1909.] BETWEEN PARALLEL CONDUCTLN'G CYLINDERS. 



157 



from the parallel plane is known, draw zOK, Fig. 7, to represent 

 the plane and on the median line OY, perpendicular to zOK mark 

 off, to scale, the polar distance a^^OA. Then to locate any 

 equipotential circle of radius <t=OE', mark off with center 0, a 

 distance d=OC ^^AE'. With center C and the required radius 

 <r, describe the equipotential circle FEB. The distance factor Y 

 for this circle will be expressed by 



F= 2 tanh 



d) 



numeric (42) 



where y.^ is the distance OF or the y coordinate of the lowest point 



d to/- J- 



y 



Fig. 7. Diagram for graphic construction of equipotential and stream lines. 



on the circle. The potential of the circle with reference to the 

 plane will be 



