Anyone who follows the history of the development of chemical science, and the enormous extensions of chemical industry, must be astonished at the number of most important achievements which made the name of A. W. von Hofman one of the best known and most celebrated in the whole arena of science.
He was born on the 8th of April, 1818, at Giessen, and was the son of J. Ph. Hofmann, the University architect. His education was obtained first at a boy's school at Mehlbach and then at the Gymanasium of his native town. In the year 1836 he visited the University of Giessen, without having decided upon any definite line of study. He soon took up the pursuit of law, which, however, he exchanged after a short interval for that of chemistry. Hofmann was a zealous student of the immortal Liebig, to whom he soon became a personal friend, and finally was appointed his assistant. His first extended investigation, which formed at the same time as his dissertation, was upon the volatile bases of coal tar (1841). Hofmann was a zealous student of the immortal Liebig, to whom he soon became a personal friend, and finally was appointed his assistant. His first extended investigation, which formed at the same time as his dissertation, was upon the volatile bases of coal tar (1841).
In this work the presence of aniline and quinoline was proved in coal tar, and it became the starting point of a series of other investigations of the greatest importance, both for theory and practice. For another paper upon the changes of indigo, in which the ambitious young chemist decided the question of the replacement of hydrogen by chlorine, at that time vigorously discussed, the Pharmaceutical Society of Paris awarded him its prize medal.
In 1845, Hofmann left Giessen to obtain a teaching position at the University of Bonn, where he lectured upon agriculture. At this time a laboratory was being erected in London, upon the plan of that in Giessen, and Hofmann, warmly recommended by Liebig, received an invitation to come to London and undertake the organisation and management of the new chemical school. The young investigator accepted this honourable position, and in the autumn of 1845, after having been appointed Extraordinary Professor at Bonn, went to London, where he soon gathered around him a circle of gifted scholars, who later became themselves eminent workers in science. In 1853, the chair of chemistry at the Royal School of Mines became vacant, by the resignation of Playfair, and Hofmann was appointed to this position, though he also remained at the head of the Royal College of Chemistry, which was affiliated by the Government to the School of Mines. In the year 1856, the position of Warden of the Mint was conferred upon him, and in 1861 he was elected president of the Chemical Society.
Hofmann had already been repeatedly solicited to return to Germany as a University professor, and at last he responded to the invitation of the Prussian Government to undertake the erection and management of a new laboratory at Bonn. In view of this work, he visited almost all the larger laboratories in Europe, in order to acquire experience to be utilised in the erection of the new building. He never, however, undertook the teaching work at the splendid institute which was thus erected, since in 1864 he was summoned to the chair of chemistry at Berlin, vacated by the celebrated Mitscherlich, and took up the work there in 1867. He also conducted the building and organisation of the first chemical institute at Berlin.
In Berlin, a rich field of work was found, in which he laboured for many years with the greatest success. As a teacher, he always gathered round him a circle of zealous students, many of whom took leading places both in science and industry; and as an investigator, he gave to the world a remarkably large number of most important researches. In the year 1868 he founded the German Chemical Society, which largely owes to him its present high position among similar associations.
We must refrain from giving even a list of Hofmann's numerous researches, which embrace all branches of chemistry, though they are chiefly connected with the development of the organic portion of the sciences, a fuller account of his work having been already given in Vol. II, No. 48, of the Journal. We must, however, mention that his continued researches upon aniline and its derivatives established a clear idea as to the relation which these most important substances bear to ammonia. Hofmann also recognised the possibility of replacing the second and third hydrogen atoms of ammonia by alcohol radicals, and this led to the more complete knowledge of the secondary and tertiary amines, and to the discovery of the quartenary ammonium bases. These same researches, moreover, as is now well known, contributed much to our knowledge of the organic bases of the vegetable kingdom, and may be considered as the fundament of the colour industry.
As an investigator, Hofmann was perhaps most widely known by his epoch-marking researches upon the colouring matters obtained from coal tar. As early as 1858 he prepared magenta by the action of carbon tetrachloride upon aniline, and devoted more that a year's work to its further examination. Shortly afterwards he discovered the well-known violet, which was at once manufactured on the industrial scale in enormous quantities. The important investigation upon methyl green (in conjunction with C. Girard), as well as on the nature of chrysoidine and eosin, and the colour so obtained from naphthylamine and xylidine, were associated with this work. Mention must also be made of Hofmann's remarkable researches upon guanidine, formaldehyde, and the isonitrils, the last of which led to the well-known isonitril reaction for the primary amines. Our knowledge of the mustard oils was also greatly extended by his work, and, finally, we must mention his work on the various alkaloids. Up to the very last days of his life, Hofmann continued his work in the laboratory and only a few months ago published in the Berichte, of the German Chemical Society, a paper entitled "Polymeric Methyl Mustard Oils", which contained the first results of an extended research which he had planned. The hope expressed at the close of this communication, that further details would be given, was however, never to be fulfilled. The other branches of Science have also largely gained by his work, and inorganic, analytical , technical, and forensic chemistry owe much to him. All are acquainted with his apparatus and method of determining the vapour densities of substances, which has rendered the most valuable service to science; and a great aid to the teaching of chemistry in schools was given by his apparatus for illustrating the fundamental volumetric relations of the gases.
The frequent requests for advice from official quarters were always met by him with the greatest readiness and unselfishness, and his wide knowledge was in many ways freely communicated. Examples of this are his remarkably lucid lectures at the Royal Institution, and in the scientific association of the "Singakademie", in Berlin. He was also active in numerous honorary posts. Thus he was one of the judges at and reported upon the exhibits in the Universal Exhibitions in London in 1851 and 1862, in Paris in 1855 and 1867, and in Vienna in 1873. In this connection he wrote a valuable treatise on organic chemistry and its application to perfumery, an instructive report on the London Exhibition of 1862, and a similar one, in conjunction with Girard and De Laire, upon the coal tar dyes at the Paris Exhibition of 1873. Well known, but unfortunately incomplete, is the report upon the Universal Exhibition of Vienna, which was also intended to be an account of the development of the chemical industry during the last decades. The reports published during the time of his residence in England upon the water supply of London (in conjunction with Graham and Miller), upon the addition of methyl alcohol to spirits of wine (with Graham and Redwood), and on the canal system of London (with Henry Witt), give ample proof of the skill, knowledge, and conscientiousness with which such subjects were handled by him.
His literary works, and the honours which were justly showered upon him in reward for his services in the cause of science, are too numerous and well-known to admit of special reference here, the greatest tribute to his memory being, perhaps, that to which special attention was drawn recently in these columns, namely, the establishment of a Hofmann Institute. With the death of Hofmann, closed a life rich in work, as fruitful of results; and his name, as an investigator and teacher, will be for ever be enrolled in the archives of chemistry, both in this country and abroad.