He is credited by Ptolemy and his commentator Theon with having found the distance between the tropics to be ---j rds.
On the other hand he is quoted by Theon of Alexandria (who observed an eclipse at Alexandria in A.D.
Of lost works by Archimedes we can identify the following: (I) investigations on polyhedra mentioned by Pappus; (2) Archai, Principles, a book addressed to Zeuxippus and dealing with the naming of numbers on the system explained in the Sand Reckoner; (3) Peri zygon, On balances or levers; (4) Kentrobarika, On centres of gravity; (5) Katoptrika, an optical work from which Theon of Alexandria quotes a remark about refraction; (6) Ephodion, a Method, mentioned by Suidas; (7) Peri sphairopeoia, On Sphere-making, in which Archimedes explained the construction of the sphere which he made to imitate the motions of the sun, the moon and the five planets in the heavens.
Loo), nor by Theon of Smyrna (c. A.D.
It is, therefore, suggested that Theon formed the shorter collection of Theocritean poems, furnished them with scholia, and wrote the second epigram quoted at the beginning of this article.