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As the Distance run is to the Radius;
So is the Difference of Longitude to the Rhumb:
And
So is the Co-sine of the Rhumb to the Difference of Latitude.
So the Difference of Longitude being 5 ½ degr. and the Di∣stance that the Ship hath run 117 Leagues; the Rhumb will be found to be E. N. E. 2 degr. 31 min. Easterly, and the Difference of Latitude 2 degr.
COUNT the Difference of Longitude upon the bot∣tome of the Chart from A to G, and upon the Point G raise the Perpendicular G F. Then take out of the Side of your Chart the Distance run, 117 Leagues, and setting one foot of the Compasses in A, with the other cross the Perpen∣dicular F G in the Point F. Now if you take F G in your Compasses, and measure it on the Side of your Chart, you shall find it to contain 2 degr. for the Difference of Latitude; and the Angle E A F, being measured by your Chord or Quadrant, will be 70 degr. 1 min. that is the E. N. E. Point 2 d. 31 m. Easterly for the Rhumb.