Stanley London Miniature 4-inch Admiral Fitzroy Storm Glass Capsule Admiral FitzRoy used the storm glass on his historic voyage with Charles Darwin. This FitzRoy Storm Glass Capsule can be used as-is, or a decorative metal or wooden housing can be made. This Storm Glass Capsule measures 3 7/8 inches (9.8 cm) tall, 1 inch (2.5 cm) in diameter, and weighs 1 5/8 ounces (46 grams). The formation of crystals are used to interpret the weather. Instructions for interpreting the crystal patterns are included.