Rudolf J. E. Clausius

The Biography

Rudolf Julius Emanuel Clausius is a famous physicist and mathematician. He conducted researches in thermodynamics, he formulated the second law of thermodynamics and introduced the concept of entropy.

Rudolf Clausius was born on 2nd January 1822 in Koszalin, Poland. He was raised by father Carl Ernest Gottlieb, who was a theologian, Pastor and regional legal advisor. He had seventeen brothers and sisters.

The brother of Clausius, Robert, wrote about him: “... all intimate with him learnt to esteem his reliability and truthfulness. The greatest confidence and trust were placed in him. His judgment was highly valued”.

Young Rudolf spent sixteen years of his life in Koszalin. Our sources of information tell us that the house of Clausius was situated near Młyńska and Piastowska Street in modern Koszalin.
He attended his father’s school “Guillame – du – Bois”, and then, at the beginning of 1838, moved with his family to Szczecin, where he graduated from Frederic the Great secondary school in 1840.
Clausius then decided to enter the Frederic Wilhelm University of Berlin. For a long period of time he was not sure which subjects he would like to study. For a while he was strongly attracted towards history, but finally he decided to concentrate on mathematics and physics. Despite his hesitation, he was noticed as one of the cleverest student. His university professor wrote: “Mr Clausius of Koszalin has attended my lectures on mathematical sciences for three months and he proved to me that he had not only mathematical talent, but he enjoyed broadening his knowledge…”

He completed his degree in 1844 and then spent a probationary year teaching at the Frederic-Werder Gymnasium. He taught the advanced classes in mathematics and physics.

In 1846 he entered Boeck's Royal Seminary and submitted his dissertation, on the problem of reflected light in the sky, to Halle University in 1847. This early work by Clausius was aimed at explaining the blue colour of the sky, the red colours seen at sunrise and sunset, and the polarisation of light. It has turned out not to be based on correct physics because it assumed the effects which were caused by reflection and refraction of light rather than being caused by the scattering of light. However in this work Clausius applied mathematics far more deeply than any of his predecessors and it is a good illustration of how physical problems drive the development of mathematics even when their physical basis is unsound. Clausius received his doctorate, with distinction, on 15th July 1848. After a year Clausius’s doctorate was published in a private mathematical periodical of Crelle. His second work, about the conditions of waves’ propagation in the crystalline bodies was published in “Annalen der Physic” in 1849.

Clausius’ third book, entitled “About the moving power of heat and the laws that can be derived from a science about heat”, was published on 18th January 1850 in volume No. 79 of “Annalen der Physic”, a private periodical of Poggendroff. That work was the beginning of a new age in the history of physics.

In 1850 Clausius was invited to take the post of Professor at the Royal Artillery and Engineering School in Berlin. He also became a Docent at the University of Berlin. Five years later, on 29th August 1855, Clausius was appointed to the Chair of Mathematical Physics at the Polytechnic in Zurich. It was an excellent place for him to work. In Zurich Clausius was provided with excellent working conditions. He developed the concept of entropy and deduced the famous Clausius-Clapeyron relation, which expresses the relation between the pressure and temperature at which two phases of a substance are in equilibrium.

Clausius spent twelve years in Zurich. In 1862 he married Adelheid Rimpam. In 1867 he decided to come back to Germany, where he was offered a Professorship by the University of Würzburg. He was soon promoted – in 1869 he accepted a chair at the University of Bonn.

Rudolf Clausius was not only a great scientist, he was also a great patriot. He took an active part in the Franco-Prussian War of 1870. He undertook the leadership of an ambulance corps, which he formed of Bonn students and he took an active part at the great battles of Vionville and Gravelotte. His brother wrote: “His burning patriotism did not permit him to stay idle at home during the war of 1870-71…”

Clausius received the Iron Cross in 1871 for his services to the German campaign.
Unfortunately he injured his leg during the battles and suffered severe pain and disability for the rest of his life. What was more, his lovely wife died in child birth shortly afterwards. Clausius then realized that he is responsible for bringing up his family. Robert, the brother of Clausius, said: “He was the best and most affectionate of fathers, fully entering into the joys of his children. He himself supervised the schoolwork of his children”. That is why Clausius decided to decrease considerably his research work and spend more time with his family. As a way to overcome the problems with his injured leg his doctor advised him to take up horse riding and, after a very short time, he became an expert horseman.

In 1884 Clausius started achieving professional successes again – he became Rector of the University of Bonn. Two years later a great fortune was stowed him also in his private life. He was remarried Sophie Stack, who bore him another child.

Rudolf Julius Emanuel Clausius continued his research work up to the end of his life, until 24th August 1888. His brother said: “Even on his last sick-bed he held an examination”.

Scientific achievements of Clausius made him famous in the scientific circles. He was elected a Fellow of the Royal Society of London in 1868 and received its Copley Medal in 1879. The other members of the Society were among others Izaac Newton, Albert Einstein and André M Ampere. This medal is the highest award from the Royal Society of London, for the most important scientific discovery or for the greatest contribution made by experiment. He also received the Huygens Medal in 1870, the Poncelet Prize in 1883, he received an honorary doctorate from the University of Würzburg in 1882 and he was elected a Fellow of the Royal Society of Edinburgh in 1888. There is also a Lunar Crater named after Rudolf Clausius.

George FitzGerald, a brilliant mathematical physicist, said: “He was a noble example of the spirit that devotes itself to directly benefiting mankind, and that does not waste time on petty elaborations of pretty problems. He was in the highest sense practical, his work is eternal, and his memory will live as long as mankind reveres its benefactors”.