Deák Antal András: A Duna fölfedezése
Tartalom - III.A DANUBIUS PANNONICO-MYSICUS, 1726
T II E DISCOVERY OF THE DANUBE Cassini, the renowned astronomer, sent him instructions in long letters about the skills needed for calculating astronomical position. 13 9 In the Danube monograph he remembered his tutor with grateful words and called him his paternal friend and one who loved him as his son. 14 0 About fifty letters from him were preserved in Marsigi's bequest. In one of them, for example, Cassini wrote that he had read out his theory on the movements of the moons of Jupiter to the Royal Academy and described his method of measuring larger distances based on astronomical position. Terrestrial measurements, he said, however carefully they are made, aggregate measurement errors, and the distances measured on journeys overland or during sea voyages can conceal mistakes. He emphasised the importance of longitude measurements. The geographical maps, which had been recently edited in Italy at that time, were much better than other, much more famous and widespread geographical maps because they contained fewer errors in longitude. However, a good telescope was needed for geographical position to observe the eclipses of the moons of Jupiter, and a precise watch with a second-hand. All the astronomers in the world who make similar observations should be furnished with similar instruments. 141 After this letter Marsigli hastened to contact Georg Christoph Eimmart 14 2 with a request that a portable instrument be prepared that would be suitable for measuring the distances between planets. By May 1696, Eimmart reported that he had already come up with the theoretical design for the sextant and made its drawing as well. He also negotiated with the technician who would make the instrument. It would cost about 60 thalers, which might seem expensive at first glance except that the sextant would take the technician two months to make. The letter also revealed that Marsigli had already measured geographical distances in Vienna and that he was asking for the opinion of the expert from Nürnberg. 14 3 Furthermore, he asked for a good telescope from Eimmart, one that was similar to Cassini's. Eimmart, however, declined his request. He thought that the instrument should be ordered in Iraly, because the best lenses of the time were made there. Francesco D. Maria, Francia from Bologna, was given the most important task of all the Italian masters concerning the preparation of the Danubius Pannonico-Mysicus. 14 4 Both Eimmart and Müller mention in their letters that the Minerals volume was engraved in Italy. They, however, did not tell the name of the engraver. We learned from Lelio Trionfetti that having seen the engravings, Müller expressed his great admiration for Maria Francas art, although he did not know him. 14 5 Another document mentions that Marsigli paid 100 liras to Franza (sic!). 146 A three volume collection of engravings is kept in the Bibliotheca Univesitaria in Bologna, composed by Francia himself from his oeuvre. Scattered in the free spaces of these volumes, Francia inserted some illustrations from the Danubius, verifying the evidence in the above argument. 14 7 13 9 BUB Mss di Marsigli Vol. I. and Vol. II. Eruditorum epistolae ad Marsilium. 14 0 Danubius Pannonico-Mysicus Vol. I. Pars II. Introduction. 14 1 BUB Mss di Marsigli. Domenico Cassini's letter to Marsigli Vol. 79. pp. 71-72. Bologna, 20 November 1695. 14 2 Georg Christoph Eimmart (1638-1705), a copperplate engraver, mathematician, astronomer and skilled precision instrument maker. He established a private observatory in Nürnberg, which he later donated to its citizens. 14 3 BUB Mss di Marsigli. G. C. Eimmart' letter to Marsiglihoz, Nürnberg, 25. May 1696. Vol. 79. p. 78. 14 4 Francia Francesco D. Maria (Bologna, October 17, 1657 -January 31, 1735) As a copperplate engraver he worked with G.M. Mitelivel and Lodovico Mattiolival. As an illustrator of books he drew many frontspieces. Bologna, Bibl. Univ. A. V. Tab. III. E. 1. 2. Vol. I-III. The individual engravings do not follow a strict chronological order, and his illustrations made for Marsigli's book are also distributed throughout the chapters. In volume I he drew Roman coins, initials and minerals. 14 5 BUB Mss di Marsigli Vol. 82. p. 27. Lelio Trionfetti; Bologna, January 23, 1703. "Inviai a Vestra Ecc. in una mia fino delli 24. ottb. /comsegnava al S. Simiani/ una mostra del primo Intaglio de minerali fatto dal S. Francia e spettante al di Lei Tomo, quale Intaglio per esser il primo /non avendo esso - Francia - per 1 addietro mai intagliato cose simili/ non penso debba apparire il migliore fra gli altri che non faccendo come appunti questi altri, che qui annessi si trasmettono potra fame il confronto..." 14 6 BUB Mss di Marsigli Vol. 82. p. 51. "Contos Netto Delia distribuzione delle due milla lire ultimamentc spedite per cambio da S. Exxelenza Al Franza a conto 100". 14 7 Francia Intaglj. Vol. I-III. BUB Mss di Marsigli A. v. Tab. III. E. 1.2. 119
