——

A peſerlption f ile Fundimentad bigger,9. A Polar Declining Plane, parallel to any Great Circle, which paſſeth

chrough the Pole, being right tothe Equinoctial, but inclining to tlie Me-

ridian. This is here repreſented by H P. 8

10. A Declining Inclining Plane, parallel to any Great Circle, whicliis right to none of the former Circles, 25 declining from the prime Ver-rical, and inclining both to the Horizon and the Meridian, and all cheHour: circles. This may here bè repreſented either by B M D, or B E D, orBK P, or any ſuch Great Circle, Which paſſeth neither through the South80 North, nor Faſt and Weſt points, nor through the Zenith, nor tePole. e 4 eEach of cheſe Planes(except the klerhbontel) hath two Faces whereonHour- lines may be drawn, and ſo there are nineteen Planes in all. TheMeridian Plane hath one Face to the Eaſt, and another to the Weft: The

other Vertical Planes have one to the South, and another to the North,and the reſt one to the Zenith, and another to the Nadir: but what is ſaidol the one, may be underſtood of the other.

To deſeribe the Fundamental Diagram.

The Deſcription of this Diagram is ſet down at large in the Uſe of mySector, Chap. 3. But for this purpoſe it may ſuffice, if it have the VerticalCircle, the Hour-cireles, the Equator, and tlie Tropicks firſt drawn in it,

other Circles may be ſupplied afterwards, as we ſhall have uſe of them?

And thoſe may be readily drawn in this manner.

Let the out ward Circle repreſenting the Horizon be drawn, and divided

into four equal parts with S N the Meridian and EW the Vertical, andeach fourth part into 90 gr. That done, lay a Ruler to the point 8, and

each Degree in the Quadrant EN, and note the Interſections where theRuler croſſeth the Vertical, ſo ſhall the Semidiameter E C be divided into

other 90 gr. and from thence the other Semidiameters may be divided inthe ſame ſort. Theſe may be numbred with 10, 20, 30,& c. from E to-ward C, and for variety with 10, 20, 30, C. from C toward W. Butfor the Meridian, the South part would be beſt numbred according to theDeclination from the Equator, and the Norch part according to the di-ſtance from the Pole. i 5

Then with relpect unto the Latitude, which here we ſuppoſe to be 51 gr.30 m. open the Compaſſes unto 38 fr. 30 m. from C toward W, and

briek chem down in thie Meridian frem C unto P, ſo this point P ſpall

repreſent thepole of the World, and through it muſt he drawn all the

Heur-circles Aas 2 Haine