Abstract
In regard to the difference of distance between Great Circle and Rhumbline, which we call Saving of Distance, we considered of the condition to give the maximum value to Saving of Distance when Great Circle Distance is constant. And, we found the condition is ψ≒λ, where ψ is the Lat. in and λ is the D. Long. During the study, we contrived following formula for approximate meridional parts. That is: -ψ'^3=ψ^3secψ where ψ'is meridional parts of the latitude ψ.
