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cutta westward to San Francisco ? from Honolulu eastward to Cape Town?
What is the difference in degrees between a place 30° east longitude and a place 45° east longitude ? What is the difference in time and which has the earlier time?
1. When it is noon, solar time, at Paris, what is the solar time at New York ?
2° 20' 15'' E. Since the earth rotates 15° in 1 hr., 15'
74° 0' 03 W. in 1 min., and 15" in 1 sec., the differ15)76° 20' 18''
ence in time is as many hours, minutes,
and seconds as there are degrees, minutes, 5° 5' 211"
and seconds in its of the difference in 5 hr. 5 min. 211 sec. longitude.
The difference in time is 5 hours, 5 minutes, 211 seconds. Since New York is west of Paris, the time in New York is earlier; that is, when it is noon at Paris, it is 6 o'clock, 54 min., and 384 sec. A.M. at New York.
What is the difference in longitude between the two places ? the difference in time? In going west from Paris to New York would a traveler set his watch forward or backward ? how much?
NOTE. — Study this diagram and make a similar one for each problem.
Find difference in degrees, difference in time, and which place has earlier time : PLACES
PLACES 2. 60° W. and 45° W. 7. 120° W. and 30° E. 3. 120° W. and 75o W. 8. 90° W. and 30° E. 4. 15° W. and 45° E. 9. 135° E. and 30° E. 5. 30° E. and 60° E. 10. 45° W. and 60° E. 6. 75o W. and 30° E. 11. 45° E. and 15° E.
When the sun's rays are vertical on the meridian of Washington, find the solar time in the following places : 12. Denver
18. Berlin 13. Chicago
19. New York 14. San Francisco 17. Honolulu 20. Pittsburg
21. When the people of Boston celebrate the opening of the new year with anvil and cannon, how much of the old year remains to the people of Honolulu ?
22. The first shock of the earthquake at Kingston, Jamaica (long. 76° 47' W.), Jan. 14, 1907, occurred at 3:25 P.M. What was the solar time at New York ? at Cape Town?
23. A ship sets sail from Liverpool for New York, Jan. 10, 1907. When in longitude 31° 6' 10" W. its chronometer reads 2:30 P.M. Jan. 15. Find the difference in the readings between the ship's time and the meridian time of New York.
24. Berlin meridian time is 6 hr. 44 min. and 111 sec. later than Chicago meridian time. Find the longitude of Berlin.
15 times the difference in time expressed in hours, minutes, and seconds corresponds to the difference in longitude expressed in degrees, minutes, and seconds.
Therefore, 15 x 6 hr. 44 min. 11} sec. corresponds to 101° 0' 26" of . longitude.
This difference in longitude would not tell us whether Berlin is east or west of Chicago, but as Berlin has faster time than Chicago, it must be east of it. Chicago is 87° 36' 42" west of the prime meridian. Therefore, Berlin must be 13° 23' 44" east of the prime meridian.
25. The “ Treaty of Portsmouth” between Japan and Russia was signed at Portsmouth, N.H., Sept. 5, 1905, at 47 minutes past 3 P.M., 75th meridian time. What was the corresponding solar time at St. Petersburg, Russia, 30° 17' 51" E. and at Tokyo, Japan, 139° 44' 30" E.?
Tokyo is east of the 75th meridian 214° 44' 30", therefore its time is 14 hr. 18 min. 58 sec. faster than Portsmouth, which has 75th meridian time. Counting this time forward from 3:47 P.M. Sept. 5, gives 5 minutes and 58 seconds past 6 o'clock A.M. Sept. 6, Tokyo solar time.
26. The President of the United States takes the oath of office at 12 noon, 75th meridian time. Find the solar time and date in each of the following places for the inauguration of March 4, 1909: Honolulu; Berlin; San Francisco; London.
International Date Line The nations have agreed upon the 180th meridian, with slight changes as shown on page 275, as the place where the new day always begins. The calendar is set forward one day on ships crossing this line sailing westward : the calendar is set back one day on ships crossing this line sailing eastward.
1. A ship sets sail from San Francisco for Manila, Oct. 9, 1906, at 9 A.M., 120th meridian time; it arrives at Manila, Oct. 27, at 9 A.M., meridian time. How long is the voyage ?
2. The same ship sets sail from Manila, Nov. 3, 1906, at 3 P.M., meridian time, and arrives at San Francisco, Nov. 23, at 3 P.M., 120th meridian time. How long is the voyage ?
Standard Time The railroads of the United States in 1883 agreed upon a system of standard time and divided our country into four time belts, as shown on the map. In the eastern time belt all trains keep the time of the 75th meridian, known as
eastern standard time. In the central belt all trains keep the time of the 90th meridian, known as central standard time. In the mountain time belt all trains keep the time of the 105th meridian, known as mountain standard time. In the Pacific time belt all trains keep the time of the 120th meridian, known as Pacific standard time.
Each railway has selected the most convenient towns on its route, as is shown on the map, to change from the standard time of one belt to the standard time of another belt. The time in any belt is 1 hour faster than the time in the belt west of it, or 1 hour slower than the time in the belt east of it. Correct time is telegraphed each day to all parts of the United States from the Naval Observatory at Washington.
1. What is the difference in time between closing of the election polls at 7 P.M. in New York and 7 P.M. Seattle, on the day for choosing presidential electors ?
2. A telegraph message was sent from Philadelphia at 11 A.M. Oct. 12, 1906, to San Francisco and delivered at 7:45 A.M. San Francisco time. Why could this be true?