what liquor filled thermometers before mercury did the job?
The alcohol thermometer is an alternative to the mercury-in-glass thermometer and has similar functions. Unlike the mercury-in-glass thermometer, the contents of an alcohol thermometer are less toxic and will evaporate away fairly quickly. The ethanol version is the most widely used due to the low cost and relatively low hazard posed by the liquid in case of breakage.
The alcohol thermometer was the earliest, efficient, modern-style instrument of temperature measurement. As is the case with many early, important inventions, there are several people credited with its invention. These include Ferdinando II de’ Medici, Grand Duke of Tuscany, who in 1654 made sealed tubes part filled with alcohol or urine, with a bulb and stem, depending on the expansion of a liquid, and independent of air pressure. Other sources, including the Encyclopædia Britannica, credit German scientist Daniel Gabriel Fahrenheit with inventing the alcohol thermometer in 1709. Fahrenheit was a skilled glassblower and his alcohol thermometer was the world’s first reliable thermometer.