This feature first appeared in September 2023 on Londonist: Time Machine, our much-praised history newsletter. To be the first to read new history features like this, sign up for free here.
Here’s a staggering fact for you. Of the 92 naturally occurring elements in the Periodic Table, about a fifth were discovered right here in London. We can thank Mayfair’s Royal Institution for most of these, but the most abundant of the London elements — helium — was first glimpsed from a back garden near Finchley Road. And not by a tenured professor of astronomy, but by a civil servant hobbyist. This is the little-known story of Norman Lockyer.
But before we get into the local history, we first need to gird our loins with some elementary science. Don’t get nervous. It involves marmalade.
“Tantalising sign of possible life on faraway world”
It’s an old trick, this ability to know what something is made of simply by looking at it. We do it all the time with our eyes. Glance at a Volkswagen and you know it’s made of metal, not wood, and certainly not marmalade. Steel absorbs and reflects light very differently to mahogany or delicious fruity preserve. Each material throws its own unique medley of wavelengths into our eyes, from where our brains make sense of it.
Similarly, astronomers can “look” at stars and other distant objects and work out what they’re made from. Just like cars and jams, different gases emit and absorb light in different ways. Each has a telltale fingerprint, which can be read like a bar code with some fairly rudimentary technology. The technique, a form of spectroscopy, is now so advanced that we can work out precisely which molecules are floating around on a planet 700 trillion miles away.
155 years ago, this spectroscopic know-how was being developed much closer to home, and with universe-changing results.
Rise of the helium man
Civil servants make the best hobbyists. Today, they tend to hoard trivia and appear on shows like Mastermind, but back in Victorian times they would often dabble in the sciences. Lockyer was one such; a keen amateur astronomer, he’d built up his reputation enough in his 20s to become a member of the Royal Institution and a Fellow of the Royal Astronomical Society. “He took astronomy because he loved it,” wrote biographer Aloysius Cortie, “and because of the appeal it made to his intellectual faculties”.
Lockyer had a particular passion for solar spectroscopy. In other words, he enjoyed pointing his ‘scope at the sun to try and work out its composition. Back in the 1860s this was still a bit of a muddle. Recent studies had used spectroscopy to detect the presence of chemical elements in the Sun. But nobody really knew what was going on up there.
In early 1865, Lockyer and family had moved to a house just off the Finchley Road in north-west London. The bewhiskered amateur set up his 6¼ inch telescope in the back garden. It was here, in 1868, that he would make a discovery that would, eventually, change our whole outlook on the universe.
Lockyer used a special spectroscope — obtained with the aid of a government grant, and now in the care of the Science Museum — to block out the disc of the Sun. This enabled him to study solar prominences, which are like solar flares, but anchored to the Sun rather than ejecting into space. It was the first time this had been possible without the rare aid of a solar eclipse.
On 20 October 1868, he noticed a prominent yellow line at a wavelength that did not correspond to any known material. Lockyer very quickly came to the conclusion that he’d found a new element, which he dubbed helium, after Helios the Greek personification of the Sun. It was a giddy leap of faith which, today, would bring shouts of “more data needed”. But his hunch was sound, and he would later be proved correct. Lockyer had detected helium in the Sun before it was ever found on Earth.
Now, helium to most people is a frivolous gas. It lifts children’s party balloons, and besqueakens the voice. Of all the gasses, helium is the silliest. But if we turn from the comic to the cosmic, helium is a very big deal indeed. The Sun produces colossal amounts of the element every second. Its core business is to fuse hydrogen ions into helium, in the nuclear process that keeps us all warm. It’s what most stars do. As such, the element makes up an estimated 25% of all the normal matter in the universe. By one measure, a quarter of all stuff is helium.
None of this was known in 1868, and decades of further scientific percolation were needed before the Sun’s composition and processes would be understood. But Lockyer had taken the first step to identifying the second most-abundant element in the universe.
Lockyer shares the honour of discovering helium with Frenchman Pierre Janssen, who independently spotted the rogue spectral line in 1868. The pair coincidentally filed their paperwork on the same day, and so take equal credit. But it was Lockyer who most confidently linked the spectroscopic result to a new element, and it was Lockyer who named it helium. His wife Winifred also takes some credit. She too had made a name for herself in the scientific world, as a translator of scientific works. She collaborated closely with her husband to verify the spectral data.
Lockyer was almost immediately elected to the prestigious Royal Society. He would be knighted many years later, when helium was first detected on the Earth.
Just off the Finchley Road
So where exactly did Lockyer make his big discovery? Most sources describe his address as West Hampstead, a staunchly middle-class suburb notable for having three railway stations within metres of one another. In fact, the house was some distance from this centre, up on Fairfax Road (then called Victoria Road). We’d probably call it South Hampstead today, or perhaps Swiss Cottage. The family home was number 24, which would place them about here:
Of course, the area was not yet as built up as we see on a modern map. Indeed, Fairfax Road was a frontier street in the 1860s, with only fields lying to the west. To the east, Lockyer was just a block or two away from the Swiss Cottage pub, which gave its name to the area and still exists today. The village of West End (now West Hampstead) was the nearest named conurbation, a short walk to the south-west. (It was here, 70 years later, that another space-gazer would spend his formative years: Gerry Anderson, who gave the world Thunderbirds and Captain Scarlet.)
The Lockyer home was well noted in astronomical circles. Learned men and curious amateurs would regularly visit its back garden to have a go on Lockyer’s telescope. One such was the Poet Laureate Alfred, Lord Tennyson, who was fascinated by the heavens. Lockyer would later write a book about the great man, called Tennyson as a Student and Poet of Nature.
Alas, the row on which the house stood has been rebuilt in the intervening years, and no hint can be found on Fairfax Road about its role in the discovery of helium. To find Lockyer’s Blue Plaque, you have to journey to Penywern Road in Earl’s Court, where the family moved in 1876. Another plaque marks his childhood home in Rugby.
Lockyer would have to wait until 1895 before his new element of helium could be definitively isolated here on Earth. The crucial experiment took place just a couple of miles away at University College. The man this time was William Ramsay, who also (collaborating with others) nailed argon, krypton, neon, xenon and radon.
Sadly, Lockyer, Janssen and Ramsay did not live long enough to learn that helium makes up a quarter of the Sun, and the wider universe. This was first proposed in the remarkable 1925 doctoral thesis of Cecilia Payne-Gaposchkin... but that’s another story.
Other achievements
In 1885 he could finally call himself a professional astronomer, when he was appointed professor of astronomical physics at the Royal College of Science, now part of Imperial College. In late life he moved to Salcombe Regis in Devon where he set up an observatory (still going, under his name) and died in 1920. His legacy lives on every time you ponder the celestial orb that makes life possible… or inflate a party balloon.
