5 n Hyrtical Plan.

2. In this Meridian J make choice of a Center at C, and there de-ſeribe an occult Circle repreſenting the Horizon.

3. I find a Chord of 11 gr. 0 n. and inſcribe it into this Circle oneither ſide of the Meridian, for the Hours of 11 and 1; in like manner,a Chord of 24 gr. 20 2. for the Hours of 10 and 2; and a Chord of38 gr. 3 1. for the Hours of 9 and 3: And ſo for the reſt of the Hours,thelr Halves, and Quarters. a

4. Idraw Right Lines through the Center, and the Terms of theſeChords, and theſe Eines ſo draun are the Hour: lines required.

The Line belonging to the Hour of 6 will be perpendicular to the Me-ridian, and che Eour- Iines before 6 in the Morning, or after 6 in cheEvening may be ſupplied by continuing their oppoſite Hour lines beyondthe Center; as the Hour- line of 7 in tile Morning continued, will be heHour- line of 7 in the Evening · And ſo the reſt. N 8Laſtly, I ſet up the Style over the Meridian, ſo as it moy cut the Planein the Oenters ane there make an Angle with the Meridian equal to theLatitude of che Place; ſ it hall repreſent the Anis of the World, andbe ne caſting of the Shadow upon che Hour- lines in an Heri-

8

cAb. v.

Tb dram the Hour- lines 2 5 Vertical Plane.

Vertical Plane is that which is parallel to the Prime Vertical

A Circle in the Fundamental Diagram, repreſented by EZ W. Ithach two Faces, the one to the North, the other to the South; in each ofthem che Subſtylar will be the ſame with the Meridian Line, and the Angleof che Style aboye the Plane will be equal to Z P, che Complement of theLatitude; and the Hour- lines here inquired may be ſupplied by imagi-ning Right Lines drawn from the Center C to the Interſections of tſle

Hour- circles EZ W. i ö 5The Triangles here conſidered are made by the Vertical, the Meridian, and the Hour- circles, in which we Know the Side Z P, the

ce: Angles