Munday, June 4. 1666.
Certain Problems Touching some Points of Navigation.
The line of Artificial Tangents, or the Logarithmical Tangent-line, beginning at 45 deg. and taking every half degree for a whole one, is found to agree pretty near with the Meridian-line of the Sea-Charte; they both growing, as it were, after the same Proportion. But the Table of Meridional degrees being calculated only to every Sexagesunal minute of a degree, shews some small difference from the said Logarithmical Tangent-line. Hence it may be doubted, whether that difference do not arise from that little errour, which is committed by calculating the Table of Meridional degrees only to every minute.