7. The difference in longitude of two places is 40°. What is the difference in time between the places?

8. The longitude of New Orleans is 90° west. Find the difference in time between this place and Philadelphia, which is in longitude 75° 10' 0" west.

9. London is on the prime meridian, and Washington is 77° 3' 6" west. What change must a traveler make in his timepiece in going from Washington to London?

10. Paris is 2° 20' east longitude, and San Francisco 122° 26' 15" west. What time is it in San Francisco when

it is 7:00 P.M. in Paris?

11. Rome is 12° 27' east, and Manila 120° 58′ 6′′ east. Dewey began firing on the defenses of Manila at 5:41 A.M., May 1, 1898. At what time, by timepieces in Rome, was the fight begun?

12. The difference in time between Philadelphia and Cincinnati is 37 min. 20 sec. What is the difference in longitude?

37 min. 20 sec.
15

9° 20' 0". Ans.

Since a difference of 1 minute of time corresponds to a difference of 15' of longitude, etc., 15 times the number of seconds of time will represent seconds of longitude, (300") and 15 times the number of minutes of time, the number

of minutes of longitude (555′), 555′ + 300′′ = 9° 20′ 0′′.

13. The time at St. Louis is 53 min. earlier than the time at Washington. What is the difference in longitude?

14. In traveling from New York to Cincinnati I find that my watch is 41 min. 32 sec. too fast. Find the difference in longitude.

15. In traveling on a parallel of latitude from 89° 32' 30" west longitude, I notice that my watch has lost 1 hr. 25 min. 30 sec. In what direction am I traveling, and what is the longitude of the second place?

16. The longitude of New York is 74° 3' west, and of Jerusalem 35° 13' east. When it is 4:30 A.M. in New York, what is the time in Jerusalem?

17. The longitude of Boston is 71° 4' west, and of New Orleans 90° west. When it is noon in Boston, what time is it in New Orleans?

18. Formulate a problem in longitude and time, getting the data from your geography. Solve the problem.

STANDARD TIME

130. In the work on longitude and time, it was shown that all places differing in longitude differ in time as reckoned by the sun. In order to avoid the confusing differences in time when each place has its own local time, the railroads of Canada and the United States in 1883 formulated a system of standard time. In this system, meridians that are multiples of 15° are selected as principal meridians, and the belts 71° on either side have the local time of the principal meridian. In practice, however, the time belts are not of uniform width, since the division terminals of railroads often extend beyond, or fall short of, the halfway points between the principal meridians. The time belts used in standard time are the Atlantic, Eastern, Central, Mountain, and Pacific, with principal meridians of 60, 75, 90, 105, and 120 degrees respectively.

A traveler leaves New York at 8 A.M. As he leaves Pittsburg, he notices that his watch, an accurate timekeeper, is an hour fast. Pulling into Ellis, Kansas, his watch is still

an hour fast, but as the train leaves the station he notes that his watch is two hours fast. When leaving Sparks, Nevada, he notes that his watch has gained another hour. His timepiece now is three hours fast, and remains so during the rest of the trip to San Francisco. Explain.

A sheet folded in two leaves is called a folio.

A sheet folded in four leaves is called a quarto. or 4to.

A sheet folded in eight leaves is called an octavo, or 8vo.

A sheet folded in twelve leaves is called a duodecimo, or 12mo.

A sheet folded in sixteen leaves is called a 16mo.

A sheet folded in twenty-four leaves is called a 24mo.

United States money consists of coin and paper money. The gold coins are the double eagle ($20), eagle ($10), and half-eagle ($5). The quarter-eagle ($2.50) and dollar, formerly coined in small numbers, are no longer issued.

The silver coins are the dollar, half-dollar, quarter-dollar, and dime. The silver five-cent piece and three-cent piece were formerly coined, but are no longer issued.

The five-cent piece now coined is made of copper and nickel; the one-cent piece is made of bronze.

NOTE. There are 23.22 grains of pure gold in a gold dollar and nearly 16 times as many grains of pure silver, 371.25 grains, in a silver dollar. This is what is meant by "the ratio of 16 to 1."

Paper money is issued in denominations of $1, $2, $5, $10, $20, $50, $100, $500, and $1000.

The mill is not coined, but is used in calculations as the tenth part of a cent. In business, the seller usually regards any part of a cent as an additional cent; but in making computations in interest, etc., anything less than five mills is disregarded, and anything between five mills and one cent is regarded as an additional cent. Thus, $2.574 is usually regarded as $2.57, $2.575 as $2.58.

In writing dollars, cents, and mills, cents are written as hundredths of a dollar, and mills as thousandths of a dollar. All operations involving the expression of dollars, cents, and mills are treated as decimals, and need not be considered as special cases.

Aliquot Parts. An aliquot part of a number is one of its equal parts. Thus, 2 is an aliquot part of 8 because it is one of the four equal parts of 8. 5 is an aliquot part of a dollar because it is one of the twenty equal parts of a dollar. Aliquot parts of a dollar are frequently used in business computations.

TABLE OF ALIQUOT PARTS OF A DOLLAR FREQUENTLY USED This table should be learned:

135. 1. At 25 a pound, how much will 16 lb. of butter cost?

of a dollar. 16 lb. of butter will cost 16 × of a

2. At 871 a bushel, how many bushels of wheat may be bought for $7?

SOLUTION: 871 = of a dollar.

$ is contained times in $7. 7 ×

3. How much will 240 pound? At 163 a pound?

=

As many bushels can be bought as

8, the number of bushels.

lb. of raisins cost at 1214 a At 25¢ a pound?

4. How much will 48 lb. of grapes cost at 121 a pound?