As it’s shaping up to be my final days in Devon, me and my #1 Nerd travelled to Barometer World, a pilgrimage we’d been promising to make since the start of summer. As the name suggests, it’s a Mecca of meteorological wonder, boasting hundreds of aneroid and mercury barometers, barographs, thermometers, hygrometers and thunder bottles. It’s a bargain at £2.50 and I encourage everyone to go.
What intrigued me most of all, though, was the strange crystals attached to many of the old barometers. This, I was told, was storm glass, a curiosity whose origins are hidden in the mists of time.
Back in the day, mercury barometers were very expensive, and only available to the wealthy. Unfortunately “wealthy” was not a word that could describe many of those who were at the mercy of the weather: farmers, fishermen, sailors, and so on. They had to rely on storm glass, an inexpensive and profoundly inaccurate divining tool. A mixture of chemicals in a sealed glass tube present a liquid that shifts from solid to crystalline under circumstances that still aren’t full understood. From these fluctuating patterns, predictions were made about the approaching weather.
In 1831, a tempestuous sea captain named Robert FitzRoy (nickname: “Hot Coffee”) set out on a voyage to chart the coasts of South America (you may have heard of the voyage: on board was a young naturalist named Charles Darwin). FitzRoy had a keen interest in meteorology and attempted to quantify the exact nature of storm glass. His observations eventually led to a standard script printed on many storm glasses, such as “A cloudy glass with small stars indicates thunderstorms” and “If there are crystals at the bottom, this indicates frost“.
In October 1859 a huge storm, the greatest in living memory, struck the British Isles. The clipper Royal Charter, on her way from Melbourne and packed with returning gold miners, was sunk with the loss of 459 lives, as were some 200 other ships. It was a national disaster. In response, FitzRoy pushed for the establishment of weather stations around the nation’s coasts to monitor atmospheric conditions. Storm glasses were distributed to fishing villages, earning them the name “FitzRoy’s Barometers”. In fact, it was FitzRoy who coined the term “weather forecast” in the course of his initiative. Reports from the land stations were sent back to London, under the management of the newly-formed Meteorological Office. The first weather forecasts published in the pages of the Times in 1860, and a system of flying cones in fishing ports to warn sailors of approaching gales developed the following year. To this day, the Met Office monitors the weather around Britain and issues regular warnings to mariners. Originally, the owners of fishing fleets objected to the system, as it meant boats were more likely to stay in port, but the fishermen themselves welcomed it, and FitzRoy is credited with saving untold lives. One of the areas covered in the Shipping Forecast, a stretch of ocean north-west of Spain, is designated FitzRoy in honour of the man. Sadly, having secretly exhausted his entire fortune in the drive to build a better weather prediction system, and battling with depression, FitzRoy committed suicide in 1863.
As mercury barometers fell in price, the mysterious and inaccurate storm glass fell out of favour, and was largely forgotten. As such, nobody is exactly sure how they work, and little research has been carried out to investigate their workings. Cecil Adams of Snopes The Straight Dope had a go, and found their predictions to be no better than chance. The fluid consists of a mix of camphor crystals, potassium nitrate, ammonium chloride, water and alcohol. As the glasses are sealed, it’s unlikely that pressure is responsible for the changes. Changes in solubility due to temperature are far more likely, but who’s to say unless you investigate it yourself?
Which brings me to my final point: all five ingredients of the storm glass aren’t that hard to get hold of. So maybe it’s time to run a few experiments of my own…