Hendrik Antoon Lorentz

Hendrik Antoon Lorentz (Arnhem, July 18, 1853 – Haarlem, February 4, 1928) was one of the greatest Dutch theoretical physicists. He was the second Nobel laureate in physics, together with Pieter Zeeman. They received the prize in 1902 for the discovery (by Zeeman) and the explanation (by Lorentz) of the Zeeman effect, the splitting of spectral lines in a magnetic field.

Lorentz's main contribution to physics was in the theory of electromagnetism in which he continued and extended the work of the Scotsman James Clerk Maxwell.

Biography

Lorentz was born in the city of Arnhem, the capital of Gelderland, a Dutch province. He was the son of Gerrit Frederik Lorentz, a successful market gardener, and Geertruida van Ginkel. When Hentje (as Lorentz was called as a boy) was five years old, he lost his mother. Five years later, in 1862, his father married Luberta Hupkes. Hentje was a quiet, cheerful, and intelligent child with an early interest in mathematics. When he was 10 years old he bought a logarithm table of his pocket money and taught himself how to calculate with it.

In 1866 Lorentz entered the third grade of the newly established high school (HBS, "Hoogere Burger School") in Arnhem. He was an excellent student, not only in the exact sciences, but also in the modern languages, French, English, and German, that, together with the Dutch language, were on the curriculum of the HBS. This type of school did not teach the classical languages, however. At that time these were required for admission to the Dutch universities. So, Lorentz took separate lessons in Greek and Latin and after passing the required exams he was admitted to the University of Leiden, in 1870.

The talents of the young student in physics and mathematics made a strong impression on his teachers, among whom the astronomy professor Frederik Kaiser. It was Kaiser's influence that led Lorentz to choose physics over mathematics. Later, in 1881, Lorentz would marry professor Kaiser's niece. In 1871, at the very early age of 18, Lorentz passed with summa cum laude the candidaatsexamen (comparable to a bachelor's). This was an oral exam with several examiners, who all were aware of Lorentz's reputation. One of the examiners declared after the examination was over that, although Lorentz's performance was satisfactory, he performed less than expected. It turned out that the examiner mistakenly thought that he participated in a doctoraal examen, an oral examination three years after the candidaatsexamen.

After having passed his candidaatsexamen, Lorentz returned to Arnhem in 1872 to teach evening high school classes to students of his own age, while continuing his studies in Leiden. He passed his doctoraal examen in 1873 (two years faster than the average student) and wrote in a period of two years a PhD thesis. On December 11, 1875, Lorentz obtained his doctorate degree under Pieter Rijke on a thesis entitled "Over de theorie der terugkaatsing en breking van het licht" (On the theory of reflection and refraction of light), in which he refined the electromagnetic theory of James Clerk Maxwell. This thesis also gained the predicate summa cum laude.

In 1878, only 24 years of age, Lorentz was appointed to the newly established chair in theoretical physics at the University of Leiden, the oldest university in the Netherlands. In January 1878, he delivered his inaugural lecture on De moleculaire theorieën in de natuurkunde (The molecular theories in physics).

In 1881 Hendrik Lorentz married Aletta Catharina Kaiser (1858-1931), the daughter of Johann Wilhelm Kaiser, director of the Amsterdam's Engraving School and professor of Fine Arts at the Rijksakademie voor Beeldende Kunsten, and designer of the first Dutch postage stamp (1852). The couple had two daughters and two sons (one of whom died in infancy). The eldest daughter Geertruida Luberta was to become a physicist as well and married later Wander Johannes de Haas, an experimental physicist of some renown.

During his years in Leiden, Lorentz was primarily interested in the theory of electromagnetism, the theory of of electricity, magnetism, and light. Lorentz theorized that the molecules might consist of charged particles and suggested that the oscillations of these charged particles were the source of light. When colleague and former student of Lorentz Pieter Zeeman discovered the Zeeman effect in 1896, Lorentz supplied its theoretical interpretation. The experimental and theoretical work was honored with the Nobel prize in physics in 1902.

Lorentz did not travel abroad at all during the first twenty years of his career. His first trip outside the Netherlands was in 1898 when he received an invitation to give a talk in Düsseldorf, a German city about 65 miles (105 km) from Arnhem, Lorentz's town of birth. However, this would soon change, after 1900 Lorentz became one of the most prominent theoreticians of Europe and did not only receive many invitations for giving lectures, but also became a much sought-after chairman of international conferences. He had eminent qualities for such a chairmanship, he spoke fluently French, German, and English and was able to switch instantly between languages. He had a very quick mind and a large knowledge of physics, so that he generally understood the lectures delivered at the conferences he was chairing, and finally he was tactful and courteous. In the capacity of chairman he did not limit himself to organizational matters, or to presiding at the meetings, but contributed vitally in preparing the scientific program, choosing the speakers, and summarizing the results. The highlights were the Solvay Councils (Conseils de Physique), the first of which was held in 1911. These conferences were sponsored by the Belgian industrialist Ernest Solvay. Lorentz presided at all conferences until 1927, the year before his death. In 1906 Lorentz traveled to the USA to deliver guest lectures at Columbia University.

In 1912, Lorentz was appointed curator of the physics cabinet of Teyler's Museum and secretary of the Hollandsche Maatschappij der Wetenschappen (Holland Society of the Sciences) in Haarlem, and he now became professor extraordinarius at Leiden. In Haarlem he gave popular lectures on science, emulating the Royal Institution of London, and at Leiden he gave a seminar for advanced physics students and colleagues every Monday morning in which he discussed new findings in physics.

In the days of Lorentz, the Netherlands contained a large bay in open connection to the North Sea, called the Zuiderzee. This salt water bay regularly flooded the surrounding areas, so that a plan originated to build a huge dam (the Afsluitdijk) closing off the bay from the sea. Of course, this dam would have a huge influence on currents and tides; to predict possible changes a committee was formed with Lorentz in the chair. From 1918 to 1926 Lorentz performed the necessary calculations on the effects of the dam on the sea currents almost single-handedly and finally he advised the government to go ahead and to build it. The dam was finished in 1932, five years after Lorentz's death and Lorentz's predictions turned out to be correct. Now the Zuiderzee is a fresh water lake (called the IJsselmeer) and large part of it has been turned into dry land (into three polders).

In 1928 he died of Erysipelas.

Publications of H. A. Lorentz

The following list is not exhaustive.

• 1875 - Over de theorie der terugkaatsing en breking van het licht/Sur la theorie de la réflection et de la réfraction de la lumière (dissertation University Leiden)
• 1878 - De moleculaire theorieën in de natuurkunde (inaugural lecture)
• 1882 - Leerboek der differentiaal- en integraalrekening en van de eerste beginselen der analytische meetkunde met het oog op de toepassingen in de natuurwetenschap
• 1886 - De l'influence du mouvement de la terre sur les phénomènes lumineux
• 1892 - La théorie electromagnétique de Maxwell et son application aux corps mouvants
• 1893 - Beginselen der natuurkunde, Brill, Leiden (textbook with many reprints)
• 1895 - Versuch einer Theorie der elektrischen und optischen Erscheinungen in bewegten Korpern
• 1899 - Theorie simplifiée des phénomènes électricques et optiques dans des corps en mouvement
• 1904 - Electromagnetic phenomena in a system moving with any velocity smaller than that of light
• 1909 - The theory of electrons and its applications to the phenomena of light and radiant heat
• 1910 - Sichtbare und Unsichtbare Bewegungen
• 1918 - Beginselen der natuurkunde, 2 volumes
• 1919- 1925 - Lessen over theoretische natuurkunde aan de Rijks-Universiteit te Leiden gegeven door H.A. Lorentz, 8 volumes
• 1922 - Problems of modern physics. Lecture notes California Institute of Technology
• 1926 -The quantum theory. Present day problems and outstanding questions of the quantum theory. Notes accompanying lectures delivered by Professor H.A. Lorentz at Cornell University, fall term 1926
• 1926 - Verslag Staatscommissie Zuiderzee 1918 - 1926
• 1935-1939 - Collected Papers, ed. Pieter Zeeman and Adriaan Fokker, 9 volumes

(To be continued)