Zone-melting chromatography involves placing a sample at some point in a solidified column of purified solvent and then distributing the sample through the solid solvent by repeated passes of the molten zone. Several workers have used this technique to study the molecular weight distribution of polystyrene. Their results indicated that a molecular weight distribution of the polymer had occurred within the solvent column after repeated passes of the molten zone and that the highest molecular weight material was at the top of the column.