Bulletin International météorologique de France

“Etat atmosphérique de divers points de la France et de l’Etranger le 9 Novembre 1857”
310 x 195 mm
Biblioteca Storica centrale della Meteorologia Italiana, CREA-AA, Roma

The astronomer Urbain Jean Joseph Leverrier, director of the Imperial Observatory of Paris, is acknowledged for having designed, founded and directed the first international telegraphic meteorological service, realizing a vast meteorological network Synoptic and uniform, in order to warn the sailors of France and Europe of the arrival of the storms, by telegraphic despatches to send to the French and foreign ports.
The project, conceived by the assistant of Leverrier, Emmanuel Liais, although it obtained the approval of Napoleon III 1855, could become operative only in 1857, due to a delay of the authorization of the Ministry of the French Navy to the port authorities with Issue Telegraph warnings as a storm approximating.
On October 22, 1857, the papal telegraphic correspondence conceived by Secchi, already active since two years and fully operational, initiated collaboration with the nascent Leverrier network, whose data were published in the Bulletin International de The Observatoire de Paris, specially designed for the service. In the page reproduced here, the station of Rome (sixth line, from below) appears for the first time. In a letter (Figure 1a-b) to Giuseppe Bianchi, director of the Observatory of Modena, Secchi explains to the colleague the modalities of the data collection and the sending of the dispatches from the Roman College.
The application of the electro-magnetic telegraph to meteorology was realized already in 1849 by Francesco Zantedeschi in Padua; it was proposed in France in 1852 and adopted in 1854 and preceded the use of the same in the papal State, which occurred in 1855. Leverrier and Secchi thus contended the primacy in the realization of the first telegraphic Meteorological service in Europe (Zantedeschi questioned it to Secchi in Italy), but for the official use of the Telegraph for a government meteorological service, one can reasonably believe that the primacy should be assigned to Secchi.
Secchi benefitted from the collaboration with the International Service for his studies on the dynamics of the atmosphere: “The observations collected by Leverrier were also lithographed and sent back to observatories. It was on these bulletins that the laws of the storms were studied from the beginning at the observatory [of the Roman College]. The analysis of the data transferred on maps of Europe helped Secchi to understand the trajectories of displacement of the atmospheric disturbances: “Having we made to build the empty charts of Europe, […] the isobaric and isothermic curves were traced on them, it was possible to recognize the well-defined direction that have in general the well circumscribed storms of cyclonic nature, from N-E [W] towards S-E “.
Indirectly, Secchi suggested the inclusion of the isobaric charts n the Bulletin, which Leverrier began to publish since September 1863 (Figure 2): “These results perhaps helped to make that similar cards were systematically build and published in Paris by Leverrier, which by the means possessessed by such a rich nation could spread them, whence was born the theory of ‘ warnings of the storms as it is used now ‘.
The daily isobaric and isothermic papers of the Roman College Observatory constitute the prototype of modern synoptic maps on the ground.

Maria Carmen Beltrano, CREA-AA
Luigi Iafrate, CREA-AA

A. Secchi, L’Astronomia in Roma nel Pontificato di Pio IX. Memoria (Roma: Tipografia della Pace, 1877);
L. Iafrate, Fede e Scienza: un incontro proficuo (Roma: Ateneo Pontificio Regina Apostolorum, 2008);
E. Liais, L'espace céleste et la nature tropicale (Paris: Garnier Frères Libraires-Éditeurs, 1865);
F. Zantedeschi, “Dei documenti comprovanti la proposta e l’applicazione da lui fatti negli anni 1849,1850,1853 e 1854, del telegrafo elettro-magnetico alla meteorologia e agli avvisi delle burrasche”, Atti dell’Imperiale Regio Istituto Veneto di scienze, lettere ed arti, dal nov. 1864 all’ott.1865, tomo X serie 3, dispensa sesta, pag. 1414-1423;
Lettera di Carlo Matteucci ad Antonio Pacinotti, 22 luglio 1865 (Archivio Villa Pacinotti)