Crystal Weather Predictors of Old

Nineteenth-century sailors relied on sealed glass tubes filled with chemicals to forecast storms. Depending on the weather, the liquid would spontaneously grow or dissolve delicate crystal formations.

These curious instruments became famous after being used by Admiral Robert FitzRoy during the voyage of the HMS Beagle. Inside the glass, a mixture of camphor, ethanol, and water creates shifting patterns that were once thought to detect atmospheric pressure changes. While modern science suggests temperature is the real trigger, these devices remain a beautiful piece of maritime history. Many people still display them today to see if a snowy or stormy day is approaching.