[Footnote 97: Tzetzes describes the artifice of these
burning-glasses, which he had read, perhaps, with no learned
eyes, in a mathematical treatise of Anthemius. That treatise has
been lately published, translated, and illustrated, by M. Dupuys,
a scholar and a mathematician, (Memoires de l'Academie des
Inscriptions, tom xlii p. 392 - 451.)]