The discovery of X-rays, a type of invisible radiation that can go through objects like human tissue, changed the game for science and medicine in the late 1800s. Wilhelm Conrad Röntgen, a German scientist, stumbled upon X-rays (also known as Röntgen rays) in November 1895. He even snagged the first Nobel Prize in Physics for this breakthrough in 1901.
This exciting find tied into the Victorian fascination with ghosts and photography. X-rays could “capture” what was normally hidden, revealing bones and the human skeleton. People got really into “bone portraits,” and photographers opened studios to showcase these eerie images of skeletons.
One of the earliest medical uses of X-rays happened in 1896 when British doctor John Francis Hall-Edwards found a needle stuck in a colleague’s hand using X-ray technology. Before long, X-rays shifted from being just a cool new photography technique to an essential diagnostic tool in hospitals and clinics.
Röntgen was a careful scientist, but it seems his discovery of X-rays might have been a happy accident while he was working with cathode rays in his lab in Würzburg, Germany.
Early Years
Wilhelm Conrad Röntgen was born on March 27, 1845, in Lennep, Prussia (now part of Germany). His dad was a German textile merchant, and his mom was Dutch. He was an only child and spent his early years in Apeldoorn, Netherlands, where his father ran a cloth manufacturing business. The family had to relocate because of political issues back in Prussia.
Röntgen went to the Utrecht Technical School from 1861 to 1863 but got kicked out after a classmate drew a funny picture of a teacher. Even though he had great grades, he wouldn’t snitch on the student and ended up not graduating with a technical diploma. In 1865, he got into the Mechanical Technical Division at the Federal Polytechnic School in Switzerland, where he earned a diploma in mechanical engineering and later a PhD in physics in 1869 with a thesis called Studies on Gases.
His supervisor was August Kundt, a German experimental physicist who created the Kundt Tube, which measured sound speed in gases. Kundt had a big impact on Röntgen’s research journey.
In 1870, Röntgen followed Kundt to the University of Würzburg, where he worked as an unpaid assistant during a time when experimental physics was really taking off. Around this time, Scottish mathematician James Clerk Maxwell was exploring electromagnetic radiation and figured out how light connects to it. He also took the first color photo in 1861 using his three-color theory, which explained how we see colors through blue, red, and green light. Meanwhile, Samuel Morse invented the electric telegraph and Morse code for sending messages over long distances, and Alexander Graham Bell came up with the telephone.
Röntgen was really intrigued by the work of German physicist Heinrich Hertz and British chemist William Crookes. Both were diving into cathode rays, which are basically invisible streams of electrons that you can see when an electric current flows between two electrodes (the cathode and anode) in a glass vacuum tube. They’re called cathode rays because the electrons come from the cathode (the negative electrode) when it gets heated up by the current, making the electron stream glow. Back in 1869, Johann Wilhelm Hittorf was the first to notice these rays glowing green in the glass of a vacuum tube, but he didn’t realize he had stumbled upon X-rays during his experiments.
Röntgen got really interested in how cathode rays made certain materials, like barium platinocyanide, glow a greenish-yellow color. This curiosity ultimately led him to discover X-rays.
Steps To Discovery
By 1895, Röntgen was a physics professor at the University of Würzburg and was really hitting his stride at 50 years old. Back in the 18th and 19th centuries, a bunch of scientists were playing around with electricity and vacuum tubes, getting pretty close to figuring out X-rays. Their work laid the groundwork for Röntgen’s big discovery.
In 1705, British scientist Francis Hauksbee (1660-1713) was messing around with static electricity. He sucked most of the air out of a glass globe and created a glow by spinning and rubbing it. In a dark room, he noticed a bluish-purple light that was bright enough for him to see the outline of his hand on the globe, but he had no clue why it lit up. Basically, he accidentally invented neon lights and showed that electrical stuff could produce light.
Fast forward to February 1890, when American physicist Arthur Willis Goodspeed (1860-1943) took the first X-ray image. He was experimenting with electrical discharges in a Crookes tube (an early vacuum tube) at the University of Pennsylvania. Nearby, unexposed photographic plates and coins got hit with X-ray radiation from the tube. When Goodspeed saw a shadowy shape on one of the developed images, he thought it was a mistake and complained to the supplier. He didn’t realize he had actually captured an X-ray photo of the coins, so he just tucked it away. It wasn’t until Röntgen published his paper On a New Kind of Rays on December 28, 1895, that Goodspeed realized he’d seen X-rays almost six years earlier. During a talk at the American Philosophical Society in February 1896, Goodspeed said:
“Now, gentlemen, we wish it clearly understood that we claim no credit whatever for what seems to have been a most interesting accident, yet the evidence seems quite convincing that the first Röntgen shadow picture was really produced almost exactly six years ago to-night, in the physical lecture room of the University of Pennsylvania.” (Goodspeed, 24)
Philipp Lenard (1862-1947), a student and assistant of Heinrich Hertz, came close to discovering X-rays himself and later felt bitter that Röntgen got all the credit. He argued that his experiments with cathode rays directly led to Röntgen’s findings and claimed he was the ‘mother of the X-rays’ because he invented the vacuum tube that Röntgen used in his experiments.Hertz had already figured out that cathode rays could go through thin metal foil.
Then in 1892, Lenard came up with a better glass tube that had an aluminum window at the end—this was called the Lenard Window. It let cathode rays escape so they could be studied outside the tube. He coated a plate with a chemical called ketone and noticed that the cathode rays darkened parts of the plate from about 8 centimeters away, while other areas lit up. This showed that cathode rays had enough energy to create visible light, but Lenard didn’t realize he was seeing a different type of ray.
Röntgen heard about Lenard’s work and wanted to try it himself. They exchanged letters, and Röntgen ordered ketone, but it took a while to arrive. Instead, he used barium platinocyanide, which was known to fluoresce under ultraviolet light. This switch, along with Röntgen’s careful observations and repeated tests, is probably why he ended up being recognized as the discoverer of X-rays, unlike earlier scientists who had unknowingly seen invisible radiation.
On the evening of November 8, 1895, in his dimly lit lab at the University of Würzburg, Röntgen wrapped a vacuum tube in black cardboard and sent a high-speed electrical current from the cathode to the anode. The covering blocked any glow from the tube. A board coated with barium platinocyanide glowed faintly yellow-green, leading Röntgen to realize that the rays from the tube caused luminescence.
He became so absorbed in his work that he locked himself in the lab, even sleeping there. Over the next few weeks, he took X-ray images, the most famous being one of his wife’s hand, called Hand mit Ringen (Hand with Rings), taken in December 1895. Anna Bertha Röntgen, who he married in 1872, was the first person to have an X-ray taken, and you could see her wedding ring and the bones in her hand. After looking at the X-ray, she remarked that she felt like she was seeing death.
So, while we usually call them X-rays (with the “X” standing for something unknown in math), back when they were first discovered, people mainly called them Röntgen rays. Röntgen showed that these rays could go through stuff like glass, paper, metal, and even human tissue. But not everyone was convinced—British physicist Lord Kelvin thought they were a scam and said so right away. There were also some disputes about who really discovered them first. One guy, Philipp Lenard, was particularly upset because he believed he deserved credit for the discovery. He had sent Röntgen a special glass vacuum tube and shared important info from his own experiments with cathode rays back in 1892. Lenard claimed that without his help, Röntgen wouldn’t have made his groundbreaking discovery.
Things got even more tense when Röntgen won the Nobel Prize in 1901, which only fueled Lenard’s bitterness. His resentment stuck around well into the 1930s, especially as he got involved in German nationalism and anti-Semitism. Even though Lenard won a Nobel Prize himself in 1905 for his work on cathode rays, he kept trying to undermine Röntgen’s achievement. The Third Reich backed Lenard’s claim that Röntgen hadn’t actually discovered what he called high-frequency rays.
More Affairs
Bone Portraits & Harmful Effects
X-rays were initially seen as this amazing new type of photography that really captured the Victorian crowd’s attention. Since X-rays could see through clothes and outline the human body, people started worrying about modesty and privacy. In an 1896 edition of Electrical World, a London company even marketed lead underwear as a protective measure. But that didn’t stop photo studios and fairs from cashing in on the X-ray trend of 1896. Folks were eager to get their skeletal images taken, with “Hand mit Ringen” being the first known bone portrait.
They even X-rayed unwrapped Egyptian mummies! Some shady spiritualists took advantage of the public’s confusion about the new tech, especially the mix-up between cathode rays and X-rays. They used clever tricks to make it look like ghostly skeletons in photos were actually people’s deceased relatives.
At first, doctors sent patients to photographers before anyone realized how useful X-rays could be for diagnosis. By 1898, though, interest had faded, and X-ray tech shifted to the medical field, with hospitals starting to offer treatments. American Émil Grubbé might have been the first oncologist, treating a breast cancer patient with radiation for an hour back in 1896.
As we moved into the early 1900s, the harmful effects of radiation exposure became clear, with reports of burns and itchy skin (which they called X-ray dermatitis). Thomas Edison’s assistant, Clarence Dally, dealt with swollen hands and peeling skin after eight years of X-ray exposure. After hearing about Röntgen’s discovery, Edison tried his hand at X-rays and created the fluoroscope, a device that shows internal organs moving like a film. He stopped experimenting when Dally had to have both arms amputated due to radiation damage. Sadly, Dally passed away from cancer in 1904 at just 39.
Another pioneer, Hall-Edwards, lost his left arm and four fingers from his right hand due to radiation issues. Émil Grubbé also suffered from radiation-related cancer, going through over 90 surgeries for severe burns and complications before he died. It wasn’t until 1921 that safety regulations were introduced in England and the U.S., but many of the early X-ray innovators had already lost their lives. Röntgen himself died from intestinal cancer shortly after, in February 1923.
These days, we know that some types of radiation can mess with DNA and cause cancer cells to grow quickly. But back in the 1920s up until the mid-1950s, shoe stores commonly had this coin-operated gadget called the Foot-O-Scope. It used X-rays to show images of kids’ foot bones and the shape of their shoes, helping parents figure out if they fit right. In England, it was known as the Pedoscope and worked with fluoroscopy. Salespeople would get zapped with radiation from the machine multiple times a day. By 1950, there were around 10,000 of these machines running in the U.S. without any rules. Then in 1957, Pennsylvania became the first state to ban the shoe-fitting fluoroscope. Interestingly, fluoroscopy was also used during World War I to X-ray soldiers’ feet without having to take off their boots.
Röntgen’s Later Years
Wilhelm Conrad Röntgen wasn’t one for the spotlight. He skipped the 1901 Nobel Prize ceremony and didn’t bother with a patent for his discovery, believing that X-ray tech should be accessible to everyone. Instead, he donated his Nobel Prize money—around $40,000—to the University of Würzburg. He was already doing pretty well financially thanks to his dad’s textile business.
In 1900, Röntgen took a position at the University of Munich, where he led the experimental physics department until he retired in 1920. Sadly, his wife, Anna Bertha, passed away in 1919 after a long illness. Then, in 1921, hyperinflation hit Germany hard, and Röntgen lost a chunk of his wealth. He even requested in his will that most of his lab notes and correspondence be destroyed, which makes you wonder if he was worried about rumors regarding who really discovered X-rays.
Nikola Tesla, the Serbian-American inventor, claimed he’d been working on X-rays (which he called shadowgraphs) since the early 1890s. However, a fire at his New York lab in March 1895 wiped out his notes and photos, so there was no way to back up his claims. Röntgen also had to deal with Philipp Lenard’s jealousy, so maybe he wanted to keep his personal records from falling into the hands of competitors or being misused.
Whatever his reasons for wanting his scientific papers destroyed, history shows that in 1895, Wilhelm Conrad Röntgen stumbled upon a brand-new type of ray in his dark lab, changing medical imaging forever.
