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. XXIV. How to know the several sorts of Dials in the Fundamental Diagram.

THese several sorts of Planes take their denomination from those Great Circles to which they are Parallels, and may be known by their Horizontal and Perpendicular Lines, of such as know the Latitude of the Place, and the Circles of the Sphere.

1. An Aequinoctial Plane, parallel to the Aequinoctial, which passeth through the Points of East and West, being right to the Meridian, but inclining to the Horizon, with an Angle equal to the Complement of the Latitude; this here is represented by EOW.

2. A Polar Plane, parallel to the Hour of 6, which passeth through the Pole and Points of East and West, being right to the Aequinoctial and Meridian, but incli∣ning to the Horizon, with an Angle equal to the Latitude; this is here represented by EPW.

3. A Meridian Plane, parallel to the Meridian the Circle of the Hour of 12, which passeth through the Zenith, the Pole, and the Points of South and North, being right to the Horizon, and the Prime Vertical; this is here represented by SZN.

4. An Horizontal Plane, parallel to the Horizon, here represented by the outward Circle ESWN.

[illustration] geometrical diagram

5. A South and North erect direct Dial, parallel to the Prime Vertical Circle, which passeth through the Zenith, and the Points of East and West in the Horizon, and

is right to the Horizon and Meridian; that is, makes Right Angles with them both: this is represented by EZW.

6. A South Declining Plane Eastward is represented by BD.

7. A South Incliner and North Recliner is represented by EQW.

8. The South Recliner and North Incliner is represented by EAW.

9. A Meridian Plane, which is the East and West Incliners and Recliners, and from the Zenith parallel to any Great Circle which passeth through the Points of South and North, being right to the Prime Vertical, but inclining to the Horizon; this is represented by SVN.

10. A declining, reclining, inclining Plane, which is parallel to any Great Circle which is right to none of the former Circles, but declining from the Prime Vertical, reclining from the Zenith, inclining to the Horizon and Meridian, and all the Hour Circles; this may here be represented either by FLC or FKC, or any such Great Circles which pass neither through the South and North, nor East and West Points, nor through the Zenith nor the Pole.

Each of those Planes, except the Horizontal, and South inclining 23 deg. hath two F••ces whereon Hour-lines may be drawn; and so there are 19 Planes in all. The Meridian Plane you see hath one Face to the East, and the other to the West: Re∣member, that it is an East and West Dial. The other Vertical Planes have one to the South, another to the North; and the rest, one to the Zenith, and another to the Nadir. What is said of the one, may be understood of the other.