The unity of the physical forces

Saggio di filosofia naturale
Angelo Secchi
Roma, Tipografia Forense, 1864
[Frontispiece]
145 x 215 mm
Library of INAF-Astronomical Observatory of Brera, Milan

This work was published for the first time in 1864 in Rome, recording in the following years a considerable editorial success in all of Europe. In Italy it had a second edition (Milan, 1874) considerably increased in two volumes, followed by a third one, posthumously (Milan, 1885). Abroad he had two French editions (Paris, 1869 & 1874), three German editions (Leipzig 1876 & 1884-85; Braunschweig 1891) and even three Russian editions (St. Petersburg 1872 & 1880; Vyatka, 1873).
In the mid-nineteenth century the main challenge, in the field of physics, concerned the unitary explanation of a multitude of phenomena collected and studied in the experimental field and related to thermal, optical, chemical, electrical and magnetic phenomena. Secchi pursued the aim of identifying a unitary general principle, capable of reducing all natural phenomena and physical laws to a single interpretative pattern, through the analysis of the correlation of forces and their motion effects. He moved in the framework of a mechanistic program in which all forces, including molecular, gravitational and electromagnetic, depended on the rotating and translational motion of matter. The latter, understood in the double sense of weightable (perceptible to the senses) and subtle (imperceptible to the senses), acted through interactions governed by the mechanical laws and in particular by the new principle of conservation of energy.
Secchi elaborated the construction of its unitary theory starting from the new kinetic theory of gases. With this theory he first built an interpretative model of caloric (chapter i), reduced to a “form of motion of the weighting material”, then extended it, in the following chapters, to the Light (chapter II), Electricity (chapter III) and the Constitution of the matter (chapter IV).
The text recorded large consensus in Italy, especially in those didactic environments where the need for a renewal of the teaching, which was in step with the research, was very felt. At the same time, however, the work aroused harsh criticisms, because of its philosophical implications. The main were in the order of the Society of Jesus, and in particular by the Jesuit Giovanni Maria Cornoldi, advocate of neotomism. Cornoldi, supported by collaborators of the magazine “Civiltà Cattolica,” attacked frontally Secchi, accusing him of adopting and propagate new mechanistic theories and atomic physics, considered by the neotomists contrary to the scholastic doctrine of  the bleeding of matter. Secchi did not hesitate to recognise in these positions the danger of a growing gap between church and science. It is significant that, one year after the death of Secchi, Neotomism was proclaimed the foundation of Catholic doctrine, with the encyclical “Aeterni Patris” of Pope Leo XIII.

Roberto Mantovani - Università di Urbino

Bibliography
Secchi, A. (1864). L’Unità delle Forze Fisiche. Saggio di Filosofia Naturale del P. Angelo Secchi D. C. D. G. Roma: Tipografia Forense; Secchi, A. (1874). L’Unità delle Forze Fisiche. Saggio di Filosofia Naturale del P. Angelo Secchi D. C. D. G. Direttore dell’Osservatorio del Collegio Romano, 2 Vol., 3.a Edizione, 2.a italiana. Milano: Fratelli Treves, Editori; Secchi, A. (1885). L’Unità delle Forze Fisiche. Saggio di Filosofia Naturale del P. Angelo Secchi D. C. D. G. Direttore dell’Osservatorio del Collegio Romano, 2 Vol., 4.a Edizione, 3.a italiana. Milano: Fratelli Treves, Editori.