Insulating liquids

True liquid behaviour is difficult to measure, owing to the formation of solidparticle bridges and surface layers on electrodes. Conduction and breakdown of oils and simpler liquids can be studied, at electric stresses of up to 1000kV/cm and above, beyond a region of bridge formation. The study of dissolved gases, electrode surfaces, electroluminescence and chemical structure has resulted in a closer agreement between industrial and fundamental work, although the ultimate theoretical appreciation of insulating liquids still eludes the investigators.