And may be made of any kynde of glasse, but the clearer the better. And so the Glasse, after that yt ys full rounde, ys made fast with syman vppon a smalle block, and so grounde by hande, vntill that yt ys bothe smoothe and allso thynne, by the edges,...
Descartes and the Hyperbolic Quest: Lens Making Machines and Their ... - Page 13
by D. Graham Burnett - 2005 - 152 pages
Full view -