It’s easy to make a storm glass – just mix the chemicals and watch crystals form and disappear. But there might be a scientific basis to its supposed powers
FOR 19th-century mariners, forecasting the weather was a matter of life and death. With few facts to go on, folklore held sway: spouting whales, porpoises entering a harbour, or even lone crows, were all thought to warn of impending storms. Yet vice-admiral Robert FitzRoy of the British Royal Navy knew better.
Captain of HMS Beagle during Charles Darwin’s voyage in the 1830s, FitzRoy went on to found the UK’s Meteorological Office. By collating data from barometers around the British Isles, he created the world’s first weather maps and finally put forecasting on a scientific footing. He even penned a bestseller to explain his ideas: The Weather Book: A manual of practical meteorology. Less well-known is his conviction that he could predict the weather by staring into a crystal ball.
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Robert FitzRoy strongly believed in the powers of his storm glass (Image: DEA Picture Library/Getty)
FitzRoy’s instrument was a “storm glass”. Inside it, tiny white crystals would form, grow and disappear, seemingly controlled by some mysterious power. If the glass was clear, FitzRoy claimed, so would the weather be; if its contents turned cloudy, rain was on the way. Crystals at the bottom were a sure sign of frost, while suspended crystals indicated snow. Today this may seem absurd. Many of FitzRoy’s contemporaries dismissed his claims as ridiculous. Yet new studies suggest there may be more to this curious instrument than sceptics imagined.
Video: Weather predictions of a storm glass
“The swollen sea rose in huge billows. The birds disappeared with the exception of the petrels, those friends of the storm. The barometer fell sensibly, and indicated an extreme extension of the vapours. The mixture of the storm glass was decomposed under the influence of the electricity that pervaded the atmosphere. The tempest burst on the 18th of May…” 20,000 Leagues Under the Sea by Jules Verne, 1870 (Image: Antoine D’Agata/Magnum Photos)
There is certainly nothing magical about the contents of a storm glass: each contains a combination of camphor, potassium nitrate and ammonium chloride, all dissolved in a mix of alcohol and water in precise proportions. FitzRoy wrote that accurate storm glasses could be bought from a shop on old London Bridge, but there were many imitations “more or less incorrectly made”. Storm glasses were around several decades before FitzRoy described them: one version was made in France in the 1780s. Ultimately, though, the origin of their design is lost in time.
Public ridicule
Are these crystals controlled by atmospheric electricity? (Image: CCO 1.0)
According to FitzRoy, the predictive powers of the storm glass arose from its sensitivity to electrostatic forces carried in the wind. He claimed the crystals responded to the direction of the wind, even if the glass was indoors. A north wind produces beautiful crystal growths “like fir, yew, fern leaves or hoar frost”, he wrote, while a south wind results in “a soft, melting substance” without crystalline lines and spikes. There were also “very remarkable differences” between an east and a west wind.
Not surprisingly, weather forecasting as a discipline encouraged doubters. In 1854, the claim that FitzRoy’s new Meteorological Office might predict the weather in London a day in advance was met by laughter in parliament. And despite FitzRoy’s attempts to publicise the benefits of the storm glass – he dedicated a chapter to it in his book, for instance – few saw it as anything more than a decorative paperweight.
To gain support for his device, FitzRoy wrote to Michael Faraday, claiming that the electrostatic effect had been proved with a “delicate galvanometer”. Yet when Faraday responded that he did not see how the glass could be affected by anything other than temperature, FitzRoy dismissed the criticism and suggested that only experienced observers could read the glass. He even ensured that both barometers and storm glasses were issued to ports to provide fishermen with alerts of stormy weather.
Then the device came to the attention of , noted scientific investigator and fellow of the Royal Society. Meteorology was a particular interest, and he was vigorous in correcting popular errors and misconceptions. Tomlinson decided to test FitzRoy’s claims scientifically.
Over several months in 1862, Tomlinson recorded the response of a storm glass to the weather. He carefully noted how and where crystallisation occurred, and his observations occasionally became lyrical: “lower deposit heaped up towards window like a steep hill hollowed out and covered with beautiful foliage.” But he reasoned that all of the phenomena were caused by . “It may be fairly concluded that the storm glass acts as a rude kind of thermometer,” Tomlinson wrote. That, combined with uncertainty over the exact composition of the camphor mixture, left him recommending that the instrument be abandoned by the Meteorological Office.
Tomlinson carried the day. Barometers remained a fundamental part of weather forecasting, while the storm glass was all but abandoned. Yet it has not been entirely forgotten.
In 2008, researchers in the UK and Japan took a fresh look at the instrument and suggested, independently, that Tomlinson may have missed something. Measurements made by geologist Allan Mills at the University of Leicester, and a team led by physicist in Kawasaki, confirmed that the crystals in the glass respond to temperature. Nagashima also proved the crystals were pure camphor and that the height reached by these crystals in the storm glass varies over a larger range than camphor crystals in ethanol or water alone. This suggests that the alchemists who came up with the original recipe managed to .
Yet both studies also hint that the storm glass is more than just a simple thermometer. The chemical cocktail inside seems to have a memory: crystal growth and shape at any one time appears to depend on the pattern of temperature changes that the instrument has experienced. “The appearance of the crystals is completely different, even at the same temperature, ,” says Nagashima. Mills found a similar thing, concluding that a rapid fall in temperature, perhaps associated with an approaching cold front, could conceivably show up as . Perhaps FitzRoy’s claims for the instrument aren’t so unlikely after all.
“The chemical cocktail in the glass seems to have a memory”
Other intriguing evidence for the storm glass’s sensitivity has emerged thanks to Edward Baranovsky and his colleagues at the Crimean Astrophysical Observatory. They have gathered data daily from separate storm glasses at their lab near Nauchny in Ukraine since 1995. They suggest that these instruments behave in similar ways: the vertical height of the crystals generally increased and decreased simultaneously during this time. More surprising, however, is their claim that these patterns were reproduced in another storm glass 2500 kilometres to the east, in Chelyabinsk, Russia ().
It’s unlikely that local weather conditions at these sites follow the same patterns. Rather, Baranovsky suggests that the storm glasses are picking up some regional or global atmospheric phenomenon – perhaps weak electromagnetic fields generated in the ionosphere – that influences the water in the instruments and so alters the growth of the crystals. It is an uncanny echo of FitzRoy’s own explanation.
Nagashima, who has studied camphor crystals for 12 years, admits that understanding the complex chemistry in the storm glass is hugely challenging: “I enjoy unravelling the mystery,” he says. However he is sceptical of any electromagnetic influence.
But don’t dismiss the idea just yet, says Nicholas Blagden, an expert in crystal formation and growth at the University of Lincoln, UK. These processes are still a bit of a mystery, he says, and the literature is riddled with reports of substances that crystallise one day and then stop. “People have talked about the effect of magnetic fields on crystallising calcium carbonate. But it wouldn’t be in my top five of possible influences.”
For now, it seems there’s just one firm forecast: to have any hope of predicting weather with FitzRoy’s jar, we’ll need to crack its chemical secrets first.
This article appeared in print under the headline “Readers of the storm”
