The paper deals with several important problems of particular theoretical and practical interest at the present time in connection with the design, manufacture, and operation of high-voltage impregnated-paper cables.In the first place, the phenomenon of dielectric absorption is discussed as a question of fundamental importance and as a basis for a proper understanding of dielectric losses. It is shown how dielectric resistance must be carefully defined in order to be of any value as a characteristic of cable quality, or in analytical discussion, and the results of experiments are given to show that whilst the usually accepted absorption expression departs from the truth, it can be used within limits. Experimental work on absorption in different dielectrics and on the effect of moisture and temperature on the constants is also described.The dependence of alternating dielectric losses on direct-current characteristics is discussed, and the author suggests a conception of the former in which they can be explained asI2Rlosses, without retaining the difficulties of a dielectric hysteresis.Several new points are brought to light and supported by experimental evidence in a discussion of the relationship between d.c. and a.c. losses. The nature of the “V” curve connecting dielectric power-factor and temperature is investigated, and an explanation of the “V” curve is suggested based on theI2Rtheory of losses.The paper also discusses the rise of power factor with voltage, the important effect of time on the breakdown strength, and the bearing which this has on the effect of surges in a system. In conclusion, some suggestions are made on the nature of breakdown and the assessment of cable quality.