12. A person living on the 90th meridian W. wishes to send a telegram to a bank in New York City, directing the bank to pay on the same day a sum of money. Up to what hour in the afternoon may he do this, allowing 30 minutes for the transmission of the telegram? (New York banks close at 3 P.M.) 13. To what difference in time does a difference of 1° of longitude correspond? Suppose two places situated so that one is directly east of the other at a distance of 1° of longitude. At which place will the sun rise earlier? How much earlier? Example 1. Find the difference between the longitudes of Austin and Honolulu. ... Honolulu is 60° 8' farther west than Austin. Example 2. Find the difference between the longitudes of Galveston and Constantinople. 94° 47' W. Constantinople, 29° 0′ 50′′ E. Here, the places are on opposite sides of the prime meridian. By going east from Galveston 94° 47′, one arrives at the prime meridian, and by going 29° 0′ 50′′ still farther east, he arrives at the meridian of Constantinople. Hence, the difference between the longitudes is (94° 47' + 29° 0′ 50′′) = 123° 47′ 50′′. To find the difference in the longitudes of two places: (1) Subtract their longitudes, if the places are on the same side of the prime meridian. (2) Add their longitudes, if the places are on opposite sides of the prime meridian. EXERCISE 101 Find the difference in longitude between : 1. Baltimore and Bismark. 2. Bangor and Detroit. 3. Boston and Havana. 4. Buenos Ayres and Chicago. 6. Cincinnati and Honolulu. 8. Havana and Rome. 9. Louisville and St. Petersburg. 10. Constantinople and Tientsin. 12. Norfolk and Paris. 13. Montreal and Mexico City. 14. Pensacola and Portland. 15. St. Louis and St. Petersburg. 16. Savannah and Dublin. 17. San Francisco and Dublin. Example 1. Find the difference in local time between Boston and Portland, Ore. Portland 122° 40' Boston W. 71° 3' 50" W. 3 22 25 Ans. 3 hr. 22 min. 25 sec. Example 2. Find the difference in local time between Washington and Manila. To find the difference in local time between two places, longitude being given, divide their difference in longitude by 15, and express the quotient as hours, minutes, and seconds, corresponding to the given degrees, minutes, and seconds. EXERCISE 102 Find the difference in the local time of: 2. Philadelphia and San Francisco. 4. Norfolk and Tientsin. 5. Chicago and Tokyo. 6. St. Louis and Rome. 7. Austin and St. Petersburg. 8. Savannah and Paris. 9. Washington and Brisbane. 10. Cincinnati and Manila. 11. Havana and Louisville. 12. Rome and Manila. 13. New Orleans and Portland. 14. Providence and St. Petersburg. 15. Montreal and Tokyo. 16. Bangor and Melbourne. 17. Baltimore and Buenos Ayres. Example 1. When it is noon, February 22, in St. Louis, it is 15 min. 6 sec. past three o'clock A.M., Feb. 23, in Adelaide, Australia. Find the longitude of Adelaide. SOLUTION. The time difference between St. Louis and Adelaide is 15 hr. 15 min. 6 sec. Multiply by 15, 15 228° 46' 30" E. of St. Louis. Longitude .. longitude of Adelaide = 138° 30' 30" E. = .. Adelaide is 228° 46′ 30′′ of St. Louis is 90° 16' W. (228° 46' 30'' - 90° 16'') E. To find the difference in longitude between two places, the difference in time being given, multiply their difference in time by 15, and express the product as degrees, minutes, and seconds, corresponding to the given hours, minutes, and seconds. EXERCISE 103 Calculate the longitude of each of the following cities, the time difference between New York City and each of them being given: 1. Berlin, 5 hr. 49.5 min. 8. Vienna, 6 hr. 1.2 min. 9. The time difference between London and Amherst, Mass., is 4 hr. 50 min. 3 sec. Find the longitude of Amherst. 10. Find the difference in the time of sunrise between two points in the same latitude which differ in longitude by 39° 20'. STANDARD TIME The use of local time was a cause of confusion, especially after railroads became important. In 1883 a system was adopted in the United States by which the country was |