Pensacola, Philadelphia, 75° 9' 3" W. 87° 16' 6" W. St. Petersburg, 30° 19′ 40′′ E. San Francisco, 122° 24' 32" W. In recent years scientific publications often give longitudes in terms of time, the + sign denoting west and the Example 1. Find the difference between the longi tudes of Austin and Honolulu. SOLUTION. Honolulu, 157° 52′ W. ... Honolulu is 60° 8' farther west than Austin. Example 2. Find the difference between the longitudes of Galveston and Constantinople. SOLUTION. Galveston, 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 98 Find the difference in longitude between : 1. Baltimore and Bismarck. 2. Bangor and Detroit. 3. Boston and Havana. 4. Buenos Ayres and Chicago. 9. Louisville and St. Petersburg. 10. Constantinople and Tientsin. 11. Paris and Pekin. 12. Norfolk and Paris. 13. Montreal and Mexico City. 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. 15)50° 36' 10" 3 22 25 Ans. 3 hr. 22 min. 25 sec. Example 2. Find the difference in local time between Washington and Manila. Washington 77° 0' 36" W. 13 11 54.6 Ans. 13 hr. 11 min. 54.6 sec. EXERCISE 99 Find the difference in the local time of: 1. Mexico City and Montreal. 2. Philadelphia and San Francisco. 3. Philadelphia and Dublin. 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 ... Adelaide is 228° 46' 30" E. of St. Louis. Longitude of St. Louis is 90° 16′ W. longitude of Adelaide (228° 46′ 30′′-90° 16′) E. = 138° 30′ 30′′ E. = EXERCISE 100 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 and which differ in longitude by 39° 20'. · STANDARD TIME Standard time is the time of a fixed meridian, generally a multiple of 15°. It was established in the United States in 1883 primarily for the convenience of railroads. It is now adopted generally throughout the civilized world. STANDARD MERIDIANS AND PLACES USING THEM 0°. Great Britain, Spain, Belgium, Holland. 15° E. Germany, Austria, Italy, Denmark, Norway. 30° E. South Africa, Egypt, Turkey. 8210 E. British India (since July 1, 1905). 971° E. Burma (since July 1, 1905). 120° E. West Australia, eastern coast of China, Phil ippine Islands. 135° E. Japan. 1421 E. South Australia. 150° E. Victoria, Queensland, New South Wales. 17210 E. New Zealand. 60° W. Newfoundland and Eastern Canada. 75° W. Eastern belt of the United States. 150° W. Tahiti. 1571 W. Hawaiian Islands. France uses Paris time, Ireland uses Dublin time. |