le 2. Seek for the departure in the difference of
latitude column. Opposite to it in the distance column will be the
figures indicating the number of minutes in the difference of longitude.
With this difference of Longitude, apply it in the same way to the
Longitude left as you applied the difference of Latitude to the Latitude
left. The result will be the new or Longitude in.

Now if a ship steamed a whole day on the same course, you would be able
to get her Dead Reckoning position without any further work, but a ship
does not usually sail the same course 24 hours straight. She usually
changes her course several times, and as a ship's position by D.R. is
only computed once a day--at noon--it becomes necessary to have a method
of obtaining the result after several courses have been sailed. This is
called working a traverse and sailing on various courses in this fashion
is called Traverse Sailing.

Put in your Note-Book the following example and the way in which it is
worked:

Departure taken from Barnegat Light in Lat. 39 deg. 46' N, Lo. 74 deg. 06' W,
bearing by compass NNW, 15 knots away. Ship heading South with a
Deviation of 4 deg. W. She sailed on the following courses:

--------+----+-------+---------+--------+------------------------------
Course |Wind| Leeway|Deviation|Distance| Remarks
--------+----+-------+---------+--------+------------------------------
SE 3/4 E| NE | 1 pt. | 3 deg. E | 30 |Variation throughout day 8 deg. W.
S 11 deg. W | NE | 0 | 6 deg. E | 55 | A current set NE magnetic
NNW | NE | 0 | 2 deg. W | 14 | 1/2 mi. per hr. for the day.
S 87 deg.E | NE | 0 | 3 deg. E | 50 | Required Lat. and Lo. in
| | | | | and course and distance
| | | | | made good.
--------+----+-------+---------+--------+------------------------------

-----------------------------------------------------------------------------
C. Cos. |Wind|Leeway| Dev.| Var.| NEW | OLD |Dist.|Diff. Lat. |Departure
| | | | |T. Cos.|T Cos. | +-----+-----+-----+----
| | | | | | | | N | S | E | W
--------+----+------+-----+-----+-------+-------+-----+-----+-----+-----+----
SSE | .. | .. | 4 deg. W| 8 deg. W| 145 deg. | S 35 deg.E| 15 | .. |12.3 | 8.6 | ..
SE 3/4 E| NE | 1 pt.| 3 deg. E| 8 deg. W| 133 deg. | S 4