Lunar eclipse diagrams. 18th-century diagrams demonstrating how the shadow cast by the Earth on the Moon during a lunar eclipse shows that the Earth is spherical in shape. The text is in both German and English. The Moon is at left and the Sun is at right. The Earth (down centre) is shown successively as a round, triangular, square and hexagonal shape. The text explains that the rounded shape of the shadow could only be caused by a spherical Earth. This argument for a spherical Earth had been known since antiquity. These diagrams were published in 'Universal Geography' (1711) by German scholar Johannes Buno (1617-1697).