The dolorous destiny of Walther Ritz (1878--1909), an ingenious theoretical physicist (Q2849289)

The book gathers the addresses delivered by some scientists in November 2009 to remember the figure and work of the Swiss mathematician and pysicist Walther Ritz (1878--1909). To be precise, the volume contains seven contributes: 1) ``Aspects of the life and of the work by Walther Ritz, Vallesian theoretical physicist'' by Jean-Claude Pont (in French); 2) ``Sion at the time of Walther Ritz'' by Patrice Tschopp (in French); 3) ``Ritz and the physics of his time'' by Jan Lacki (in French); 4) ``Walther Ritz experimenter'' by Nicolas Produit (in French); 5) ``Walther Ritz's theoretical work in spectroscopy, focussing on series formulas'' by Klaus Hentschel; 6) ``From Euler, Ritz and Galerkin to modern computing'' by Martin J.~Gander and Gerhard Wanner; 7) ``Electrodynamics in the physics of Walther Ritz'' by Oliver Darrigol. NEWLINENEWLINENEWLINE NEWLINEThe principal parts of this book are those by Jean-Claude Pont, Klaus Hentschel, Gander and Wanner, and by Olivier Darrigol. Pont, after recounting the life of Walther Ritz (pp.~17--40), moves to sketch the three fields in which Ritz obtained his most notable results: spectroscopy, electrodynamics and relativity as well as mathematics (pp.~41--68). Spectroscopy and Ritz's combination principle are the object of Hentschel's paper, who links Ritz's work in issue with Bohr's model of the atom. The mathematical side of Ritz is the matter of Gander and Wanner's text, who show that the Galerkin method was actually worked out by Ritz. Unfortunately, this result was not taken into account from Western European mathematicians. Interested in it, at least at first, were three Russian mathematicians, Timoschenko, Bubnov and Galerkin. Galerkin quotes Ritz in the references of his [\textit{B. G. Galerkin}, ``Series occurring in various questions concerning the elastic equilibrium of rods and plates'' (Russian), Vestn. Inzh. 19, 897--908 (1915)], speaking literally of the ``Ritz method''. The authors notice the indifference of Courant and Hurwitz towards the Ritz method in 1922, but also Courant's late interest in it (1941). As a matter of fact, the Ritz method is a precursor of that finite method envisaged by Courant in order to solve the Dirichelet problem. This is the most elaborate (and interesting) section of the volume. NEWLINENEWLINENEWLINE NEWLINEDarrigol, instead, focusses on electrodynamics and relativity; Walther Ritz was convinced that an adequate foundation for pyhsics was enabled by electrodynamics: i.e. phsyics could be reduced to electrodynamics. The dispute against Einstein arose on the nature of the speed of light; while Einstein, rejecting Galilean kinematics, considered the speed of light as constant, according to Ritz the speed of light was a function of its source. This emission theory caught the interest of John Fox in the 1960s but with little fortune. NEWLINENEWLINENEWLINE NEWLINEConsidering the other contributions, Tschopp relates the life and culture in Vallesia at the time of Ritz. Produit advocates Ritz as experimenter, stating that only the bad health of Ritz hindered him to continue on this way. Finally, Lacki contextualizes Ritz's work in the physics of the 19th and 20th centuries. NEWLINENEWLINENEWLINE NEWLINEAt the end of the volume the paper in which Walther Ritz exposed his finite method is reproduced. The text, being composed for the Prix Vaillant in 1907, is in French. Unfortunately, Ritz did not win the first prize. The prize was awarded to Hadamard. Pont, in the first section of this book, reports on Ritz's disappointment. Indeed, Poincaré (who was part of the jury of the Prix Vaillant in charge to review Ritz's paper) did not pay much attention to this paper and thought that it was flawed. After a dispute, Poincaré acknowledged his fault.