Weems and Plath 200 This mysterious weather predictor has been used since 1750. Admiral Fitzroy, the famous sailor and meteorologist, used the storm glass aboard the HMS beagle during his historic voyage with Darwin. After 250 years, how the storm glass works is still a mystery, but it is believed that it has to do with the electromagnetic changes caused by weather and sun storms. Features: -Brass finish. -Appearance of the crystals inside the glass indicates changes in the weather. -Packaged in a handsome velvet-lined black gift box with brass mounting accessories. -Include the base, self tapping screw, finial and mounting accessory. -To enable either wall or counter / table top fixed mounting. -Beautiful and unique gift for the home, boat or office. -Sealed glass chamber holds the crystals. -Encapsulated in a beautifully crafted brass cylinder. -Displayed freestanding or mounted to a boat bulkhead. -Wall using an optional mounting bracket. -Dimensions: 6.5 H x 1.25 W x 1.25 D.