Planets.- Huygens (Christiaan) Kosmotheoros, sive de terris coelestibus, first edition, title with woodcut printer's device, 5 folding engraved plates (some copies have plate 4 in two states), woodcut head-piece and decorative initials, plates closely trimmed at outer margin, occasional spotting, some light staining or browning, particularly to some upper margins, contemporary mottled calf, richly gilt spine in compartments and with red leather label, joints splitting, but holding firm, corners worn, rubbed, small 4to, The Hague, Adrian Moetjens, 1698.

⁂ First edition of Huygen's work on celestial worlds, in which he discusses the possibility of life on other planets, and how the movements of the heavenly bodies must appear to those living there. In the second book he is critical of Descartes.