**Georg Simon Ohm** was a German mathematician best known for *Ohm's Law* on electrical resistance.

- Georg Simon entered Erlangen Gymnasium at the age of eleven but there he received little in the way of scientific training.
- It is worth stressing again the remarkable achievement of Johann Wolfgang Ohm, an entirely self-taught man, to have been able to give his sons such a fine mathematical and scientific education.
- In 1805 Ohm entered the University of Erlangen but he became rather carried away with student life.
- Ohm went (or more accurately, was sent) to Switzerland where, in September 1806, he took up a post as a mathematics teacher in a school in Gottstadt bei Nydau.
- Karl Christian von Langsdorf left the University of Erlangen in early 1809 to take up a post in the University of Heidelberg and Ohm would have liked to have gone with him to Heidelberg to restart his mathematical studies.
- Langsdorf, however, advised Ohm to continue with his studies of mathematics on his own, advising Ohm to read the works of Euler, Laplace and Lacroix.
- Rather reluctantly Ohm took his advice but he left his teaching post in Gottstadt bei Nydau in March 1809 to become a private tutor in Neuchâtel.
- After three semesters Ohm gave up his university post.
- This was not the successful career envisaged by Ohm and he decided that he would have to show that he was worth much more than a teacher in a poor school.
- After Ohm had endured the school for three years it was closed down in February 1816.
- On 11 September 1817 Ohm received an offer of the post of teacher of mathematics and physics at the Jesuit Gymnasium of Cologne.
- This was a better school than any that Ohm had taught in previously and it had a well equipped physics laboratory.
- As he had done for so much of his life, Ohm continued his private studies reading the texts of the leading French mathematicians Lagrange, Legendre, Laplace, Biot and Poisson.
- The Jesuit Gymnasium of Cologne failed to continue to keep up the high standards that it had when Ohm began to work there so, by 1825, he decided that he would try again to attain the job he really wanted, namely a post in a university.
- He had already convinced himself of the truth of what we call today "Ohm's law" namely the relationship that the current through most materials is directly proportional to the potential difference applied across the material.
- The result was not contained in Ohm's firsts paper published in 1825, however, for this paper examines the decrease in the electromagnetic force produced by a wire as the length of the wire increased.
- The paper deduced mathematical relationships based purely on the experimental evidence that Ohm had tabulated.
- In two important papers in 1826, Ohm gave a mathematical description of conduction in circuits modelled on Fourier's study of heat conduction.
- These papers continue Ohm's deduction of results from experimental evidence and, particularly in the second, he was able to propose laws which went a long way to explaining results of others working on galvanic electricity.
- The second paper certainly is the first step in a comprehensive theory which Ohm was able to give in his famous book published in the following year.
- What is now known as Ohm's law appears in this famous book "Die galvanische Kette, mathematisch bearbeitet" Ⓣ(The galvanic chain, processed mathematically) (1827) in which he gave his complete theory of electricity.
- We should also remark that, despite Ohm's attempts in this introduction, he was not really successful in convincing the older German physicists that the mathematical approach was the right one.
- In neither the introduction nor the body of the work, which contained the more rigorous development of the theory, did Ohm bring decisively home either the underlying unity of the whole or the connections between fundamental assumptions and major deductions.
- It is interesting that Ohm's presents his theory as one of contiguous action, a theory which opposed the concept of action at a distance.
- Ohm believed that the communication of electricity occurred between "contiguous particles" which is the term Ohm himself uses.
- As we described above, Ohm was at the Jesuit Gymnasium of Cologne when he began his important publications in 1825.
- Ohm had believed that his publications would lead to his receiving an offer of a university post before having to return to Cologne but by the time he was due to begin teaching again in September 1827 he was still without such an offer.
- Although Ohm's work strongly influenced theory, it was received with little enthusiasm.
- Ohm's feeling were hurt, he decided to remain in Berlin and, in March 1828, he formally resigned his position at Cologne.
- One factor may have been the inwardness of Ohm's character while another was certainly his mathematical approach to topics which at that time were studied in his country a non-mathematical way.
- There was undoubtedly also personal disputes with the men in power which did Ohm no good at all.
- He certainly did not find favour with Johannes Schultz who was an influential figure in the ministry of education in Berlin, and with Georg Friedrich Pohl, a professor of physics in that city.
- Electricity was not the only topic on which Ohm undertook research, and not the only topic in which he ended up in controversy.
- He succeeded in discrediting Ohm's hypothesis and Ohm had to acknowledge his error.
- In 1849 Ohm took up a post in Munich as curator of the Bavarian Academy's physical cabinet and began to lecture at the University of Munich.
- Only in 1852, two years before his death, did Ohm achieve his lifelong ambition of being appointed to the chair of physics at the University of Munich.

Born 16 March 1789, Erlangen, Bavaria (now Germany). Died 6 July 1854, Munich, Bavaria, Germany.

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Origin Germany, Special Numbers And Numerals

**O’Connor, John J; Robertson, Edmund F**: MacTutor History of Mathematics Archive