AN
EPITOME of ASTRONOMY;
AS ILLUSTRATED BY THE
Eídouraníon,
OR
TRANSPARENT ORRERY.
This elaborate Machine is 20 feet diameter: it stands vertical before the spectators; and its globes are so large, that they are distinctly seen in the most distant part of a Theatre. Every Planet and Satellite seems suspended in space, without any support; performing its annual and diurnal revolutions without any apparent cause. It is certainly the nearest approach to the magnificent simplicity of nature, and to its just proportions, as to magnitude and motion, of any Orrery yet made: and besides being a most brilliant and beautiful spectacle, conveys to the mind the most sublime instruction: rendering astronomical truths so plain and intelligible, that even those who have not so much as thought upon the subject, may acquire clear ideas of the laws, motions, appearances, eclipses, transits, influences, &c. of the planetary system.
Scene 1.
THE SUN AND EARTH:
With the Zodiacal Constellations.
As information is the primary object of this lecture, it is thought more useful to exhibit parts of the solar system, separately, before a grand display was made of the whole. This scene therefore, opens with only the Sun and the Earth. The Sun seems suspended in the middle of the system, and by spots on his face, is seen to turn round on his axis in 25¼ days; light issues from his orb in all directions; in the blaze of which is suspended the Earth, turning on its axis to produce day and night, and revolving round the Sun to produce the seasons: its axis inclines 23½ degrees from a perpendicular to the plane of its orbit; and by that axis keeping parallel to itself during this annual journey, the northern and southern hemispheres are alternately addressed to the Sun; shewing, when it is summer in one, it is winter in the other, and vice versâ. This scene so naturally exhibits the cause of day, night, twilight, summer and winter, spring and autumn, long and short days, &c. that a bare inspection of the Machine is sufficient to convey the clearest idea of these phænomena.
The Earth in this scene ought to be unshackled with meridians or parallels of latitude:—to be a free and independent ball, with land and water represented as they would appear to a distant spectator looking at the real Earth. But as globes are seldom seen without these appendages, a globe of two feet in diameter, equipped with meridians and parallels of latitude (being requisite for illustration) will perform a diurnal and annual motion round the Sun, and explain the above phænomena on so large a scale, that their effects on the smallest island may be seen from the most distant part of the theatre.
This scene is surrounded by transparent paintings of the twelve signs of the Zodiac, shewing how the Sun, or rather the Earth, enters and passes thro’ Aries, Taurus, Gemini, Cancer, &c.