Hopkins and Underwood's New Arithmetics Volume 2; Advanced Book (Paperback)

This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1907 Excerpt: ... the nations to which these cities belong. The International Geodetic Congress, which met at Washington in 1884, recommended that the meridian passing through the observatory at Greenwich, a suburb of London, be the prime meridian. This recommendation is now generally adopted by the great nations of the world. The meridian of Greenwich is taken as prime meridian in this book. Longitude is reckoned in either direction halfway around the earth from the prime meridian. The greatest longitude a place can have is 180 E. or 180 W. The meridian 180 E. or 180 W. of the prime meridian is a continuation of the prime meridian on the other side of the earth, and forms with the prime meridian what is called a great circle passing through the poles. The earth rotates on its axis from west to east. Consider two places not on the same meridian; for example, New York City and St. Louis. New York being farther east will come the sooner under the influence of the sun's rays. Therefore, when it is noon in New York City it is before noon in St. Louis. Since the earth's motion is uniform, and furthermore, since in 24 hr. the earth rotates 360, ... in 1 hr. the earth rotates 15;...in 1 rain, the earth rotates 15';... in 1 sec. the earth rotates 15." A difference of 15 of longitude corresponds to a difference of 1 hr. of time. A difference of 15' of longitude corresponds to 1 min. of time. A difference of 15" of longitude corresponds to 1 sec. of time. Hence, to convert difference of longitude into difference of time, divide by 15. EXERCISE 97 1. When it is noon at London, what is the time at New Orleans, 90 W.? % 2. When it is 9 o'clock A.M. on the meridian 75 W., what is the time on the meridian 90 W.? 3. The longitude of Denver is 105 W. When it is 3 o'clock P.m. in De...