468 Mr. L. Schwendler on the General Theory 



which contradicts the regularity-condition /= b + d so long as d 

 is different from zero. 



Thus in order to fulfil the regularity-condition and the maxi- 

 mum current for the differential method simultaneously, we 

 must put //— 



However, it has been shown that in order to have immediate 

 balance, when adjusting balance by a variation in the resistances, 

 we have to alter the resistances of the four branches b -\-d, a + h, 

 f, and w + /9 simultaneously according to a relation already given. 

 Thus it is proved that adjustment of balance by an alteration of 

 the resistances must be rejected, since, as pointed out before, a 

 variation of the resistances of the coil b is impracticable. 



We are obliged therefore to adjust balance by moving the coils 

 or their armatures ; and the further solution of the problem is 

 only required when this mode of adjustment is adopted. 



Maximum Magnetic Moment, 



It has now been proved that d is to be made zero in order to 

 be able to fulfil the conditions of regularity and maximum cur- 

 rent simultaneously, and that therefore, to obtain immediate 

 balance, readjustment of balance is to be effected by a movement 

 of the two coils a and b or their armatures, and not, as has been 

 generally proposed, by an alteration of the resistance in the 

 branches (a + h and b + d). 



Hence h appearing in the denominator of P only, and h > 

 not being any more required for adjusting balance, the best 

 value we can give to h is 



h=0, 

 which will make P obviously largest*. 



Substituting therefore in the expression for P 



h = d=0, 

 f =w + i3 = b) 



we get 

 and 



E" 

 F = 2(a" + </') + 6 " ^ f ° r Stati ° n L * 



E' 



P "= or hfuAi A" for station II. 



* The resistances d and h, without exerting magnetic force, were origi- 

 nally introduced in order to investigate the possibility of adjusting balance 

 by an alteration of the resistances in the branches. But since it has been 

 shown that this mode of adjustment is to be rejected, it is of course clear 

 that the dead resistances in these branches should be made zero, when P 

 will become largest. 



