Time-Scales

Extract

W. Palmer's note on Standard Time (this Journal, Vol. 25, page 535) may mislead some readers. He tends to confuse ‘Time’, as an abstract philosophical concept, with the measures of time, or time-scales, used in practice by astronomers, navigators, surveyors, physicists, electronic engineers and the general public. Such measures of time may be based on any recurrent phenomenon, whether uniform or not, ranging from the growth of coral to atomic transitions; and, for this reason, those professionally concerned use precise terminology to distinguish the many time-scales in current use. Unlike Mr. Palmer, they do not use ‘Time’ for a particular time-scale; and, for example, they restrict ‘standard’ to its generally understood application to the meridian to which the legal time of a country is referred. There are a number of factual errors arising from this confusion (e.g. G.H.A. Aries is equivalent to sidereal time) which need not be elaborated here.