A discussion of the thermal expansion and conductivity in liquid helium II

The negative coefficient of thermal expansion of He ii is shown to be a consequence of the disordering process which takes place as the temperature rises. The conclusion is reached that the thermal energy of He ii is mainly energy of disorder; the vibrational energy of the sound waves amounts only to a few per cent of the whole energy. A theory of heat conduction considered as a flow of disorder is put forward and is shown to be not incompatible with the experimental data at present available.