Solar system astronomy, 19th-century diagrams. At top left (figure 1) is the Earth with lines of longitude and latitude. Next to the Earth is the Sun (figure 2, not to scale). Below this is the Earth-Moon system (figure 3) and the relationship between the Earth, Venus and the Sun (figures 5-7). At right is the Earth and Sun with the 24 hours of the day in Roman numerals (figure 8), the seasons from Earth's axial tilt (figure 9), and the phases of the Moon (figure 10). These diagrams are from 'The Works of James Ferguson, F.R.S.' (1823) containing works by Scottish astronomer and instrument maker James Ferguson (1710-1776).