Mendeleev: The history of a table

2019 marks the 150^th anniversary of the periodic table of elements. To celebrate this anniversary, the Mines ParisTech Library and Mineralogy Museum have teamed up to create the exhibition Before Mendeleev: Genesis of a Table, on view until 31 January 2020. The exhibition traces the contributions of the scientists who preceded Mendeleev and led him to present the periodic table of elements, which has since served as a reference for all scientists and students.

To celebrate the 150^th anniversary of the periodic table of elements, Mines ParisTech is presenting the exhibition Before Mendeleev: Genesis of a Table until 31 January 2020. Visitors have the opportunity to discover the scientists who contributed to formulating this classification and to developing knowledge over the years. Amélie Dessens is a curator at the library and head of Mines ParisTech’s heritage collections and Sarah Hijmans is a PhD student at the Université de Paris’ SPHère laboratory. They created the exhibition in collaboration with Didier Nectoux, curator at the Mineralogy Museum, to showcase and share the rich cultural collections of the school’s library and museum. “It’s this type of exhibition, along with school partnerships,” says Didier Nectoux, “that allows us to keep this heritage alive outside of the school.” He adds, “this rich heritage must be preserved and shared. And these collections are still essential today. The transformations of the 21^st century are driving us to study new possibilities to find alternatives, and we need documentation, archives, in order to know which avenues have already been studied and abandoned, and the reasons why.”

The exhibition, which is presented in chronological order, starts on the doorstep of the Library with the beginnings of the study of elements: alchemy. “The alchemists were not just interested in turning lead into gold,” explains Amélie Dessens. “Beyond the esoteric sense with which alchemy is often related today, it was also – and more importantly – the beginning of chemistry and of identifying the elements that are presented here.” In display cases, eight minerals accompany the works. The first seven elements identified, and bismuth, the earliest written record of which dates from 1558 by the German scholar Georg Agricola. However, it was already well-known in European mining centers prior to this date. This also demonstrates the importance of accompanying discoveries with publication, which is crucial to situating knowledge in time.

A long road to developing the table

From Bergen to Lavoisier, Döbereiner to Newland, a series of display cases present the various steps of the advances, decisions and research that shaped the study and classification of the elements. First, there was Lavoisier, who brought about a true chemical revolution by introducing a scientific method to prove his theories, proposing the first classification of the “33 simple substances,” and working with Berthollet to develop a chemical nomenclature, which made it possible for everyone to use the same names for the elements. The second major turning point came in the 1860s, when scientists realized that elements could have similar chemical properties based on their atomic weight. They thus started to classify them based on these criteria and proposed potential classification formats, which are presented in the exhibition through diagrams, notes and publications.

For example, there was Alexandre-Émile Béguyer de Chancourtois, geologist, mineralogist and professor at the school of Mines de Paris, who made a significant contribution in 1862. He was the first to demonstrate the principle of periodicity through a spiral-shaped classification: the telluric screw. “Mendeleev was not the first to demonstrate periodicity, or to indicate where the missing elements should be placed in the table,” explains exhibition curator Amélie Dessens, “but unlike the others, he dared to predict the properties of the missing elements.” Dmitri Mendeleev published his table in 1869. When gallium was discovered in 1875, confirming his predictions, the news spread throughout the scientific community. It was at this point that Mendeleev’s classification would make its mark in history and earn its place in our textbooks.