William Walker

An epitome of astronomy, with the new discoveries William Walker

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 51/4 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 231/2 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.