FitzRoy’s Glass: Victorian Weather Marvel Or Glorified Thermometer?

FitzRoy's storm glass is a sealed vessel containing alcohol, water, camphor, saltpeter, and sal ammoniac that forms dramatic crystal patterns. Vice Admiral Robert FitzRoy promoted it in the 1860s as a weather prediction tool, believing 'electrical tension' in wind drove its behavior. Scientific studies, including an 1863 critique and a 2008 paper, found it functions essentially as a crude thermometer with little actual predictive correlation to weather. Despite this, the device remains a popular decorative curiosity, and the chemistry behind its dendritic crystal formations is genuinely interesting.