Young's Type, Made Of Borosilicate Glass. Column Comprises PrecisionBore Tubing With Accurately Fitted Pear Shaped Bulbs. The Close Fit Of TheBulbs, Each Of Which Is A Separate Unit, Form A Liquid Seal Between TheBulbs And The Wall Of The Column, Which Increases The Efficiency Of TheUnit. The Ascending Vapour Causes The Bubbles, Which Are ThemselvesSurrounded By Liquid, To Oscillate, Thus Effecting The Intimate Mixing OfLiquid And Vapour.