286 M. A. F. Sundell on Galvanic Induction, 



the same z is taken, we obtain the following result of this 

 series : — 



z . . 1-5 10 15 20 25 30 40 

 J . . 176-0 127-4 93-3 66-1 46-8 33 f 8 179 



Series 2. Here the two greater coils were used; 2 = tan* 14°, 

 wi=31, ?i=32, and 1=59. 



1. 



z . . 100 

 J . . 5-6 

 5-6 



5-8 

 5-8 



2. 



90 

 8-0 

 8-2 

 8-0 

 8-0 



3. 4. 5. 6. 7. 

 80 70 60 50 40 

 11-0 15-4 22-4 35-2 57-4 

 11-2 15-2 22-6 35-4 57'6 

 11-0 15-6 22-6 35-0 57-8 

 11-0 150 22-8 



8. 

 35 

 74-8 

 76-0 

 76-0 

 75-6 



J (mean) 



z . . . 

 J. . . 



5-7 



9. 

 30 

 100 

 100 

 100 



8-1 



10. 



25 

 134-0 

 134-2 

 134-0 



11*1 15-3 22-6 35-2 57*6 



11. 12. 13. 14. 



20 20 25 30 

 185-0 183-0 134-2 101-0 

 185-2 184-0 134-4 100-6 

 185-2 



75-6 



15. 

 35 

 74-6 

 750 



J (mean) 



z . . 

 J . . 



100 134-1 185-1 183-5 



16. 17. 18. 19. 

 . 40 50 60 70 

 . 57-6 35-4 22-4 15-2 

 57-2 34-6 22-4 15-0 



134-3 100-8 74-8 



20. 21. 22. 

 80 90 100 

 11-0 76 5-8 

 10-8 7*8 5-6 



J (mean) 57'4 350 22'4 15'1 10'9 7'7 57 

 The result is : — 



z . 20 25 30 35 40 50 60 70 80 90 100 

 J . 184-3 134-2 100-4 7b-2 57*5. 35-1 22'5 15-2 11*0 7'9 57 



Series 3. Instead of the wooden bar, a cathetometer was used 

 in this series. The secondary coil was fixed to its movable tele- 

 scope-holder ; the other coil was placed at the top of the vertical 

 pillar. For the rest, the coils had the described relative posi- 

 tion • viz. the planes of the wire spirals were parallel to each 

 other and perpendicular to the straight line between their 

 centres. The two smaller coils were used — z=-tan20°, m=53, 

 n = 46, J=86*l. 



1. 2. 3. 4. 5. 6. 



Z ; . 10 15 20 25 30 40 



J . . 155-0 69 35-2 19-8 11*8 5-4 



1542 69 35-0 200 12*0 5-6 



1540 12-0 5-6 



J (mean) 154*4 69 35-1 19-9 11-9 5-5 



