Deák Antal András: A Duna fölfedezése

Tartalom - III.A DANUBIUS PANNONICO-MYSICUS, 1726

T II E DISCOVERY OF THE DANUBE VOLUME VI. MISCELLANEOUS OBSERVATIONS The 'miscellaneous' volume is a collection of those observations and scientific results that did not fit organically into the topics of the other volumes. In the Prodromus, he still intended to call the volume Tomus analectorum, but then, as he explained in the preface, he found the title Miscellaneous observations (miscellanearum observationum) more appropriate. Although the volume is rather multidisciplinary or even eclectic, the uniqueness of his observations give it remarkable value. He studied the sources of the Danube in 1702, when he was able to spend a few weeks in the Black Forest. An earlier misconception held that the source of the Danube lay in the Donaueschingen estate of the Fissemberg family. Marsigli had sent two engineers to the location to survey the area, measure heights and discovere water-courses.

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3 According to their data he came to the conclusion that the real source of the Danube must be elsewhere, namely near Brukelrein. He proved his statement with the help of three maps on which he showed the springs welling up above Donauesch ingen. With the help of a barometer, he measured the altitude of the springs above sea level. These data are indicated on map no. I (plate I). Besides this, he drew the trough from which animal drank, the pens, the sheds or barns and an artificial pond above Brukelrein, the water of which had been diverted to drive a mill. Map II shows the territory between Brukelrein and Donaueschingen with all the water courses. He remarked that the springs of a brook could be found there at Donaueschingen, which was traditonally called the Danube. Topographic drawing III shows the Donaueschingen branch, which was mistakenly identified as the Danube, the Brige brook, and the brook that local people called Brege and that Marsigli thought to be the veritable Danube. Then, he made a detour beyond the source area of the Danube and represented in a summary map the sources of the brooks, mostly in Swiss territory, that fed the Rhein. Finally, he drew the cross-section of the whole territory applying the well-tried methodology from volume I, in which the relief, the larger mountains and mounds that could help with orientation were depicted with altitude values measured with a barometer. He made anatomical observations on water fowls, the great sturgeon and an otter. Of the birds he encountered, he dissected an eagle, birds that feed on fish and wading birds, all of which are illustrated in three figures. That the great sturgeon really captivated him is indicated by the 13 picture plates of its dissection. This huge fish, which can reach a thousand kilograms, was, as is well known, only a visitor in the Danube: it swam up from the Black Sea in search of a suitable spawning place to the great delight of the Danubian fishermen. The dissected specimens were caught by fishermen below Orsova in 1690 when Marsigli was stationed with the army on an island in the region. Here, as he told the story, fishermen caught and opened up 50, 60 or even 100 great sturgeons a day. He did not mention any personal experiences concerning the otter. He believed it spent most of its life in water. The dissected inner organs are illustrated in two plate pictures in altogether 5 figures. The velocity measurements of Danube and the Tisza are important from a hydrographical point of view, not because of the resulting values, but due to the measurements themselves. The method that was applied with the velocimeter quadrants of his day did not permit accurate measurements to be made. The reason is that the cord that indicated the value of the speed on Marsigli's quadrant which was fixed to a boat was bent into a curve in the direction of the flow and, thus, 29

3 BUB Mss di Marsigli Vol. 61. Itincrarium Villinganum és Itinerarium Schafihusense. IMAGE No. 42 on page 80: The topographic illustration of the highest, and thus, the true spring of the River Danube (Marsigli used barometers for measuring heights.) IMAGE No. 43 on page 81: In the 17th century people believed that the Danube rose from the spring at Donaueschingen Castle. Marsigli explored the river-head of the Danube and contravened this misbelief IMAGE No. 44 on page 81: An anatomical drawing of a sturgeon 153