Paraffinic hydrocarbons, or paraffin wax, are straight chained or branched saturated organic compounds with the composition C_nH_2n+2 (Figure 4). The purity of paraffin is a question of refining degree. The industrially used paraffin and paraffin candles consists mostly of different molecular structures. The macrocrystalline paraffin wax that we used chiefly consists of saturated, normal C₁₈- C₃₀ hydrocarbons and smaller amounts of iso-alkanes and cycloalkanes with a molecular weight between 250-450. At room temperature the paraffin crystals are needle or plate shaped. A crystallographic change called allotropic transition occurs in an equilibrium transition temperature range below the melting point. The higher temperature phase is characterised by concentration of defects and a molecular structure that can rotate along the long axis (Kwang-Sup 1984). At still higher temperatures, the stable structures are systems of higher symmetry. The crystal structure depends on the molecular composition of paraffin. C₁₈-C₂₆ has triclinic crystal symmetry and C₂₈-C₃₆ has a monoclinic symmetry. Paraffin wax is usually described by the range of its melt temperature, rather than chain length (e.g. 56^o-58^oC wax). The rheological behaviour of paraffin wax has been investigated experimentally by several authors (Mancktelow 1988, Cobbold 1975, Neurath &Smith 1982). All investigated types of paraffin wax exhibit a power low creep behaviour over the limited but experimentally relevant temperature range with stress exponents of 2.6 (Cobbold 1975), 1.8 (Neurath & Smith 1982) and 2.4-4.1 (Mancktelow 1988).