DIFFERENCE IN TIME BETWEEN DIFFERENT PLACES.

SECTION XXXVI.

THE earth is 360 degrees in circumference, and turns on its axis every 24 hours; it consequently passes through of 360 degrees, or 15 degrees, in an hour, which is 1 degree in 4 minutes.

OBS. When it is noon at any particular place, it is after noon east of that place, and before noon west of that place.

1. The longitude of Boston is 71° W., and that of Chicago 87 W.; what is the difference of time between the two places ? SOLUTION. 87° — 71° — 161°. The difference in time is 4 minutes to each degree. 16 times 4 min. = 66 min., or 1 hour 6 min. ANS. 1 hour 6 min.

2. What o'clock is it in Boston when it is noon in Chicago?

3. What time is it in Chicago when it is noon in Boston ?

4. A gentleman travels west from Boston to Louisville, in Kentucky, and his watch keeps accurately Boston time; is it too fast or too slow by the Louisville time? how much so, the difference in longitude being

144 degrees time is it in Louisville when it is noon in

Boston? what time is it in Boston when it is noon in Louisville?

6. Portsmouth, N. H., is in the same longitude with Boston, and St. Louis is in 90 degrees west longitude, what is the difference of time between Portsmouth and St. Louis?

7. What time is it in Boston when it is 7 o'clock, A. M., in St. Louis? what time is it in St. Louis when it is noon in Boston?

8. The difference of time between two places is 5 h. 20 min.; what is the difference of longitude? (54 X 15° 80°.)

9. If the difference of longitude between two places is 80°, what is the difference of time?

10. What is the difference of longitude, where the difference of time is 2 hours 20 min. ? 6 hours 48 min. ? 7 hours 24 min. ?

11. The capital of the United States is 77 degrees west of London; what is the difference of time between the two cities?

12. If the difference of time between Madrid and Washington is 4 hours 56 min., what is the longitude of Madrid?

13. If the difference of time between St. Petersburg and Boston is 7 hours 8 min., what is the longitude of St. Petersburg?

14. What is the time in Washington when it is noon in St. Petersburg?

15. Eastport, Maine, the most eastern seaport of the United States, is in 67° W. longitude, and San Francisco, California, the most western, is in 124° W.; what is the difference in time?

16. What time is it in San Francisco when it is noon in Eastport?

17. What time is it in Eastport when it is noon in San Francisco ?

18. The longitude of Liverpool is 3° W., and that of New York 74° W.; what is the difference of time be tween the two cities?

19. New Orleans is in 90° W. longitude; what time is it in New Orleans when it is noon in Liverpool?

20. What time is it in Liverpool when it is noon in New Orleans?

21. How many degrees of longitude make 1 hour's difference in time? why?

DIFFERENCE OF TIME BETWEEN TWO DATES.

SECTION XXXVII.

SUBTRACT the first date from the last, taking days from days, months from months, and years from years.

OBS. January is the 1st month, February the 2nd, March the 3d, &c.

OBS. In finding the difference between two dates, each month is usually reckoned as 30 days.

1. What is the difference of time between January 4 and September 18, of the same year?

SOLUTION. 4 days from 18 days leave 14 days; January is the 1st month, September the 9th month; 9-1= 8. ANS. 8 months, 14 days.

2. What is the difference of time between February 18 and November 10, of the same year?

SOLUTION. As I cannot subtract 18 days from 10 days, I borrow 30 days, or 1 month, from the months in the minuend, and subtract 18 days from that; 30 12; 1210 (the number of days in the minuend) 22. February is the 2nd month, and November is the 11th month: 11

18:

=

borrowed) days.

1 (the month that was 8. ANS. 8 months, 22

3. What is the difference of time between July 4, 1845, and September 6, 1848?

4. What is the difference of time between August 9, 1841, and October 1, 1848?

5. What is the difference of time between November 29, 1842, and April 4, 1846?

6. What is the difference of time between May 18, 1842, and December 2, 1847 ?

7. What is the difference of time between June 6, 1850, and February 4, 1852 ?

8. What is the difference of time between January 8, 1852, and January 4, 1853 ?

9. What is the difference of time between August 1, 1840, and May 1, 1853?

10. What is the difference of time between April 12, 1848, and June 6, 1852 ?

11. What is the difference of time between May 10, 1843, and April 8, 1853 ?

12. What is the difference of time between June 6, 1849, and May 3, 1853?

13. What is the difference of time between January 12, 1835, and October 8, 1852 ?

14. What is the difference of time between September 18, 1846, and February 24, 1853 ?

15. The pilgrims landed at Plymouth, in Massachusetts, December 22, 1620; the first settlement at Boston, the capital of the state, was made September 17, 1630; required the difference of time between the settlement of the two places.

16. America was declared independent July 4, 1776; the treaty of peace with Great Britain was signed Sept. 23, 1783; how long a time elapsed between the declaration and peace?

17. The last war with Great Britain was declared June 12, 1812; the treaty of peace was signed December 24, 1814; what was the length of the war?

18. Washington was inaugurated President of the United States April 30, 1789; President Pierce was inaugurated March 4, 1853; what is the difference of time between the inauguration of the two Presidents? 19. The first book was printed August 14, 1457 ; required the time that has elapsed since.

20. A gentleman gives his note for value received, March 18, 1853, and promises to pay February 10, 1862; in what time will the note be payable?

21. How do you find the difference of time between two dates ?

DECIMALS.

SECTION XXXVIII.

A DECIMAL FRACTION is one or more equal parts of a unit divided into tenths, hundredths, &c. It is usual to write only the numerator of a decimal fraction, with a decimal point prefixed. The denominator is 1, with as many ciphers annexed as there are figures in the nu

merator.

The first place at the right of the point is the tenths' place, the second is the hundredths' place, the third is the thousandths' place, &c.

We read a decimal as if it were a whole number, and finish by giving the denominator.

Ten-thousandths.
Hundredths.
Hundred-thousandths.
Thousandths.
Tenths.
co Millionths.

Ten-millionths.

.6 7 9 4 5 3 2

This is enumerated thus: 6 tenths, 7 hundredths, 9 thousandths, 4 tenthousandths, 5 hundred-thousandths, 3 millionths, 2 ten-millionths. It is read thus: six millions, seven hundred ninety-four thousand, five hundred thirty-two ten-millionths. The lowest denomination expressed is the denomination of the whole.

In decimals, as in whole numbers, any figure moved one place to the left expresses ten times its former value. .05 × 10 - .50 .5.

1. In what place from the decimal point must 2 be written to express 2 tenths? ANS. First place. To express 2 hundredths? to express 2 thousandths?

2. In what place from the decimal point must 7 be written to express 7 hundredths? to express 7 ten-thousandths? to express 7 millionths?

3. What part of unit would a figure express in