The storm glass was popularised by Admiral Robert Fitzroy after his historic voyage on the HMS Beagle. How 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). This is a gorgeous decorative gift idea for the adult who has everything or someone who finds meteorology fascinating. How to read: A: Clear Liquid – Bright and clear weather B: 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 weather D: Large Flaky Crystals – Cloudy skies, snow in winter. E: Threads of Crystals At The Top – Winy Weather F: Crystals At The Bottom – Frost may be coming.