Storm glass

The inventor is unknown but the device became popular in the 1860s after being promoted by Royal Navy Admiral Robert FitzRoy who claimed that if fixed, undisturbed, in free air, not exposed to radiation, fire, or sun, but in the ordinary light of a well-ventilated room or outer air, the chemical mixture in a so-called storm-glass varies in character with the direction of the wind, not its force, specially (though it may so vary in appearance only) from another cause, electrical tension.

The compositions of the liquid in a storm glass varies but usually contains "camphor, nitrate of potassium and sal-ammoniac, dissolved by alcohol, with water and some air."

[2] The liquid within the glass is a mixture of several ingredients, most commonly distilled water, ethanol, potassium nitrate, ammonium chloride, and camphor.

This specific mixture was promoted by Admiral Robert FitzRoy although similar devices existed even two decades earlier with variants in Italy, France and Germany.

[3][4][5][6] FitzRoy carefully documented his claims on how the storm glass would predict the weather:[3][failed verification] A version of the device was available in the 18th century in France and the inventor is unknown.