Parkinson's law He also wrote the book "Mrs. Parkinson's Law: and Other Studies in Domestic Science". Parkinson's law Parkinson's law is the adage that "work expands so as to fill the time available for its completion". It is sometimes applied to the growth of bureaucracy in an organization. This law is likely derived from ideal gas law, whereby a gas expands to fit the volume allotted. Articulated by Cyril Northcote Parkinson as part of the first sentence of an essay published in "The Economist" in 1955 and since republished online, it was reprinted with other essays in the book "Parkinson's Law: The
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