Phil. Mag. Ser. 6, Yol. 27, PI. VIII. 



Fig. 7. — Case I. i Q = 4 amperes. 



Fig. 8. — Case II. i = 3 amperes. 



muw ni i imiHP 



WPP9W9 



i-iVilVi-— — — -- 



Fig. 9. — Case III. a' = 2-<3 amperes. 



