How this storm glass really works is a mystery, but it is believed that electromagnetic changes in weather patterns activate crystals inside (sealed-glass chamber fills with crystals when air pressure decreases). Famed meteorologist Admiral Fitzroy used a storm glass in 1859. Guidelines: If there are large flakes throughout the liquid, it will be overcast in temperate seasons or snowy in the winter. If there are threads near the top, it will be warming or windy. If the liquid contains small stars on sunny winter days, then snow is coming. If there are crystals at the bottom, this indicates frost. A cloudy glass with small stars indicates thunderstorms. If the liquid in the glass is clear, the weather will be bright and clear. The Storm Glass is standing on a Mahogany wood base and is 9 inch tall.