Maximilianus Hell (1720-1792) - Munin

the Parallax of the Sun Deduced From Observations of the Transit of Venus of the Year 1769’
(De Parallaxi Solis ex Observationibus Transitus Veneris Anni 1769). The memoir contains
both a detailed calculation of the solar parallax and a furious attack on Lalande. As Hell wrote
in one of his letters accompanying the monograph (to Wargentin, dated Vienna 15 July
1772): 122
If my style, so untypical of me until now, seems a little over-aggressive to you,
I would like you to consider the un-heard-of, and totally unfounded, accusation
of having made up or altered the data that has been put forward by Monsieur
Lalande against my person (who did not exactly start my career in astronomy
yesterday); this had actually deserved a much stronger response. In more than
one letter, I have advised Lalande to abstain from defending the Cajaneborg
observation and cease attacking the one from Vardø, but in response to my
friendly, even privately, communicated advice, he has decided to brand me in
public, an act I deemed I should certainly not pass by in silence.
In the De Parallaxi Solis, Hell blames Lalande for having shown too much of that arrogance
characterising some representatives of great powers. Lalande, he argues, must clearly have
felt dismayed that neither Hell nor the court in Copenhagen asked for his advice in the
planning of the Vardø expedition. Besides, he and his French colleagues were obviously
offended that Hell did not dispatch an extract of his observation journal in manuscript directly
to Paris, “as to a tribunal of astronomy” (tamquam ad Tribunal astronomicum), with the first
express mail possible. Hence, when the report finally arrived, they judged that it must have
been “adulterated”. 123 This prejudice must have brought Lalande to neglect the fact that
Planman had been been stationed at a site (Kajaani) where the Sun was extremely low above
the horizon, causing the limbs of the sun to undulate strongly, whereas Hell in Vardø had
enjoyed perfect atmospheric conditions with the Sun elevated more than 6 ½ and 10º above
the sea during ingress and egress respectively. Hell meant he could prove Planman to have
either defined the longitude of his site erroneously by at least 35 seconds, or observed the
exterior contact of egress wrongly by 35 seconds. 124 Lalande, on the other hand, who
considered Hell’s report worthy of rejection, had made various sophisticated calculations in
order to make the Kajaani observation as complete as he needed it. The interior contact of
122 Hell to Wargentin, dated Vienna 15 July 1772 (CVH): “si Tibi stylus meus, mihi hactenus insolitus,
concitatior videatur, perpendisse Te velim, quod inauditum fictionis, aut correctionis crimen à celeberrimo de La
Lande, mihi, qui non heri natus sum Astronomus, sine ullo fundamento intentatum, longe majora meritum
fuisset; non unis à me De La Landius admonitus est litteris, ut à defensione Cajaneburgensis observationis
abstineret, Wardhusianumque impugnare cessaret; pro amica hac, eaque privata admonitione publicam mihi
inurere voluit notam, quam sine dubio silentio prætereundam non censui”.
123 Hell 1772, pp. 86-93.
124 Hell 1772, pp. 8-39.
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