This document discusses the calibration of various glassware used in dairy analysis laboratories. It provides methods for calibrating volumetric glassware like burettes, pipettes, and volumetric flasks using comparison, BIS, and mathematical methods. Milk butyrometers and lactometers are calibrated by comparison to standard instruments or using BIS methods involving mercury or salt solutions. Thermometers are calibrated by comparison, locating zero and boiling points. Freezing point depression thermometers are calibrated using molal solutions that depress freezing points by known amounts. Burettes are checked for accuracy at intervals by measuring delivered volumes.