OF DIALING. 347 



quadrant of altitude in the respective number of degrees LECT. 

 from the zenith, that each of these hours is from XII on ^^^-^ 

 the dial. And note, that when the first meridian goes 

 off the quadrant at the horizon, in the forenoon, the 

 hour-index shews the time when the sun will come upon 

 this dial ; and when it goes off the quadrant in the after- 

 noon, the index will point to the time when the sun goes 

 off the dial. 



Having thus found all the hour-distances from XII, 

 lay them down upon your dial-plate, either by dividing 

 a semicircle into two quadrants of 90 degrees each (be- 

 ginning at the hour-line of XII) or by the line of chords, 

 as above directed. 



In all declining dials, the line on which the stile or 

 gnomon stands (commonly called the substile-line] makes 

 an angle with the twelve o'clock line, and falls among 

 the forenoon hour-lines, if the dial declines towards the 

 east; and among the afternoon hour-lines, when the 

 dial declines towards the west ; that is, to the left hand 

 from the twelve o'clock line in the former case, and to 

 the right hand from it in the latter. 



To find the distance of the substile from the twelve 

 o'clock line ; if your dial declines from the south towards 

 the east, count the degrees of that declination in the 

 horizon from the east point towards the north, and bring 

 the lower end of the quadrant of altitude to that degree 

 of declination where the reckoning ends : then, turn the 

 globe until the first meridian cuts the horizon in the 

 like number of degrees, counting from the south point 

 towards the east ; and the quadrant and first meridian 

 will then cross each other at right angles, and the 

 number of degrees of the quadrant, which are inter- 

 cepted between the first meridian and the zenith, is * 

 equal to the distance of the substile line from the twelve 

 o'clock line ; and the number of degrees of the first me- 

 ridian, which are intercepted between the quadrant and 



