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15. Archangel and Bergen? 21. Brest and Bourdeaux ? 16. Christiania and Gottenburg ? 22. Corunna and Oporto ? 17. Stockholm and Tornea ? 23. Lisbon and Cadiz ? 18. Petersburgh and Dantzig? 24. London and Genoa ? 19. Copenhagen and Hamburg ? 25. Newcastle and Leghorn in 20. Amsterdam and Dunkirk ?

Italy? Required the difference of latitude between, 26. St. Salvador and Surinam. 29. Vera Cruz and Cape Horn. 27. Porto Bello & Magellan's St. 30. St. Helena and Manilla in 28. Trinidad Is. and Trincomalé. the Philipines.

PROBLEM IV.

To find the Difference of Longitude and of Time between two

places. If the longitude of both places be of the same name, subtract the less from the greater; if of different names, add them together for the answer in degrees.

The distance of two places can never be greater than half the circumference of the globe, or 180°; when, therefore, in adding, the sum exceeds that, subtract it from 360°, for the true difference.

Divide the number of degrees by 15 for the answer in hours; if there be a remainder, multiply it by 4 for minutes.

To reduce Hours into Degrees.—Multiply them by 15.

The principle of these rules is this: the sun, in his apparent motion round the earth, does his daily journey of 360° in 24 hours, which is at the rate of 15° in an hour, or lo in 4 minutes.

EXAMPLES 1. What is the diff. of long. and time between Lisbon and Philadelphia ? Ans. 66° 9'=4 hrs. 24 min.

2. What is the difference of longitude and time between Newcastle and Moscow ? Ans. 39° 9'=2 hrs. 36 min.

3. Between Constantinople and Pekin? 4. Otabeite and Tongataboo, in the Pacific Ocean? 5. London and Quebec? 6. Acapulco and Macao ? 7. Port Sir Francis Drake, in America, and Nankin ? 8. Pico, one of the Azores, and Botany Bay ? 9. Vera Cruz and Siam ? 10. Bergen and Bombay ?

11. Bermudas Islands and Island of Rhodes ?
12. Mount Hecla and Mount Vesuvius?
13. Constantinople and Batavia ?
14. Juan Fernandez and New Caledonia ?
15. Easter Island and Tongataboo ?
16. Marquesas and Navigator's Islands ?
17. Christmas Island and the Pelew Islands?
18. Owhyhee and the Ladrone Islands ?

19. Oonalashka, on the north-west coast of America, and Jesso, on the north-east coast of Asia ?

EXAMPLES FOR A MAP OF EUROPE AND ASIA. What is the difference of longitude between the following places ? 20. Gibraltar and Barcelona ? 28. Bombay and Calcutta ? 21. Malaga and Naples ? 29. Smyrna and Canton ? 22. Toulon and Venice ? 30. Calicut and Aracan? 23. Rome and Athens ?

31. Ormuz and Okhotsk ? 24. Corinth and Akerman ? 32. Mocha and Pondicherry ? 25. Marseilles and Ancona ? 33. Rhodes and Nankin ? 26. Bilboa and Leghorn ? 34. Iscanderoon and Madras ? 27. Genoa and Azof?

35. Surat and Batavia ?

PROBLEM V. To find all those Places that have the same Latitude with a

given Place. BY THE GLOBE.-1. Bring the given place to the brass meridian, and observe the latitude.

2. Turn the globe round, and all places that pass under the latitude will be those required.

By Maps.—1. If a parallelof latitude be drawn through the given place, observe all those places which lie on it.

2. If not, an imaginary line may be drawn evenly with the nearest parallel.

The variety of the seasons, and the difference of the lengths of the days and nights, depending upon the difference of latitude, all places that have the same latitude have their seasons exactly alike, except what difference may arise from the local situation of the place: they have also the days and nights of the same length at the same time; but the hours of the day are different.

EXAMPLES. 1. What places have the latitude of Stockholm?

Answ.-Petersburgh; Vologda ; Narym and Okhotsk, in Asia ; Lake Athabasca; Churchill Fort, on Hudson's Bay; Cape Chidley, in Labrador ; Cape Farewell, in Greenland; and Mainland, one of the Shetland Islands.

2. What places have nearly the same lat. as Edinburgh?

Answ.-Elsinore, Memel, Polotsk, and Moscow, in Europe ; Casan and Tomsk, in Asia ; Bhering's Island; and Alashka and Severn-House, in America.

What places have nearly the same latitude as, 3. London?

8. St. Helena ? 4. Philadelphia ? 9. Cape of Good Hope ? 5. Jerusalem ? 10. Cook's St. in New Zealand ? 6. Jamaica ?

11. Tranquebar ? 7. Quito?

12. Batavia ?

PROBLEM VI.

To find all those Places that have the same Longitude with

a given place. BY THE GLOBE.—Bring the given place to the brass meridian, and mark all the places then under the meridian, for the answer required.

By Maps. Find the longitude of the given place; then observe all those places that are upon the same meridian, or that are situated at the same distance from the nearest meridian as the given place.

All places that have the same longitude have noon and midnight at the same time, the other hours of the day also correspond.

EXAMPLES. 1. What places have nearly the same longitude as London ? Answ. Poictiers, in France; Valencia and Alicant, in Spain; Oran ; and Cape Coast, in Africa.

2. What places have nearly the same longitude as

Genoa ? Answ. Christiansand, Bremen, Berne, Corsica, Sardinia, and Tunis.

What are the places whose longitude is nearly the same. as that of the following ?

3. Cape of Good Hope? 9. Dublin? 4. Petersburgh ?

10. Sandwich Islands ? 5. Ispahan?

11. Pelew Islands ? 6. Pekin?

12. Stockholm? 7. Jamaica ?

13. Bombay ? 8. Quebec ?

14. Isle of Tinian?

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15.

QUESTIONS FOR EXERCISE IN SECTION 1. What are the latitudes and longitudes of, 1. Bergen? 5. Turin ?

9. Candia ? 2. Moscow ? 6. Upsal ?

10. Jeddo? 3. Elsinore? 7. Alexandria?

11. Lubec? 4. Barbadoes? 8. Prague?

12. Mocha? What places correspond to the following latitudes and longitudes ? 13. 33° 20' n. L.

44° 24' E. L. 14.

6 15 s. L. 106 25 E. L. 36 31 n. L.

6 12 w.L. 51 6 N. L.

13 31 E. L. 49 59 N. L.

1950 E. L. 30 12 N. L.

91 20 E. L. 19. Lord Nelson obtained a victory over the French fleet near lat. 31° 11' N., long. 30° 22 E.: point out the place on the globe.

20. What places are in the same longitude as Moscow ?
21. What places have the same longitude as Delhi ?
22. What places have the same longitude as Astrachan ?
23. What places have the same longitude as Malacca ?
24. Where else is it midnight when it is midnight at Lima ?

25. In the summer of 1827 Captain Parry arrived at 82° 45' N. lat., 20° E. long. ; point out the place.

QUESTIONS FOR EXAMINATION IN SECTION 1. Into how many degrees is a circle divided? What is the axis of the earth? What are the poles ? What is the equator? What are meridians ? What is the brazen meridian? How is it divided and numbered ? How are meridian lines drawn on maps?

What is latitude? How many kinds of latitudes are there? What is the greatest latitude any place can have? Are there any places that have no latitude ?

What is longitude ? Which is the first meridian ? How is longitude marked upon the globe and upon maps ? What are parallels of latitude ? How are parallels of latitude drawn on maps ?

How are the latitude and longitude of any place found upon the globe? How are they found upon maps ? How may east longitude be distinguished from west ? When the longitude is taken from Ferro Island, how is it reduced to the meridian of London ?

The latitude and longitude of a place being given, how is the place found ? How is the difference of latitude between places found? How is the difference of longitude found? What is the greatest difference of longitude that can be between two places ? If, in finding the difference of longitude between two places of different names, the sum is more than 180°, how is the true difference found ?

How are degrees reduced into hours, and the contrary? How are all those places found which have the same latitude as any given place ? How are all those places found which have the same longitude with a given place ? Have places of the same longitude the same hours of the day at the same time?

SECTION II.

DEFINITIONS. 1. The horizon is either rational or sensible.

2. The rational horizon is a great circle, dividing the upper from the lower hemisphere.

3. The sensible horizon is that circle which is the boundary of our sight, or which separates the visible from the invisible portion of the earth's surface.

The sensible horizon increases in proportion to the elevation of the spectator ; thus a person at the top of a mountain has a more extensive prospect than another person at the bottom.

The horizon of a place varies according to its latitude and longitude.

The horizon, on the globe, is a circular flat piece of wood, which sustains the globe, and which represents the rational horizon. It contains several circles : the innermost is marked with the points of the mariner's compass; the next exhibits the twelve signs of the zodiac : beyond which is a calendar, showing the months and days of the months, corresponding with the signs and their respective degrees; these

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