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.

CHAP. XIII. How to observe the Reclination or Inclination of any Plane.

WHat Reclination and Inclination are, hath been shewed Chap. 8. and you will have it following in a Diagram by it self.

All Reclining and Inclining Planes have their Bases or Horizontal Diameters lying in the Horizontal Diameter of some Azimuth; but the top of the Plane leaneth back from the Zenith of your place in the Vertical of the Plane (which is the Azimuth cutting the Plane at Right Angles) so much as the Reclination hap∣neth to be: and the Pole of the Plane, on that side the Plane inclines to, is sunk as much below the Horizon, as the top of the Plane is sunk below the Zenith; and the opposite Pole is mounted as much.

Let ESWN be Horizon, Z the Zenith, EW the Horizontal Diameter of the Plane and of the East Azimuth, EOW a Plane not declining but reclining South∣wards from the Zenith by the Arch ZO 45 deg. and his opposite Face inclining to the Horizon according to the Arch OS 45 deg. the Pole of the reclining Face is at P in the Meridian CP, which here is also Vertical of the Plane, and is elevated 45 deg. in the Arch NP, equal to the Arch of Reclination ZO, the Pole of the inclining Face is depressed as much on the other side under the Horizon.

To find the Quantity of the Reclination, you shall draw a Vertical Line on the Plane by Chap. 3. and thereto apply a long Ruler, which may overshoot the Plane either above or below: to that Ruler apply any Semidiameter of a Quadrant, and the Degrees, between that Semidiameter and the Plumb-line, shall be the Degrees of Reclination. Or stick up in the Vertical Line two Pins of equal height, and perpen∣dicular, and placing your self either above or below the Plane, as you find most easie, direct the Sights of your Quadrant to the Heads of the two Pins, being in a right Line with your eye; and the Plummet shall shew the Reclination on the Side of the Quadrant, and the Inclination, which is always the Complement thereof, on the other.