This paper sets forth the possibilities of standard‐frequency radio transmissions in connection with time‐standards. The subject is approached from the radio viewpoint but the usefulness of the transmissions to certain classes of needs for time‐service is apparent. A clear distinction should be understood at the outset, that between calendar time, on the one hand, and time‐intervals or rates, on the other. There is no known method by which calendar time can be given other than by the furnishing of time‐signals, of which the United States Naval Observatory time‐signals are the outstanding example. As for the second class of service, it is abundantly evident that time‐signals destined for the first purpose could never be given at sufficiently frequent intervals to serve all the needs for accurate standards of time‐diffe