Does cold fusion exist

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Does cold fusion exist?

Viewpoint: Yes, the experiments of Martin Fleischmann and Stanley Pons offered legitimate proof that cold fusion exists, and subsequent efforts by other scientists have supported their claim.

Viewpoint: No, Fleischmann and Pons did not utilize proper control experiments, failed to address errors, and incorrectly used significant figures. Properly conducted experiments by other scientists have not supported their claims.

Nuclear fusion is the coming together of two smaller atomic nuclei to form a larger one, with the release of energy. Nuclei, which consist of protons and neutrons, are positively charged. They tend to repel one other, and it is difficult to get a fusion reaction started.

If the nuclei can be forced very close together, the attractive nuclear force, which is effective only at close range, overcomes the repulsive electro-static force. This is what happens in the hot core of a star, where the force of gravity pulls the nuclei into a densely packed condition in which fusion can take place.

To an industrialized world with dwindling supplies of fossil fuels, being able to harness the energy that powers the stars is a very attractive prospect. However, here on Earth, forcing the nuclei close together over the opposition of the electrostatic force requires slamming them into each other at very high speeds. This is done using particle accelerators or complicated reactors in which extremely high temperatures and densities are achieved. Nuclear fusion is not a practical energy source given current technologies.

For decades, scientists have wondered whether it was possible for nuclear fusion to occur at or near room temperature. Such "cold fusion" research has concentrated on dissolving deuterium, a form of hydrogen with an extra neutron, in a solid such as palladium metal. The theory is that the structure of the solid would confine the deuterium nuclei, and the negatively charged electrons in the metal would help to counteract the electrostatic repulsion. The deuterium can in fact dissolve to high concentrations under such conditions, with the nuclei getting even closer together than they would in a pure solid form. However, most scientists point to theoretical calculations indicating that the nuclei would not be anywhere near close enough for detectable fusion to result.

In the late 1980s University of Utah electrochemists Martin Fleischmann and Stanley Pons were working on a cold fusion experiment involving an electrolytic cell, in which current was passed between a palladium cathode and a platinum anode, immersed in a solution containing deuterium. The reaction causes deuterium to enter the palladium cathode. Pons and Fleischmann built their cell into a calorimeter, or heat-measuring device. At some points they measured 10% more power than they were using to run the cell. This excess heat, they reasoned, indicated that fusion was taking place.

Pons and Fleischmann knew that Steven Jones, a researcher at nearby Brigham Young University, was also working on cold fusion. Concerned about getting their results out first, they took an unusual step that severely hampered their credibility in the physics community. Instead of subjecting their work to the peer review inherent in the normal scientific publication process, they held a press conference on March 23, 1989. The potential economic implications of cold fusion sparked a media circus, and serious scientific debate became difficult.

Many scientific teams attempted to reproduce the results. But none saw the gamma radiation expected to be produced in fusion reactions, and both the larger nuclei that were supposed to be produced and the excess heat were detected only sporadically. Most researchers concluded that the Fleischmann-Pons results were due to experimental error. The excess heat could have come from the experimental equipment. The helium nuclei that were occasionally detected, which could have been fusion products, could also have come from the helium naturally present in the air. And no theory adequately accounted for the absence of the gamma radiation.

On May 1, 1989, at a meeting of the American Physical Society, strong presentations refuting cold fusion were made by several respected physicists. As a result, papers on the subject are rarely accepted by peer-reviewed journals or presented at mainstream scientific conferences in the United States. Some research in the field is still ongoing, in the United States, Japan, Italy, and elsewhere. But the absence of peer review makes it difficult to distinguish the bearers of new ideas from ordinary "crackpots." All in all, it is clear that the story of cold fusion research did not unfold in a way that was well suited to separating new physics from experimental error.

—SHERRI CHASIN CALVO

Viewpoint: Yes, the experiments of Martin Fleischmann and Stanley Pons offered legitimate proof that cold fusion exists, and subsequent efforts by other scientists have supported their claim.

Cold fusion is a label loosely applied to nuclear reactions that occur in materials without the usual application of very high energy. Much attention has been applied to making these reactions occur in palladium that has been saturated with deuterium. However, a wide range of materials appears to have this ability, from super-conducting oxides to gold and nickel. The extent of this phenomenon is just beginning to be understood.

The first systematic attempt to initiate such reactions was undertaken in 1927 by Fritz Paneth and Kurt Peters, who thought they had succeeded in making helium from hydrogen; instead they discovered how to flush helium out of quartz using hydrogen. They retracted their cold fusion claim, thereby setting the standard some people hoped would be applied when cold fusion was rediscovered six decades later.

The Fleischmann-Pons Research

In 1949, Martin Fleischmann began to wonder whether deuterium in palladium might undergo a fusion reaction. He was unable to test this notion until he and Stanley Pons started on a self-financed project in 1983. They were blessed from the start because, if the hypothesis was correct and they were able to detect any extra energy, the neutron emission would have killed them, or so it was thought at the time.

Fleischmann and Pons, who were affiliated, respectively, with Great Britain's Southampton University and the University of Utah, considered using four methods of loading palladium with deuterium: electrodiffusion, electrochemical charging, highly reducing or super basic media, and super acid media. Because they are electrochemists, they finally settled on electrochemical charging, which they understood in detail, although it is an extremely difficult technique.

Since 1989 many other methods of loading palladium have been used successfully to produce the cold fusion effect, including gas loading, ion beam loading, electrodiffusion, transient cavitation bubbles, sparking, and high temperature electrochemical glow discharge. These other methods are considered easier than the original technique, and their success rate is often higher. In this regard, Fleischmann and Pons were not so lucky.

Several years into their project, they found what they were seeking. In a few test runs, the palladium deuteride produced measurable levels of anomalous excess heat. That is to say, the palladium cathode in the electrochemical cell grew hotter than it should have, given the amount of electricity being fed into electrolysis. It was producing a fraction of a watt more heat than the power being fed in. Chemical sources of heat were ruled out. The cell contains only water and a few grams of metal, which are chemically inert. (Water does not burn at room temperature.) Not only was there no chemical fuel in the cell, no chemical ash was found after the reaction, and the heat continued for days at a time, producing

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in the aggregate far more energy than any chemical fuel. The small palladium wire was apparently putting out thousands of times more energy than any match, candle, rocket fuel, or battery of the same mass.

Only one source of this much concentrated heat energy is known to science: a nuclear reaction. However, it was obvious that this reaction was not like any known form of nuclear fusion or fission. A conventional reaction that produces a fraction of a watt of heat will also generate deadly neutron radiation so intense that it would kill an observer in a few minutes, yet the alarms showed nothing dangerous, and Fleischmann, Pons, and their colleagues safely observed the cell for hours. They had discovered a whole new field of safe nuclear interactions.

In 1989, they were still at work, planning to keep their results secret for at least five more years, while they investigated and confirmed their findings, but news of the research leaked out. A worldwide mass-media brouhaha broke out. Many peculiar and mistaken ideas about the research began circulating, and many circulate even today. Some scientists attacked the research because they thought the results were theoretically impossible. They made statements that violate scientific ethics and common sense. To this day, the spokesman for the American Physics Society (APS) brags that he has never read a single experimental paper on cold fusion but he knows it must be wrong.

Scientists Replicate the Research

Science works its wonders by examining nature rather than by attacking other scientists. To learn the truth, a scientist skilled in the technique does the experiment again, independently, using the same materials and methods, to see whether the same results occur. Changes are then made and new patterns of behavior are sought. Gradually, a picture emerges and the phenomenon is understood. Everyone who examined the problem knew such an understanding would be difficult to achieve. Pons and Fleischmann were well-known experts, and they warned it had taken them years to master the technique. Distinguished electro-chemist R. Oriani, who successfully replicated some of the results, says it was the most difficult experiment he encountered in his 50-year career.

Despite the difficulties, within a few years several hundred skilled scientists replicated and published more than 1,000 positive papers in peer-reviewed journals and conference proceedings. Many of these scientists worked in prestigious laboratories, including the Los Alamos and Oak Ridge National Laboratories, the Naval Research Laboratory, the Bhabha Atomic Research Centre in Bombay, and many others. A skilled researcher who pays close attention to the literature will find it easier to replicate cold fusion today than in 1989, although the task remains challenging.

The first challenge is to get the cell to produce energy, and to be sure that the energy is real. In early replications, the experiment was performed very much the way Pons and Fleischmann did it. That was not good enough. Many other variations were called for, using entirely different instruments and techniques. Other kinds of nuclear evidence had to be confirmed. Pons and Fleischmann had only $100,000, barely enough to do a rudimentary experiment with simple instruments, looking for a few signs of a nuclear reaction. If everyone had performed the same experiment using the same type calorimeter they used, researchers would not have learned much more than Pons and Fleischmann already knew. What is worse, it is conceivable that dozens of scientists worldwide might all make the same systematic error.

To ensure against this remote possibility, in the years following the announcement, many different instrument types were employed. Heat measurement, for example, was first performed using single-wall isoperibolic calorimeters. Later, many errors were removed by using the double-wall type. Mass flow calorimeters and a variety of electronic Seebeck calorimeters were also used. Sometimes these techniques were used simultaneously; heat from the same sample was measured with different methods. Although many experiments produce only marginal heat, or no heat, every type of instrument has seen examples of strong positive results, or what is called a large signal-to-noise ratio.

The same principle applies to the measurement of nuclear effects. Autoradiographs with ordinary X-ray film often show that a cathode has become mildly radioactive during an experiment. But suppose the sealed film is somehow affected by the minute quantity of deuterium gas escaping from the cathode? Very well, devise a plastic holder that keeps the film a millimeter away from the metal surface, and put the cathode and the film together into a vacuum chamber, so the outgasing hydrogen never reaches the sealed X-ray film. When that works, try again with an electronic detector. The outgasing deuterium cannot have the same effect with all three methods, yet the shadow of radioactivity from the hot spots in the cathode surface shows up every time. Every conventional type of spectrometer has been harnessed to detect tritium and metal transmutations, time after time, in experiment after experiment. A researcher will examine a specimen with SIMS, EPMA and EDX spectroscopy, to be sure he sees the same isotope shifts with different instruments. He will probably examine the specimen before and after the experiment, and compare it to an unused sample.

This is the cheap and easy technique, but researchers at Mitsubishi were not satisfied with it. They developed highly sensitive on-line spectroscopy that takes data as the reaction is occurring. Such equipment costs tens of millions of dollars, but the results are highly reliable, and they tell us far more about the nature of the reaction than static results taken after the nuclear process has ceased. For the past six years Mitsubishi has been able to perform the experiments several times per year, with complete success each time. They observe excess heat, transmutations and gamma rays.

Dozens of parameters can be changed in a cold fusion experiment, but only one reliably predicts the outcome: the metallurgical and physical characteristics of the active material. For example, researchers at the National Cold Fusion Institute in Utah did twenty different types of experiment. In the final and best version, they achieved 100 percent reproducible tritium production, proof that an unusual nuclear reaction had occurred. Four out of four heavy water experiments produced significant tritium, while none of the light water controls did. The final report said, "tritium enhancements up to a factor of 52 were observed," meaning there was 52 times more than the minimum amount their instruments could detect. In these tests, 150 blank (unused) samples of palladium were tested extensively, by dissolving in acid and by other exhaustive methods. None of the blank samples had any measurable level of tritium.

What Conclusions Can Be Drawn?

Because myriad different instrument types have detected some cold fusion effects time after time, in experiment after experiment, in hundreds of different laboratories independently throughout the world, often at a high signal-to-noise level, we can now be sure the effect is real. To be sure, some of the nuclear effects have been seen only by a handful of laboratories, mainly because it costs millions of dollars to detect them, and only a few Japanese corporate researchers have this kind of funding. Nevertheless, most of the important nuclear reactions have been observed in several independent laboratories.

We could not have known that cold fusion is real until hundreds of man years of research were completed and reported in the peer-reviewed scientific journals. In 1989, no one could have predicted this is how things would turn out, yet the possibility was generally rejected. In experimental science, there can be no assurance at the outset, and no rush to judgment. Once a result has

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been confirmed in hundreds of independent, quality replications, it has to be real. There is no other standard to judge reality. To reject cold fusion at this point would be tantamount to rejecting the experimental method itself.

Finally, it should be noted that some critics demand "an explanation" or a theory before they will believe that cold fusion phenomena exist. Never, in the history of science, has this been held as a standard for belief. If it had been, biologists would have denied that cells reproduce until 1953, when the nature of DNA was unraveled. Physicists would not believe that high temperature superconductors exist. Needless to say, there are an infinite number of other natural phenomena beyond our present understanding. Textbook theory can only be an imperfect guide, not the absolute standard.

A person might reasonably ask why the claims have been so hard to duplicate. The environment in which the nuclear reactions occur is rare and difficult to produce. If this were not the case, we would have seen this effect long ago. In 1989, most people who attempted to duplicate the claims unknowingly used defective palladium. Gradually researchers discovered how to identify useful palladium that does not crack when it loads, and how to treat the metal so that it would become active. As a result, the effect can now be duplicated at will. Such understanding of how the properties of a material affect a phenomenon is slow to develop because a large number of variables have an influence. Research in semiconductors and catalysis was hampered for many years by similar problems. Skepticism must be tempered by patience.

Overreaction by the Nay-sayers

The reader may wonder why so few research papers on this subject are available in mainstream science journals in the United States, and why no news of it appears in the mass media. More than 500 positive replications of cold fusion were published in the five years after the 1989 announcement, mainly by senior scientists who had enough clout to perform controversial research. This led to a crackdown. In the United States, most of the scientists who published positive results were ordered to stop, demoted to menial jobs, forced into early retirement, or in some cases summarily fired. As a result, the field is largely ignored in the United States. Fortunately, it is tolerated in Japan and Europe. In Italy the government funds modest programs at the National Physics Laboratory.

Some skeptics point to the dwindling number of publications as proof that the subject is moribund, but cold fusion researchers believe that many more papers would be published if traditional academic freedom was respected. Nobel laureate and cold fusion theorist Julian Schwinger protested the crackdown by resigning from the APS. He wrote: "The pressure for conformity is enormous. I have experienced it in editors' rejection of submitted papers, based on venomous criticism of anonymous referees. The replacement of impartial reviewing by censorship will be the death of science." One might well ask what this attitude means to science in general in the United States.

—JED ROTHWELL

AND EDMUND STORMS

Viewpoint: No, Fleischmann and Pons did not utilize proper control experiments, failed to address errors, and incorrectly used significant figures. Properly conducted experiments by other scientists have not supported their claims.

"Cold fusion" is a term that has been applied to a number of phenomena from the natural fusing of atoms that occurs randomly due to cosmic rays to the supposed deliberate fusing of heavy hydrogen as a fantastic source of power with almost no side effects. It is this last definition that is generally associated with the term in the public imagination. However, cold fusion as a source of power does not exist. It is a myth, and one so seductive that people around the world are still chasing it.

Early Research in Cold Fusion

The first attempts to fuse hydrogen at "cold" temperatures (as opposed to "hot fusion," which is an attempt to mimic the processes that occur inside the sun) took place in the 1920s. Two German chemists, Fritz Paneth and Kurt Peters, were attempting to manufacture helium from hydrogen, to fill airships. They used the properties of the metal palladium, which can absorb a great deal of hydrogen and compress it to high pressures within the atomic lattice of the metal, in the hope that such pressure would force the hydrogen to fuse. Initially, their experiments seemed to produce helium, but they were fooled by the ability of glass to absorb helium from the air and release it when heated. Their basic premise was also flawed, because they were unaware that normal hydrogen atoms, which are merely a single proton with one orbiting electron, do not contain enough atomic material to form helium by fusion, as they lack neutrons. (Helium atoms consist of two protons, and one or more neutrons.)

Neutrons were not discovered until 1932. This achievement prompted a Swedish scientist, John Tanberg, to revisit the Paneth and Peters experiment. He had already attempted to duplicate it earlier with the added method of electrolysis, passing an electric current through water to break some of it into hydrogen and oxygen. Tanberg used palladium as the negatively charged electrode, so that hydrogen atoms lacking an electron (and therefore positively charged) collected inside it. Tanberg then modified the experiment to use heavy water. Heavy water is made from hydrogen and oxygen, just like normal water, except that the hydrogen used contains an extra atomic ingredient, a neutron. Now, Tanberg theorized, he would have enough atomic material inside the palladium for fusion. However, the experiments did not work, and Tanberg went on to other things.

Sensational News from Utah

The modern flirtation with cold fusion began on March 23, 1989, when two chemists, Martin Fleischmann and Stanley Pons, announced in Utah they had created fusion at room temperature on a desktop, with nothing more sophisticated than palladium rods and beakers of heavy water. The timing of the announcement was fortuitous, as that night the Exxon Valdez ran aground off Alaska, creating a huge oil spill. Cleaner energy was a hot topic, and a media frenzy ensued.

Their news was broken in an unusual manner for a scientific discovery, by publication in the London Financial Times and the Wall Street Journal and in a hastily organized press conference. However, they did not publish any of their results in scientific journals, or give conference papers on their breakthrough either before or immediately after their announcement.

One possible reason for the hasty release of Fleischmann's and Pons's results is that other nearby scientists were also researching cold fusion, and about to publish. They may have felt they were in a race. However, the second group, at Brigham Young University, was looking at results barely above background radiation, and made no extravagant claims for their work.

The Fleischmann and Pons press conference sparked a wave of positive press coverage, and high-level funding negotiations. If the claim was true then cold fusion was worth billions. Big money was forthcoming for the big claims. However, what was missing was big evidence. Details of Fleischmann's and Pons's experiment were sketchy at best. Their press releases seemed more concerned with the economic potential of the discovery than the scientific specifics. The lack of information frustrated those in the wider scientific community, many of whom were rushing to reproduce the experiment, to confirm or refute the claims.

There had been a similar rush just two years previously when another unexpected scientific breakthrough, high-temperature superconductivity, had been announced. However, whereas the discoverers of that phenomenon, Georg Bednorz and Karl Mueller, had published their work in peer-reviewed journals, and shared information on all details of their experiment, Fleischmann and Pons did not. Within weeks of the announcement of high-temperature superconductivity, successful reproductions were reported everywhere the experiment was reproduced.

Other Scientists Unable to Confirm

The lack of details from Fleischmann and Pons led to spy tactics being employed by physicists and chemists attempting to reproduce their work. Press photos and video coverage were closely examined for information. Groups of scientists began to recreate the work of Fleischmann and Pons as best they could.

Given the lack of details, the rush of initial confirmations that appeared was surprising. Scientists at Texas A&M and Georgia Tech announced positive results. From India and Russia came more confirmations. However, most groups that were to confirm the work would only confirm either the excess heat or the neutron emissions, but not both.

Then came the retractions. Experimental errors and inaccurate equipment had given rise to false positives in many cases. Texas A&M scientists had announced that not only had their reproduction with heavy water worked, but so had their control experiments using normal water and carbon rods. They eventually isolated the excess heat generated in their work to the experimental setup itself. After correcting their error they never saw excess heat from any further experiments. Georgia Tech scientists realized that they had not been measuring neutrons at all. Rather their detector was overly sensitive to the heat of their experiment. Other labs admitted they had had similar errors.

Soon after came a wave of negative announcements from many labs across the world. Even the Harwell lab in England, the only lab to be given the full details, from Fleischmann himself, and equipment from Utah including supposedly "working" cells, announced that it had failed to reproduce the experiments. It usually takes longer to refute a claim than to confirm it, and the slow process of careful scientific study does not always fit with popular attention spans and media coverage. Most of the negative results were not widely reported.

How the Utah Research Went Wrong

Aside from the problems of reproduction, there were also growing concerns regarding the original experiments of Fleischmann and Pons. In essence their work was very similar to that of Tanberg more than fifty years earlier. Using heavy water and electrolysis, together with palladium rods, they hoped to force heavy hydrogen atoms close enough together to fuse. They ran several experiments using different-sized palladium rods, and noticed excess heat from at least one. They also appeared to get positive readings of neutron emissions from their experiment, which they interpreted as a sign that fusion was taking place.

The fusion of two deuterium atoms is one of the most studied of nuclear processes. Normally the nuclei of the atoms will repel each other, as they are both positively charged. However, if they can be forced close enough together they can fuse to form a new, heavier nucleus of helium. In the process excess energy is released, and about half of the time a high-speed neutron. If fusion was really occurring in the Utah experiments then both helium and neutron emissions should have been obvious. There should also have been a large amount of gamma radiation; so much, in fact, that it would have been fatal. However, no precautions had been taken, and no health problems had arisen in the Utah lab. Pictures showing the two chemists holding one of their working cells in bare hands suggested to many scientists that something was wrong.

Fleischmann and Pons had not performed control experiments with normal water, which should have been standard practice. Indeed, this was to become a major sticking point for the cold fusion claims. Many later experimenters got the same readings for normal water, which would imply that what was occurring was not fusion, as there would not be enough nuclear material to form helium atoms, just as in the original Paneth and Peters experiments.

The little information that had been published contained many errors and omissions. There was a revelation that Fleischmann and Pons had doctored some of their results to make it seem that they were seeing gamma radiation, misrepresenting some of their data to make it seem significant. Further setbacks for the cold fusion claims mounted. Fleischmann and Pons admitted that their biggest claims for excess heat were from projected work that had never been completed.

Perhaps the most damning criticism was that of the missing neutrons. Fusion of the power they claimed should have produced a billion times more neutrons than detected. In effect even those they claimed to have detected were subject to doubt, as they were close to background levels, and could have been from experimental errors or background fluctuations. There was also a lack of other by-products from the supposed cold fusion. Fleischmann and Pons had claimed that inside their cells a new and unknown type of fusion was taking place that made much more helium than normal. However, their experiments showed much less helium than would have been expected even in conventional fusion, and that may have come from sources other than fusion.

An American government panel that investigated the claims of cold fusion pointed to a lack of control experiments, failure to address errors, and incorrect use of significant figures, among other problems. It was also noted by many that the original basis for the experiment was flawed. Heavy hydrogen molecules inside palladium are actually further apart from each other than they are in gaseous form, and so are less likely to fuse, not more so.

Cold Fusion Remains a Dream

Despite all the refutations and flaws, Fleischmann and Pons continued to claim that they had produced fusion. The lack of reproducibility was attributed to poor methods by other experimenters, caused by their having insufficient details or their poor understanding of the intricacies of the experiment (which were the fault of Fleischmann and Pons themselves). However, even those few who were privileged with all the technical details could not reproduce the results. Supporters of cold fusion have made various claims ever since, ranging from effects that are barely detectable, to claims of limitless energy production, and beyond. Some claim the process works with normal water, others that it can be used to transform any element into another. A number of cold fusion companies have been formed and have spent millions of dollars of investors' money in research and development. While amazing claims for the potential of cold fusion have been made, not one working device has ever been demonstrated or patented.

Supporters point to hundreds of reports of cold fusion, but forget the many retractions, the more widespread negative results, and the errors and misrepresentation in the original work by Fleischmann and Pons. Advocates are also quick to point out that "well-respected" laboratories have done cold fusion research. However, most quickly abandoned such work after obtaining only negative results. Those that persisted, including NASA and the Naval Research laboratories as well as at least two large Japanese corporations, have done so for reasons that have more to do with gambling than science. Cold fusion research is very cheap compared with many other "alternative fuels" experiments, but the potential payoffs would be astronomical, so even a minute chance is seen as worth pursuing by some. However, the vast majority of scientists place the probability at exactly zero, and call such research a waste of time and money.

Many casual followers of the cold fusion saga are struck by the claims of excess heat. Even if fusion is not occurring, surely the excess heat is still worth investigating? However, the experiments of Fleischmann and Pons were not closed systems, and the heat could easily have come from the atmosphere or electrical current in the apparatus. Their reports of the greatest amounts of excess heat were only in projected, not actual, experiments. And finally, if a nuclear process was not occurring then the claims of excess heat would violate one of the most ironclad principles of physics, the first law of thermodynamics and the conservation of energy. Fusion allows the transformation of mass into energy, a process most famously noted in Einstein's E=mc² equation. However, without such a transformation it is impossible to generate more heat from a system than is put into it (which is what makes perpetual motion impossible). In short, if fusion is not occurring in the so-called "cold fusion" experiments, then they cannot be producing excess heat, and there is no compelling evidence for fusion in any of the work done to date.

Cold fusion is impossible. It contradicts all that we know in nuclear physics, and no concrete evidence, theoretical or experimental, has ever been forthcoming. No single working device has ever been demonstrated, and there have been no explanations for the shortcomings in the work of Fleischmann and Pons or later followers. The only journals that publish papers on cold fusion today are pro-cold fusion journals, which seek to promote the field, rather than critically examine it. Cold fusion is a dream, a golden promise of a world with unlimited energy and no pollution, but a dream nonetheless.

—DAVID TULLOCH

KEY TERMS

CALORIMETER:

An instrument that measures heat energy, of which there are five basic types. In one type, the sample is surrounded by flowing water. By combining the rise in water temperature with the flow rate and the heat capacity of water, the amount of heat being generated can be determined.

DEUTERIUM, DEUTERON, DEUTERIDE:

Deuterium is heavy hydrogen, that is, a hydrogen atom with one additional neutron. The individual nucleus is called a deuteron. A deuteride is a metal combined with deuterium.

ELECTROCHEMISTRY:

When electric current passes from one electrode to another through a liquid, electrolysis breaks apart the molecules of liquid into ions. The positively charged ions are attracted to the negative electrode (the cathode), and the negative ions to the positive electrode (the anode).

HEAVY WATER:

Water composed of oxygen and deuterium, instead of hydrogen. Ordinary water contains one part in 6,000 heavy water. Heavy water is 10 percent heavier than ordinary water.

NEUTRON:

A subatomic particle with no charge, and roughly the same mass as a proton. Atoms heavier than hydrogen are composed of electrically negative electrons, surrounding a nucleus composed of positive protons and neutrons with no charge.

TRITIUM:

Super-heavy hydrogen, with two neutrons per atom. Hydrogen with one neutron is called deuterium. Tritium is radioactive, with a half-life of 12.3 years.

THE N-RAY AFFAIR

René Blondlot "discovered" n rays in 1903 and named them after the University of Nancy in France, where he did his research. He had been experimenting with x rays, found in 1895 by Wilhelm Conrad Roentgen. X rays had been big news and were considered one of the most important scientific discoveries of the time. Blondlot hoped his n rays would be just as significant.

Many strange claims were made for n rays. Supposedly, they could penetrate many inches of aluminum but were stopped by thin foils of iron; they could be conducted along wires, like electricity; and when n rays were directed at an object there was a slight increase of brightness. Blondlot admitted, however, that a great deal of skill was needed to see these effects. A large number of other, mainly French, physicists confirmed and extended his work, and many scientific papers were published on n rays.

The American physicist R. W. Wood had been unable to reproduce the n-ray work, and so he visited Blondlot's laboratory to observe the experiments firsthand. Blondlot demonstrated to Wood that he could measure the refractive indexes of n rays as they passed through a prism. Wood was startled by the degree of accuracy Blondlot claimed to observe, and he was told that n rays do not "follow the ordinary laws of science." Wood himself could see nothing and was very sceptical of Blondlot's claims. The story goes that Wood managed to quietly pocket the prism in the experiment without anyone noticing, and then he asked for the measurements to be repeated.

Blondlot obtained exactly the same results, down to a tenth of a millimeter, confirming Wood's suspicion that there was no visible effect at all, merely self-deception on Blondlot's part and all those who had confirmed his results.

Wood wrote an account criticizing n rays, published in Nature, and this effectively ended n-ray research outside of France. However, the French continued to support Blondlot's work for some years, and many other French physicists reconfirmed his results. National pride seems to have fueled a defiance of foreign scientific opinion. Eventually the nonexistence of n rays was accepted in France, and Blondlot's career was ruined, leading to madness and death.

—David Tulloch

Science in Dispute