Earthing is first considered in relation to the various regulations applicable in Great Britain. These regulations relate to the generation, transmission and use of electricity, and the last item covers use in all types of consumers' premises. Particular attention is given throughout the paper to the peculiar difficulties attendant upon supply in rural areas, where protection is difficult to obtain. The factors affecting the resistance of earth electrodes are their size and shape, and the resistivity of the soil. All these items are dealt with in detail, including an analysis of the effect of rainfall on electrodes, both with and without artificial treatment. This analysis is based on the results of E.R.A. tests which have been in progress for 7 years. Only brief reference is made to the means of avoiding voltage gradients around earth electrodes which are dangerous to cattle, since this has been fully considered elsewhere. Current loading capacity is treated somewhat more fully in view of the important nature of the work and the fact that this is the first occasion on which any such results have been made public. The paper concludes with a section on the design of earth electrodes in which an attempt is made to correlate all the essential features bearing on electrodes, to show them in their true perspective in relation to the whole problem of earthing, and to relate the whole to practical requirements in which the question of cost plays a very important part.