Page - 164 - in Maximilian Hell (1720–92) - And the Ends of Jesuit Science in Enlightenment Europe

Chapter 3164 even Baudouin now urged Hell to publish his work, the time was ripe for an elaborate engagement of the subject.84 Hell’s argumentation was based on experiments whereby he had succeeded in creating optical illusions, where a tiny, illusory bright spot was produced beside a larger, real gleaming object, viewed through a tube in a dark chamber. Most astronomers realized that with this, the case was settled. As one reviewer remarked about Hell’s “sagacious remarks and experiments” (scharfsinnigen Bemerkungen und Versuchen): “It is a shame that the moon of Venus has disap- peared: some of the jokers here had already decided to call it by the witty name of ‘Cupid.’”85 In 1768, Hell’s treatise was reissued in the Nova acta eruditorum of Leipzig.86 Even so, there were observers looking—naturally, to no avail—for traces of this moon during the 1769 transit as well.87 84 Maximilian Hell, De satellite Veneris (Vienna: Trattner, 1765), 3–15. 85 Krünitz, “Verzeichniß,” 117–18. 86 Nova acta eruditorum (February–March 1768): 49–126. 87 The observers organized by the Russian Academy in 1769 were given specific orders to look for the moon of Venus. Cf. Stepan Rumovskii, Nabliudeniia iavleniia venery v solntse v rossiiskoi imperii v 1769 godu uchinennyia s istoricheskim preduvedomleniem (St. Peters- burg: Imperatorskaia Akademia Nauk, 1771), 45. Christian Mayer in his report on the Ve- nus transit of 1769 also explains that he has been on the lookout for the moon of Venus but saw no trace of it; see Christian Mayer, “Expositio utriusque observationibus et Ven- eris et eclipsis Solaris factae Petropoli in specula astronomica,” NcASIP 13 (1768; published 1769): 559. In the more elaborate treatise addressed to Catherine ii, he denies the exis- tence of this moon, see Mayer, Ad […] Catharinam […] Imperatricem expositio, 285; cf. 140. Likewise, two Uppsala astronomers looked for the moon of Venus in 1769 but saw no trace of it. Eric Prosperin, “Utdrag af Observationerna på Veneris inträde i Solen, d. 3 Jun. 1769, som blifvit gjorda på observatorium i Upsala,” Kongliga Vetenskaps Academiens Handlin- gar (hereafter: kvah) 31 (April–June 1769): 158–59; Fredric Mallet, “Berättelse om det som kunnat observeras uti Pello, vid Veneris gang förbi Solen, den 3 och 4 Junii 1769,” kvah 31 (July–September 1769): 222–23. The British observers also seem to have been instructed to look for the moon of Venus in 1769; cf. Kragh, Moon That Wasn’t, 58. Despite the universal failure to see a moon besides Venus on the Sun’s disc, the debate arose again in the mid- 1770s when an astronomer at the Berlin Academy of Sciences, Johann Heinrich Lambert (1728–77), produced an article criticizing Hell’s monograph (“Essai d’une théorie du satel- lite de Vénus,” Nouveaux Mémoires de l’Académie Royale des Sciences et Belles-Lettres [1773; published 1775]: 222–50) and even went as far as announcing, in the Berlin Astronomisch- es Jahrbuch for the years 1777–78, that the moon of Venus would be visible in front of the Sun on June 1, 1777. Hell refutes this prediction in the Ephemerides 1778 (1777), 7, and in several contributions to the Wienerisches Diarium and the Realzeitung. He also mentions Lambert’s prediction unfavorably in some of his letters (see the letters to Fixlmillner, dated Vienna, August 31, 1776, November 27, 1776, and February 15, 1777; published with comments by Rabenalt, “Astronomische Forschung,” 119–23). For further sources, see also Kragh, Moon That Wasn’t, esp. 80–84.