The storm glass was popularised by Admiral Robert Fitzroy after his historic voyage on the HMS Beagle. This storm glass is the same size and shape as our 28cm Galileo Thermometers, and they make an attractive pair on the windowsill.\nHow the Storm Glass works is still a mystery, but it is believed that electromagnetic changes in weather patterns activate the crystals inside (sealed glass chamber fill with crystals when air pressure decreases).\nThis is a gorgeous decorative gift idea for the adult who has everything or someone who finds meteorology fascinating.\nHow to read:A: Clear Liquid -Bright and clear weatherB: Cloudy Liquid -Sometimes with small stars and crystals at the top. Cloudy weather and often predicts thunderstorms and rain.C: Small Stars in Liquid -Humid or foggy weatherD: Large Flaky Crystals -Cloudy skies, snow in winter.E: Threads of Crystals At The Top -Winy WeatherF: Crystals At The Bottom -Frost may be coming.