This thermometer is based on a thermoscope invented by Galileo Galilei in the early 1600`s. It`s made from a clear glass 23.5 inch (60 cm) high, 2.25 inch (6 cm) diameter liquid filled, sealed glass tube with a 3.5 inch (9 cm) diameter base, and 11 colored liquid filled floating glass bubbles. A metal tag engraved with varying degrees is attached to each bubble acting as counterweights for temperature readings as the bubbles rise and float with the changing temperatures. The bubble floating in the gap between those at the top and bottom indicates the ambient temperature. It makes a wonderful gift for history buffs, or those that like really cool things, and a fun conversational piece for your own home or office!