Some Notes Concerning the Wenner Configuration*

This paper deals with the four electrode method of electrical resistivity prospecting using direct current. It is shown that three resistances can be measured for any four electrode configuration, and a simple relation between them is derived. The particular case of the Wenner electrode configuration is discussed and a further relation derived between the three apparent resistivities corresponding to the three resistances. The practical value of the ‐resistance relation as a means of avoiding experimental errors is indicated. In general the three apparent resistivities are different in magnitude although there are certain particular cases where they are equal to one another. Their actual values are determined for a number of simple problems and the possibility of having a negative apparent resistivity is illustrated. Finally, examples of field tests are given in which the three resistances were measured, and it is concluded that the method can often provide a simple way of distinguishing between the effects of lateral and vertical resistivity variations.