Episode 1 - The man who had X-ray Vision (Wilhelm Röntgen, 1901)

Wilhelm Röntgen had perhaps the most impressive beard of any man ever to win the Nobel Prize, and that's saying something. Long, dark and unkempt, it gave him a fearsome appearance entirely at odds with his modest, retiring personality. Invited to accept the first ever Nobel Prize in Physics in 1901, the thought of speaking in public so unnerved him that when he arrived in Stockholm he turned down the coveted opportunity to present his findings to the Royal Swedish Academy of Sciences. By awarding Röntgen their inaugural prize, the Nobel Committee were acknowledging the tremendous potential of his most significant discovery, X-ray radiation. Nowadays, X-ray machines are taken for granted, and from identifying bone fractures in your body to detecting razor blades in your luggage, X-rays are a part of everyday life. But 120 years ago, no one was even aware that they existed. Their discovery became the first science scare story of the modern age, and it's not hard to understand why. X-rays were powerful, they were mysterious, they were invisible, and they had been under Röntgen's nose the whole time, much like his beard. Wilhelm Conrad Röntgen was born on the 27th of March, 1845, in a small town in western Germany. The house he was born in had walls, a roof and a door, and in that respect was probably very similar to any of these. When Wilhelm was three years old, countries across Europe were thrown into chaos by the revolutions of 1848, a year of widespread political turmoil that came to be known as the Springtime of Nations. In order to escape the increasingly uncertain situation in what was then Prussia, the Röntgens left for the Netherlands, where their son could grow up and acquire a decent education. Biographers trying to defend him from charges of stereotypically Teutonic humorlessness have had their work cut out for them, as the closest he gets to cracking a joke is when, at the age of 17, a technical school in Utrecht expels him for drawing an offensive caricature of his teacher. Suppress any thoughts you might have of the young Röntgen as a cheeky, fun-loving youngster, though, as we soon find out, he was merely taking the blame for an unknown classmate. An act of such infuriating nobility makes you want to bang your head against the wall. This act of self-sabotage would prove a substantial setback to his academic career, and over the coming years he had great difficulty finding permanent placements. His passion for physics and reputation for outstanding experimental work eventually paid off, however, and after stints at Zurich, Strasbourg, Hohenheim and Gießen, by 1895 he had become the rector of the prestigious University of Würzburg. There, in room 119A of the Technical College, he spent his days experimenting with a new technology no self-respecting physicist could afford to ignore. The Crookes tube, named after the English physicist William Crookes, is the predecessor of the cathode ray tube, which, in turn, is the predecessor of a type of television set that nobody uses anymore. Not that anybody uses a television set anymore, anyway. The Crookes tube is a glass container containing a very small quantity of air, across which a high voltage has been applied. This voltage causes the atoms of air within the tube to collide with each other, knocking the negatively charged electrons away from the much heavier nuclei. The electric field then attracts the larger, positive particles to the cathode, where they knock loose large quantities of electrons that accelerate to the tube's other end. In the late 19th century, these fast-moving bursts of electrons were known as cathode rays, and the near vacuum that exists in the Crookes tube means they have fewer obstacles to avoid while zooming to the other side. When the cathode rays finally collide with the far wall of the tube, they raise the energy of the electrons in the tube walls, surplus energy which is then released in the form of a yellowy-green fluorescent light. On the 8th of November 1895, with the help of his Crookes tube, Roentgen would make what has been called one of the most bizarre and serendipitous observations in the history of science. He was determined to test the hypothesis, then making the rounds of physics departments in Germany, that Crookes tubes were capable of emitting highly penetrative rays, rays with so much energy that they could pass straight through the glass face of the tube and interact with objects beyond it. In an attempt to search for these rays, he placed a thin paper screen coated in fluorescent barium-platinocyanide crystals a metre in front of the tube, and eliminated all possible sources of light in the laboratory. He covered the apparatus with sheets of black cardboard, extinguished the lights, and drew the curtains. He flicked a switch, which applied pulses of 35,000 volts across the Crookes tube, and waited. Suddenly, out of the corner of his eye, he thought he saw a faint glimmer appearing on the sheet of paper across the room. Astonished, he cut the voltage and saw the glimmer disappear. Now, not only is Roentgen looking for an extremely faint green glow on the other side of the laboratory, but owing to a childhood illness he can barely see out of one eye, and the eye he can see out of is effectively colourblind. What seemed at first like a difficult observation now appears impossible. But Roentgen's career has been exemplified by a devotion to accuracy, and like many individuals with impaired vision, he has developed techniques to compensate. These eyes of his are equipped with a penetrative power that make x-rays look like spitballs. Determined to identify the source of the fluorescence, he places an additional sheet of black cardboard between the tube and the screen, and repeats the experiment. All sources of light are completely blocked, but the green light still dances across the surface of the screen. He then removes the cardboard and interposes a 1,000-page book he just happens to have lying around. Little wonder that his reputation for humorlessness survives. We'll have to make do with five 200-page books instead. Again, the glow remains. Roentgen is fascinated, and starts hunting about his laboratory for anything else he can stick in front of the tube. Meanwhile, his dinner is getting cold, and Anna Bertha, his wife of 13 years, is nervously fingering her wedding ring, wondering what on earth is keeping her husband this time. This wedding ring is going to play an important part in our story, so let's put it in a safe place for the moment. Roentgen is eventually dragged to the table, where he sits, fidgeting, unable to concentrate on anything other than what he's just witnessed. He returns to his laboratory after dinner, and stays there around the clock for much of the next two weeks. He is so captivated by what he sees that this most reliable of experimenters forgets to note down a single observation for the first seven days. When he eventually recovers his composure, he remarks that these mysterious rays can penetrate a wooden shelf, tin foil, hardened rubber, a glass of water, a pack of playing cards that a more fun-loving friend must have left in the lab, and a thin sheet of aluminium. It is only denser materials, such as copper, silver, gold, platinum, and, no doubt, whatever this cheap ring I bought from Claire's Accessories is made of, that appear to stop the radiation. He then reaches for a thin disk of lead, a material with a similar density to gold, and holds it up to the Crookes tube. There, on the screen behind him, he notices two things. Firstly, the rays cannot penetrate lead. But secondly, and most peculiarly, they can penetrate human tissue. In a scene worthy of the most grisly horror story, Roentgen can see the outline of his own skeleton. His first thought was that he must be seeing things. Roentgen had lost a number of close friends and mentors over the preceding year, and he was worried that grief might be making him delusional. There was a history of Crookes tube experiments as becoming obsessed with the occult, and William Crookes himself had developed a fascination for the supernatural after the death of his brother. This had lost him the respect of the scientific community, and the exceptionally rational Roentgen was right to be wary. Later asked by a magazine reporter what his first thought had been upon seeing his own phalanges thus projected onto the screen, he calmly replied, I didn't think. I investigated. He repeats the observations, and is soon convinced of the magnitude of his discovery. He also knows that it's only a matter of time before somebody else stumbles across the same results. After all, Crookes tubes have been emitting these mysterious rays in rival laboratories for the past twenty years. It's a wonder no one's noticed them before. Roentgen has no idea just how lucky he is. By 1895, a Ukrainian physicist by the name of Ivan Pulyui was already making very similar observations, and the future Nobel laureate Philip Lennard had twice missed out on discovering this very form of radiation. Twice! Even William Crookes, way back in the 1870s, had noticed that photographic film tended to go cloudy in the presence of energetic cathode rays, but assumed that the film must be faulty, and had it sent back. The customer complaints department must have laughed themselves silly over that one. Roentgen has to get a scientific article published, and quickly. Realizing the medical implications of a ray that would allow doctors to see into the human body without the need for scalpels or leeches, he chooses a journal interested in medical as well as purely physical matters, the Sitzung Berichte der Physikal-Medizinischen Gesellschaft zu Würzburg, a journal whose soporific nature shouldn't be judged purely by the quantity of Z in its title. On the 28th of December 1895, his paper is admitted. It is tantalizingly called Eine neue Art von Strahlen, a new type of rays. Not sure what to call these mysterious rays, he borrows the algebraic convention of referring to the unknown by the letter X. As yet, nobody knows what they are, although Roentgen has certain very firm ideas about what they are not. Calling them X-rays is a way of giving his ignorance a name so as to make it easier to define. Scientists are always doing this, calling unexplored continents terra incognita, or referring to the mysterious mass that makes up most of the universe by terms such as dark matter or dark energy. As teenagers around the world will no doubt attest, knowing someone's name doesn't mean you understand them. Roentgen knows that in order to convince the world he will need photographic evidence, and realizes that his rays will leave an impression on exposed photographic film. He quickly prepares three separate photographs, one of a purse full of coins, one of the interior of a shotgun, and one, most important of all, if the potential of his new rays is to be properly understood, of his wife's hand. See? I told you this wedding ring would be important. Still cheap, though. He rushes the images to the publishing house, but learns that the printers won't be able to reproduce them in time for the next issue. Instead, he decides to send copies to some of the most famous scientists in Europe, Friedrich Kollrausch in Göttingen, Arthur Schuster in Manchester, Henri Poincaré in Paris, Lord Kelvin in London, and Franz Exner in Vienna. The Exners have invited friends over for Exmas and the New Year, and Franz entertains them with these ghoulish X-ray images. One of his guests, Ernst Lecher, shows a particular interest in the subject. His father, Z. K. Lecher, edits the Viennese newspaper Die Presse, which is struggling to keep up with the competition in turn-of-the-century Vienna. Sensing a scoop which could rescue his father's publication, Lecher asks to borrow the images, and spends much of the night trying to explain the science to his incredulous father. By the 5th of January, 1896, weeks before Roentgen's academic paper is to be published, and totally unbeknownst to him, the story has hit the newsstands, and his name is in the headlines. Or at least, it would have been, if they knew how to spell it. Over the coming weeks, as the story spreads, his name is variously rendered as Rothgen and Rautgen. His age is miscalculated, and he is said to be from both Vienna and Württemberg. Winston Churchill once said that a liar can get halfway around the world before the truth has a chance to get its pants on. We're excited, because then it doesn't matter if the truth has its pants on or not. The findings are shocking. So shocking that the London Standard has to reassure its readers that this is a serious finding from a serious German professor. Some people prove harder to convince. The eminent Lord Kelvin, for instance, declares X-rays to be a hoax, which, given so much of what Lord Kelvin said in later life, was pretty strong proof that they were real. The general public, for the most part, is in a panic. This is the first truly global science scare story, and in the dying days of the Victorian age, sensibilities are at their most delicate. Clothes manufacturers start advertising X-ray-proof undergarments for women. Cartoonists depict ladies and gentlemen going about their daily business in suits of armour to protect their modesty. And in the state of New Jersey, Assemblyman Reid of Somerset County proposes a bill prohibiting the use of X-rays in opera classes in theatres. Roentgen, as you can tell from this picture, and indeed any other picture, was not amused. In a few days I was disgusted with the business, he said. I could not recognise my own work in the reports anymore. How many scientists have echoed this plaintive cry down the years? As the most famous scientist of his day, he is inundated with requests for interviews and invitations to deliver lectures. Much of his reputation as a media-shy recluse no doubt comes from his annoyance at the world's intrusion into his laboratory, preventing him from carrying on with his work. One of the few who wheedles his way in to see the esteemed Herr Doktor is Henry J. W. Harry Dan, a Californian journalist with a slippery reputation, often suspected of fabricating evidence in the Jack the Ripper cases ten years earlier. In between rhapsodic tributes to the Würzburg beer, Dan enigmatically describes Roentgen as something like an amiable gust of wind. He goes on to clarify that Roentgen is a tall, slender and loose-limbed man whose whole appearance bespeaks enthusiasm and energy. He wears a dark blue sack suit and his long, dark hair stands straight up from his forehead as if he were permanently electrified by his own enthusiasm. His voice is full and deep. He speaks rapidly. His eyes are kind, quick and penetrating and there is no doubt that he much prefers gazing at a crook's tube to beholding a visitor. True to form, Roentgen declines every speaking invitation which comes his way, with a notable exception of two, one at his beloved Würzburg and the other to Kaiser Wilhelm II at the palace. While speaking to his colleagues at Würzburg, he indulges in a piece of showmanship when he performs a live X-ray of the hand of the celebrated physician Albert von Koerlicker. After being exposed to what nowadays would be considered a highly dangerous dose of radiation, von Koerlicker somehow still has the energy to cry out three cheers for Roentgen and to rapturous applause insists that this new form of radiation bears his name. To this day, a host of languages including Armenian, Czech, Dutch, Finnish, German, Hebrew, Hungarian, Japanese, Russian, Swedish and Turkish still refer to Roentgen rays, Roentgen radiation or Roentgen images when going to the hospital. But no matter what they're called, people still have no idea what these damned things are. The English physicist William Bragg is convinced they must be discontinuous particles. Roentgen himself believes they are a form of longitudinal wave which vibrates along the direction of motion rather than a transverse wave which vibrates up and down. Better demonstrations of that exist online. As a good form of compromise, Max Felix von Laue proposes that they are small discontinuous waveforms, known as impulses. The reality is altogether a great deal simpler. X-rays are just a form of light that is so energetic it can actually travel through solid material. The denser the substance, the more likely it is to absorb the X-rays, which is why bone and metal appear as solid whereas paper and soft tissue are virtually transparent. One of the problems with such highly energetic waves is that they can easily split electrons away from their atoms and even break whole molecules apart. This means that repeated exposure to X-ray radiation can pose health risks and doctors do what they can to minimize the number of X-ray scans any individual has to undergo in a given period. Fortunately for Roentgen, he himself was always shielded behind a sheet of zinc or lead whenever interacting with the X-rays. Ironically enough, these precautions were probably taken to protect his experimental setup from his body and not vice versa. Whatever the reason, he himself was almost completely protected at all times. This is in stark contrast to many future Nobel laureates who would not be so forward thinking. Roentgen is also surprisingly modern in that he refuses to patent any of his discoveries, believing that any potential benefits that arise from the use of X-rays should be humanities to enjoy freely. By the time the Nobel committee came around to deciding the recipient of their first prize for physics in 1901, the winner was clear. No other living physicist could lay claim to a discovery or indeed an attitude so utterly in keeping with Alfred Nobel's dream of bettering the future of mankind. Up against eleven other astonishingly gifted nominees, eight of whom would go on to win future Nobel prizes themselves, Roentgen is overwhelmingly chosen to win. He travels to Stockholm, accepts the prize, turns down the opportunity to speak in front of the Royal Swedish Academy of Sciences and promptly donates the £150,000 of prize money to his university. This modesty is typical of Roentgen and will also go on to turn down the offer of a title from the Kaiser. His death 22 years later, virtually bankrupt as a result of hyperinflation in post-war Germany, will prove a tragic end to such a self-sacrificing life. For the rest of his days, Roentgen will be dogged by petty jealousy and criticisms that his discovery owed more to luck than to skill. Philip Lennard, who you will remember had twice looked the wrong way at the critical moment, would be particularly bitter. When accepting the 1905 Nobel Prize for his research on cathode rays, Lennard could not resist using the opportunity to remind the world he had lent Roentgen valuable equipment to facilitate in the discovery. If Roentgen was the midwife to the discovery of x-rays, he would later add I was the mother. As the most prestigious German physicist to play an active role in the Nazi movement, Lennard's capacity for egotism, brutality and short-sightedness are well documented to slip momentarily into the American argot. Lennard was a mother, all right. Whether what took place on that fateful night of 8th November 1895 was a chance discovery or not, Hugo Münsterberg put it best when he compared Roentgen to the great pioneer of electricity, Luigi Galvani, by saying, History is full of such chances. Only the Galvanis and the Roentgens are few. Over the next century, physics will concern itself ever more with phenomena too small, too vast or too complex to be seen with the naked eye. The discovery of a beam of light so energetic it can pass through solid matter will prove invaluable in helping physicists stretch their limitations and understand the world on these tiny scales. A further three Nobel Prizes will be awarded for X-ray-related research within Roentgen's lifetime. In setting out to capture the impossible on film, Roentgen would be setting a precedent for physicists of the future. One such Nobel laureate, barely a year old at the time of Roentgen's triumph in Stockholm, would go on to revolutionise the field of optics by making the two-dimensional appear fully 3D. And that's it for episode one of 66mm Wide. Thanks for watching, I hope you enjoyed it and if you didn't, then I hope you at least learned something. If you didn't enjoy it and didn't learn anything then I hope you had a good nap and that this doesn't wake you. Keep an eye out for episode two in which I attempt to play a tennis match with myself to explain how holograms work and you'll be introduced to Dennis Gabor, the winner of the 1971 Nobel Prize for Physics. In the meantime, feel free to subscribe, like, dislike, comment and generally let us know what you think. Well, I say us, it's just me really as though you couldn't already tell that from the production values. Regular updates will be up on Twitter at 66mmWide and visit the WordPress page for more stories and insights that didn't make the cut or only occurred to me after the video was uploaded. Thanks for dropping by and hope to see you soon.