The distillation apparatus seen here can be used to separate a mixture of liquids with different boiling points. The mixture in the left-hand bulb is being heated over a Bunsen burner. The thermometer monitors its temperature. The most volatile compound will boil off at the lowest temperature. Its vapour passes into the condenser, a tube which is surrounded by a cooling water jacket. The hot vapour cools and condenses on the walls of the tube and is then collected in the \receiver\" flask on the right of the photo."