Example.
I would make an Erect Dyal declining from the South to∣wards the East 27. degrees: The Globe, Quadrant of Altitude, Vernal Colure, and Hour Index Rectified, as before, I bring the lower end of the Quadrant of Altitude to 27. degrees counted from the East point of the Horizon towards the North: Then
I turn the Globe East-wards till the Index points to | 11 | a clock, or till 15. deg. of the Equa∣tor pass through the Meridian, and find the Colure cut the Quadrant of Altitude in | 9.43 | counted from the Zenith. |
10 | 19.0 | |||
9 | 25.57 | |||
8 | 35.10 | |||
7 | 45.56 | |||
6 | 60.15 | |||
5 | 79.45 |
And these are the distances of the Fore-noon Hour-lines, which I seek in the West side of the Plane, viz. from B to∣wards C; and through these distances I draw lines from the Cen∣ter, and these lines shall be the Fore-noon Hour-lines.
Now herein is a difference between Declining Dyals, and Di∣rect Dyals: For having found the distances of the Hour lines for one half of the Day, be it either for Before Noon or After Noon in a Direct Dyal, you have also found the distances for the other half Day; because, as was said Prob. 3. Equal number of Hours have equal distance from the Noon line: But in Declining Dy∣als it is not so: Because the Sun remaining longer upon that side of the Plane which it declines to, then it doth upon the contrary side, there will be a greater number of Hour lines upon it, and by consequence the distance of the Hour lines less then on the con∣trary side of the Plane.
Therefore for finding the After Noon Hour lines, I turn about the Quadrant of Altitude upon the Zenith point till the lower end of it come to the degree of the Horizon opposite to that de∣gree of Declination that the Quadrant of Altitude was placed at when I sought the Fore Noon Hour lines, viz, to 27. degrees