21. He again reaps a 12'-swath entirely round the field. How many square rods does he reap the second round? The third round?

22. A farmer plows an 18"-strip entirely round a rectangular piece of ground 20 rd. X80 rd. How many sq. ft. does he plow?

23. He continues plowing round the rectangle (problem 22) until he has a plowed strip 1 rd. wide entirely round it. How many acres has he then plowed?

24. How many acres has he plowed when the plowed strip is 2 rd. wide? 4 rd. wide?

25. How many acres has he plowed when the unplowed strip of problem 22 is 4 rd. wide, the plowed strip being of the same width all round the rectangle?

26. How many acres have been plowed when the unplowed strip remaining is 3 rd. wide? 2 rd. wide? §111. Locating and Describing Places on the Earth.

On page 190 is a map of the eastern and the western hemispheres of the earth, showing the lines that are used for locating and describing places on the earth.

An imaginary line, called the equator, runs entirely round the earth, dividing its surface into the northern and the southern hemispheres. This equator is shown on the map by the heavy horizontal line.

The heavy curved line going through the north and south poles, crossing the equator of the eastern half of the map at 0°, and of the western half at 180° is called the prime meridian.

Answer all you can orally.

1. What do the numbers 15°, 30°, 45°, etc., mean, that stand along the equator to the right and left of 0°?

2. What part of the map is north? South? East? 3. How many degrees are there between the curves that run up and down on the map through the poles?

4. How many degrees are there between the curves that run across the map from right to left?

5. Show the place on the map that is 15° west of the zero (0°) point; 30° west of 0°; 60° W.; 105° W.; 150° W.

6. Show the place that is 15° east of the 0° point; 45° E.; 60° E.; 90° E.; 120° E.; 150° E.; 165° E.

7. Point to the place that is 15° north of 0°; 30° N.; 30° south; 45° S.; 60° N.; 75° S.; 90° N.; 90° S.

8. Show the place that is 30° W. and 15° N.; 30° W. and 30° N.; 30° W. and 15° S.; 60° and 30° S.W.; 60° E. and 15° N., 60° E. and 30° S.

9. Point out the places that have the following positions:

Degrees measured toward the west and toward the north are written with a plus (+) sign before them. Degrees measured toward the east and toward the south are marked with a minus (-) sign before them.

10. Point out the following places, the first number being the longitudes:

Use pencil and paper only when needed.

11. Write down about the correct distances in degrees westward or eastward, and northward or southward from 0°: of the mouth of the Amazon river; of the Mississippi river; of the Nile river; of the Ohio river; of the Niger river (Africa).

+ or

12. Write about the positions of these places, using signs: Washington, D. C.; New York City; Boston; Chicago; Denver; New Orleans; London; Paris; Berlin; the south point of Florida; the south point of South America; the east point of South America.

13. About how many degrees long is South America? Africa? The Nile river?

14. About how many degrees wide is South America? Africa? The United States?

The curved lines running from west to east are called parallels; those running from north to south, meridians.

15. About how many degrees wide is the United States along the 30° parallel? Along the 45° parallel?

16. About how many degrees wide is South America along the equator? Along the -30° parallel? The -15° parallel?

17. Answer similar questions for Africa.

18. How many degrees are there between the prime meridian and the meridian of the mouth of the Nile river? Between the prime meridian and the meridian of the southeast point of Arabia? Of the southwest point of Arabia?

19. How many degrees are there between the 45th meridian and the meridian of the mouth of the Mississippi river?

20. Chicago is about how many degrees west of New

York City, that is, about how many degrees are there between a meridian through New York City and a meridian through Chicago?

21. About how many degrees is Chicago north of New Orleans? Of Panama? Of Rio de Janeiro? Of the mouth of the Amazon river?

22. About how many degrees west from New York City is Denver? San Francisco? The mouth of the Ohio river? Distances measured westward or eastward in degrees along a parallel from the prime meridian are called longitudes.

Distances measured in degrees along a meridian northward or southward are called latitudes.

23. About what is the difference between the longitude of New York and of Chicago? Boston and Denver? Philadelphia and New Orleans? New Orleans and San Francisco?

24. Give the differences of latitude of the same pairs of places.

The latitude and longitude in degrees of some important seaports are given here:

25. What is the difference of latitude of San Francisco

and Honolulu? The difference of longitude?

26. What are the differences of latitude and of longitude of San Francisco and Yokohama? Of San Francisco and Valparaiso? Of Hamburg and Savannah? Of Queenstown and Quebec? Of Cape Town and Stockholm? Of