VERTICAL AND INCLINED SURFACES OF SEPARATION 



285 



Qf. from {qi f^)^ from the VEP points, since this sharp deviation of Q/^ from 

 (Qi k)L should be lacking for curves in which d < 2H. 



When the separations are orientated parallel to the plane of contact, the 

 VEP curves for cases c and d on Fig. 1 are given for a doubledayered cross- 

 section in Fig. 11 and for a tripledayered cross-section j Qq = 9qi ; Aq ~ — ^i 



in Fig. 10. The VES curves are so distorted that a change in the type of curve 



. d 

 is observed as the ratio — decreases. The observed deformation in the 



H 



curves is smooth and comes about as a result of variation in the electric 



cross-section in the direction of the contact. 



H 



A double -layered curve for Q^ ~ °° ^^^^^ d <^ — is transformed into 



a three-layered curve with ^3 < Q2, and for d < ^H into a two-layered curve 

 with terminal restivity Q2 — ^Qi- 



A three -layered curve of type H with g^ = <x> for d > ^H is transformed 

 into a four -layered curve with Q^ <. ^3, and for d << ^H into a three-layered 

 curve of type H but with terminal resistivity ^3 = 2qi. 



The nature of the deformations on VEP curves for (p^ [^)j^ >- ^2 described 

 above corresponds to the case when the medium Q2 ^^ homogeneous. In 

 practice one has to deal with contacts with inhomogeneous media on both 

 sides, and, in particular, with a two -layered medium. 



p. 



Fig. U. a — approximately constructed curves for q^ > (g^ ^)^; h — approximately 

 constructed curves for q^ < (g^ ^)j ; c — VEP curves for a horizontally homogeneous 



medium. 



