Absolute Expansion Of Mercury Apparatus Dulong And Petit To determine the co-efficient of absolute expansion of mercury. Glass tubes with vertical limbs contained within glass jackets approx.460x 25 mm height x diameter, are closed by bungs and fitted with inlet and outlet tubes. Upper ends of these vertical limbs are angled on emergence from the jackets to produce two short, adjacent limbs placed against a silvered glass scale 0 to 12 cm x 1 mm. Mounted on stand 610 x 230 mm, height x width. Overall height 750 mm approx., supplied without mercury.