Elegant Fitzroy Storm Glass - Fascinating Weather Instrument and Home Décor Piece

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Watch as this Unique Swan shaped Storm Glass forms different crystal patterns that correspond to changing weather formations.


A storm glass works on the premise that temperature and pressure affect solubility, sometimes resulting in clear liquid, causing precipitants to form. However, the method by which this works is not fully understood. Although it is well-established that temperature affects solubility, some studies have simultaneously observed several different storm glasses forming similar crystal patterns at different temperatures. In addition, sealed glasses are not exposed to atmospheric pressure changes and do not react to the pressure variations associated with weather systems.

How the Fitzroy 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).

The Admiral Fitzroy storm glass came into use in the early 1700s. Sailors attached a similar instrument to the mast of their ships. By interpreting the constantly changing crystal formations, they relied upon it to forecast good weather and foreboding conditions at sea. As a commander of the HMS Beagle, Admiral Robert Fitzroy (1805-1865) participated in Charles Darwin's expedition (1834-1836) and conducted a detailed study of this instrument. He refined the chemical formulation and published the following observational guidelines:

-CLEAR LIQUID - Bright and clear weather.
-CLOUDY LIQUID WITH SMALL STARS AND CRYSTALS AT THE TOP - Cloudy weather and often predicts pending thunderstorms.
-SMALL DOTS IN THE LIQUID - Humid or foggy weather.
-LARGE FLAKY CRYSTALS - Cloudy skies or snow in winter.
-THREADS OF CRYSTALS AT THE TOP - Windy weather.
-CRYSTALS AT THE BOTTOM - Frost may become.

Instructions included.

  • Height: 7 inches
  • Width: 7 inches
  • Depth: 3 inches