Page - 291 - in Maximilian Hell (1720–92) - And the Ends of Jesuit Science in Enlightenment Europe

291Observing Venus and Debating the Parallax 8.63″.105 During the controversy, he was virtually bombarded with letters by both Hell and Lalande, and the latter even went as far as asking the pupil of Euler to act as a judge in the quarrel that had broken out between himself and the Viennese Jesuit.106 Lexell’s correspondence with Hell and Lalande has— with one exception—not been available for this study. His reactions to their activities can be studied, however, in the frequent letters he sent to Wargentin in this period, all preserved in Stockholm.107 In fact, Lexell found the argu- ments of both Hell and Lalande unconvincing. For one thing, he was puzzled that Planman (and Lalande) was so sure about the accuracy of the Cajanbeorg observation.108 Instead of rejecting one of the observations, Lexell argued that the duration of the transit as observed in Vardø and Cajaneborg had to be ad- justed by at least ten seconds in each of the two places.109 In one of his pub- lished memoirs on the parallax, we find him criticizing Lalande and Hell equally when he sums up his arguments by explaining that I could not bring myself—contrary to all probability, and in favor of a single observation—to accuse all others of being erroneous, nor to put such faith in one particular astronomer, however experienced he may be, that I reckon him to be in possession of some sort of prerogative over oth- ers for being infallible.110 105 Anders Johan Lexell, “Determinatio accuratior verae parallaxis Solis et reliquorum ele- mentorum,” in Anonymous, ed., Collectio omnium observationum quae occasione transitus Veneris per Solem A. mdcclxix iussu Augustae per Imperium Russicum institutae fuerunt una cum theoria indeque deductis conclusionibus (St. Petersburg: Academia Imperialis Sci- entiarum, 1770), 533–74, esp. 538–39 and 556; Anders Johan Lexell, Disqvisitio de investi- ganda vera qvantitate parallaxeos Solis, ex transitu Veneris ante discum Solis anno 1769: Cui accedunt animadversiones in tractatum Rev. Pat. Hell de parallaxi Solis (St. Petersburg: Academia Imperialis Scientiarum, 1772), esp. 59. 106 Lexell to Wargentin, St. Petersburg, October 5, 1772 (cvh). 107 Altogether, 111 letters from Lexell to Wargentin are kept at the Centrum för Vetenskaps- historia in Stockholm. Of particular interest are his reaction to Lalande’s Mémoire sur le passage, dated July 13, 1772 and his reaction to Hell’s De parallaxi Solis, dated September 7, 1772. 108 Lexell to Wargentin, St. Petersburg, July 13, 1772 (cvh): “I find it awkward of Planman to maintain that his observations are so infallible, when I can demonstrate to him that, as sure as two and two makes four, his observation of the last contact is wrong by at least ten seconds.” 109 Lexell, “Disqvisitio de investiganda parallaxi Solis ex transitu Veneris per Solem anno 1769” as printed in the Novi commentarii for the year 1772 (1773): 609–72, esp. 639–47. 110 Lexell, “Disqvisitio de investiganda […]” (1773): 669.