16. Sulfur: No Mistakes, Only Happy Accidents

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From Vulcan to vultures, today’s element brings stories of unintended consequences.

Featured above: A painting of Charles Goodyear discovering the vulcanization process.

Show Notes

Bacterial Birth Control: So why is prontosil so effective in humans (and mice) if it did absolutely nothing in the petri dish? There are two main reasons: It needs to be biologically processed into something else, and it doesn’t actually kill bacteria.

Prontosil is actually a precursor to the drug that works its magic, sulfonamide. Mammalian cells crack prontosil in half to produce sulfonamide, so it wasn’t actually present in the petri dish.

As far as its mechanism of action, sulfonamide merely inhibits bacterial growth — but this is enough. Slowing down or stopping bacterial reproduction means the immune system can attack the bacteria naturally without becoming overwhelmed.

Some doctors are looking toward this class of drugs again as traditional antibiotic resistance becomes more of a problem.

Fun with Fricatives: You may be more familiar seeing element 16 spelled with a ph, as in “sulphur.” That’s just as correct as “sulfur!” The same situation is going on here as happened with aluminium: The IUPAC recommends a particular spelling, in this case the one with the F, but — even though “sulphur” is the common spelling in the UK — does not see that as an acceptable variant.

Episode Script

“On the wicked, the Lord will rain fiery coals and burning sulfur; a scorching wind will be their lot.”

Bookended by last episode’s luciferous reactions and the cleansing fire of chlorine we’ll discuss next episode, today we remain trapped on all sides by a hellish inferno. Not many chemical elements get called out by name in the Bible, but sulfur gets no fewer than 15, usually in a punitive context, as in the preceding quote from Psalm 11, verse 16. In some translations it’s called “brimstone,” but make no mistake: element 16 is the projectile in question.

This is due to its propensity to burn, known since ancient times, often with a distinct smell that’s quite appropriate to accompany a serving of supernatural ire.

Sulfur compounds are infamously pungent. The scents of rotten eggs, a skunk’s spray, and halitosis are all thanks to the presence of today’s element.

It’s not all bad, though. Sulfur is also responsible for the characteristic smells and tastes of some beloved vegetables, especially in the genus Allium — leeks and shallots and the like. This is also fitting for our current elemental expedition through perdition: According to some legends, as Satan slunk away from the Garden of Eden, from his left footprints sprang garlic, and from his right footprints sprouted onions.¹

You’re listening to The Episodic Table Of Elements, and I’m T. R. Appleton. Each episode, we take a look at the fascinating true stories behind one element on the periodic table.

Today, we’re holding our noses as we investigate sulfur.

Surprisingly, pure sulfur has no odor. But if even trace impurities are present, sulfur’s smell can repel like nothing else. So perhaps it’s not so surprising that some of the most important chemical discoveries involving sulfur have come about entirely by accident.

Many, many of science’s most important and famous discoveries happened serendipitously, but on the short list of contenders is Charles Goodyear’s discovery of vulcanization.

Goodyear was an inventor, chemist, and entrepreneur born in New Haven, Connecticut on December 29, 1800. This made him just the right age to be young and hungry when all of America got caught up in a bit of a craze over rubber.

In the 1820s and 30s, rubber-coated boots became quite popular due to their excellent ability to keep people’s feet dry. That all changed within a few months, however, when customers found themselves with footwear that had an unfortunate tendency to become sticky and melt in the summer heat.²

Pretty much every rubber manufacturer went out of business within five years due to the material’s instability, but Goodyear thought he was the man who could make a fortune by manufacturing rubber that didn’t liquefy in the heat, nor turn brittle and crack in winter’s cold.

Coincidentally, around that time his prior business failures landed him in debtor’s prison, but he didn’t let this deter his curious mind. While jailed, his wife brought samples of rubber to Goodyear, where he began his experiments to synthesize a more viable material.

After his release from prison, he continued his experiments for many years, treating natural latex rubber with magnesia, and quicklime, and nitric acid. Goodyear’s refined mixtures improved over time, but each one suffered some kind of fatal flaw that made it impossible to sell. Pretty much everyone told him to give it a rest, including his brother-in-law, who didn’t believe it was possible to make a useful substance out of rubber.

His financial troubles weren’t getting any better, either. Experiments cost a lot of money, and he wound up selling his own furniture and his children’s textbooks to recoup the cost. He held on to a set of fine china, not out of sentimentality, but because they made good mixing bowls for rubber and turpentine.³

Working with hazardous chemicals was taking a toll on his health, as well. He was working closely with lead, he almost suffocated on one occasion, and he nearly died of a fever brought on by harsh chemical vapors.

This string of bad luck went on for many years, and in truth it would continue for many years afterward. But on one winter day in 1839, Goodyear had one very fortunate moment. By accident, he combined rubber and sulfur over a hot stove. The details, sadly, are lost to history, but the substance was transformed. Here, by a fluke, Goodyear had finally produced the form of rubber he’d been seeking all those years. This stuff was stronger and more elastic than natural rubber, and didn’t melt when it got warm outside.⁴

Inspired by Vulcan, the Roman god of fire, Goodyear patented the process under the name “vulcanization.” This was the breakthrough that eventually led to rubber raincoats, tires, and even a certain famous blimp bearing his own name, although that only happened long after he died. We do love our dirigibles here on the Episodic Table of Elements.

But whatever you think of Goodyear as a scientist, there’s no doubt he was a terrible businessman. Under his patent, the license was so cheap that he couldn’t really make any money off of it. Worse yet, other swindlers infringed on his patent, and soon Goodyear was drowning in lawyer’s fees.

He never recovered. When Charles Goodyear died in 1860, he was $200,000 in debt — about five and a half million in today’s dollars. But for as motivated as he had been by money, he seems to have known there were things more important than personal wealth. Shortly before his death, he wrote,

In reflecting upon the past, as relates to these branches of industry, the writer is not disposed to repine and say that he has planted, and others have gathered the fruits. The advantages of a career in life should not be estimated exclusively by the standard of dollars and cents, as is too often done. Man has just cause for regret when he sows and no one reaps.”⁵

Goodyear’s interest in vulcanization was purely academic. Or perhaps more accurately, economic. But the point is, he could afford to take his time with his inventions. Our next scientist found himself dealing with a problem far more personal in nature, and racing against a much faster clock.

Gerhard Domagk was a German pathologist who, in the 1930s, was trying to cure infectious diseases with industrial dyes. One of the theories floating around at the time was that bacteria could be killed by turning their internal organs the wrong color, so he was testing a sulfur-based red dye called prontosil.

In one trial, he infects two groups of lab mice with ten times the lethal dose of streptococcal bacteria. He treated the first group with prontosil, and left the second alone as a control group. A few days later, all the mice treated with prontosil were alive, and all the rest were dead.

This was the experiment that would be stuck in his head a few years later, in 1935, when Domagk’s six-year-old daughter, Hildegard, tripped and broke off a sewing needle in her hand. A doctor cleaned the wound as best he could, but in the ’30s, that didn’t mean very much. Even small cuts and scrapes like this were prone to infection that was often lethal. In 1924, President Calvin Coolidge’s son got a blister on his foot from playing tennis, and within a week, was dead from bacterial infection.⁶ Sure enough, Hildegard became bedridden with a high fever. Soon, the doctor warned, she would require an amputation to prevent the infection’s spread from her arm to the rest of her body.

Domagk could only think of the mice who had been able to fight off an infection just like this with prontosil. But mice are not humans, and other trials provided Domagk with a heaping portion of doubt. When doused with prontosil in a petri dish, streptococci fared just fine. They didn’t die off, or appear to suffer any ill effects whatsoever. What few human trials had occurred didn’t conclude anything definitively, except that prontosil reliably caused people’s skin to turn a bright red color.

This was a harrowing dilemma for Domagk. He knew that amputation was a last-ditch effort that was likely to merely delay the inevitable, but he was also aware that by administering experimental drugs, he could very well make himself liable for the death of his own daughter.

Whatever his thought process, he came down on the side of action. He quietly purloined samples of the red dye from his lab, took them home, and injected them his daughter’s veins. One can only imagine what he must have thought when Hildegard quickly took a turn for the worse.

Her fever spiked, then fell, then spiked again, over the course of weeks. Finally, on Christmas Eve, 1935, she stabilized and made a full recovery — and was able to keep both her arms.

Domagk was elated, of course, but had to keep the news of this miracle to himself. He didn’t want to introduce bias to the important scientific work he and his colleagues were doing. This actually paid off, and he did receive his accolades the following year, when prontosil helped another, more prominent child survive a streptococcal infection: Franklin D. Roosevelt, Jr. What a difference twelve years of medical research can make, even if you’re a president’s son.⁷

For his discovery, Domagk was awarded the 1939 Nobel Prize in Medicine. In previous episodes, we’ve seen how this can sometimes be a mixed blessing, and so it was for today’s hero. See, earlier in the ’30s, the committee had awarded the Nobel Peace Prize to Carl von Ossietzky, a German journalist, pacifist, and socialist who was outspoken against the Nazi regime.

This really agitated Adolf Hitler, particularly since von Ossietzky was at the time locked away as a traitor. The movement in favor of awarding the prize to von Ossietzky campaigned with the slogan, “Send the Peace Prize into the concentration camp.” Hitler found himself unable to prevent von Ossietzky from receiving the prize, but he did everything in his power to ensure that no German would win another Nobel Prize under his watch. He made it effectively illegal for any German citizen to accept any Nobel Prize.⁸

So when Domagk accepted the award in 1939, things did not go well for him. He was arrested and beaten by the Gestapo, who held him for a week with no official charges. When he explained to a curious prison guard that he was imprisoned for receiving the Nobel Prize, the guard rolled his eyes and tapped his head as if to tell his fellow jailers, “Get a load of this guy.”^{9 10}

Domagk did finally receive his Nobel Prize in 1947, but by that time, he was no longer allowed to collect the monetary portion of his award.¹¹ Perhaps instead he found some solace knowing that by discovering the world’s first antibacterial drug, he was at least partly responsible for saving countless lives during World War II. Among those saved by this treatment, following a bout with pneumonia, was none other than Winston Churchill.¹²

Not every accidental finding is so beneficial. Sometimes, a discovery is simply disgusting.

In 1889, a chemical factory in the German city of Freiburg was working to isolate a sulfurous molecule called thioacetone. Unfortunately, they succeeded.¹³

Thioacetone, they were about to discover, is the most terrible and potent smell anyone has yet discovered. An official report on the incident mentions “an offensive smell which spread rapidly over a great area of the town causing fainting, vomiting and a panic[ked] evacuation.”¹⁴ As in, the entire population fled the city to escape the stinking cloud.¹⁵

A soap factory in Leeds suffered a similar catastrophe the next year, and after that, it seems like no one really took a crack at the stuff until 1967. At Esso Research Station in Abingdon, England, a stopper popped off a small test tube containing thioacetone. It was replaced without hesitation, but scientists working in an entirely separate building two hundred yards away immediately began complaining of nausea. According to that official report, “Two of our chemists who had done no more than investigate the cracking of minute amounts of trithioacetone found themselves the object of hostile stares in a restaurant and suffered the humiliation of having a waitress spray the area around them with a deodorant.”¹⁶

An embarrassing ordeal, no doubt, but at least this time, no one wound up in prison.

Sulfur is another one of those elements that gets piped directly into our homes, and it’s precisely because of its pungent properties. A sulfur-containing chemical called mercaptan smells a lot like rotten eggs, and it’s deliberately added to natural gas to provide as a warning sign whenever there’s a leak.¹⁷

Gas leaks don’t just happen in the home, though. Sometimes, the large pipelines that ferry natural gas across the countryside break open, too. Since mercaptan smells roughly similar to decaying carrion, those leaks tend to attract turkey vultures that fly overhead. Undoubtedly this results in disappointment for the birds, but it is a helpful sign for the repairman who needs to fix the leak.¹⁸

But searching beneath a group of ominously circling vultures is likely to lead to disappointment for the element collector as well. Even assuming that the scavengers have located a natural gas leak and not some freshly prepared roadkill, mercaptan is a light, colorless gas that disperses easily.

Fortunately, solid sulfur is easy to get a hold of. It’s an integral part of Epsom salt and alum, which you might have picked up after the episodes on magnesium and aluminum, respectively. It’s also in some other common minerals, like pyrite and gypsum, which is frequently sold as chalk.

The discerning collector will have a similarly easy time of things this week, as sulfur is one of the few elements that can be found free in nature. It’s most commonly found near active volcanoes, appropriately enough, so you could use this as an excuse to snap up a plane ticket to Hawaii. But you don’t need to go that far. Powdered sulfur is good at making soil more acidic, and is affordably sold for that reason — so you only really need to go as far as your local garden center.¹⁹

Thanks for listening to The Episodic Table of Elements. Music is by Kai Engel. To learn why prontosil did nothing to the bacteria in the petri dish, and why it works on humans, visit episodic table dot com slash s.

Next time, we’ll take a dip with chlorine.

This is T. R. Appleton, reminding you that it’s a real bad idea to look back at that city the Lord is obliterating with fire and brimstone.

1. Salon, Eating Satan’s Footprints. Susan McCarthy, October 29, 1999.
2. Interesting Engineering, Charles Goodyear: The Father Of Vulcanization. Christopher McFadden, December 17, 2017.
3. Connecticut History, Charles Goodyear And The Vulcanization Of Rubber. Ann Marie Somma.
4. Make, Charles Goodyear And The Vulcanization Of Rubber. William Gurstelle.
5. They Laughed At Galileo: How The Great Inventors Proved Their Critics Wrong. Albert Jack, 2015.
6. BC Medical Journal, Never Say Dye. J. C. A. Morrant, March 2012.
7. Chemistry Chronicles, Miracle Medicines. David M. Kiefer, 2001.
8. Time, The Tragic Nobel Peace Price Story You’ve Probably Never Heard. Noah Rayman, October 10, 2014.
9. Gerhard Domagk: The First Man To Triumph Over Infectious Diseases, p. 85. Ekkehard Grundemann, 2006.
10. NPR, The Saga Of A Sulfa Drug Pioneer. Scott Simon, December 23, 2006.
11. Science History Institute, Gerhard Domagk. December 4, 2017.
12. Sulfanilamide (And Its Relatives), Simon Cotton, Uppingham School, Rutland, UK.
13. Real Clear Science, The Dangerous Stink Of The World’s Smelliest Chemical. Ross Pomeroy, July 31, 2017.
14. In The Pipeline, Things I Won’t Work With: Thioacetone. Derek Lowe, June 11, 2009.
15. ThoughtCo., 10 Molecules You Don’t Want To Mess With. Anne Marie Helmenstine, June 4, 2017.
16. io9, This Is The World’s Smelliest Chemical. Esther Ingliss-Arkell, May 19, 2015.
17. SafeGas.org.
18. Popular Science, Gas Leaks Are Designed To Attract Turkey Vultures. Kelsey D. Atherton, January 25, 2016.
19. PeriodicTable.com, Sulfur. Theodore Gray.