This beautiful conversation piece combines two ancient technologies - the Admiral Fitzroy Storm Glass and the Galileo Thermometer. The Admiral Fitzroy Storm Glass: How this storm glass really works is a mystery, but it is believed that electromagnetic changes in weather patterns activate crystals inside (sealed-glass chamber fills with crystals when air pressure decreases). Famed meteorologist Admiral Fitzroy used a storm glass on a historic voyage (1831-1836) with Charles Darwin A storm glass works on the premise that temperature and pressure affect solubility, sometimes resulting in clear liquid; other times causing precipitants to form. However, the method by which this works is not fully understood. Although it is well-established that temperature affects solubility, some studies have simultaneously observed several different storm glasses forming similar crystal patterns at different temperatures. In addition, sealed glasses are not exposed to atmospheric pressure changes and do not react to the pressure variations associated with weather systems. The Galileo Thermometer: The Galileo thermometer consists of a sealed glass tube that is filled with water and several floating bubbles. The bubbles are glass spheres filled with a colored liquid mixture. Attached to each bubble is a little metal tag that indicates a temperature. These metal tags are calibrated counterweights. The weight of each tag is slightly different from the others. Since the bubbles are all hand-blown glass, they aren't exactly the same size and shape. The bubbles are calibrated by adding a certain amount of fluid to them so that they have the exact same density. So, after the weighted tags are attached to the bubbles, each differs very slightly in density (the ratio of mass to volume) from the other bubbles, and the density of all of them is very close to the density of the surrounding water. Galileo thermometer is showing temperatures of 64 to 80 degrees.