# Walther Ritz

Walter Ritz (or Walther Ritz, born February 22, 1878 in Sion (Sion), † July 7, 1909 in Göttingen) was a Swiss mathematician and physicist. He was an eminent Swiss scientist and researcher, although he already died after a brief career at age 31.

## Life

Walter Ritz ' Father Raphael Ritz was born in the Valais and a well-known painter. His mother, with the birth name of Nördlingen was the daughter of an engineer from Tübingen. Ritz was a particularly gifted student and attended the local secondary school in Sion. In 1897 he entered the Polytechnic School in Zurich, where he studied engineering. He soon found out that he could not live with the approximations and compromises that are connected to the engineering and so he moved to the mathematically precise physical sciences.

1900 Ritz ill with tuberculosis, possibly also to pleuritis ( pleurisy ), where he was to die later. In 1901 he moved to Göttingen for health reasons. There he was influenced by Woldemar Voigt and David Hilbert. Ritz wrote a dissertation on the spectral lines of atoms and received his doctorate summa cum laude. The subject later led to the Ritz combination principle and 1913 model of the atom by Ernest Rutherford and Niels Bohr.

In the spring of 1903, he heard lectures in Leiden by Hendrik Antoon Lorentz via electrodynamic problems and its new electron theory. In June 1903 he was in Bonn at the Heinrich Kayser Institute, where he found a spectral line in potash, which he had predicted in his thesis. In November 1903 he was in Paris at the École Normale Supérieure. There he worked on infrared photo plates.

In July 1904, his illness worsened and he moved back to Zurich. The illness prevented him until 1906 to further scientific publications. In September 1907 he moved to Tübingen, his mother's place of origin, and in 1908 again to Göttingen, where he became a lecturer at the university. There he published his work " Recherches critiques sur l' Électrodynamique Générale ".

Ritz had as a student, friend or colleague contacts with many contemporary scholars such as Hilbert, Andreas Heinrich Voigt, Hermann Minkowski, Lorentz, Aimé Cotton, Friedrich Paschen, Henri Poincaré and Albert Einstein. He was a fellow student in Zurich Einstein, who was studying there as well.

## Scientific achievements

Ritz delivered by the method of Ritz ( Ritz method ) a calculation method of engineering mechanics and theoretical guidance for the finite element method ( FEM). The Ritz method is also known as the Ritz Variationsprinizp. ( See also Rayleigh - Ritz principle. )

Ritz 1908 found empirically that bears his name Ritz combination principle. Thereafter, the sum or difference of the frequencies of two spectral lines is often the frequency of another line. Which of these calculated frequencies is actually observed, was later explained by selection rules that follow from quantum mechanical calculations. This was based on the Spektrallinienforschung ( Balmer series) by Johann Jakob Balmer.

Walter Ritz represented as other emission theory, a so-called " ballistic " theory of light similar to the Newtonian emission theory, as an alternative to Lorentz electrodynamics and special relativity. It is worth knowing that the emission theory of Ritz dealt with the Galilean transformations of velocity of light, instead of the structure of space and time, as well as the Lorentz transformations of velocities. Also discussed Ritz with Einstein about it and led 1908/1909 until his death in the " Physical Magazine " a scientific dispute with him. However, the emission theory is refuted. ( For further details see the corpuscular theory. )

The physical unit Ritz- standard is named after the Ritz. With Johannes Rydberg Ritz worked on the Rydberg - Ritz formula.

## Writings

- Theories of Aether, gravity, relativity and electrodynamics. Step -Verlag, Bern 1963 ( step series, No. 6).
- On the role of the ether in physics. In: Scientia 1908, No. VI: "You rôle de l' éther s physique"
- Recherches critiques sur l' Électrodynamique Générale, Annales de Physique et Chemie, 13, 145, 1908
- Collected Works - oeuvres. Issued by the Société Suisse de Physique, Gauthier -Villars, Paris, 1911.