Computation.,
To find the distance by plane sailing
Sine course 670 30

9-96561 : Departure 112

2'04922 :: Radius

10'00000

: Distance 121°2

2°08361

To find the difference of latitude by plane sailing,

Cosine middle latitude 37° 17' ar. co. 0*21770 : Tangent course

10'38277 :: Difference of latitude 46'4

I'66645

67 30

: Difference of longitude 1849

2 26692

By By the Traverse Table. With course 6 points, and distance 112 miles, is found difference of latitude 46°3, and distance 121. And with comiddle latitude 37° as course, and the same departure, is found 186 = the difference of longitude in the column of distance.

Solution by Mercator's Sailing:

Construction.

D

Construct the triangle DAC, as before, and find the present latitude. From the two latitudes and their corresponding meridional parts find the

E

B meridional difference of latitude, which set off to the southward from D to E. Draw EB to the eastward from E, and parallel to CA. Continue DA till it intersect EB in B.

EB will be the difference of longitude.

Computation. The distance and difference of latitude are found by plane sailing, as has already been done ; and thence the two latitudes. Lat. from which she sailed 53° 07 N. Mer. parts 3775 Lat. to which she is come 52 21 N. Mer. parts 3699

To find the difference of longitude.
Proper diff. lat. 464 ar. co.

8'33355
: Mer. diff. lat. 76

188081 .:: Departure II2

2'04922

: Diff. long

18345

2'263,58

By By the Traverse Table. The difference of latitude and distance being found, as before, under the course 6 points, the difference of longitude 1839 is found in the departure column ; under the same course, against 76, the meridional difference of latitude, taken as difference of latitude.

8. A ship in latitude 36° 20' S, by observation, meets another ship, that had made 210 miles easting or departure from Cape Lagulhas. What is her present longitude, and also the bearing and distance of the Cape ?

5

Solution by Middle Latitude Sailing. Cape Lagulhas lat. 34° 44' S. Long. 20° 32' E. Ship’s latitude

36 30

Difference of latitude 1 36 or 96m. N. from the ship.

The line AE will be the difference of longitude, the angle CDA the course or bearing of the Cape, and the line DA the distance.

Computation.

To find the course or bearing by plane sailing.

Longitude of Cape Lagulhas

20° 32' E. Difference of longitude E. from the Cape 4' 13

Ship's longitude

24 50 E.

Ву

By the Traverse Table.

Seek difference of latitude 96, and departure 210, in the table ; the ncarest found ars 97:6 and 20994, which correspond with 65° course, and 231 distance. Again, with comiddle latitude 54o as course, and 210 departure, is found 260 difference of longitude in the column of distance.

The bearing and distance are found by plane sailing, as before.