point on the inner sphere trace out a figure-eight shape, or hippopede. Callippus, a Greek astronomer of the 4th century, added seven spheres to Eudoxus's...

Menaechmus and his brother Dinostratus, Theudius of Magnesia, Athenaeus of Cyzicus, Hermotimus of Colophon, and Philippus of Mende, and says that Euclid came...

Chodkiewicz Callendar effect – Guy Stewart Callendar Callippic cycle – Callippus of Cyzicus Calvin cycle (a.k.a. Calvin–Benson cycle) – Melvin Calvin (and Andy...