Miraculous liquid thermometer It is not exactly known when the first liquid thermometer was invented. Galileo Galilei probably worked between 1593 and 1603 on an instrument measuring temperature. He called this instrument “Thermoscope” This invention lead us to the thermometer we know nowadays. Although the working of the thermometer in the eyes of many is miraculous, it is based on a simple Physical law, the Archimedes principal. A body floating in liquid sinks when temperature is rising because the effective density is increasing. The other way is when temperature is increasing and effective density is going up the body in the water will rise. The temperature you can read on the Galileo thermometer on the small labels connected to the glass balls. With this instrument you can read the temperature accurate to 1 degree Celsius. The precision is very high because we use a liquid that has a very accurate effective density by using minerals and crystals and a high solution of mineral gemstone concentrate like the well known Hildegart von Bingen principal.