https://www.sciencing.com/hydrometer-calibration-procedures-5501425/
A hydrometer is a device that measures the specific gravity of a liquid. They can't be adjusted, so calibration consists of determining a correction factor to...
calibration procedureshydrometer
https://www.instructables.com/Measuring-Alcohol-Content-With-a-Hydrometer/
Measuring Alcohol Content With a Hydrometer: The first couple times you brew your own beer or wine, you're more concerned about the end product - delicious,...
alcohol contentmeasuringhydrometerstepspictures