Martin Fleischmann, who had been a well-regarded but relatively obscure British scientist until something that he apparently did not do brought him far more fame and notoriety than anything he had done, died Aug. 3 at his home in Tisbury, England. He was 85.

His son, Nicholas, confirmed the death to the Associated Press. Dr. Fleischmann had Parkinson’s disease, according to news accounts.

In claiming to have produced energy by a process known as “cold fusion,” Dr. Fleischmann seemed to offer the world a brighter future. But when the claim could not be satisfactorily substantiated, science turned its back on him.

Dr. Fleischmann’s story embraces powerful and tragic themes, including the conflict between human aspiration and the laws of nature. From some vantage points, it might suggest the ancient Greek legend of Prometheus, who sought to bring the heavenly fire to mankind and was punished for defying the gods.

Among the fascinating episodes of Dr. Fleischmann’s life were childhood escapes from the Nazis in Europe in the days before World War II. After a penniless arrival in England, he grew up to earn honor and respect for his achievements in the field of electrochemistry.

But much of this professional honor was of no use in a controversy that began in 1989, when Dr. Fleischmann and a colleague claimed to have made a scientific breakthrough that was interpreted as the beginning of a new era of cheap, clean and plentiful energy.

Dr. Fleischmann and Stanley Pons of the University of Utah claimed, essentially, that they had produced cold fusion, an accomplishment likened to a medieval alchemist’s dream of turning lead into gold.

Cold fusion would have meant a simple route to creating on Earth the titanic energies of the sun and the stars — a benign way of harnessing the process behind the hydrogen bomb — and it might have solved the world’s energy problems.

Nuclear reactors produce energy by fission, or the splitting of atoms, with well-known hazards. Energy production by nuclear fusion would be more desirable, but controlled fusion has yet to be achieved.

In 1989, Dr. Fleischmann and Pons announced that they had done it in a glass jar. A relatively simple, room-temperature experiment, it was carried out at the University of Utah and was announced in Salt Lake City. The news made magazine covers and the front pages of newspapers.

To be accepted, scientific achievements must be reproducible and explicable. Scientists who tried their hands at Dr. Fleischmann’s experiment found that they could neither reproduce nor explain the effects that he had reported.

Dr. Fleischmann and Pons became the targets of denunciations, hostility and ridicule.

The hope of achieving cold fusion has never entirely vanished, however. An obituary for Dr. Fleischmann published in Utah in the Deseret News suggested an uptick in recent activity. While not claiming cold fusion, some scientists have said that what was demonstrated was another sort of nuclear reaction, which could also produce energy.

Martin Fleischmann was born March 29, 1927, in Karlovy Vary, Czechoslovakia. His mother was Catholic, and his grandfather on his father’s side had been adopted as an orphan by a Jewish family named Fleischmann.

As a boy, Dr. Fleischmann twice escaped the Nazis with his family. Once they fled the Nazi-occupied region of Czechoslovakia into another part. Then, when Nazi power expanded, they left for England, with at least one close call. After leaving Prague by train, they had crossed Europe to the border of Netherlands. There, Dr. Fleischmann recalled, according to the Telegraph in London, the Germans were clearing refugees from the train.

“We were in the last coach, and my father said: ‘No, sit tight; don’t get off the train.’ ”

That refusal to obey apparently saved their lives. With the family still on board, the train left the station, making possible their arrival in England.

Dr. Fleischmann attended the Imperial College in London on a scholarship and received a doctorate there in the early 1950s. In 1967, after teaching at Newcastle University, he was named professor of electrochemistry at the University of Southampton.

The department won worldwide renown, and Dr. Fleischmann was known for achievements in his field and for being a fount of ideas. He retired in 1983.

The Royal Society of Chemistry awarded him a medal, and he was also honored, years before the cold fusion controversy, by the Electrochemical Society in the United States.

According to the University of Southampton, survivors include his wife of 61 years, the former Sheila Flinn, and two children.

It was reported that Dr. Fleischmann and Pons moved to France in 1992, continuing their work on cold fusion. Friction apparently broke out between the two, and Dr. Fleischmann returned to England a few years later.

“This has been a terrible experience,” he told a German news site in 2005.