Page - 293 - in Maximilian Hell (1720–92) - And the Ends of Jesuit Science in Enlightenment Europe

293Observing Venus and Debating the Parallax I strongly dislike the all too harsh controversy that has arisen between Lalande, Hell, and Planman, over the observations of the last transit of Venus. There ought to be no doubt that both Hell and Planman have ex- erted all their efforts—their eyes as well as their intellect—while observ- ing, and that they have published it bona fide. They may have made mistakes of a few seconds each, for they are, after all, human beings […]. The safest solution would therefore have been to concede something to each observer, by placing one’s faith in a mean parallax, calculated on the basis of both observations.116 The effect of Wargentin’s (and perhaps other sensible minds’) diplomacy can be seen in the Journal des Sçavans for February 1773, where Lalande allowed the printing of a “letter concerning the calculations by Monsieur Lexell and Father Hell” as well as a “letter on the solar parallax.”117 The tone had become milder. Father Hell […] appeared to declare war on all the astronomers of Paris in his booklet, by contesting the quality of the observation of Monsieur l’Abbé Chappe, by bringing back old disputes concerning the alleged moon of Venus, the longitude of Vienna, the geodetic measurements made in Germany […], but he should make these concessions to me: that our correspondence has always been filled with friendship and respect from my part, that I have praised him on every occasion, and that I have never given place in our dispute for any personal complaints except that which concerns his having made the astronomers wait for so long for an observation that was so necessary to them.118 Furthermore, Lalande was careful not to attack Lexell, and even admitted some errors in the Memoire sur le passage that the latter had pointed out. As to the parallax, he still believed that the value of 8.50″, or a maximum of 8.55″, was most likely to be true. But with surprising humbleness he added: “To sum up, if the parallax is 8.55 arc seconds or 8.70, the difference is no more than a fifty-seventh part of the total, and the expedition of Father Hell will neverthe- less have the advantage of having contributed to draw closer the limits of our 116 Wargentin to Weiss in Trnava, dated Stockholm, March 9, 1773, in Vargha, Correspondence de Weiss, 106–7. 117 JS (February 1773), “Lettre sur les calculs de M. Lexell et du P. Hell” (90–93) and “Lettre sur la parallaxe du Soleil” (113–15). 118 JS (February 1773): 113.