386 Prof. H. Nagaaka on Magnetic 



Deviation of fourth order for Y-component : — 



tt(3P-24fV + V)="c - (19) (tig. 5.) 

 Asymptotes: ±1.9° 52' 33"; ±59° 2Q ! 40". 

 Normals at the vertices : 0°; 180°; +40° 53' 36" ; 



±90°. 



Deviation of sixth order for Y-component : — 

 2i6-(1235f-630^V4 840f97 4 -1127; 6 )=c. (20) (Fig. 6.) 

 Asymptotes : ±69° 41' 34". 

 Normals at the- vertices : 0°; 180°; ±90°. 



Gaugain-Helmlioltz Coils. 



For the calculation of the double coils at distance equal to 

 the radius of the coil, we have 



4a£ 

 ** = - ~-„ r., .... (21) 



(« + ?) 2 +(§±4 



where <f sign refers to the first coil and — sign to the 

 second. 



Expanding h 2 and expressing q according to the formula 

 connecting q and k, we obtain the following sets of 

 formulae : — 



. _4 7} - 4 v 2 , ,— K L . n ^ 16 



9 



s ±=£{ 



^± 2oa 2 \ da 2oa- v v '125ft 3 J ' 



9 ±~ 125a 3 l 5a + 25a 2 ^ "* J ' 



, 4 = _! 4 _il T ^_, i 



'± 625a* I 



> (22) 



*± == 625^l 1 + ~5«" + ■•• )' 



n° = — - 4- 



2 ± 3125a 9 ^ *" 



v *± V Dal 5a 2du 2 v * ' ' y 12oa c 



+ (-3ip + 20(«V-8(V)g^ ? + 



