The contribution of Gustav R. Kirchhoff to the dynamics of tapered beams

Gustav Kirchhoff has been credited, among many other renowned achievements, as the first scientist who tackled and solved the problem of studying the transversal vibrations of beams with variable cross-section. His contribution, which was presented in 1879 and published in the following year, is nowadays almost forgotten in the international scientific community, with the only exception of the German-speaking countries. For this reason it is rediscovered and thoroughly discussed here, with an exegetical approach. For completeness¡¯ sake an unabridged translation into English (the first one, to the best of the authors¡¯ knowledge) is provided in the appendix for the interested readers.