20J

Of Dialing'

of 90 degrees each (beginning at the hour-line of XII) or by the lineof chords, as above directed.

In all declining dials, the line on which the stileor gnomon stands(commonly called the subßile-line) makes an angle with the twclveo’clock Une, and falis among the forenoon hour-lines, if the dial de-clines towards the east; and among the afternoon hour-lines, when thedial declines towards the weif ; that is, to the lest hand from the twelveo’clock line in the former case, and to the right hand from it in thelatter.

To find the distance of the fubstile from the twelve o’clock line j ifyour dial declines from the fouth toward the east, count the degrees ofthat declination in the horizon from the east point toward the north, andbring the lower end of the quadrant of altitude to that degree of decli-nation where the reckoning ends: then, turn the globe until the firstMeridian cuts the horizon in the like number of degrees, counted fromthe fouth point toward the east; and the quadrant and first meridianwill then crofs one another at right angles, and the number of degreesof the quadrant, which are intercepted between the first meridian andthe zenith, is equal to the distance of the fubstile line from the twelveo’clock line ; and the number of degrees of the first meridian, whichare intercepted between the quadrant and the north pole, is equal tothe elevation of the stile above the plane of the dial.

If the dial declines westward from the fouth, count that declinationfrom the east point of the horizon towards the fouth, and bring thequadrant of altitude to the degree in the horizon at which the reckoning• ends; both for finding the forenoon hours, and distance of the fubstilefrom the meridian: and for the afternoon hours, bring the quadrant tothe opposite degree in the horizon, namely, as far from the west towardsthe north, and then proceed in ali refpects as above.

Thus, we have finilhed our declining dial; and in fo doing, we madefour dials, viz.

1. A north dial, declining east ward by the fame number of degrees.S. A north dial, declining the fame number west. 3. A fouth dial,declining east. And, 4, a fouth dial declining west. Only, placingthe proper number of hours, and the stile or gnomon refpectively, uponeach plane. For (as above-mentioned) in the fouth-west plane, thefubstilar-line falis among the afternoon hours; and in the fouth-east, ofthe fame declination, among the forenoon hours, at equal distancesfrom XII. And so, all the morning hours on the west decliner willbe like the afternoon hours on the east decliner: the fouth-east declinerwill produce the north-west decliner j and the fouth-west decliner, the

D d 2 north-