he made it. They included toxic pesticides, halogens such as chlorofluorocarbons (CFCs) that have been eating away at the ozone layer, carcinogenic compounds and many kinds of explosives. Second, it is very cheap and portable. "You can make one of these for a few hundred quid even now," says Lovelock. There are probably tens of thousands in use around the world today.

Lovelock's first customers were scientists at Shell, manufacturer of some of the world's most potent pesticides, and the US government's Food and Drug Administration. "These two groups wanted to use it to look for traces of these pesticides in food. They analysed food all round the world and found pesticides everywhere," he remembers. It was like opening a new window on the planet. With Lovelock's device, researchers discovered that the entire natural world was becoming contaminated by pesticides, too.

It soon became clear why Western countries had been experiencing mass deaths of many wild birds and animals in the Fifties as the use of pesticides such as DDT soared. But it also emerged that the same chemicals were showing up in the fat of Antarctic penguins and the milk of nursing mothers in Finland. "That work provided the hard data that allowed Rachel Carson to write her book Silent Spring," says Lovelock, a book that was one of the triggers for the start of modern environmentalism. And it launched an international campaign to ban DDT and PCBs.

The device turned out to have a "nose" for troublesome chemicals, and could be used as a first predictor of possible carcinogens. "In the early days, I suggested that many of the chemicals it was most sensitive to must be carcinogenic; things like chloroform, trichloroethylene and vinyl chloride," says Lovelock. Critics said that must be rubbish. These chemicals were in use all the time and generally regarded as being completely safe. But subsequently, it turned out that he was right and many of them proved to be carcinogens.

Are there any more potential poisons revealed by the detector? Lovelock says that phthalates, "gender-bender" poisons recently found in infant formula milk, show up strongly using his detector. "I sometimes wonder if they have a sinister role."

Lovelock's invention had an even more dramatic impact on the world of atmospheric sciences. Here, too, the device totally altered our perceptions of the extent of human impact on nature. As he beavered away in his north London laboratory inventing the electron-capture detector, the atmosphere outside was from time to time consumed by great peasouper smogs. But nobody believed these smogs were more than local events - until Lovelock bought a holiday cottage on the shores of Bantry Bay in south-west Ireland, facing out across the Atlantic ocean.

Here, in 1966, far from the industrial centres of Europe, he smelled smog. "It was just like Los Angeles. The Met Of-fice denied that any smog could get that far, but I knew what I'd smelled." He decided to take his equipment on holiday and look for man-mad chemicals in the air. He chose CFCs, highly stable gases manufactured since the Twenties for use in aerosols and fridges worldwide, but which have no known natural source.

"I found them, at 50 parts per trillion, in supposedly clean air blowing off the Atlantic and, when the wind came from Europe, at 150 ppt," he says. This was the first ever scientific measurement of long-range pollution. Weather maps revealed that the polluted air had come all the way from Italy and France, where it had picked up city smog and the exhaust fumes of millions of European holidaymakers' cars.

But Lovelock was even more interested in that 50 ppt of CFCs in the supposedly clean Atlantic air. "I wondered whether CFCs were accumulating in the Earth's atmosphere. " To find the answer he went literally to the end of the Earth. In 1971, he hitched a ride with his detector on a British research ship, the Shackleton, going to Antarctica.

The idea that he could measure pollution so far away was initially scoffed at by the science establishment. But he went ahead and collected daily measurements showing that CFCs were now as ubiquitous in the atmosphere as pesticides were in food.

At first he wasn't believed. The full might of the US Academy of Sciences asserted for many years that his Shackleton measurements were false. "It wasn't that they had better observations, but my numbers did not fit the predictions of their theoretical models. It has since been proved that my data, collected with equipment assembled by me for a few hundred pounds, was correct and their hugely expensive models were wrong. " Lovelock has a withering contempt for scientific establishments.

From Lovelock's measurements, the Californian chemists Sherry Rowland and Mario Molina developed their theory - published in 1974, but only confirmed a decade later with the discovery of an ozone hole over Antarctica - that CFCs were present in the atmosphere in such quantities that they were destroying the ozone layer.

Other measurements taken on the Shackleton trip revealed to Lovelock a mass of other chemicals present in tiny amounts in the atmosphere, such as dimethyl sulphide given off by algae in the oceans. These observations showed strong evidence that living organisms were controlling the chemical make-up and even the temperature of the atmosphere and oceans, keeping them stable and habitable for life over hundreds of millions of years. From this slowly emerged the Gaian idea of the entire planet, both its animate and inanimate parts, as a single "superorganism" with its own metabolism.

For all his scientific fame, Lovelock has scarcely made his fortune. British boffins in the Fifties regarded patenting an invention as bad sportsmanship. "I never thought about patenting the detector, any more than I had the microwave," says Lovelock. Months after revealing the secret of the device to a meeting in Oxford, Lovelock took a year's sabbatical to Yale University in the US, where he set about improving it further. His American hosts swiftly insisted he put in a patent application, in which they said Lovelock would have a third-share, with the university taking the rest. "I didn't see why they got a share, but I went along with it," he says. The patent was issued in 1963.

But worse followed. "I got a letter from the US government's Surgeon- General demanding that I hand over the patent rights to the US government. I was told they funded the department I was work-ing in at Yale, and a condition of the funding was that the government got patent rights, and that included mine."

With threats ringing in his ears that the department could lose all future funding, Lovelock caved in. Later he tried to get the British Medical Research Council to take up the case, but, he says, "it got lost in their bureaucracy and nothing ever happened".

For Lovelock personally, this particular scientific swindle probably cost about $20 million in lost royalties. But he claims no malice. Indeed, until now, he has never mentioned the matter publicly. "The money would have done me no good. I would have sat back, bought more equipment and done less work," he says with a smile.

His widget may have changed our perceptions of the world radically, but it changed Lovelock very little. He just went back to the laboratory, where he has continued to gain a modest income from his inventions, including many variants on the original electron-capture detector. He reckons refinements mean he can now detect some compounds at concentrations of one part in a million billion. For 30 years he was paid a retainer by Hewlett Packard, the US computer and scientific equipment company in return for giving them first refusal on elaborations of his device. The latest cash infusion came with the Volvo Prize, awarded for his detector in October 1996.

Contemplating the success of the electron-capture detector today, he has misgivings. Its very sensitivity creates problems by encouraging cranky environmentalists. "People get hysterical about detecting even the most trivial quantities of toxins. Not being very numerate, they don't understand how fantastically small a part in a trillion is."

It also gets regulators in trouble. Often they set rules which stipulate "zero presence" of some pollutant. "What they mean by zero is that there shouldn't be sufficient for it to be measurable. But the detector upsets that completely because it can measure such tiny amounts." "The poison", as he often points out "is the dose". Even the most deadly nerve gases are harmless at the levels that his device can detect.

Lovelock has grown weary of those who claim the data from his device shows how vulnerable nature is to man-made chemicals. Far from it, he says, nature is extremely robust. In his view, his detector has revealed the Gaian mechanisms by which nature controls the planet's environment in a way that leaves humans humbled.

But, watching him return to the workbench, you sense that Gaia is just another invention: a magnificent and beautiful device for understanding the planet, but still a device. Lovelock, the man who accidentally invented modern ideas about the environment, and who in Gaia gave them an almost theological framework, is at heart the white-coated boffin at the bench. And, if forced to choose between Gaia and the electron-capture detector, you feel that he might well choose the latter.