Page - 285 - in Maximilian Hell (1720–92) - And the Ends of Jesuit Science in Enlightenment Europe

285Observing Venus and Debating the Parallax astronomy.” No hint of skepticism is detectable, except that Hell’s observation had been awaited “with impatience.”84 Even though substantial parts of Hell’s correspondence are lost or await dis- covery, there is enough evidence to demonstrate that he was informed of far harsher accusations. In a letter dated June 23, 1770, the archbishop and ama- teur astronomer Paul d’Albert de Luynes wrote the following: My Honorable Father! I have received, My Honorable Father, and read with the greatest possible pleasure, the details of Your observation of Ve- nus passing in front of the disc of the Sun. I admire Your good fortune in having had clear weather, and perfectly clear weather at that, during the two most important moments, as well as the excellent methods that You have employed to meet the lack of commodities that You were facing. Ef- forts have been made at our academy [i.e., the Académie des Sciences] to raise objections concerning the fact that the details of your observation reached us so late, a delay that was capable of making room for criti- cisms, claiming that Your lateness may give rise to suspicions that You, having had the time to receive the other observations, could have made Your observation match them.85 De Luynes did not state who had raised these allegations, but he vigorously rejected them, and assured the Viennese Jesuit of his full support. Neverthe- less, at this time a five-year-long scientific controversy was already in the mak- ing, whose subject matter was not Hell’s alleged manipulation of data, but the related issue of the solar parallax. The parallax had already been a matter of debate in the aftermath of 1761. At one end stood Alexandre Guy Pingré, who observed the transit from the Cape of Good Hope in Africa. His observation was hard to reconcile with other data- sets, and besides struggles over the accuracy of his observation, Pingré had a hard time defending his solar parallax of more than ten arc seconds. At the very other end of the scale was Anders Planman, who argued for a solar paral- lax of about 8.3 arc seconds. In this situation, Hell opted, in the Ephemerides for the year 1764, for a preliminary parallax of about nine arc seconds. Lalande agreed completely, and used almost exactly the same wording as Hell in the first edition of his textbook Astronomie, published in 1764. In a letter dated December 29, 1763, Lalande reveals to Hell that 84 Journal encyclopédique (May 1770): 344–52, quotation from 345. 85 De Luynes to Hell, dated Paris, June 23, 1770 (a copy in the handwriting of Hell at wus).