Justus Liebig Life and Work

ACTA UNIVERSITATIS LODZIENSIS FOLIA CHIMICA 13,2004 JUSTUS LIEBIG LIFE AND WORK by Helmut Gebelein Justus Liebig University, Department of Chemical Didactics, Heinrich Buff-Ring 58, 35392 Giessen, Germany Fig. 1. Freiherr Justus von Liebig, 1864 Liebig was not only one of the most prominent chemists of the 19th century, he had also done important work in agriculture and in nutrition. He even wrote articles about philosophical problems, he improved a special method of fresco painting, and with his Chemical Letters he produced one of the best books on chemistry for the laymen. A similar work on modern chemistry is still lacking. Liebig was born on the 12th of May 1803, in Darmstadt, a town some 20 kilometres to the south of Frankfurt. At this time Darmstadt was the capital of Hessen-Darmstadt, one of the small German states. Duke Ludwig 1 of Hessen-Darmstadt was interested in the advancement of the sciences. He even had a university at Giessen, founded in 1607. This university is today called Justus Liebig-University after its most prominent scientific scholar. Liebig’s father had a drysalt and hardware shop and he owned a small laboratory where he produced drugs and materials, e.g. pigments for colours. Through the father’s laboratory Justus became interested in chemical processes already in his youth and he wanted to become a chemist. He read all the books on chemistry he could get hold of. The court library where he borrowed most of these books was unfortunately not very up to date. He could not learn modern chemistry in this way. But it might be that his later interest in history of chemistry came from these readings. But this life didn’t start very promisingly. At the age of 14 he left school without any qualification. It must be said that in this time this was not unusual. In Heppenheim, a small town to the south of Darmstadt, he started a apprenticeship to an apothecary, but after 6 months he had to quit. It is most probable that his father was not able or willing to pay for his son. He himself wrote later that he had to leave after 10 month because he had conducted dangerous experiments. For the next two years he stayed at home. On the market place he observed a man producing caps of silver fulminate. He investigated this reaction and published the results in his first article in 1822 with the help of Professor Karl Wilhelm Gottlob Kastner (1783-1853)', an acquaintance of his father. Kastner even invited him to study chemistry at the University of Bonn. At this time it was possible to study without any formal school education. In 1820 he began to study chemistry in Bonn. When Kastner went to Erlangen in 1821, he took Liebig with him. As a member of a student society he ran into political trouble and - not to be arrested - had to flee home to Darmstadt. The Duke of Hessen-Darmstadt, Ludwig I. - again with the help of Kastner - sent him to Paris, at this time the most important university for chemistry. There he met not only the important French chemists like Joseph Louis Gay Lussac (1778-1850), and Louis Jacques Thenard (1777-1857) but also Alexander von Humboldt, who was very impressed by this young scientist and supported him. In the meantime Kastner managed to arrange that Liebig could get his doctorate at the University of Erlangen in absentia. His thesis was entitled About 1 It seems that no picture of Kastner exists. the relation of mineral chemistry to the chemistry of plants (Über (las Verhältnis der Mineralchemie zur Pflanzenchemie) and touchcd on a problem he was later on very much engaged with. Now he was able to start an academic career. When he came back to Darmstadt on the advice of Kastner and Humboldt, Ludwig I. nominated him for the position of Professor of Pharmacy and Chemistry at his university in Giessen. Here he ran into a lot of problems, as he was appointed by the duke without the university being consulted. Only when he gained the interest of the students did the attitude of the university change. In 1833 his private institute was integrated into the university as the chemical institute. In 1826 he married Henriette Moldenhauer and with her he had 5 children: Hermann, Georg, Agnes, Johanna and Marie. In 1831 he - or probably his glass blower - invented the Kaliapparat with five glass bulbs. With this invention, elementary analysis was dramatically improved. The Kaliapparat became the emblem of Liebig’s students, which they wore as a badge. From 1831 Liebig belonged to the publishing team of the Magazine of Pharmacy (Magazin fiir Pharmazie). From 1840 on it was published under the name of Annals of Chemistry and Pharmacy (Annalen der Chemie und Pharmazie). In this function he also acted as a competent judge of the articles although his criticism was - according to Partington - sometimes beyond all reason. In 1839 he was able to build his new laboratory. With this design he created the prototype for all laboratories in universities and industry. The old laboratory still looked like that of an alchemist. Fig. 2. The old laboratory in the Liebig Museum Giessen Fig. 3. The new laboratory in the Liebig Museum Giessen In 1845 he was ennobled and from this time on he was Justus Freiherr von Liebig. He himself had urged the duke to take this step, arguing that he should have the same title as the famous French chemists. Until 1852 Liebig was a professor in Giessen. During this time 700 students studied in Giessen, among them nearly 200 from foreign countries. An impressive number, as at this time the town had 5500 inhabitants and around 300 students in all faculties. Then the King of Bavaria invited him to come to Munich. There he was also appointed President of the Bavarian Academy of Science. In Munich he was given a great house, a laboratory and a lecture hall with 300 seats. At one of his first public lectures, there was an incident. He performed the experiment of burning carbon disulphide in laughing gas (nitrous oxide). The public was enthusiastic, so he decided to repeat the experiment. But he made a mistake: instead of laughing gas he took a vessel with oxygen, the result was an explosion, and a few persons, even some of the Royal Family were injured, fortunately not seriously. In the journal Allgemeine Augsburger Zeitung he reported - anonymously - about this incident and wrote that he was not blamed for his mistake and that the King even asked him about his wounds. He died on the 18"' of March 1873 in Munich and is buried there. Let us now have a look at Liebig’s most important contributions to the sciences. Chemistry as it is regarded today is a young science. It can be said that it started with the work of Antoine-Laurent Lavoisier (1743-1794). His theory of burning, which states that oxygen is taken up in this process, can be regarded as the starting point of modern chemistry. In his Chemical Letters Liebig describes the strange celebration in which Madame Lavoisier in the costume of a priestess throws the books of the phlogistonic system into the fire whilst a requiem is played. Lavoisier did this to promote his system. Wc, in our time, cannot find this celebration very amusing. The new theory of burning was not readily accepted in Germany. The old theory - the phlogistonic theory - was formulated by the German alchemists Johann Joachim Becher (1635-1682) and Georg Ernst Stahl (1660-1734). This theory explains burning as a loss of a substance named phlogiston. It seems thal national interests may have played a role in the lack of acceptance of the new theory. Christoph Girtanner, in a book on antiphlogistonic chemistry, wrote that he promoted this new system, which was opposed by all great chemists, only because it was true, and that he would defend it only as long as he was convinced that it was true. The long tradition of alchemy had come to an end, and the modern chemistry began. In contrast to his contemporaries, Liebig regarded alchemy as an important epoch in the history of science, as can be read in his Chemical Letters. There he states that alchemy was, with regard to the knowledge of nature, ahead of all other sciences. It was only because they were unaware of the history of chemistry that most chemists, overestimating their own knowledge, looked back with disgust on the period of alchemy as if the very learned men like Francis Bacon, Spinoza, Leibniz were interested in absolutely senseless ideas. But at the time of Liebig modern chemistry was only in its beginnings. One reason was that in 1850 only 52 of the 92 naturally-existing elements were known, and that it was not clear, which substances were really elements. As a result more than 170 spurious elements were reported in the 19lh century. Analyzing substances in order to find out if they can be reduced to an elementary state was therfore of the greatest interest. Not very much was known about chemical compounds too, due to the lack of good analytic methods. It can be said that the developing ot analytical methods was of the highest importance at this time. The study of chemistry can be regarded as consisting of analytical, preparative, and theoretical chemistry. Liebig had contributed to all these branches. Liebig started in Giessen as a pharmaceutical chemist. This is not surprising since chemistry was part of medicine at this time. In 1831 lie was able to produce chloroform (CHCI3), used as an anaesthetic for quite a long time.

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