TABLE 3. 
Difference of Latitude and Departure for 30° (150°, 210°, 330°). 
Dep. } Dist. 
240. 5] 541 
In Plane Sailing. 
For converting Dep.into Diff’. Long.and Diff. Long.into Dep. 
In Middle Latitude Sailing. 
Forconverting Dep.into Diff. Long.and Diff. Long.into Dep. 
In Mercator Sailing. 
For multiplication of numbers by sines and by cosines, or 
solution of plane right-angled triangles. 
