│Jean Baptiste André Dumas│ was born on July 14, 1800, at Alais, where he was apprenticed to an apothecary. In his sixteenth year he went to Geneva and entered the pharmaceutical laboratory of Le Royer. Without, apparently, having received any systematic instruction in chemistry, he commenced the work of investigation. With Coindet he established the therapeutic value of iodine in the treatment of _goître_; with Prevost he attempted to isolate the active principle of _digitalis_, and studied the chemical changes in the development of the chick in the egg. In his twenty-fourth year Dumas went to Paris and became _Répétiteur de Chimie_ at the École Polytechnique. He joined Audouin and Brongniart in founding the _Annales des Sciences Naturelles_, and began his great work on _Chemistry Applied to the Arts_, of which the first volume appeared in 1828. At about this time he devised his _method of determining vapour densities_, and published the results of a number of estimations made by means of it. With Boullay he began an inquiry on the _compound ethers_, out of which grew the _etherin theory_, which served as a stepping-stone to the theory of compound radicals—subsequently elaborated by Liebig and Wöhler. Dumas discovered the nature of _oxamide_ and of _ethyl oxamate_, isolated _methyl alcohol_, and established the generic connection of groups of similarly constituted organic substances, or, in a word, the doctrine of _homology_. His work on the _metaleptic action of chlorine_ upon organic substances eventually effected the overthrow of the electro-chemical theory of Berzelius and led to the theory of types, which, in the hands of Williamson, Laurent, Gerhardt, and Odling, was of great service in explaining the analogies and relationships of whole groups of organic compounds. He worked in every field of chemistry. He invented many analytical processes, established the _gravimetric composition of water and of air_, and revised the _atomic weights_ of the greater number of the elements then known. Dumas exercised great influence in scientific and academic circles in France. He was an admirable speaker, and had rare literary gifts. On the creation of the Empire he was made a Senator, and was elected a member of the Municipal Council of Paris, of which he became president in 1859. He died on April 11, 1884.