Barometers Illegal in Garbage & Drains Contains Mercury Hazardous Waste Aneroid vs. Mercury Barometers Aneroid barometers are circular and have a pointer and dial face. These barometers do not typically contain any mercury, even though the unit of measure is inches or millimeters of mercury. For a mercury barometer, the reading is taken from the height of the mercury in a glass column, much like a thermometer. Never Throw Away Mercury Barometers Most antique barometers contain about 4 ounces of mercury that can be released into the environment if disposed of improperly. If your barometer contains mercury, dispose of it with hazardous waste. Ways to Reuse Repair Antique Barometers If you have a broken antique barometer, have it repaired instead of throwing it away. Check out Barometer Fair – they offer restoration and repair services.