As a student, Eötvös started to research surface tension and developed a new method for its determination. The Eötvös rule was first found phenomenologically and published in 1886. In 1893 William Ramsay and Shields showed an improved version considering that the line normally passes the temperature axis 6 K before the critical point. John Lennard-Jones and Corner published (1940) a derivation of the equation by means of statistical mechanics. In 1945 E. A. Guggenheim gave a further improved variant of the equation.