The mariners magazine, or, Sturmy's mathematical and practical arts containing the description and use of the scale of scales, it being a mathematical ruler, that resolves most mathematical conclusions, and likewise the making and use of the crostaff, quadrant, and the quadrat, nocturnals, and other most useful instruments for all artists and navigators : the art of navigation, resolved geometrically, instrumentally, and by calculation, and by that late excellent invention of logarithms, in the three principal kinds of sailing : with new tables of the longitude and latitude of the most eminent places ... : together with a discourse of the practick part of navigation ..., a new way of surveying land ..., the art of gauging all sorts of vessels ..., the art of dialling by a gnomical scale ... : whereunto is annexed, an abridgment of the penalties and forfeitures, by acts of parliaments appointed, relating to the customs and navigation : also a compendium of fortification, both geometrically and instrumentally / by Capt. Samuel Sturmy.

By the Tables.

THen in this Triangle CAQ, Right-Angled at Q, there is required CA the nearest Distance of the two Places in the Arch of a Great Circle; and the Angle ACQ of Direct Position from the Island Lundy to the Amazones: and the Angle

CQO being the Complement of the Angle of the Direct Position of the Island of Lundy.

For the nearest Distance CA,

As Radius, is to Co-sine of Difference of Longitude 41 d. 22 m.	987534
So is Co-sine of the Latitude or Difference 51 deg. 22 min.	979699
To the Co-sine of the Distance 61 deg. 57 min.	967233

which 61 deg. 57 min. converted into Leagues, is 1237 ⅓ as before, the nearest Di∣stance between those two Places.

For the Angle of Direct Position from the Amazones toward Lundy, NAER,

As the Radius, to the Sine of the Differ. of Longitude 41 d. 22 m.	982011
So is the Co-tangent of Difference of Latitude 51 deg. 22 min.	990267
To the Co-tangent of the Angle of Position 27 d. 50 m. NAER	972278

For the Angle of Position ACQ,* 1.1

As Radius 90, is to Co-sine of Differ. of Lat. 51 d. 22 m. QC	989273
So is Co-tangent of Differ. of Longitude 41 deg. 22 m. AQ	1005522
To the Co-tang. of the Angle of Direct Position 48 d. 25 m. ACQ	994795

The same Proportions will hold by the Artificial Lines on the Scale.

And thus you see, he which will sail the nearest way from the Amazones to the Lizard, shall at first shape his Course 27 deg. 50 min. from the Meridian to the Eastward; that is, N. N. E. almost ½ a Point Easterly. Now if the Wind should serve that you might sail this Course, it is to be understood, that in this kind of sail∣ing he is not to continue this Course long; but to shift it, and incline more and more to the Eastward, as often as occasion requires: which how it may be done, shall be shewed in the following Discourse.

Notes

• * 1.1

  Measure NR on the half Tan∣gents, and the Angle of Posi∣tion, and the Distance is all one as before.