Present status of the international electrical units

This paper summarizes the present legal standing and practical usage of the international electrical units, particularly us maintained in the United States. The international agreement reached in 1910 was provisional and requires some revision. Further investigations of the international standards, as well as of the absolute units, are urgently needed to put the system on a satisfactory basis for work of high precision. Legal authority to deal with electrical units has now been given the International Committee on Weights and Measures. This provides a permanent working organization through which international agreements can be reached and can be made effective throughout the world. When the committee takes up the question of electrical units for formal international adoption, it will have to decide whether to maintain as nearly as is practicable the values accepted at present or to revise them so as to accord with the fundamental c. g. s. system, With regard to primary standards, it will have to choose between the mercury ohm and silver voltameter, on the one hand, as against direct determination of the units by methods based on mechanical dimensions. The Bureau of Standards has under way several investigations planned to give a better technical basis for final decisions on these questions. It is desirable also that they be discussed by those interested in making precise and accurate electrical measurements in order that all the advantages and disadvantages of the changes proposed may be given adequate consideration.