Weems & Plath Chrome Stormglass with Display The Weems stormglass set is a mysterious weather predictor that is sure to intrigue. Stormglass instruments have been in use since the 1750s. Admiral Fitzroy, the famous sailor and meteorologist, mounted an instrument similar to the stormglass on the mast of HMS Beagle as a storm warning instrument during his historic voyage with Darwin in the 1830s. The premise of the Weems stormglass is that changing weather affects the solubility of the mixture of chemicals in the sealed glass tube. Some believe that the changes in crystal structures have to do with the electromagnetic changes caused by weather and sun storms. Displayed on wood freestanding or wall-mounted plaque Sealed glass chamber holds the crystals of the stormglass Chrome & black plate displays a key detailing crystal formations andstormglass history Instructions & mounting hardware included Lifetime guarantee Weight: 2.3 lbs.