260. The inclination of that part of the Ecliptic to the Horizon in
which the Moon is at any time when horned, may be known by the position
of her horns; for a right line touching their points is perpendicular to
the Ecliptic. And as the Angle that the Moon’s orbit makes with the
Ecliptic can never raise her above, nor depress her below the Ecliptic,
more than two minutes of a degree, as seen from the Sun; it can have no
sensible effect upon the position of her horns. Therefore, if a Quadrant
be held up, so as one of it’s edges may seem to touch the Moon’s horns,
the graduated side being kept towards the eye, and as far from the eye
as it can be conveniently held, the arc between the Plumb-line and that
edge of the Quadrant which seems to touch the Moon’s horns will shew the
inclination of that part of the Ecliptic to the Horizon. And the arc
between the other edge of the Quadrant and Plumb-line will shew the
inclination of the Moon’s horns to the Horizon at that time also.
[Sidenote: Fig. I.