History of Chemistry, Volume 2 (of 2) / From 1850 to 1910

by T. E. Thorpe

Jean Baptiste André Dumas

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.

It was largely through the influence of these master-minds that chemistry took a new departure. Prior to their time organic chemistry hardly existed as a branch of science: organic products, as a rule, were interesting only to the pharmacist mainly by reason of their technical or medicinal importance. But by the middle of the nineteenth century the richness of this hitherto untilled field became manifest, and scores of workers hastened to sow and to reap in it. The most striking feature, indeed, of the history of chemistry during the past sixty years has been the extraordinary expansion of the organic section of the science. The chemical literature relating to the compounds of carbon now exceeds in volume that devoted to all the rest of the elements.

In the middle of the nineteenth century chemists began to concern themselves with the systematisation of the results of the study of organic compounds, and something like a theory of organic chemistry gradually took shape. From this period we may date the attempts at expressing the internal nature, constitution, and relations of substances which, step by step, have culminated in our present representations of the structure and spatial arrangement of molecules. In 1850 the dualistic conceptions of Berzelius ceased to influence the doctrines of organic chemistry. The enunciation by Dumas of the principle of substitution, and its logical outcome in the nucleus theory and in the theory of types, had not only effected the overthrow of dualism, but was undermining the position of the radical theory of Liebig and Wöhler. The teaching of Gerhardt and Laurent had spread over Europe, and was influencing those younger chemists who, while renouncing dualism, were not wholly satisfied with a belief in compound radicals. Williamson’s discovery, in 1850, of the true nature of ether and of its relation to alcohol, and his subsequent preparation of mixed ethers, served not only to reconcile conflicting interpretations of the process of etherification, but also to reconcile the theory of types with that of radicals. Lastly, his method of representing the constitution of the ethers and their mode of origin gave a powerful stimulus to the use of type-formulæ in expressing the nature and relations of organic compounds.

Thomas Graham.

From a painting by G. F. Watts, R.A., in the possession of the Royal Society.

Other representative men of the middle period of the nineteenth century, in addition to Williamson, were Graham and Bunsen. The three men were investigators of very different type, and their work had little in common. But each was identified with discoveries of a fundamental character, constituting turning-points in the history of chemical progress, valuable either as regards their bearing on chemical doctrine or as regards their influence on operative chemistry.

Thomas Graham was born in Glasgow on December 21, 1805, and, after studying under Thomas Thomson at the University of that city, attended the lectures of Hope and Leslie in Edinburgh. In 1830 he succeeded Ure as teacher of chemistry at Anderson’s College in Glasgow, and in 1837 was called to the Chair of Chemistry in the newly-founded University of London, in succession to Edward Turner. In 1854 he was made Master of the Mint. He died in London on September 16, 1869.