Etienne-Francois Geoffroy, French chemist, 17th-18th century.
© Science Museum / Science & Society Picture Library
Portrait from an engraving of Geoffroy (1672-1731), physician, pharmacist and chemist, also known as Geoffroy the Elder. He obtained a medical degree at Paris in 1704 and was professor of medicine at the College Royal from 1709, and dean at the Faculty of Medicine, 1726-1729. Geoffroy put forward the general proposition that if two combined substances encounter a third with which one of the two has a greater affinity, that one will leave the original combination and unite with the third substance, forming a new compound. He created tables showing the order of such displacements, known as 'Tables of Affinity.' He contributed to a pharmacopoeia published by the Paris Faculty of Medicine in 1732. Illustration from 'Das Buch Der Grossen Chemiker, Band I' , by Gunther Bugge, published in Berlin, c 1929-1930.