156 



KEN NELLY— Till-: LINEAR Rl'.SISTANCE 



[April 24, 



The linear resistance between the cylinders can now be determined 

 by finding the linear resistance of each to the infinite conducting 

 plane by formula (i) and then taking the diiTerence between these 

 linear resistances. 



Thus, let o-i = 4 cm., a. :=--- 2 cm., D ^ i cm. Then 2 = 6. A = 2, 

 and rfi = 6.5 cm., d. = S-S cm- 



The resistance factor for ih by the table is 0.2657. 



The resistance factor for </, by the table is 0.1697. 



The resistance factor between d. and </, 0.0960. 



^ O 



Fig. 6. Two parallol cxccntric cylinders, one enclosing llie other, and (he 

 inferred common y.ero-potential plane. 



which multiplied by the resistivity of the medium gives the linear 

 resistance between the cylinders. 



Through the use of fornuilas (40) and (41) all cases of excen- 

 tric cylinders may be computed l)y reduction to the equivalent pair 

 of plane-cylinder systems. 



Graphic.vl Construction of Equipotential and Stream Lines 

 IN a Plane-Cylinder Sv.stem. 

 To draw the ecpiipotential and stream lines of a plane-cylinder 

 svstem, when the polar distance 0./ or distance a of the polar axis 



