Idrodinamica e idraulica. Le raccolte sul moto delle acque. La questione del Reno

The aim of this thesis is to illustrate the role of mathematicians in the history of hydraulics in Italy in the 18th century by focusing on two aspects. The first aspect is more general and deals with the main contributions of Italian mathematicians to the collections on the motion of water that were published in Italy in five editions between the 18th and the first half of the 19th century in Florence, Parma and Bologna. The second aspect is more specific and deals with the problem of the regulation of the river Reno. The first part of the thesis is dedicated to an examination of five collections on the motion of water that were printed in Italy between 1723 and 1845. There were two Florentine editions, one published in three volumes in 1723 and the other published in nine volumes between 1765 and 1774. Another edition was edited by the Jesuit Jacopo Belgrado (1704-1789) in Parma in seven volumes between 1766 and 1768. Bologna produced two editions, both of which were edited by Francesco Cardinali (1776-1861) in the first half of 19th century. The first one was printed between 1821 and 1826 in ten volumes, while the second one was printed between 1823 and 1845 in seven volumes. As these collections represent very difficult and expensive works, it is important to identify not only the editors of them, but also the printers. In this PhD thesis the five collections on the motion of water have been examined and compared. They contain both theoretical and practical contributions to the science of waters, starting from the Hydrostatics by Archimedes. Many authors appear in different editions, like the main exponents of the Galilean school: first of all Benedetto Castelli, then Vincenzo Viviani and Famiano Michelini. The works of other important mathematicians are in these collections, like Guido Grandi, Domenico Guglielmini, Eustachio Manfredi. To facilitate consultation of and comparison between the five collections, a database has been created and can be found at the end of the work (Tavole). It allows the user to research by means of author, subject or collection.The prefaces of these five collections have been transcribed and can be found in the appendix. Many of these works share the same theme, i.e. the problem of the regulation of the river Reno, that is connected with the second part of the thesis. Each collection on the water’s motion contains papers on this subject. The second part of the PhD thesis deals with the regulation of the river Reno in the middle of the 18th century and, in particular, with the visit of Cardinal Conti, that took place between 1761 and 1762. The Reno is an Italian river and before its deviation it was the main right tributary of the river Po. This river had a very irregular path in the Po river plain between the provinces of Bologna, Ferrara and Ravenna. In its lower course the Reno receives the water of numerous streams, some of which are seasonal, that carries great quantities of stones and gravel. That’s why its floods were so frequent and dangerous. From the 16th century on this problem became unacceptable and the authorities whose job it was to deal with this damage decided to tackle the situation in a definitive way. However, this was just the beginning of a long series of quarrels that involved the provinces of Bologna, Ferrara and Ravenna. Many Italian mathematicians took part in this long debate. The first chapter of the thesis involves a historical study of the sequences of the river Reno, regarding the variations of its path and the main intervention in its regulation during the Medieval age (chapter I.1), in the 15th and 16th centuries (chapter I.2), in the 17th century (chapter I.3) and in the first part of the 18th century (chapter I.4). In chapters II, III and IV the main part of the thesis is developed. The second chapter deals with projects for the Reno and debates between Bologna and Ferrara in the period 1740 - 1760. It is divided into seven sections: Gabriele Manfredi as a mathematician (chapter II.1), Manfredi’s project (chapter II.2), Manfredi’s scientific heritage (II.3), the Ferrarese project by Bertaglia and Bonati (chapter II.4), Paolo Frisi ad a mathematician (chapter II.5), Frisi’s project (chapter II.6), Fantoni’s project (chapter II.7). The third chapter is devoted to the so-called “Visita Conti”, that took place between May 12th 1761 and July 5th 1762. All the issues related to the “Visita Conti” are described in the third chapter: Tommaso Perelli as a mathematician (chapter III.1), Tommaso Perelli and the visit of the cardinal Conti (chapter III.2), Perelli’s Relazione (chapter III.3), Jacquier and Le Seur as mathematicians (chapter III.4), Jacquier’s and Le Seur’s Parere (chapter III.5), the debate between Perelli and Jacquier (chapter III.6), Teodoro Bonati as a mathematician (chapter III.7). The Visita Conti was not conclusive, so three other mathematicians had to be consulted: the main one was the Jesuit Giovanni Antonio Lecchi (1702-1776), whose project for the Reno was the definitive one. The fourth chapter is entirely dedicated to the figure of Lecchi and to his plan for the settlement of the Reno: Lecchi as a mathematician (chapter IV.1), the hydrodynamics and Boscovich (chapter IV.2), the three technicians (chapter IV.3), Lecchi’s plan and its realization (chapter IV.4). The last chapter (chapter V) deals with some issues related to the Reno’s path in the last year of the 18th century. To complete the thesis three documents have been transcribed. Two of them are manuscripts: the summary of the Visita Conti and twenty-two letters from Giovanni Antonio Lecchi to Ruggiero Giuseppe Boscovich. The other one has been already published: it is the report of the Visita Conti by Tommaso Perelli: Relazione sopra il regolamento delle acque delle tre province.