FROM SUNDIALS TO by James Jespersen and Jane Fitz-Randolph Illustrated by John Robb Library of Congress Catalog Card Number: 77-600056 National Bureau of Standards Monograph 155 For sale by the Superintendent of Documents, U.S. Government Printing Office, Washington, D.C. 20402 Stock No. 003-003-01650-1 Price: $4 (Add 25 percent additional for other than U.S. mailing). Time and its measurement is, simultaneously, very familiar and very mysterious. I suspect we all believe that the readings of our clocks and watches are somehow related to the sun's position. However, as science and technology developed, this relationship has come to be determined by a very complex system involving—just to name a few-astronomers, physicists, electronic engineers, and statisticians. And because time is both actively and precisely coordinated among all of the technologically advanced nations of the world, international organizations are also involved. The standard time-of-day radio broadcasts of all countries are controlled to at least 1/1000 of a second of each other; most time services, in fact, are controlled within a very few millionths of a second! The National Bureau of Standards (NBS) mounts a major effort in developing and maintaining standards for time and frequency. This effort tends to be highly sophisticated and perhaps even esoteric at times. Of course, most of the publications generated appear in technical journals aimed at specialized, technically sophisticated audiences. I have long been convinced, however, that it is very important to provide a descriptive book, addressed to a much wider audience, on the subject of time. There are many reasons for this, and I will give two. First, it is very simply—a fascinating subject. Again, we often have occasion to explain the NBS time program to interested people who do not have a technical background, and such a book would be an efficient and—hopefully-interesting means of informing them. Finally, this book realizes a long-standing personal desire to see a factual and yet understandable book on the subject of time. James A. Barnes Preparation of this document was supported in part by the 1842nd Electronic Engineering Group, C2/DCS Division, Air Force Communications Service. |