ON STANDARDS lOK USE IN ELECTBICAL JIEASDEEMENTS. 



439 



Ifc is of course unnecessary that the subdivisions of the 1-ohm coil 

 should be exactly equal, provided their ratio is kno-wu, and this can easily 

 be found by the drum--wire itself. Thus the coil is substituted for the 

 series of 20 ohms, before referred to, and the readings observed on the 

 drum -when galvanometer connection is made consecutively at the six 

 contact-points of the divided coil. These observations will coincide very 

 nearly -with readings in the foregoing table -which are independent of the 

 subdivisions of the coil. Therefore, by applying the proper tabular 

 corrections, the true ratio of these subdivisions is determined. 



