Contents include; historical; single surface working; the nature of grinding and polishing; dioptric substances; production of lenses in quantity; manufacture of spectacle lenses; microscope lenses; production of prisms in quantity;, non-sperical surfaces; testing optical work; higher interferometers for testing prisms and lenses, and other interferometers cognate therewith; surface treatments, testing optical glass, annealing and normalizing; large object glass and mirrors; reference books on optics and optical glassworking
About the Author
Frank Twyman was a skilled craftsman in all aspects of optics. He joined Otto Hilger in 1898 to work on the production of simple spectroscopes costing less than £10 each. After the death of Otto Hilger, Twyman became Managing Director of Adam Hilger Ltd., a company known for the finest quality optical and mechanical work. He worked here from 1902 to 1946 and was very concerned with the practical aspects of instrument making; he designed many of the instruments himself and constantly strove to improve the techniques of optical grinding and polishing. In 1916 Twyman and Alfred Green, the foreman of the Hilger optical shops, patented the now-famous prism and lens testing interferometer that bears their names. Twyman also undertook fundamental studies in the annealing process for glass and invented new spectrophotometers and spectrographs.
