.

Imagine that it is the year 1900, when we are both dissolved into carbonic acid, water, and ammonia, and our ashes, it may be, are part of the bones of some dog that has despoiled our graveswho cares then whether we have lived in peace or anger; who thinks then of thy polemics, of the sacrifice of thy health and peace of mind for science?—Nobody. But thy good ideas, the new facts which thou hast discovered, these, sifted from all that is immaterial, will be known and remembered to all time. how comes it that I should advise the lion to eat sugar?

But

It was thus in philosophic contentment, happy in his work, in his home life, and in his friendships, that Wöhler lived out his fourscore years and two. He made Göttingen famous as a school of chemistry; at the time of the one-and-twentieth year of his connection with the university it was found that upwards of 8000 students had listened to his lectures or worked in his laboratory. There was hardly an academy of science or a learned society which did not in some way or other recognise his services to science. He was made a Foreign Member of the Royal Society in 1854, a Corresponding Member of the Berlin Academy in 1855, Foreign Associate of the Institute of France in 1864, and in 1872 he received the Copley Medal from the Royal Society. He died on 23rd September 1882.

ΧΙ

JEAN BAPTISTE ANDRÉ DUMAS

A LECTURE DELIVERED TO THE ROYAL DUBLIN SOCIETY, MARCH 1885

JEAN BAPTISTE ANDRÉ DUMAS was born on 14th July 1800 at Alais, in the department of Gard, where his father held the position of town-clerk. After having passed through the small school of his native town, it was intended that young Dumas should enter the navy, but the disasters of 1814-15 put an end to the project, and he was eventually apprenticed to an apothecary in Alais. There was much that was congenial to the boy's tastes in such a calling. The bent of his mind towards natural science had already declared itself, and the career of a pharmacist seemed to offer opportunities for its pursuit. Moreover, there were many things in and about Alais to stimulate his interest in matters relating to chemistry. In its glass works, and manufactories of earthenware, in its limekilns, and its smelting-houses of lead and antimony, the young apothecary had occasion to observe the connection. of the science with technical processes; and in his subsequent writings we find frequent mention of his early impressions.

Alais, however, did not hold Dumas long. He was barely sixteen years of age when he determined to

leave his native town; and he set out on foot for Geneva, where he had relatives, and entered the pharmaceutical laboratory of Le Royer.

Geneva was then, as now, a centre of academic life, and the boy found everything there to stimulate his intellectual activity and to quicken his thirst for knowledge. Gaspard de la Rive at that time lectured on chemistry, Pictet on physics, and De Candolle on botany-all honoured names in the history of science.

It was said of Dumas in later years that he seemed predestined to presidency, and we find him even in his student days taking a leading place in the various scientific associations and social gatherings of his fellows. They suggested that he should give them a course of instruction in experimental chemistry; and it was with the aid of a few glass tubes, a syringe for an air-pump, lamp chimneys made into gas jars, and a balance constructed by a watchmaker, that he made his debut as professor. He came under the notice of Theodore de Saussure and of De Candolle; and probably at their instigation, or possibly prompted by his latent naval predilections, he sought to qualify himself for service in an exploring expedition. One outcome of this work of preparation was a monograph on the Gentianæ, compiled with a view of familiarising himself with the conceptions and terms of botanical science.

But Dumas soon turned into other paths. As his knowledge increased the range of his horizon widened. The brilliant discoveries of Davy, of Berzelius, and of Gay Lussac and Thénard, had fired his enthusiasm, and to an active vigorous mind like his to peruse their memoirs was to conceive of new problems and fresh fields of work. The chemical student of that period was not overburdened with text-books. Dumas was

nurtured on such fare as the great Treatise of Lavoisier and the Statique Chimique of Berthollet, and in the Annales de Chimie et de Physique he had a series of magnificent models of the art of scientific investigation. He was soon led to try his 'prentice hand at this art. The story of his first attempts was told by him to Professor Hofmann, to whom I am indebted not only for this, but also for many other accounts of incidents in Dumas's personal history. "When analysing various sulphates, and other salts of commerce, Dumas had observed that the water they contained was present in definite equivalents. He had not found this recorded anywhere, and had therefore taken great pains to establish the accuracy of his observations. When the investigation was finished, he went one morning early to M. de la Rive, and timidly submitted to him the manuscript embodying the results of his inquiry. Whilst glancing over it, M. de la Rive could not conceal his surprise. When he had come to the end he said to the young student, ‘Is it you, my boy, who have made these experiments?' 'Certainly.' And they have taken you a good deal of time to perform?' 'Of course they have.' Then I must tell you that you have had the good fortune to meet Berzelius on the same field of research. He has preceded you; but he is older than you, and so you ought not to bear him ill-will on this Come along and breakfast with me.' The kindly feeling thus shown to Dumas by his teacher never subsequently failed, and on more than one occasion De la Rive gave him substantial proof of his friendship.

account.

Nor was his next excursion along the road of discovery attended with more success. "He thought that, knowing the atomic weight of a solid or liquid

body, and likewise its density, it might be possible to arrive at the volume of the solid or liquid atom. He was thus led to determine, with great accuracy, the density of a number of simple and compound substances, the purity of which could be depended upon. Having worked for some time, he drew up a paper upon the subject, which was presented to M. de la Rive. But his friend, though admitting the novelty of the point of view from which the question was treated, did not encourage him to pursue this line of research. Young Dumas was rather disheartened when he left his patron. The first time,' he said to himself, my experiments were good, but they were not new; this time they are new, but they do not appear to be good. I shall have to try again." Dumas was thus the forerunner along a line of research which is inseparably associated with the name of Hermann Kopp, whose work on the specific volumes of solid and liquid substances constitutes one of the classics of chemical physics.

Dumas's name first appears in chemical literature when he was eighteen years of age, and in connection with Coindet's method of healing that extraordinary enlargement of the thyroid gland, known as goître, which is so prevalent in certain parts of Switzerland. Prior to the year 1818, the most successful mode of treating this disease was by the employment of carbonised sponge, in which Coindet, from its habitat, was led to suspect the presence of the element iodine, which Courtois had discovered some six years before in the liquid obtained by the lixiviation of burnt sea-weed. Dumas, at Dr. Coindet's request, examined sponges for iodine; he detected the presence of the new element, and suggested its employment as a tincture, as potassium iodide, and as iodised potassium iodide, all of which Y