High-frequency absorption phenomena in liquids and solids

The war-time extension of the electrical frequency spectrum to beyond 1010 c/s opens up a field of dielectric study which promises to give great assistance towards a fuller understanding of the liquid and solid states. The paper discusses briefly the work on liquid and solid dielectric substances carried out in this country during the war period, when the emphasis was necessarily on the provision of information on substances of technical importance such as polythene, water and ice, and during the immediate post-war period when a fuller attempt was made to study the scientific significance of this data and also to supplement it with measurements on simpler systems. This work has revealed more convincingly than had previously been possible the limitations of existing theories of dipolar absorption in liquieds and solids, and refers to the possibility of observing resonance absorption effects in solids in the microwave region.