Magnetic-Circuit Units as Adopted by the I. E. C.

The decisions of the International Electrotechnical Commission (I. E. C.) at Oslo in July 1930, with respect to international magnetic units and unit names, are briefly reviewed. So far as concerns the c. g. s. magnetic units, the decisions appear likely to meet with general favor; but the series is incomplete and might advantageously be supplemented by at least one name- that for the c. g. s. unit of reluctance. The series of units in the practical or volt-ampere-ohm system is also incomplete; but apparently cannot be completed satisfactorily without first deciding two questions: (a) whether the system should be rationalised and (b) whether the m. k. s. or the c. g. s. s. system should be endorsed. It is recommended that these questions be left for the present undecided, until they have been widely discussed, and illustrative literature developed in aid of international decision.