The Chemical News/Justus Liebig (obituary)
JUSTUS LIEBIG was born in the small German town of Darmstadt, on May 13, 1803, and educated in Bonn and Erlangen. He was originally intended for a pharmaceutist, but having found the means of visiting Paris, and passing some time in the laboratories of the great French chemists who flourished in the year 1823, and, having achieved a success as a chemist, he was at once enrolled by Humboldt in the ranks of the German professoriat, being in 1826 nominated Professor in Ordinary in the University of Giessen, after having for the two preceding years held office as Extraordinary Professor in the same university.
Liebig began to publish very early. In the Annales de Chimie et de Physique for the year 1823, tome xxiv., p. 294, there is a paper entitled "Mémoire sur l'Argent et le Mercure Fulminans, par le Dr. Justus Liebig." About the same period there is also a note by Dr. Leibig. "Sur une Couleur Verte," which is an account of some observations on the making of arsenite of copper. It appears, however, that there were some publications of still earlier date, inasmuch as he refers to his own work in Buchner and Kasner's journal. The first publication, however, which excited attention was the one on the fulminates, which was first mentioned: Analyses of fulminate of mercury and fulminate of silver, and the preparation of most of the other fulminates, together with their analyses. We can understand that Humboldt was struck with the young chemist's ability who had accomplished such a task.
In his professorship at Giessen, Liebig displayed the greatest activity, and gathered around him a knot of men whose names are household words among chemists. It was in Liebig's hands that ultimate organic analysis assumed the importance which it has acquired; and it was mainly owing to him that it was so popularised among chemists as to become one of the commonest resources of the laboratory. In Poggendorft's Annalen for the year 1831 may be read Liebig's own account of his improvements in the management of a combustion and in the apparatus. The following passage, which is exquisitely pithy and exquisitely modest, winds up the description:- "In this apparatus there is nothing new but its simplicity and thorough trustworthiness."  The paper is a study of chemical method, and might be read with advantage by chemists living in the year 1873. We must, says Liebig, separate the determination of nitrogen from the determination of carbon, and make two distinct and independent analyses. We must have a method which admits of operating on 3 or 4 grms. of substances which are poor in carbon, and on ½ to 1 grm. of substances which are rich in carbon. Liebig chose to weigh the carbonic acid instead of to measure it. In 1831 the measurement of gases was a matter of much greater difficulty that it is to-day, and the advantage gained at that period, by making the common combustion not to involve a gaseous measurement, was more striking that it is at present. Still, even to-day, there would be no gain in the substitution of measurements of carbonic acid for weighings of it, and the belief which some chemists entertain, that there would be, has its origins only in mental confusion and want of appreciation of the practical conditions under which analyses are accomplished and limited.
Much of that which is best established and most familiar to us in organic chemistry is the work of Liebig, and was accomplished long ago. The constitution of chemical history of benzoic acid was made out by Liebig and Wöhler. Hippuric acid was explored by Liebig. Aldehyde, which previously bore the name "light oxygen ether," and was known only in a very impure condition, was first rendered intelligible by him. Tyrosine, sarcosine, and creatinine, which are delivered from flesh, as his discoveries. Though not the originator of the theory of compound radicals, he was one of its most powerful supporters, and contributed much of that which has proved to be most enduring in it. The theory of the existence of the radical ethyl is Liebig's, and the splendid investigation which led its authors to speak of the radical benzoyl was conjointly Liebig's and Wöhler's.
The application of chemistry to agriculture, and to many of the wants of daily life, received so powerful an impulse from Liebig, that the popular mind has taken him for the representative of the science in its application to practical purposes. So great, indeed, has his fame become as a technologist, that writers in English newspapers have overlooked the fact that he was one of the greatest chemists of the century.
Liebig left Giessen in the year 1852, and went to Munich, where he became Professor of Chemistry in the University and President of the Academy of Sciences. In 1845 he had been created a Baron. He died at Munich on the 18th of this month.
- "An diesem Apparate ist nichts neu als seine Einfachheit und die vollkommene Zuverlässigkeit, welche er gewähst."