The concept that decreasing atmospheric pressure predicts stormy weather was postulated by Lucien Vidie -- and it"s the basis for a weather prediction device called a storm glass or liquid barometer. * A narrow spout connects to the body below the water level and rises above the water level, where it is open to the atmosphere. * Includes limited 2 year factory warranty. * Includes glass drip cup to avoid staining. Clear glass bulb with world map etching. * Note: You can vary the water color by adding food coloring of your choice. The image above is shown in blue.