Galileo Galilei (1564-1642)
Il Saggiatore, Rome, 1623
Florence, Biblioteca Nazionale Centrale, Magl. 3.2.406, p. 217

In this work Galileo interprets the comets as vapour rising from the Earth and condensating in cosmic space. He also adds an engraving depicting the phases of Venus and the planet's considerable variation in size when observed from Earth, as it moves through its cycle