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Dating back to the 1600s, thermometers were filled with brandy instead of mercury.

The thermometer is essentially the same as those used today, except that it was filled with brandy rather than mercury.The illustration is from the book Ma'yan Ganim (A Fountain of Gardens), published in 1629 and written by the physician and rabbi Joseph Solomon Delmedigo.

An air thermometer , an open-ended tube partly filled with water or alcohol ,a sealed liquid thermometer, at near right. The air thermometer was already well known at the time, but historians had previously credited the liquid thermometer to Ferdinand II, Grand Duke of Tuscany, in 1654. The small lettering to the right of the liquid thermometer says oleh, "ascending," the direction of the brandy when the bulb gets warm.

The instrument had an open top, making it an imprecise and impractical instrument needing frequent refills to replace evaporated alcohol. "Delmedigo's thermometer was in fact accurate enough, "that you could measure the change in temperature from day to day.