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.

PROBL. XI. Having the Latitude of the Place, and the Declination of the Sun given; to find the Suns Azimuth at the Hour of Six.

THis is represented in the Convex-Sphere by VZ in the Parallel of Altitude of the Sun VSB; Prick VB from C to W, and with the distance VS draw the Arch upon W at h, and lay the Ruler just touching the said Arch, cuts the Circle in Y; the distance HY measured on the Chords, sheweth the Azimuth, or the distance G 00, on the Concave-Sphere, applyed only to the Line of ½ Tangents, shews the Azimuth to be 13 deg. 07 min. and so much is the Sun to the Northwards of the East and West of the hour of Six.

In the Right-Angled Spherical-Triangle ZNS of the general Diagram, we have known first, ZN, the Complement of the Latitude 38 degr. 32 min. (2.) NS the Complement of the Suns Declination 69 degr. 30 min. to find the Azimuth of the hour of Six, represented by the Angle NZS.

I say,

As the Radius 90 is in proportion	10
to the Compl. Sign of the Latitude 38 deg. 32′ ZN	979446
So is the Co-Tangent of NS 69 deg. 30 min.	957273
to the Co-Tangent of the Azimuth NZS 76 d. 53′	936719

Or extend the Compasses from the Co-Sign of the Latitude to the Radius; the same extent will reach from the Tangent of the Declination, to the Azimuth 76 deg. 53 min. as before; the Suns Azimuth from the North part of the Meridian in the Latitude of 51 degr. 28 min. and Declination 20 degr. 30 North, (13 degr. 07 min is from the West.)