On the Distribution of Standard Time in the United States【電子書籍】[ William F. Allen ]

＜p＞This book treats of the problem of the Distribution of Standard Time in the United States.＜/p＞ ＜p＞“For the ordinary purposes of life in a state of society which is not yet complex, a very simple system of recording the lapse of time is sufficient. Sunrise and sunset are local phenomena, which from the earliest times forced themselves upon the attention of every one, and which throughout the early centuries sufficed for the division of time.＜/p＞ ＜p＞A further division of the duration of the day (as defined by the continuance of sunlight) was obtained by noting the time of ＜em＞noon＜/em＞, and there is no historic period known in which the method of obtaining a rough approximation to this instant by means of the shadow of a vertical rod or pillar was not understood.＜/p＞ ＜p＞Probably the observation of such a ＜em＞gnomon＜/em＞ or ＜em＞style＜/em＞ constituted the first step in ＜em＞astronomy of precision＜/em＞ as distinguished from that astronomy in which numbers do not play the most important pa．．．楽天市場のショップで商品詳細の続きを見る