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a Sutton's Quadrant in hand, it will do in this caſe; but, if neither are in your poſſeſſion, then the Planisphere will be ſufficient for this work. Thus, hang a ſmall plummet by a fine hair to the center-pin, then ſtick a fine pin in the morning hour line of 6, and another in the ſame line near the center, both perpendicular to the Plane, then hold the Planisphere up with the Southern 12 to the Vertex, and the Eaſt ſide next the Sun, and elevate the index, till the ſhadow of the outermoſt pin falls on the other, and then the hair will show the Altitude on the lower limb of the index, counting each division for a degree from the Northern 12 to the right hand.—Thus, for Example, on Auguſt the 13th, 1802, I find the Sun's Altitude in the forenoon 43°. Required the Horary Angle, or apparent time from noon?
| Take the Secant of the Latitude rejecting the index, - | 51° 31' - 0,20601 |
| And the Secant of the Declination, - | 14° 53' - 0,01482 |
| Subtract the Declination from the Latitude, and the difference is, - - | 36° 38' |
| To which add the Complement of the Altitude, - | 47° |
| And it makes - | 83° 38' |
| And their difference is, - | 10° 22' |
| Then take the half of - | 83° 38' |
| Which is, - - | 41° 49'=ſine, 9,82396. |
| And take half the difference, | 5° 11'=ſine, 8,95590 |
