The Storm Glass was, as far as we know, first used in about 1750 by sailing ships to predict stormy weather.

The first proper report concerning its use on board a ship stems from the Darwin Expedition in 1831-1836. On December 27th 1831, Charles Darwin set off in the three-masted bark “HMS Beagle” under the command of Captain Robert Fitzroy (1805-1865), who throughout his career at sea and on land used the Storm Glass as a way of predicting the weather. Fitzroy was also a meteorologist who later became director of the British Meteorological Office. He wrote the famous “Weather Book” popularising the art of forecasting the weather. 

Fitzroy believed that the Storm Glass worked because of  static electricity in the fields around us. A somewhat revolutionary thought at the time! He claimed that "if fixed, undisturbed, in free air, not exposed to radiation, fire, or sun, but in the ordinary light of a well-ventilated room or outer air, the chemical mixture in a so-called storm-glass varies in character with the direction of the wind, not its force, specially (though it may so vary in appearance only) from another cause, electrical tension".

In 1859, violent storms struck the British Isles. In response, the British Crown distributed storm glasses, then known as "FitzRoy's storm barometers", to many small fishing communities around the British Isles for consultation by ships in port before setting sail.

The Storm Glass is thought of as a form of barometer. You can consult it daily to see what the weather is going to do in the next 24 hours or so. Others apparently use the Storm Glass to predict when the fish are biting! The mechanism by which it works is still debated. While a barometer measures the atmospheric pressure, an article in the 2008 Journal of Crystal Growth concluded that temperature change is the sole cause of crystal growth in storm glasses.

For optimum use, place the Storm Glass in a cool place, for example in a north-facing window or on a boat. Once it has settled down, the pattern of crystals inside the storm glass is supposedly an accurate indication of the weather over the next day or so. A historical curiosity and certainly a fascinating talking piece. See the illustrations for the different crystal patterns. 

Made with polished brass, the bracket to hang it up is included.  

Height 145mm
Weight 450g