John Marshall: the making of true spectacles.

Bryden, D J; Simms, D L · BMJ

Where this comes from

Abstract

In 1693 John Marshall of London devised a novel method of grinding batches of identical, good quality, lenses of a specified focal length. Its commendation by the Royal Society led to a trade war between Marshall and rivals in the Worshipful Company of Spectacle Makers. Despite initial opposition the method was rapidly adopted by London opticians and, though much modified, it forms the unrecognised basis of present day practice.

Medical subject headings