302 A. TANAKADÂTE 



external coil if it lias one. When these are once determind it is not 

 necessary however to test all the three from time to time, since the 

 ratios of the constants amongst themselves depend only upon the 

 configuration of the instrument. These ratios being determined once 

 for all, any change in the value of the constants due to a change in 

 the moments of the magnets or the strengths of springs can be 

 readily discovered by testing for any one of them, say, that for the 

 internal coil. 



