23 Tie Deſeriptim th Hoat- linecheſe 24 f. 20 iv. in the Horizon of che Rundamental Diagram from Eunto B, according to the ſituation of che Plane, and there draw the Ver-tical B Z D, which ſhall repreſent the Plane propoſed.

The two Poles of this Plane will fall in the Horizon at H and Q. andtherefore the proper Meridian drawn through che Poles of che Plane andthe Pole of the World muſt be the Circle HQ Which here croſſeththe Plane at Right Angles in che Point of R, and inclineth to PZ S cheMeridian of the Place, according to the Angle R PZ. 3

The quantity of, chis Iaclination may be readily feund by the Hour-

Citcle where the proper Meridian falleth. As here it falleth on tlie ſecond

Hour- circle, and ſo the Inclination is 30 gr.

Ihe height of the Pole above che Plane, Which gireth the height of theStyle above the Subſty lar, is here repreſented by the Ark PR. For as inthe Horizontal, ſo in this and all other Planes, che Line QP the Axis ofche World is always the Axis of the Style, and the neareſt Line that canbe drawn upon the Plane to the Anis of the World is che fitteſt for theSubſtylar, and that is the Line C R: ſo the Angle PCR is the Anglebetween che Axis and the Plane, commonly called the Height of cheStyle, and the meaſure of this Angle is the Ark P R. This Ark is always

leis than tlie Cemplement of che Latitude, and may be eſtimated bytaking the diſtance PR with the Compaſſes, and meaſuring it in che Me-ridian from Ptoward Z. So in this Example it will appear to be abouta 1 5 5 8 ifle diſtance of che Subſtylar from the Meridian is here repreſenteckby che Ark Z R: For the Meridian Line upon the Plane is C Z, the Sub-ftylar Line is CR; ſo che Angle contained between them is Z CR, andthe mealpre of chis Angle is the Ark Z R, which taken with che Com-paſſes, and mealured in che Semidiameter& W, from C toward W, willbe found about 18 gr. a ö ö.The diſtances of each Hour- line from the Subſtylar are here repreſentedby the Arks of the Plane between the Point R and the Interſections ofche Hour- circles: For the Subſty lar Line is C R, and the Hour: cirele of1 croſſing the Plane in the Point O, the Hour. ine of 1 upon the Planemauſt be CO; ſo the Angle between che Subſtylar and the Hour- line of1 is RC, and che meaſure of this Angle is the Ark RO. In likemanner, the Hour-line of 12 will be C Z, and the diſtance from theSubſty far RZ: the Hour: line of 11 will be CX, and the diſtance fromche Subſtylar RX: and ſo the reſt. Thele diſtances R Os R Z, RX,&c.may alſo be taken with the Compaſſes, and meaſured as before. 75i N Beſides

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