The controversy over the introduction of corrections to standard time, so as to force agreement between Atomic Time and Mean Solar Time seems to have its roots in an erroneous concept of the meaning or concept of the entity we call Time. For example, the preamble to H. M. Smith's paper on ‘Time Data and Navigation’ suggests that ‘…Greenwich Time and longitude are inseparable…’ and in D. H. Sadler's paper on U.T.C. there is an odd confusion in noting that Time is a measure of the rotation of the Earth on its axis and at the same time that the rotation is not uniform.