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.

III. Sailing upon the fifth Rhomb, until I alter my Latitude 1 deg. 35 min. I demand how far I have Sailed?

AS sailing from A to C, S. W. b. W. till the Difference of Latitude be 31 Leagues 67/100, I demand the Distance run AC.

[illustration] geometrical diagram

First, By the Traverse-Table, Look in the Foot of the Table for the fifth Rhomb, and over N. S. in that Column, look for 31 Leagues 67/100, and in the Common Angle of Meeting, to the left hand, under Distance Sailed, you will find Distance Sailed 57 Leagues AC required.

By the Line of Sines and Numbers.

EXtend the Compasses from the Complement-Sine 33 deg. 45, to 31 67/100 the Diffe∣rence of Latitude; the same Extent will reach from 90 deg. to 57 Leagues.

Or, Extend the Compasses from 33 deg. 45 min. to 90; the same Distance will reach from 31 67/100 Leagues, to 57 Leagues, the Distance AC, as before.

Say by the second Case in Plain Triangles,

As the Sine-Complement of the Rhomb, 33 deg. 45	9,744739
Is to the Difference of Latitude 31 67/100 Leagues	3500648
So is the Sine of 90 deg. Radius	10000000
To the Distance run AC 57 67/100 Leagues	3755909