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COURSE NUMBER 6 As this course is 16° 52', the difference of latitude and departure are taken from Table 2 for 17°, which is found at the top of the page. There being no decimals in the distance, which is 19 miles, the difference of latitude, 18'.2, and departure, 5'.6, are at once entered in the traverse table.

COURSE NUMBER 7 This course is 42° 30' and is interpolated for by taking out the difference of latitude and departure for 42° and 43°, which are found at the top of the page. The distance being 63.6 miles, 636 miles is used, which necessitates moving the decimal points in the numbers from Table 2 one place to the left. But 636 miles is beyond the limits of Table 2, and for that reason half of it, 318 miles, is used.

Course 42° dist. 318' Dif. lat.

23.63 Dep. 21.28 " 43 " 318 “ “

+23.26 "

+21.69 " " 46'.9 = 46.89 “ 43'.0 = 42.97 The sum of the numbers take from Table 2 are not divided by 2 because half the distance was used, and the sums are placed in the proper columns of the traverse table as they are.

COURSE NUMBER 8 · This course is 88° 30' and is interpolated for by taking the difference of latitude and departure for 88° and 89°, which are found at the bottom of the page. The distance being 64.4 miles, 644 miles is used, which necessitates moving the decimal points in the numbers from Table 2 one place to the left. As 644 miles is beyond the limits of the table, half of it, 322 miles, is used. Course 88° dist. 322' def. lat.

2 Dep.

32.18 " 89 “ 322 “ "

+ .56 " + 32.20 “ “ I'.Z

=1.68 “ 64'.4 = 64.38

The sum of the numbers taken from Table 2 are not divided by 2, because half the distance was used, and the sums are placed in the proper columns of the traverse table as they are.

COURSE NUMBER 9 This course is 56° 22' and is interpolated for by taking the differences of latitude and departure for 56° and 57°, which are found at the bottom of the page. The distance being 61.4 miles, 614 miles is used, which necessitates moving the decimal points in the numbers from Table 2 one place to the left. As 614 miles is beyond the limits of the table, half of it, 307 miles, is used.

Course 56° dist. 307 Dif. lat.

I7.17 Dep. 25.45 " 57 " 307 “

+ 16.72 " +25.75

“ “ 33'.9 = 33.89 “ 51'.2 = 51.20 The sum of the numbers taken from Table 2 are not divided by 2 because half the distance was used, and the sums are placed in the proper columns of the traverse table as they are.

COURSE NUMBER 10

As this course is 34° 46', the differences of latitude and departure are taken for 35°, which is found at the top of the page. The distance being 3.2 miles, 32 miles is used, which necessitates moving the decimal points in the numbers from Table 2 one place to the left, the result being difference of latitude 2.65, reduced to one decimal place is 2.7. The departure, 1.79, also reduced to one decimal place, is i'.8, which are placed in the proper columns of the traverse table.

COURSE NUMBER II This course is 3° 30' and is interpolated for by taking the difference of latitude and departure for 3° and 4°, which are found at the top of the page. The distance being 137.4 miles, 1374 miles is used; but it is beyond the limits of the table. As half of it, 687 miles, is also too large, a third, 458 miles, is used.

2.40

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Course 3° po' dist. 458' Dif. lat.

45.73 Dep. “ 4 oo' “ 458 “ “

45.69 “ 3.19 2)91 .42

2)5.59 “ 3 30' “ 45.8 “ “

45.71 "

2.79 X 3

x 3 " 3 30 “ 137.4 “ “ 137'.1 = 137.13 “8.4 = 8.37

By this operation the mean of the numbers from Table 2 are for one-third of the distance, which is 45.8 miles, which are multiplied by 3 to obtain the difference of latitude, 137'.I, and departure, 8'.4, for the whole distance, 137'.4.

TO FIND COURSES AND DISTANCES FROM TABLE 2

When all the differences of latitude and departures have been entered in the traverse table, each column is added separately. The difference is then found between the sums of the north and south columns and is given the name of the greater. The difference is also found between the sums of the east and west columns, which takes the name of the greater. With the difference of latitude and departure thus found, enter Table 2. If the difference of the latitude is greater than the departure, it shows that the course made or wanted is nearer to north or south than to east or west and the course is less than 45°, which must be found at the top of the page. On the other hand, if the departure is greater than the difference of latitude, the course must lie nearer to east or west than to north or south and then the course must be more than 45° and is found at the bottom of the page. Where the difference of latitude and departure are found to agree nearest in Table 2, the course and distance are taken.

To find the numbers in Table 2 which nearly agree with the difference of latitude and departure found by the traverse table, open Table 2 at any degree and find either the difference of latitude or departure in the proper column, turn over one page, and if the two more nearly agree, continue that way until they do agree as near as possible. Otherwise go the other way until they agree as near as possible.

1. Example: With difference of latitude 107'.2 S. and departure 64'.3 E., find the course and distance.

Dif. lat. 107'.2 S. L = Course S. 31° E. distance 125'.
Dep. 64 .3 E. 5 -

2. Example: With difference of latitude 297'.6 N., departure 193'-4 E., find the course and distance.

Dif. lat. 297'.6 N.
Dep. 193-4 E. ) = cours

į = Course N. 33° E., distance 355'.

3. Example: With difference of latitude 542'.2 S. and departure 28'.7 W., find the course and distance.

Dif. lat. 542.2 S =Course S. 3° W., distance 543'.
Dep. 28.7 W. S-

4. Example: With difference of latitude 322'.8 N. and departure 74'.8 W., find the course and distance.

Dif. lat. 322'.8 N. 2.

{=Course N. 77° W., distance 331'. Dep. 74.8 W. S = Course

5. Example: With difference of latitude 48.9 S. and departure 930'.4 E., find the course and distance.

In this case the departure, 930'.4, is beyond the limits of the table, which require that half of it, 465'.2, be used with half the difference of latitude, 24.4, which will give the course and half the distance.

1/2 dif. lat. 48'.9 S. = 24.41

{ = Course S. 87° E. and half the

-Cources Aso Fond ha 1/2 dep. 930.4 E. = 465.25 distance, 466' X 2= distance 932'.

6. Example: With difference of latitude 347'.1 N. and departure 347'.2 E., find the course and distance.

Dif. lat. 347'.1 N. L-
Dep. 347 2 E.

= Co. N. 45° E., distance 491'.

When the difference of latitude and departure are the same, the course is 45°.

7. Example: With difference of latitude 2'.4 S. and departure 3:7 E., find the course and distance.

When these quantities are so small, the correct result cannot be taken from the table unless the decimal is moved one place to the right and then the course and distance can be found; but when the distance is taken out, the decimal point must be moved one place to the left.

Dif. lat. 2.4 S.} = Course S. 57° E., distance 4.4

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