C. Northcote Parkinson C. Northcote Parkinson Cyril Northcote Parkinson (30 July 1909 – 9 March 1993) was a British naval historian and author of some 60 books, the most famous of which was his best-seller "Parkinson's Law" (1957), in which Parkinson advanced Parkinson's law, stating that "work expands so as to fill the time available for its completion", an insight which led him to be regarded as an important scholar in public administration and management. The youngest son of William Edward Parkinson (1871–1927), an art master at North East County School and from 1913 principal of York School of Arts and Crafts, and
Fermat's principle prefers the path such that there are other paths, arbitrarily nearby on either side, along which the ray would take almost exactly the same time to traverse. Fermat's principle can be used to describe the properties of light rays reflected off mirrors, refracted through different media, or undergoing total internal reflection. It follows mathematically from Huygens' principle (at the limit of small wavelength). Fermat's text "Analyse des réfractions" exploits the technique of adequality to derive Snell's law of refraction and the law of reflection. Fermat's principle has the same form as Hamilton's principle and it is the basis of Hamiltonian