Alexandre-Émile Béguyer de Chancourtois was a geologist born in Paris, France, on January 20, 1820. His main contribution was to observe the periodicity of the chemical elements. It was one of the first to classify the elements and thus form a periodic table.
Son of Louis Aimé César Béguyer de Chancourtois and Amélie Louise Clerget, he attended the Polytechnic (1838) and the School des Mines de Paris. He was a professor of underground topography at the Des Mines School until 1852. Then he was assistant to a geology chair in 1856.
Chancourtois was Prince Napoleon's chief of staff and undertook an expedition with the latter (1856) becoming one of the youngest Legion of Honor officers and later commander (1867). He was Deputy Director of the Geological Map Service of France until 1875 and was promoted Inspector General of Mining and Inspector of the North and West Division in 1880.
Observed the periodicity of the physical and chemical properties of the elements. In 1862, he arranged the elements in ascending order of atomic masses, placing them on a helical line that covered a cylindrical surface forming a snail. This model was called the Chancourtois Earth Screw.
Chancourtois proposed that the properties of the elements were the properties of numbers and noted that these properties were repeated every seven elements. Using this representation, he was able to predict the stoichiometry of various metal oxides. The regularities he found did not work for all the elements known until then. The idea, therefore, did not receive much attention.
He died on November 14, 1886 in France.