Scene 2.
SUN, EARTH, AND MOON:
PHASES AND ECLIPSES.
Consists of the Sun, the Earth, and the Moon. The object of this scene is to display the cause of the waxing and waning of the Moon, and of solar and lunar eclipses: for this purpose the Earth perform its annual and diurnal motions, and projects a conical shadow opposite to the Sun during its journey round him. The Moon borrows her light from the Sun; and which, in reflection to the Earth, is not more than one three hundred thousandth part so strong: and performing her rotation round the Earth, every 29d. 12h. 44m. will sometimes shew us more and sometimes less of the enlightened part of her body. Hence, when she is between the Earth and the Sun, her dark side is towards us, and we lose sight of her, and call this part of her period the change; but as she revolves round the Earth from West to East (the same way the Earth turns on its axis) in a few days we see her above the Sun in the West, and seeing a small part of her enlightened face, call the appearance the Horned, or new Moon: (for her dark side, receiving no reflection of light from any neighbouring body, cannot be seen except in very clear weather). As she proceeds on her monthly journey, when the Sun sets in the West, we see her near our meridian, and then she appears an half Moon, and we say she is at the first quarter; as she approaches the full, more of her enlightened side may be seen, and she assumes an oval or gibbous appearance. At the full she is opposite to the Sun, when the inhabitants of the Earth look at her in the same direction as the rays of that luminary, and of course see the whole of her enlightened face. In performing the other half of her journey, she wanes; and exposing less and less of her enlighted side to us, again disappears.
This scene receives also auxiliary illustration, before the grand scene opens: and in maps of the Moon during its exhibition, particularly one of five feet diameter, made from telescopes of the largest magnifying powers, and laid down with the most minute correctness, with maps of the appearance of the Earth as seen from the Moon, indicating from this similarity, that they are worlds of nearly similar construction.
In the thirteen revolutions she will make while the Earth travels round the Sun, it will evidently appear that the Earth is a Moon to her, but appearing thirteen times as large as the Moon to us; that she does not shine by her own light; that she has no diversity of seasons; that she keeps the same side always turned towards the Earth, and therefore turns on her axis every 29½ days; that her surface is mountainous[1]; and that she shines without setting, every second fortnight, on the arctic or antarctic parts of our globe, during winter: a very sublime and simple provision for the otherwise long continued darkness that at opposite seasons of the year would invelope the polar regions of the Earth.
If the Moon moved in the same plane or level with the Earth, we should have an eclipse every full and change; but as she travels 5¾ degrees to the North of it, and the same to the South of it, every lunation, she only crosses the plane of the Earth’s orbit in two places, which points of intersection (called the Moon’s nodes) though in a trackless path, move 19¾ degrees towards the West every year, and therefore pass round the Heavens in 18 years and 225 days; which is the golden number of our calendar. Hence, when one of these nodes is between the Earth and the Sun at the change, the Moon’s shadow is thrown on the Earth, and she eclipses the Sun; and if she comes to the full when either node is opposite to the Sun, she falls into the Earth’s shadow, and loses for a short time her borrowed light: hence, as she mostly passes above or below the Earth’s shadow, we have Eclipses very seldom. These phænomena are produced in the Eidouranion as they are in nature, and perfectly evident on inspection.