The Wilkins lecture, 1988 hand and mind in time measurement: the contributions of art and science

Abstract

I was dining some years ago at the Society of Fellows—a now venerable Harvard institution modelled largely on the Fellows of Trinity College, Cambridge—and had the good fortune to be seated next to a handsome grey-haired gentleman by the name of Norman Ramsey. What do you do? I asked. I’m a physicist, he said. What kind of physics? I measure time. Imagine that, I said, it so happens that I’m writing a book on the history of time measurement. Well it was a good dinner, and I learnt a great deal about today’s methods of high-frequency time measurement, of which more later. But the one sentence that made the most impression on me and that I have never forgotten was the remark: ‘Any stable frequency is a clock. The counting we can leave to the technicians. ’ The importance of this remark, to me at least, was twofold. First it transformed my sense of the priorities. All the material I had been reading on antiquarian horology and the history of clockmaking focused on the escapement mechanism: that part of the clock which, among other things, counts the beats and thus ticks the passing of time. Now I came to understand (why hadn’t I understood this sooner?) the primary significance in time measurement of the controller—the device that generates the frequency whose even rhythm tries to match the perfectly even units of ideal passing time.