Fitzroy Storm Glass Weather Predictor

A sealed glass vessel of clear liquid, mounted on a small wooden base, in which crystals form, dissolve and drift as conditions around it change. The design goes back to nineteenth-century ships, where Admiral Robert FitzRoy popularised it as a barometer of sorts. Whether it forecasts anything reliably is a question people have argued about for two centuries; what is beyond argument is that it is quietly fascinating to have on a desk.

The readings are traditional and easy to learn. Clear liquid was taken to mean fair weather ahead. Small clouded crystals suggested rain. Crystals climbing or floating high in the vessel meant a storm was on the way, and feathery, scattered formations were read as snow or frost. In practice the glass responds mainly to temperature, so it changes most visibly when a room warms up or cools down across a day.

Three sizes are available, from a small desk piece to a larger shelf ornament. The base is solid wood and the vessel is sealed glass. Keep it out of direct sunlight and away from radiators, both of which will drive the crystals to one extreme and hold them there. This is a decorative object, not a scientific instrument or a substitute for a forecast. Keep it out of reach of children and pets, and do not attempt to open the sealed glass.

• Sizes: S 12 x 6cm, M 18 x 8cm, L 22 x 10cm
• Sealed glass vessel on a solid wood base
• Crystals shift with ambient temperature and conditions
• Decorative object - not a scientific instrument
• Keep out of direct sunlight and away from radiators
• Do not open the sealed vessel
• Keep out of reach of children and pets
• Dust the glass with a dry cloth