ience,
_Navigation_, as follows:

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 _Sexagesimal_ 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. {216}

Mr. _Oughtred_ in the VI. _Chap._ of his _Navigation_, annexed to the Book,
entituled, _The Circles of Proportion, and the Horizontal Instrument_ &c.
mentions an Artifice, by himself discover'd, by which it may be effected,
that the small Parts of the _Meridian_ be not _one_ minute (which on the
face of the _Earth_ answers to above an _English_ Mile) but the
hundred-thousanth, or, if need be, the millioneth part of a minute, scarce
exceeding one fifteenth part of an Inch: Which thing, _he saith_, he is
able to perform in _Tables_ unto the _Radius_ 10000000; yet nothing at all
differing either in their form or manner of working from those that are now
commonly in use.

But which way this is to be done, this _Author_ hath not made known to the
Publick. And, though such _Tables_ unto the _Radius_ 10000000, had been
brought to light, yet would they not be sufficient to prove the identity or
sameness of the said two Lines, as to continue the comparison between them
as far, as the one of them, _videl._ the _Logarithmicall Tangent-line_, is
already calculated, that is; to Ten places, besides the _Charactoristick_.

Now therefore, if a certain Rule could be produced, by which the Agreement
or Disagreement of the said two Lines might be shew'd, not only to that
Extent of places, to which that _Tangent Line_ is already calculated, but
also to as many more, as the same may be yet further extended unto, in
_infinitum usque_; surely that rule would not only save us the labour of
making _Tables_ unto the _Radius_ 10000000; but also the _Helix_ or Spiral
Line of the Ships Course would be reduced to a more precise exactness, than
ever was pretended by Him: and this most Noble and Useful Science (as He
justly calls it) which is the Bond of most disjunct Countries, and the
Cons