Consider everything around you as if it was a ‘bake-off’ — the air, your elbow, a phone. The list of possible ingredients — the chemical elements — is usually reckoned to number 92. London can boast the discovery of a fifth of these, including bone-building calcium, precious palladium, and radioactive radon. Counting discoveries is tricky, but here’s our round-up of those identified in the city.
Always make water when you can, said the Duke of Wellington. Answering the call of nature in an intellectual sense was natural philosopher Henry Cavendish. He was not the first person to make hydrogen but, in 1766, he was the first to realise, at his rural laboratory in Clapham, that it was an element. He called it "inflammable air" but it was later given the more convenient name of hydrogen, coming from the Greek for ‘make water’ because Cavendish showed it to be a constituent of water.
He had not finished with ‘airs’. Air is a mixture of gases and Cavendish puzzled over a residue of his samples that refused to react with anything. This unfinished business lingered on for a century.
Palladium is a lustrous metal, one of the four precious metals that need a hallmark. It was named after the asteroid Pallas, discovered around the same time in 1803.
Palladium is chemically like platinum, a substance studied by William Hyde Wollaston at his laboratory just off Fitzroy Square. He discovered palladium in residue from his platinum experiments. Many elements have been discovered in odd residues leftover when work was supposedly finished.
Wollaston did not trumpet his discovery but put palladium on sale under the name 'new silver' at a Mr and Mrs Forster's shop at 26 Gerrard Street and offered a huge £20 prize to anyone who could assemble it from other elements in front of witnesses. No one was able to claim the prize and Wollaston unmasked himself as the discoverer of palladium in 1805. He also discovered rhodium (in a residue).
Boron crops up in Cockney rhyming slang and it was indeed isolated a couple of miles from Bow bells. To those born within the sound of the bells, 'boracic lint' means skint. Oddly, 'skint' (penniless) derives from 'skinned' and borax, a boron compound, has long been used to soothe the skin.
Experiments involving the new-fangled electric current from a huge battery in the basement of the Royal Institution in Mayfair were conducted by Sir Humphry Davy. He isolated first metallic potassium then sodium in 1807, and in 1808 came boron, barium, calcium, strontium and magnesium.
His assistant, Edmund Davy described the moment Sir Humphrey had his breakthrough: "When he first saw the minute globules of potassium burst through the crust of potash, and take fire as they entered the atmosphere, he could not contain his joy — he actually danced about the room in ecstatic delight." Sodium is similar and both are usually stored under oil as they react violently with water. Magnesium’s dazzling flame peps up fireworks. But boring boron must have been something of a disappointment.
The Royal Institution claims the discovery of 10 elements. After various tests Davy decided chlorine was an element in 1810. But he nailed iodine in a hotel room in France. So we discount iodine. We'll come back to the other one later.
Thallium poisoning was a murderous modus operandi used by detective story writer Agatha Christie, devious because of the delayed onset of its effect and the symptoms which might suggest other causes. In Victorian times thallium was used as a rat poison and sometimes even used medically. It was also an early suspect in the recent Litvinenko case.
The element was discovered in 1861 by William Crookes, who had a home and laboratory at Mornington Terrace, Euston. After an observation by Wollaston of dark lines in the light spectrum obtained from the sun, followed by further discoveries that certain colours were characteristic of certain elements, Crookes observed a brilliant green colour in a flame and went on to show that he had a new element, which he named after the Greek for bud, a nod to its green flame.
Sunshine on Kilburn
Helium had the distinction of being discovered in the sun before any was found on earth, also given away by its colour signature. Norman Lockyer, a civil servant at the War Office, deduced the existence of a new element in 1868 with the aid of his telescope in the modest and smoggy environs of his home in Kilburn.
You Wait for Decades, Then Several Turn Up at Once
Science sometimes advances by picking at niggling details. Lord Rayleigh, at the Royal Institution again, was puzzled by Cavendish’s tiny residue of air when everything known had been extracted. It turned out to be argon, and was described in 1894. Argon is one of the ‘inert’ gases. Another, helium, was finally caught seeping from rocks by William Ramsay at University College in 1895 and he went hunting for others.
Xenon, krypton and neon came in 1898 when he wondered if his argon sample was pure, and found that it wasn’t. Radon was first collected in 1910. It is a natural but invisible hazard in mines and granite buildings. Rayleigh and William Ramsay picked up Nobel Prizes in 1904 for finding the inert gases. These gases are surprisingly useful despite being inert, and find application in refrigeration, welding, diving, lighting, lasers and medical imaging.