text: The liquid in the outer jacket is heated until no more air escapes from the side tube. Then, a graduated tube  filled with water is inverted over the side tube dipping in a trough filled with water. A small quantity of substance is weighed exactly in a small stoppered bottle and is dropped in the Victor Meyer's tube and sealed immediately. The bottle falls on the asbestos pad and its contents suddenly change into vapour, blows out the stopper and displaces an equal volume of air in graduated tube. The volume of air displaced is measured by taking the graduated tube out, closing its mouth with thumb and dipping in a jar filled with water. When water levels inside and outside the tube is equal, the volume of air displaced is noted. The atmospheric pressure and laboratory temperature are noted.