Struggling with Pictures in the Early Académie Royale des Sciences: The Case of Giovanni Domenico Cassini’s *Grand Selenography* (1679)

Antoine Gallay

University of Geneva

Email: antoine.gallay@unige.ch

Phone: +41 76 531 09 42

Declaration of interest statement

The author reports there are no competing interests to declare
Abstract

In 1679, the astronomer Giovanni Domenico Cassini published a large print detailing the entire visible surface of the moon with unprecedented meticulousness. This *Grand Selenography* is undoubtedly one of the most spectacular pictures ever produced within the Académie royale des sciences. However, it has remained widely neglected by historians up to now. This study offers the first account of the making and early reception of the print. It argues that the latter remains uncompleted because it failed to satisfy Cassini and his contemporaries. Furthermore, its history allows to shed new light on the range of issues that savants using pictures might have encountered during Louis XIV's reign.

Keywords

Moon; Selenography; Scientific illustration; Epistemic image; Illusion; Pareidolia; Utility; Resemblance; Accuracy; Giovanni Domenico Cassini
Acknowledgments

This work was supported by a postdoctoral fellowship at the Cohn Institute for the History and Philosophy of Science and Ideas, Tel Aviv University. It could not have been possible without the help and guidance of the staff of the Archives de l'Académie des sciences and the Bibliothèque de l'Observatoire in Paris. Earlier versions were presented during a research seminar supervised by Jan Blanc at the University of Geneva in 2017, at the 2019 History of Science Society Annual Meeting at the University of Utrecht, and at the 2022 Annual Conference of the Isreali Society for the History, Philosophy and Sociology of Science at Tel Aviv University. I thus wish to thank the participants of those events, as well as Chantal Grell, Dalia Deias, and William Tobin, for the fruitful exchanges we had. I am especially grateful to Oded Rabinovitch and Katie Reinhart for their invaluable help at the final stages of this work. I am also indebted to the two anonymous reviewers for their insightful comments.
Introduction

During the last three decades, numerous studies have discussed the crucial role
of visualization in early modern science.<fnref n="1" /> It is now well known that, thanks to the
joint development of printmaking and new modes of naturalistic and diagrammatic
representations, the epistemic uses of prints and drawings dramatically increased
during the sixteenth and seventeenth centuries and partly contributed to the growth
of modern science. Moreover, the study of such pictures also helped historians gain
a more finely-grained view of early modern scientific practices and practitioners.
Pictures might indeed convey some of the social strategies of those who made and
used them; they might even reveal some of their ideas about nature, their epistemic
values, or their moral stance.<fnref n="2" />

In general, pictures are thus understood as if they could exemplify the
intentions of the savant who conceived them. However, this view might neglect
whether a picture, as a concrete object, genuinely corresponds to the picture that
the savant initially sought to obtain. The question is especially crucial in regard to
the fact that the savant was generally not the one who actually made the picture; his
task more often involved explaining to a professional draughtsman or engraver
what he wanted to represent and supervising the work. In addition to various other
causes, the collaborative process could fuel a discrepancy between the savant's
original intention and the resulting picture.<fnref n="3" />

<footnote n="1">¹ For a useful historiographical introduction to early modern scientific pictures, cf. Marr 2016.</footnote>

<footnote n="2">² In this respect, the most ambitious recent work is certainly Daston and Galison 2007.</footnote>

<footnote n="3">³ I discuss this question more thoroughly in Gallay 2023 and Gallay 2024.</footnote>
One should thus carefully consider the savant's attitude toward the pictures he produced. It is well known that prints and drawings were not always praised by those who conceived or used them. Savants also expressed concerns about the potential issues pictures could raise<fnref n="4" />. For example, they worried that the draughtsman failed to represent things as he should or that the printer distorted a figure by poorly applying ink on the copperplate. They might have also feared that a picture had been made with fallacious motives or that ignorant readers could misinterpret its content. Undoubtedly, such elements could provide crucial insight into the way pictures were conceived and used within early modern scientific circles. It is thus all the more surprising that little focus has been hitherto given to the specific failures a savant could ascribe to his own pictures – or the pictures made under his guidance. Indeed, a savant could be prone to criticize others' pictures for various reasons that are not always connected to his epistemic values. On the contrary, what he deemed faulty in his own pictures could provide a unique entry point to what he regarded as “correct” for the production and communication of truthful knowledge. Hence, reconstructing the difficulties a savant met when producing a specific picture or identifying what he considered failures in the latter may shed some new light into the epistemic values shared within a defined chronological and geographical context.

<footnote n="4">⁴ Many studies have stressed the issues that early modern savants met with pictures. See for example Kemp 1993, Freedberg 2002; Lüthy 2006; Daston and Galison 2007; Zittel 2011; Kusukawa 2012; Kusukawa, 2015; Hunter 2013; Daston 2015; Henderson 2019; Wragge-Morley 2020.</footnote>
It is with this approach in mind that I will attempt to uncover some of the
changing values within the early Académie royale des sciences, by focusing on a
single picture that has been hitherto widely neglected. During the 1670s, a large
engraving of the moon was conceived by one of the young institution's most
prominent members, the astronomer Giovanni Domenico Cassini (Figure 1).<fnref n="5" />
Because the print remains untitled and its function unclear, I have chosen to refer
to it by using a conventional title, that is the *Grand Selenography*. Reconstructing
the possible goals that Cassini and other academicians might have initially ascribed
to this picture will lead me to discuss the range of issues that it progressively raised,
and how these may be connected with some new epistemic concerns developed
within the institution.

Since the late nineteenth century, the early Académie royale des sciences has
generated a substantial literature discussing the relationship between science and
politics, notably focusing on the effects of the former's institutionalization or, more
recently, on the relationship between courtly practices and scientific ones.<fnref n="6" /> For this
purpose, historians have progressively unveiled the central function of the prints
published in the two first grand books of the institution, the *Memoires pour servir
à l'histoire naturelle des animaux* (1671–1676) and the *Memoires pour servir à*

<footnote n="5">⁵ On Cassini, cf. the useful biography by Anna Cassini (2003). For a rich and up-to-date bio-bibliographical synthesis, cf. Deias 2024.</footnote>

<footnote n="6">⁶ Besides the three classical monographs on the Ancien régime Académie (Maury 1864 ; Maindron 1888 ; Hahn 1971), more specific works have been devoted to the production and functioning of the institution during Louis XIV’s reign, such as Saunders 1980; Hirschfield 1981; Mallon 1983; Lux 1990; Briggs 1991; Licoppe 1994; Biagioli 1995; Stroup 1987; Stroup 1990; Stroup 1992; Meynell 2000; Guerrini 2015.</footnote>
l'histoire des plantes (1676) (cf. Stroup 1990; Guerrini 2010; Rabinovitch 2013; Guerrini 2010; Guerrini 2015; Reinhart 2015; Sahlins 2017; Guerrini 2019). While this approach has proven highly valuable, the epistemic values developed and defended within the early Académie have remained little studied, especially compared to the recent work on the other foremost institution at the time, the Royal Society (Kusukawa, 2019; Wragge-Morley 2020; Doherty 2022).

With respect to the main historiographical trend on the Académie, the neglect of the *Grand Selenography* seems even more surprising: it was undoubtedly one of the most ambitious and expensive prints ever made during Louis XIV's reign. Moreover, the print is far from being unknown: for more than a century, it has attracted attention because of the fascinating small profile of a woman represented near the Promontorium Heraclides (Figure 2), recently identified as a portrait of Cassini's wife (Launay 2003; Launay and Sheehan 2010).<fnref n="7" /> While this new interpretation probably contributed to the print's growing fame nowadays, it is unfortunately supported by little evidence since the history of the production and early reception of the print has been barely discussed up to now. For example, most commentators have called the picture a “map”, although there is no clear evidence that it was one.<fnref n="8" /> On the one hand, it lacks a nomenclature – one of the most proper elements of a map. On the other, while Cassini and his colleagues often talked about

<footnote n="7">⁷ For evidence of the early interest raised by the small profile of a woman on Cassini's print, see Flammarion 1891; Moreux 1894. Useful information on the print can also be found in Wolf 1902, 164–170; Whitaker 1955; Kopal and Carder 1974, 21–22; Weimer 1979; Cassini 2003, 302–304; Zittel 2019, 48–51.</footnote>

<footnote n="8">⁸ Jean-Dominique Cassini IV was largely responsible for this conception: when he recovered the plate in the late eighteenth century, he added the title “Grande carte de la Lune” (see below, n. 10).</footnote>
“maps of the moon”, the *Grand Selenography* was usually described as a “figure” or a “plate” (*planche*) within the Académie and the Bibliothèque du Roi (AAS, *Registres*, 7, fol. 239v; BnF, Est. Rés., Ye-144 and Ye-160).

The absence of any textual information on the print, combined with the scarcity
of evidence about its making and function, may have discouraged historians from
pursuing further investigation. I shall begin by arguing that the lack of such
elements should, in fact, be considered as evidence of the print's failure in the eyes
of the contemporaries. In order to explore the possible reasons behind this failure,
it is necessary to reconstruct the initial functions attributed to the print. After
considering the latter's place within the broader cultural production dedicated to
glorifying Louis XIV, I will discuss its various possible epistemic purposes.
Although figures of the moon were often made as an aid for the observation of
eclipses, I will show that the *Grand Selenography* could not have been made with
this intent in mind. Instead, its fabrication appears to stem from Cassini's curiosity
about astronomical bodies and his ambition to explore their physical nature. I will
then argue that the former aspiration could, however, not be fulfilled by the picture
and that the small female profile might have served to express the inherent
limitations of the whole endeavor. Lastly, I will suggest that the print faced criticism
for its perceived lack of utility, which ultimately led to its abandonment. Hence, the
progressive discrepancy between Cassini's initial intentions and the resulting
outcome will enable us to shed light into some notable changes in the epistemic
ambitions and values embraced within the early Académie.
Cassini’s print and the Cabinet du Roi: the failure of a grand project

On the night of 14 September 1671, a few hours after he settled down in the newly built Paris observatory, Cassini began to collaborate with the draughtsman and engraver Sébastien Le Clerc to produce drawings of the moonscape seen through a telescope. A year and a half later, Le Clerc had given up this job (Gallay, 2021, 244–246). He was replaced by Jean Patigny, who executed numerous drawings up to 1678, sixty-seven of them having been preserved in an album by the astronomer’s great-grandson, Jean-Dominique Cassini de Thury, known as Cassini IV (Figure 3–6).<fnref n="9" /> These drawings, almost all of them made with black and white chalk on blue paper, only show specific aspects of the lunar relief determined by the limited field of view offered by the long reflective telescopes the astronomer was generally using<fnref n="10" />. Cassini and Patigny gathered these drawings to reconstruct progressively the entire visible surface of the moon in several larger drawings (Figure 6). Then, they had to combine and select all the data they wanted to retain and transfer them on the copperplate. To express the outlines, shades, and highlights, Patigny only employed horizontal and parallel lines, meticulously carved with varying thickness. Eventually, on 18 February 1679, the engraving was

<footnote n="9">⁹ Patigny received a first payment on 6 October 1673 “pour avoir dessigné pendant cinq mois les tasches de la lune” (Guiffrey 1881–1901, 1, col. 712). All the drawings retained in Cassini IV’s album are thus by his hand since the earliest one is dated 26 August 1673, which is when Patigny already began to work for the astronomer.</footnote>

<footnote n="10">¹⁰ I have discussed in more detail the drawing process in Gallay 2021, 245–246. However, I found no precise mention of the kind of telescopes used for these drawings (the information provided in Zittel 2019, 49–50 is not substantiated).</footnote>
completed (Figure 1), and Cassini presented a proof to the Academy so that the
other members could carefully examine it (AAS, *Registres*, 7, fol. 239v).

After this event, the print was quickly forgotten. Only very few impressions
have been pulled, and the copperplate was left behind in the corner of the
Imprimerie royale – only to be rediscovered a century later by Cassini IV, who
recognized its historical value and printed one hundred new impressions.<fnref n="11" /> In fact,
the plate appears to have remained uncompleted: in 1681, Cassini told the young
Edmond Halley – who had requested four copies for himself and his colleagues in
the Royal Society – that the print was still “not as then finished” (Halley 1932, 51–
52). Besides, while the engraving of the figure appears to be complete, it is doubtful
that such a lavish picture would have lacked the usual ornaments, not to mention a
short inscription such as the outline of the project, the name of the astronomer, or a
dedication to the King. At a certain point, during the 1680s, Cassini thus decided to
interrupt the production of his *Grand Selenography*.

<footnote n="11">¹¹ There are indeed very few known impressions made before the reprint of the plate in 1787 by Cassini IV – which bears the inscription “Carte de la Lune | Jean Dominique Cassini” (see Launay 2003, 15–16). I have only been able to identify early impressions in the Bibliothèque nationale de France (Cartes et plans, GE D–12812; Est., Rés., AA–5, (Patigny, Jean)), in the Archives de l’Observatoire de Paris (inv. I.1576), in the Royal Astronomical Society, London (MSS Add. 268), in the Harry Ranson Humanities Research Center, University of Texas, Austin (5H FF 59.13), in the Albertina, Vienna (DG12518), and in a private collection (Sotheby’s sale, Paris, 18 December 2014). In the Bibliothèque nationale, there are also two proofs before all lettering (Cartes et plans, GE C–11096 et GED–5014), which bear, on a small paper pasted on the margin of the print, the address of editor Jean-Claude Dezauche, active between 1770 and 1824. It is likely that those were also early impressions.</footnote>
The astronomer's decision is highly intriguing since the print was not some minor project that could be easily set aside. It was the result of an exceedingly painstaking work, entirely funded by the Bâtiments du Roi, and it was thus most probably intended to serve Louis XIV's glory.<fnref n="12" /> Indeed, all the prints made under the academicians' supervision were financed by the crown, but some of the most prestigious ones were also planned to integrate a set of lavish albums, later called the Cabinet du Roi.

The complex history of the Cabinet du Roi began on 22 December 1667 with the ratification of a royal decree announcing that “the plans and elevations of the royal houses, the painted and sculpted ornaments in those houses, the paintings and antique pieces retained in the cabinet of His Majesty and elsewhere, as well as the figures of plants and animals, and all things scarce and singular” (cited in Deutsch 2015, 201; all translations are mine unless stated otherwise) should only be engraved by printmakers selected by Colbert himself. These various prints were then intended to be gathered and bound together thematically (cf. Grivel 1985; Grivel 2010; Castex 2019). For example, “the figures of plants and animals” became the magnificent prints published a few years later in the *Memoires pour*

<footnote n="12">¹² For his work in the Académie between May 1673 and April 1679, Patigny earned a total amount of 6960 livres tournois (Guiffrey 1881–1901, 1, col. 712, 780, 781, 874, 928, 994, 1089, 1208, 1211). Contrary to what Alice Stroup says (1987, 54, n. 5), some payments also include other prints made for Cassini. However, it is true that his main work focused on drawing and engraving the lunar topography, as far as the short descriptions of the accounts can tell, meaning that most of the 6960 livres should have served – directly or not – in the making of the *Grand Selenography*. Although the exact cost of the print cannot be known, a comparison with the price of other prints paid by the Bâtiments du Roi is eloquent: most of the largest prints made after the paintings retained in Louis XIV’s collections only cost between 1000 and 1500 livres (Grivel 1985, 43–45).</footnote>
servir à l'histoire naturelle des animaux and the *Memoires pour servir à l'histoire des plantes*. All the prints were gathered into different thematic volumes intended to be offered to deserving courtiers, foreign princes, and ambassadors so they could all marvel at the extraordinary magnificence of Louis XIV's reign (Grivel 1985, 47). Since its very beginning, the print production of the Académie was thus included within a more extensive project entirely devoted to the "fabrication" of the King's glory (Burke 1992).

Although the *Grand Selenography* could not have been mentioned in the 1667 decree since it was not even conceived, the print was certainly later meant to be included in the Cabinet du Roi, the same way several other enterprises – such as the reproductions of Charles Le Brun's tapestries and paintings – were later added to the set during the 1670s (Gallay 2021, 162–163). The academicians knew that their position and stipend entirely depended upon Louis XIV's will, and they thus had to make their work worthy of the King's interest (Sturdy 1995, 65). When Cassini presented his *Découverte de deux nouvelles planetes autour de Saturne* (1673), he claimed that it did so “in order to respond to some extent to the honor that [the King] gave me”, stressing that “those new planets, which are perpetual and raise beyond all the others [...] will carry much further the name of [His] Majesty” (Cassini 1673, n.p. [epistle]).<fnref n="13" /> While the discovery of new astronomical bodies combined with the appropriate rhetoric was undoubtedly an efficient strategy to

<footnote n="13">¹³ Moreover, the number of planets in the solar system increased up to fourteenth, so it has “now the honor of being united to the august name of Louis” (Cassini 1673, n.p. [epistle] cited and translated in Heilbron 1999, 101).</footnote>
please a powerful patron, as Galileo's famous example shows (Biagioli 2007, 127-134), it was also a once-in-a-lifetime event at best. In comparison, the painstaking compilation and modeling of astronomical data on which Cassini worked during most of his life were much more challenging to valorize: other strategies should thus have been deployed.<fnref n="14" /> The example of the *Histoire des animaux* might have inspired him: the production of lavish illustrations had proven to be a very successful means to contribute to Louis XIV's glory while at the same time pursuing tedious empirical research on animal anatomy (Guerrini 2015, 162-163). In this respect, it seems significant that the astronomer initially hired Sébastien Le Clerc, the engraver of the plates for the *Histoire des animaux* and the only printmaker to work exclusively for the Cabinet du Roi at this time (Gallay 2021, 134-200).

A detailed and lavish figure of the moon was certainly a good way to
demonstrate Louis XIV's magnificence since it could attest to the kind of
achievement that the King's liberality enabled. Indeed, these observations were
made possible by the powerful telescopes that Cassini acquired, largely thanks to
Colbert himself, who dedicated considerable time to securing the best lenses
available (Wolf 1902, 156-160). Hence, the print could have also functioned at a
more symbolic level. In the same way the prints of exotic animals for the *Histoire
des animaux* evoked the ascendancy of the French kingdom over the rest of the
world (Guerrini 2015, 136), the *Grand Selenography* might have been read as a

<footnote n="14">¹⁴ Most of the academicians struggled to find adequate solutions to contribute to the King’s glory (Licoppe 1994, 224–226).</footnote>
metaphorical conquest of the moon.<fnref n="15" /> Significantly, Cassini had already used a
similar rhetoric in his *Découverte de deux nouvelles planetes*, arguing “that the right
of the discovery already gives two [new worlds] to Your Majesty, whose conquests
cannot be limited to the earth, and spread up to the most sublime regions of the
Heavens” (Cassini 1673, n.p. [epistle]). To some extent, the extreme detailedness
of the print might have been a way to claim a symbolic appropriation of the satellite,
made possible through the powerful instruments provided by the crown.

Why did Cassini disengage from such a promising project, especially when the
latter was so close to completion? One may suggest a connection between this event
and the economic crisis that struck in the late 1670s. The latter indeed impacted the
entire print production of the Cabinet du Roi to the extent that the initial encomiastic
instrument had to be transformed into a commercial enterprise (Grivel 1985, 47–
53). However, this change seems to have had little effect on the print production
for the Académie since the plates for the *Histoire des animaux* and the *Histoire des
plantes* continued to be engraved at a fairly constant rate up to 1691 (Saunders 1980,
66–77; Guerrini 2015, 228). Moreover, the expense for lettering the *Grand
Selenography* would have been negligible compared to the entire cost of the
enterprise.<fnref n="16" /> Hence, it is doubtful that financial restrictions would have impeded
such a minor work had the latter been wished.

<footnote n="15">¹⁵ The ideological aspects of astronomical research during Louis XIV’s reign have been discussed in Hutchinson 1987 and Ayala 2014.</footnote>

<footnote n="16">¹⁶ About the price for lettering the prints of the Cabinet du Roi, see Grivel 1985, 43.</footnote>
Interestingly, the many objects that the King observed during his two visits to the Académie on 5 December 1681 and 1 May 1682 were duly reported in the institution's registers, and yet no mention was made of the print (AAS, *Registres*, 9, fol. 159v and 10, fol. 85r-85v). The official history of the Académie, written a few decades later by Bernard Le Bouyer de Fontenelle, may provide more insight into the reason for this absence. It relates that, during the second visit, the King "paid much attention to the various figures of the moon drawn after M. Cassini's observations". Fontenelle then added that such pictures were ascribed a specific function: they should "serve, during the observation of eclipses of this planet [i.e., the moon], to distinguish better the spots [i.e. the craters] and their entry in and their exit from the shadow of the earth" (Fontenelle 1733, 348). By implicitly including the *Grand Selenography* within a more extensive set of different pictures of the moon used for eclipse observations, Fontenelle's narrative denies the extraordinary aspect of the print: it was implicitly presented as a useful tool among others instead of as a singular object of prestige. It seems that this apparent confusion may offer some guidance to explain the print's incompleteness: either the *Grand Selenography* was indeed made for the observation of eclipses and failed to serve its purpose adequately, or it was genuinely made for another purpose which was later deemed unworthy.

## Pictures of the moon as tools for the accurate measurement of lunar eclipses

First, it should be stressed that the narrative provided by Fontenelle is quite convincing. During the 1670s, the Académie's astronomers worked hard to bring
the many apparent irregularities of the moon’s orbit into a coherent model, and
crucial data were obtained through the precise measurement of eclipses (Cassini,
1693, 34).<fnref n="17" /> The most obvious way to proceed was simply to record when the
earth’s shadow appears on the lunar edge and when it disappears. However, this
method was widely deemed inaccurate, and Cassini favored a “new method that
had been developed by Mr. Gassendi”.<fnref n="18" /> Around 1635, Pierre Gassendi and
Nicolas-Claude Fabri de Peiresc noticed that, instead of observing the eclipse’s
beginning and end, they should record each moment the earth’s shadow covers a
specific “spot” and use these data in order to extrapolate the precise path of the
shadow (Humbert 1931, 195). This method was considered much more reliable, as
Cassini pointed out, because the earth’s shadow appears more sharply defined in
this way than when it is mixed with the shadowed edges of the moon’s body.<fnref n="19" /> It
was thus systematically used during the 1670s and 1680s, and its exactness was
frequently stressed.<fnref n="20" />

<footnote n="17">¹⁷ There is unfortunately no in-depth study of Cassini's study of the moon's motions, as pointed out in Deias, 2024, 26.</footnote>

<footnote n="18">¹⁸ "[...] la nouvelle methode qui avoit esté projetée par Mame Gassendi [...] d'observer par la lunete les immersions et emersions des divers taches de la lune" (AO, B4/1 (35), p. 456).</footnote>

<footnote n="19">¹⁹ “Car elle a verifié par l’expérience ce qui paroit aussi par le raisonnement, qu’il est bien plus facile de determiner avec justesse l’entrée d’une tache dans l’ombre quand nous voyons ses bornes dans le disque de la Lune que l’entree du bord de la Lune desja teint de la penombre dans l’ombre veritable, quand nous ne voions pas encore la difference du teint qu’il y a entre l’une et l’autre, outre que le grand nombre des Taches qui s’eclipsent l’une apres l’autre donne la commodité de vérifier la mesme difference des meridiens en plusieurs manieres” (AO, B4/1 (35), p. 457).</footnote>

<footnote n="20">²⁰ See, for example, *Journal des savans* 1675, 215.</footnote>
However, it also requires much more preparation: all the lunar spots used as
markers had to be precisely located and referenced. In this context, detailed figures
of the moon were a useful aid.<fnref n="21" /> It is no coincidence that, according to the account
of the Bâtiments du Roi, Patigny engraved several prints of the satellite well before
the *Grand Selenography*.<fnref n="22" /> While none of these pictures can be identified, this
indicates that the *Grand Selenography* was – as Fontenelle’s statement suggests –
not the only print of the moon made during this time.

In fact, the earliest development of lunar cartography was closely connected to
the observation of eclipses. Gassendi and Peiresc's method might have been the
main reason for undertaking a series of pictures of the moon to produce an accurate
map that different observers could have used to share their measurements. In 1636,
they succeeded in convincing the famous printmaker Claude Mellan to produce a
figure of each lunar phase, but Peiresc's death on 14 June 1637 quickly put an end
to the project. Mellan only completed three prints, each showing a distinct phase: a
full moon, a half-moon, and a waxing gibbous (Figure 8).<fnref n="23" /> Cassini was well aware

<footnote n="21">²¹ As it is proven by Cassini’s later mention that he used a “figure de la lune faite [pour] l'eclipse du mois de fevrier de l'an 1682” (AO, B4/1 (34), p. 394).</footnote>

<footnote n="22">²² Payments for these prints are recorded in the accounts of the Bâtiments du Roi: five years before the completion of the large print, Patigny was paid “pour avoir travaillé pendant huit mois à graver les taches de la lune” and, two years later, “pour plusieurs desseins et graveures de la lune, qu’il a faits à l’Observatoire pendant les six derniers mois” (Guiffrey, 1881–1901, 1, col. 780, 874). Moreover, in July 1677, the British astronomer John Flamsteed informed a colleague that he had already received “from Paris some mapps of the Moone which were sent by Sign[o]r Cassini” (Flamsteed to Richard Towneley, 12 July 1677, in Flamsteed 1995–2002, 1:561).</footnote>

<footnote n="23">²³ About Peiresc and Gassendi’s project on lunar topography and Mellan’s prints, cf. Humbert 1931; Tiberghien 1932; Chapin 1957, 23–27; Préaud 1988, 115–116, no. 147; Ashworth 1994; Whitaker 1999, 25–35; Zittel 2012; Zittel 2019.</footnote>
of their work, and he might have initially intended to pursue Peiresc's project.

Indeed, in late 1671 or early 1672, he sought to obtain "some copies of Mellan's moon that one should have [...] to compare [them] with the moon itself, and to observe and draw the phases of the moon".<fnref n="24" /> This model was clearly in Patigny's mind since he clearly borrowed to Mellan his peculiar engraving technique with parallel lines varying in thickness.<fnref n="25" /> But instead of having each phase of the satellite engraved, Cassini eventually favored a single picture of the complete relief of the moon, a choice which might a priori support the hypothesis that the *Grand Selenography* was intended for the observation of eclipses. Indeed, pictures of the moon's various phases cannot be used to record the motion of the earth's shadow through the lunar disc: only a representation of the visible relief of the full moon could allow for it.

The relationship between Cassini's *Grand Selenography* and Mellan's prints is highly intriguing. Strikingly, Peiresc's topographical project had already been pursued by other astronomers who had chosen to proceed in a very different way. As early as 1645, the Dutch astronomer Michael Van Langren published a complete figure of the moon (Figure 9), whose use for eclipse observations may be implicitly

<footnote n="24">²⁴ “Il seroit utile d’avoir [...] quelques copies de la Lune de Melan qu’il faudroit avoir peu avant pour conferer à la Lune meme pour y designer dans l’observation les fases de la Lune” (AO, D1/11 (B24-32)). The manuscript is undated, but it was apparently written after Jean Picard’s departure to Uraniborg in July 1671 and before September of the same year because, at this time, Cassini seems to have already obtained the requested copies: on 14 September, he indeed noted that the three islands at the entrance of the Mare Humorum “a Melano satis bene expressae” (AO, D1/1).</footnote>

<footnote n="25">²⁵ Mellan’s peculiar technique is well discussed in Ashworth 1994. However, contrary to what Ashworth claims, Cassini’s print is undoubtedly the only representation of the moon in the seventeenth century which clearly shows the influence of Mellan’s technique.</footnote>
drawn from the lengthy inscription on the print.<fnref n="26" /> However, Van Langren favored a style highly different from Mellan’s one. While Peiresc and Gassendi wanted their pictures to be verisimilar, Van Langren chose to represent the lunar topography in a highly conventional way: the maria are simply figured as dark and uniform zones, and only the most remarkable spots are depicted as small circles of various size, with their central part sometimes shadowed. Moreover, the astronomer developed an entirely new terminology to name the maria and spots. Based on the practices developed for terrestrial cartography, Van Langren’s print was the first representation of the moon conceived as a genuine map (Haddad 2019, 30–34).

Two other lunar maps were then developed simultaneously, one by Giovanni Battista Riccioli and Francesco Maria Grimaldi (Figure 10), and the other by Johannes Hevelius, in his famous *Selenographia* (1647) (Figure 11). While the two pictures are very different from each other, they both rely on a highly codified system of representation, as evidenced by the shape of the spots in Grimaldi’s print or by the numerous small mountains in Hevelius’s one.<fnref n="27" /> Hevelius was exceedingly careful about the way his pictures should be made, and he acknowledged his preference for a system of representation based on conventional signs rather than a more naturalistic depiction of the relief (Müller 2010, 372). Although his point extends far beyond proper lunar maps, since it is also applied to the figures of the

<footnote n="26">²⁶ A French translation of the map's epistle may be found in Bosmans 1910, 251–254.</footnote>

<footnote n="27">²⁷ Hevelius’s pictures of the moon have been curiously described as “naturalistic” (Winkler and Van Helden 1993; Vertesi 2007), but this view was rightly criticized in Zittel 2012, 282–284.</footnote>
phases, it was fully coherent with the development of codification in terrestrial cartography (cf. Orgeix 2009).

Such comparisons not only reinforce the hypothesis that the *Grand Selenography* was never conceived as a map, but they also raise doubts about its so-called function for eclipse observations. Firstly, as I have pointed out, the names of the various topographical features are lacking, even though Cassini and his colleagues used the nomenclature developed by Riccioli in their records of lunar eclipses.<fnref n="28" /> But more strikingly, eclipse observations simply did not require a complete topography of the moon: during their observations in the 1670s, Cassini and his colleagues indeed recorded no more than a few dozen spots, and when they later used a small map of the moon (Figure 12), the astronomer emphasized that he chose to depict “only the spots which seem well defined during the eclipses and which are the most visible, *the others being not necessary for this observation*” (Cassini 1692a, 112). A few main spots were actually enough to measure the various positions of the earth’s shadow. Consequently, the extreme detailedness and verisimilar aspect of the *Grand Selenography* were not adequate for recording the motion of the earth’s shadow on the moon. On the contrary, the more schematic the map was, the more valuable it proved to be, as Cassini implicitly acknowledged in 1692: this time, he published another small print that shows the various positions of the earth’s shadow and only represents the outlines of the main elements of the moonscape (Figure 13).

<footnote n="28">²⁸ See, for example, *Journal des savans* 1675, 46–47.</footnote>
In fact, not only was the extreme detailedness of the *Grand Selenography* useless, but it might have also proved counterproductive. In 1675 John Flamsteed had already stressed that there are so many spots on the lunar surface that “it will be an impossible thing to delineate all and indeed needlesse since never more then 30 or 40 are made use of” (Flamsteed 1995–2002, 1:376). Cassini’s ambition to obtain a picture of the moon’s entire relief would thus have been deemed futile by the British astronomer: not only was it unpractical, but it was also intrinsically pointless since there was no way such an ambition could be properly satisfied.

Finally, it is also highly doubtful that the *Grand Selenography* was used as a model for future maps reduced and simplified for eclipse observations. Cassini simply mentions that the small print was drawn after “exact observations” without referring to the large print (Cassini 1692a, 112). Moreover, there are several differences between the two pictures, the most striking one being the emphasis on the ray system of crater Tycho in the small print, while the trails are almost invisible in the large one. The position of several craters and maria at the border of the disc also diverge significantly: in the large print, there is a wide surface covered with many craters between the Mare Frigoris and the very bottom of the disc, while in the small one, this surface is much thinner; another example is the large and dark crater named Grimaldi, which is very close to the right border of the disc in the
small map, but far enough to let some room for the crater Riccioli in the large print.<fnref n="29" />

Such differences were due to the specific way each picture was produced. The *Grand Selenography* was the result of a complex process. Most of the drawings made by Patigny only reproduce a discrete part of the relief, situated at the terminator – that is, the zone between the bright side and the dark side of the lunar body – where light is grazing (Figure 3). It means that all the parts of the moonscape were observed and reproduced under very different lighting conditions so that the representation resulting from their combination is deprived of a single light source. Consequently, to produce a seemingly coherent picture of the whole, the printmaker and the astronomer had to smooth out the figures of the various drawings, that is, to rebalance the highlights and the shadows and distribute them more or less evenly on the entire surface. This process partly explains the disappearance of Tycho’s ray system since the latter is not due to the relief but to the high reflective power – or albedo – of the trails. On the contrary, the small map is covered with few spots and shows Tycho’s ray system very clearly, simply because it was made for eclipse observations and thus had to match with the appearance of the full moon – that is when the difference in albedo is more visible than the relief itself.

The small print’s unambiguous function also explains its differences with the large print in the positions of the craters and maria on the lunar disc. Indeed, another

<footnote n="29">²⁹ These differences prove that the small map was not copied after the large print, contrary to what is still repeated nowadays (see, for example, Haddad 2019, 53–54) despite that Françoise Launay had already acknowledged this point (2003, 14).</footnote>
critical difficulty that Cassini and his printmaker faced when they made the *Grand Selenography* was due to the slight swaying of the satellite during a lunar month. Because of this apparent motion known as libration, a specific phase may reveal parts of the lunar relief hidden during other phases, meaning that repeated observations enable one to see more than half of the moon's surface. Since Patigny made drawings of different phases, he reproduced almost all of the visible parts of the relief, and he could have recombined them within the engraved figure. He was thus able to represent parts of the surface – such as the crater Riccioli or the relief beyond the Mare Frigoris – that are invisible during a full moon, and therefore lacking in the small print. These comparisons show that the *Grand Selenography* was not designed to study eclipses, nor was it used as a model for lunar maps made specifically for this purpose. Consequently, one should now investigate how Cassini came up with this project before he even considered it to be a suitable object for the Cabinet du Roi.

## Topography and the natural-philosophical study of celestial bodies

To understand Cassini's initial intention regarding lunar topography, one should return to the model he first had in mind. As we saw, when he arrived in the observatory, he apparently intended to depict the different phases of the moon the same way Mellan had done instead of using the technique of the more widely spread plates of Hevelius's *Selenographia*. This choice attests that he consciously favored the verisimilar aspect of the former over the more schematic style of the latter. In fact, while Hevelius's prints are remarkable because of the specific "visual
language” that the astronomer had developed (Winkler and Van Helden 1993), they were also criticized for their oversimplified rendering of the relief. In his *Micrographia* (1665), Robert Hooke compared Hevelius and Riccioli’s pictures of the crater Hipparchus with his own figure so that the reader could appreciate “how far short both of them come of the truth” (Hooke 1665, 242) (Figure 14). In this case, Hooke’s main concern was not to obtain a “map” of the moon but an accurate picture of the lunar relief that could help answer fundamental questions about its physical nature, such as the causes of the craters’ shape or the kind of vegetables with which the moon seems to be covered (Zittel 2019, 33–37). Thus, one could suggest that, when using Mellan’s verisimilar model, Cassini also planned to gather precise empirical data about the entire visible moonscape to better understand the nature of the satellite’s surface.

Cassini’s adoption of a more natural-philosophical approach of astronomical objects is not implausible. Indeed, while most of his observations on planetary topography were intended to refine the modeling of planetary motions (Cassini 1810, 300–304), he also proved to be interested in the physical nature of celestial bodies. For example, his acute study of solar spots led him to speculate that, “like the globe of the earth”, the sun was made of two different matters, the luminous one being liquid and the dark spots being like rocks appearing and disappearing because of tides (Cassini 1810, 306). In this case, his approach seems to contrast with the rather instrumentalist position he seems to have held in most of his astronomical work. While his epistemological modesty about the genuine configuration of the world system might be ascribed to his cultural and religious background (Heilbron
1999, 185–187), one may wonder how he turned to a more realist approach when speculating on the physical nature of celestial bodies.

In the case of the sun, his curiosity was supported by the explicit analogy with the earth, and it might have been similarly aroused in the case of the moon.<fnref n="30" /> Indeed, seventeenth-century astronomers widely acknowledged that the moon is not the perfect and immutable solid described in Aristotelian physics, but an irregular body, apparently covered with mountains, valleys, and even seas and oceans. Hence, the moon's uncanny resemblance with the earth raises wonderous thoughts and crucial interrogations about its very nature (Hallyn and Shea 2000, 83–104; Aït-Touati 2011; Bouyre 2014; Pineda de Ávila 2015). Cassini's curiosity about the physical nature of the moon might have led him to conceive a complete and accurate representation of the satellite.

There is all reason to believe that curiosity was initially considered the main driving force behind this enterprise. In the seventeenth century, curiosity had become a central and virtuous motivation for investigating the natural world (Daston 1995; Daston and Park 1998, 303–328; Harrison 2001). It led to the recognition and the valuation of the pleasure derived from scientific enquiry (Wragge-Morley 2020). In this respect, investigating the moon's marvelous appearance could be deemed a fully legitimate endeavor. For example, in 1663, Christiaan Huygens had admired Christopher Wren's lunar globe made for Charles II (cf. Bennett 1982, 40–41) by emphasizing how “pleasant” it was “with all its little spots and round valleys” (Huygens 1888–1970, 4:369). More strikingly,

<footnote n="30">³⁰ No study on Cassini's research on the solar surface has yet been done (Deias 2024, 25).</footnote>
one of Cassini’s closest colleagues, the mathematician Philippe de La Hire, clearly expressed his fascination for the moon in a 1706 article: while he recognized that the understanding of planetary motions “was enough for the usefulness of life”, he also claimed that the human mind is “never satisfied with what he has” and is naturally tempted to investigate the physical nature of celestial bodies (La Hire 1706, 108).

Interestingly, this discourse was not just rhetorical: it seems that La Hire and Cassini genuinely shared a similar interest in lunar topography. Indeed, the very same day his colleague presented the *Grand Selenography* in the Académie, La Hire showed a three-dimensional “sample of the relief of the moon” (AAS, *Registres*, 7, fol. 239v). A few years later, in 1686, he completed nothing less than a four-meter painting of the satellite.<fnref n="31" /> Since this painting was lost in the early twentieth century, we do not know how the moon was represented there, but we can reasonably assume that La Hire tried to emulate Cassini and surpass the accuracy and detailedness of the 1679 print.<fnref n="32" />

The mysterious nature of the moon might have been the driving force of such ambitious works. Animated by a genuine fascination for the moon refashioned into a virtuous curiosity for the lunar relief, Cassini began to gather disparate empirical information on the moonscape and then considered reuniting all the data into a single picture. Consequently, while Mellan’s pictures and Hooke’s enterprise might

<footnote n="31">³¹La Hire’s painting is described in Boinet 1924, 85, no. 105, and its early provenance may be found in La Lande 1792, 3, part. 1, 310.</footnote>

<footnote n="32">³²The painting was curiously lost after its transfer from the Bibliothèque Sainte-Geneviève to the Observatoire in February 1926 (Zehnacker and Petit 1989, 124, no. 250).</footnote>
have been Cassini's primary sources of inspiration, the astronomer eventually chose a bolder solution. Instead of representing spatial and temporal fragments of the moon's appearance, he sought to obtain a synoptic picture (cf. Daston 2014) of the entire lunar relief. With the serial form of Mellan's prints, the recognition of the moonscape features still depends upon the user's mental ability to reconstruct the genuine relief of the satellite. On the opposite, the *Grand Selenography* supposedly allowed the beholder to discover, in one single glance, the entire lunar surface with all its details. Ideally, the examination of the picture would thus replace the examination of the moon itself since it should immediately provide *more information* on the lunar relief than any direct observation of the satellite. It is likely that the making of the *Grand Selenography* was initially supported by a truly natural-philosophical ambition: contrary to drawings that are simple records of the moon's appearance at a specific time, the print was intended to show something about the very nature of the lunar relief.

The epistemic endeavor supported by curiosity might be thus combined with the imperialist symbolism that Cassini probably ascribed to the print: it would have been a kind of victory against an object recalcitrant to reveal its true nature. In this respect, the epistemic and encomiastic purposes might have been successfully conflated into the print, one supporting the other. With this hypothesis in mind, it becomes even more difficult to understand why the *Grand Selenography* failed to be completed. It is thus necessary to clarify the extent to which the figure was really considered an adequate representation of the true appearance of the moon.
The problem of the synoptic image: how to represent the “true form” of the
moon?

In the late 1660s, the academicians had already acknowledged the need for
pictures directly made after nature: information recorded by *autopsia* – by
observation through one’s own eyes – was claimed as the only way to get a proper
understanding of natural beings and to correct the many errors from the past. This
was not a purely rhetorical strategy: most of the plates for the *Histoire des animaux*
and the *Histoire des plantes* were indeed based on drawings made after nature.<fnref n="33" /> It
is worth mentioning that such awareness was not widely spread at that time: even
though treatises on natural history had emphasized the value of *autopsia* since the
middle of the sixteenth century, savants had often failed to follow their own
precepts when it came to pictures.<fnref n="34" /> During Cassini’s time, a similar disparity
between discourses and practices may still be observed in works such as Jean-
Baptiste Du Tertre’s *Histoire Générale des Antilles* (1667–1671) (cf. Gallay 2021,
205–217) or the original project of the Royal Society’s *Historia piscium* (1686)
(cf. Kusukawa 2000, 185–186).

<footnote n="33">³³ There were several exceptions for the *Histoire des animaux*, as Anita Guerrini has pointed out (2019, 283). However, most plates were based on Perrault sketches made after nature. For a detailed study of this process, see Gallay 2021, 232–242.</footnote>

<footnote n="34">³⁴ As William Ashworth (1985) demonstrated, the empirical turn of natural history during the sixteenth century did not affect pictures: those were seldom made after nature but rather achieved either by copying pre-existing figures or simply by relying on textual descriptions. For a more recent account on so-called “from life” or “ad vivum” representations, see also Balfe and Woodall. 2019.</footnote>
The academicians' commitment toward pictures after nature however led them to identify several specific issues raised by the translation between what was seen and what ought to be represented. Some of the figures of the *Histoire des plantes* thus raised criticism because they did not match the academicians' expectations (Stroup 1990, 80–82; Gallay 2024). More strikingly, the anatomist Joseph-Guichard Duverney recognized some flaws in Claude Perrault's way of producing anatomical figures, and he chose to work differently, by relying on highly trained draughtsmen and engravers to which he gave higher responsibility and recognition (Gallay 2023; Gallay 2024).

In this context, the *Grand Selenography* also raised issues, notably because of its synoptic function. Indeed, nothing a priori guarantees that such a picture may be trustworthy. The more complex the process is, the more different the picture may be from the object's appearance, and the more difficult it is to verify how accurate the representation is. Besides, the manipulations required to make the *Grand Selenography* were not based on any geometrical method that could be easily analyzed and reproduced. Not only is there no trace of a grid in Patigny's drawings, but the libration of the moon would have hampered any attempt to reconstruct the lunar topography with a geometrical method by using a micrometer.<fnref n="35" /> To account for libration, Hevelius and Riccioli simply presented two superimposed circles (Figure 10 and 11), while Cassini chose to retain the circular shape of the figure. Hevelius's and Riccioli's solution was far from being satisfactory, but Cassini's

<footnote n="35">³⁵ It was only in the second half of the eighteenth century that Tobias Mayer was able to produce a series of moon maps using a geometrical method (see Haddad 2019, 58–72).</footnote>
one was no better since it implies that the surface near the border had to be stretched
to fit within the figure.<fnref n="36" /> In the same way Cassini and Patigny had to rebalance the
shadows and highlights of the moonscape, they also had to modify the elements of
relief to make them fit within a single circle.

Although the astronomer remained silent about the difficulties that he and
Patigny met, Robert Hooke's commentary on the issues raised by microscopic
observations might help us understand the complexity of their work:

[...] because of these kind of Objects there is much more difficulty to discover the
true shape, then of those visible to the naked eye, the same Object seeming quite
differing, in one position to the Light, from what it really is, and may be discover'd
in another. And therefore I never began to make any draughts before by many
examinations in several lights, and in several positions to those lights, I had
discover'd the true form. For it is exceeding difficult in some Objects, to
distinguish between a *prominency* and a *depression*, between a *shadow* and a *black stain*, or a *reflection* and a *whiteness* in color. (Hooke, 1665, n.p. [preface], cited
in Doherty 2022, 117–118)

As Hooke implicitly suggests, getting the “true form” of a human-scale object
was rather unproblematic: the object may be observed very quickly from all its
different angles and in various light conditions. However, when working with a
microscope, the observer can only access a limited number of points of view, each

<footnote n="36">³⁶ Hevelius and Riccioli's mode of representation is far from being perfect since it ignores the changes caused by the spherical shape of the moon, and, more importantly, it does not take into account the libration in longitude – even though Hevelius was well aware of the latter (Haddad 2019, 41–49).</footnote>
requiring several manipulations. The process by which one can hope to "discover" the "true form" of microscopical elements was much more demanding than in the case of human-scale objects (cf. Doherty 2012).

The similarities between the issues acknowledged by Hooke and those that Cassini and Patigny might have faced are obvious, and yet some significant differences can be identified. Contrary to Hooke, who memorized what he saw before he shifted the lighting and the point of view, Cassini and Patigny were confronted with an object whose appearance only changed once a day without any possible manipulation: they had to produce a drawing of every single observation. Hooke's reconstruction was entirely based on mental images, while the making of the "true form" of the moon relied on real pictures. Furthermore, the use of Patigny's drawings was not so different from some well-known examples of epistemic uses of pictures in astronomical research, such as Galileo's prints to demonstrate the nature of the sunspots or Huygens' method to discover Saturn's rings (Biagioli 2007, 135-217; Van Helden 1974). Thanks to a combination of pictures of the same object seen from different angles, one can indeed induce the object's real nature: the same way one can finally understand that dark spots are actually on the surface of the sun or that the two "anses" of Saturn are part of a single ring, one should be able to determine the nature of the moonscape by observing the shifting pattern of the shadows.

However, this was not as simple as one might think. Despite Galileo's early demonstration of the irregularities of the lunar surface supported by the interpretation of the changes in the shadow pattern (Cohen 1980; Winkler and Van
Helden 1992), the identification of some relief elements was still disputed in the
1670s. For example, in a letter to one of his colleagues, Henry Oldenburg, the
secretary of the Royal Society, criticized scholar Isaac Vossius’s description of
spots as mountains by rightly pointing out that their top should be enlightened first
if they were mountains: since light first appears on the border, the spots should be
cavities instead (Oldenburg 1965–1986, 11:310). More significantly, when La Hire
made his three-dimensional sample in 1679 (see p. ##), his ambition was to verify
his assumptions about the nature of the lunar relief. He was thus able to confirm
that “when [the sample] was exposed to the sun in different ways, it gave more or
less the same appearance as the part of the moon that it represented” (La Hire 1706,
111).

Not only was the reconstitution of the genuine lunar topography challenging,
but the latter's transcription into the print was even more complex. Indeed, to depict
the relief elements in a verisimilar way, Patigny had to represent their shadows and
highlights. As I already mentioned, he could not have represented them as resulting
from a single light source. The only way to represent the entire lunar topography
was thus to overemphasize the relief and neglect the roundness of the satellite. This
is why the moon appears flattened and its craters bulky, almost like a disc covered
with bubbles.

Such distortions did not remain unnoticed. Edmond Halley acknowledged that
the *Grand Selenography* is “very exact”, but he found “the shaddowes not neer soe
well done as those of Mr. Hevelius” (Halley 1932, 52). Flamsteed thought that the
pictures he received in 1677 “are neatly done [and] the spots better placed and
most commonly more like then in Hevelius”, but that Cassini “still exceeds them in
the true proportions of the lights and shades” (Flamsteed 1995–2002, 1:561).
Despite their moderation, the two astronomer’s criticisms suggest that there might
have been a broader disapproval of the way Cassini and Patigny represented the
moon.

Another issue was raised by the fact that the variation of the shadow pattern
was not only due to the relief but also to the differences in albedo. In this respect,
the most striking feature is the spectacular ray system of crater Tycho. While we
saw that Cassini later chose to depict Tycho’s trails in the small print made for
eclipse observations, he necessarily had to consider whether or not he should
represent them in the *Grand Selenography*. Patigny’s drawings indeed show both
aspects of Tycho: one of the drawings made during a full moon reproduced the ray
system (Figure 7), while others, done when Tycho was at the terminator, only show
the relief (Figure 3). It seems pretty likely that Cassini already understood that these
specific appearances were due to the high reflective power of the trails. In 1665,
Hooke had already noticed the difference in albedo between the interior and the rim
of Hipparchus, and a few decades later, La Hire clearly set forth that the changes in
the appearance of Tycho’s surroundings were due to their high albedo (Hooke 1665,
242; La Hire 1706, 112).

Cassini thus had to choose what aspect should be represented in the print, and
he favored the craters around Tycho over the latter’s ray system. However, he still
retained some of the trails in the Mare Nubium and the Mare Cognitum. Similarly,
he chose to highlight Kepler’s ray system by using Patigny’s drawings made when
the sunlight was well reflected by the trails (Figure 4). It suggests that while he
might have considered the relief to be more significant than the differences in
albedo, he would have ideally preferred to represent both aspects of Tycho on the
print. The absence of Tycho's ray system was not supported by a rhetorical or
epistemic claim. It was more simply a default choice: the astronomer just felt it was
impossible – or at least too difficult – to combine both the relief and the differences
in albedo.

Consequently, the pictorial representation of the “true form” of the moon was
not something that could have been fully achieved in the *Grand Selenography*.
Following the growing awareness of specific issues raised by the production of
pictures after nature, Cassini might have realized the difficulty of interpreting visual
cues to reconstruct a real object beyond its appearance. Indeed, while there is no
textual evidence that he genuinely acknowledged such limits, a visual element
might actually suggest that he eventually considered that getting the “true form” of
the satellite was, in fact, illusory. As I will attempt to demonstrate, the small female
profile in the Promontorium Heraclides (Figure 2) was perhaps conceived to warn
beholders about the very limits of the representation.
The lady on the moon, between visual play and epistemological modesty

The figure of the lady on the moon was first observed in the late 1660s, and it quickly grew famous.<fnref n="37" /> In August 1677, Henri Justel told Leibniz that “people of the court have seen it, and everybody agreed” that it “should be an illusion” (Leibniz 1923–[ongoing], series 1, 2:289–290). In other words, the female profile was widely recognized as what we call today a pareidolic image, resulting from the natural tendency of the mind to interpret random visual cues as significant objects.

Pareidolic images were already well known to Renaissance artists and scholars (Janson 1961; Findlen 1990) and have remained a source of amazement during the following centuries. In the middle of the seventeenth century, someone like Athanasius Kircher could have still considered that such appearances were meant to express some of the real properties of the object, but this view was entirely abandoned in the early Académie des sciences. For example, the botanist Denis Dodart condemned the “ridiculous affectation” of Abraham Bosse’s figure of the mandragora (Figure 15); he required it to be corrected and warned “not to fall for these visions” (cited in Stroup 1990, 300, n. 43). In this case, he was obviously dissatisfied with the anthropomorphic aspect of the figure, which kept the plant within its occult tradition.<fnref n="38" /> A few decades later, a surgeon named Saint-Donat

<footnote n="37">³⁷ In the second edition of his *Entretiens sur la pluralité des mondes* (1687), Fontenelle noticed that the appearance of the lady on the moon was first observed “depuis près de vingt ans” (p. 279), that is in the late 1660s.</footnote>

<footnote n="38">³⁸ Compare Dodart’s criticism with an earlier formulation of the problem by William Turner in Daston 2015, 13–16.</footnote>
discovered in one of his patients’ testicles a tumor with the shape of an infant: a
fantastic story about the man’s pregnancy quickly spread. Once again, these tales
were immediately dispelled by the Académie’s most distinguished anatomist
Joseph-Guichard Duverney who stressed, after having examined the tumor, that
these were just “polypous materials to which the hazard gave a false appearance”
(Duverney 1761, 2:553).

While pareidolic images became devoid of any meaning, their mysterious
beauty however continued to be praised. When reporting Saint-Donat’s discovery,
the academicians still considered that, although the story was false, “there was no
need of such tales to marvel” (ibid., 2:563). In his *Description et usages de plusieurs
nouveaux microscopes* (1718), the naturalist Louis Joblot published a picture of a
fascinating animalcule whose “body was covered by a beautiful and neatly shaped
mask of a human figure, perfectly well done, as one can judge by the drawing”
(p. 57–58) (Figure 16). Here, the description and the print simply aimed to arouse
the reader’s curiosity, and the figure’s resemblance with an actual face was thus
emphasized for such a purpose.<fnref n="39" /> Similarly, Cassini might have exhorted Patigny
to engrave the lady’s hair with curved lines instead of the horizontal lines used in
the rest of the print because it was a way to stress the profile’s verisimilitude. The
figure would just have been a playful detail intended to amaze those among the
court who had never heard of the appearance or to delight those who had been able
to observe it.

<footnote n="39">³⁹ The figure indeed raised a certain fascination since it was copied in later treatises on microscopy (Ditzen 2015, 135–156).</footnote>
However, there might have been an additional reason. It seems that Cassini was genuinely struck by the figure. In the album gathered by Cassini IV, the two only remaining drawings focusing on the Promontorium Heraclides show quite clearly the female profile. The vaguely sketched figure made in June 1675 was willingly added to the main drawing in the left part (Figure 5), even though it did not precisely fit with the latter because of the size of the paper sheet: at this time, the appearance was probably not expected, and it was quickly added in the drawing. On the contrary, the profile in the second drawing, completed in October 1678, (Figure 6) is so neatly done that it could only have been the result of a planned observation. Indeed, because it was due to the angle of the sunlight, the appearance was quite scarce: it only happened between the tenth and the eleventh day of the lunar cycle (Leibniz 1923–[ongoing], series 1, 2:289–290; AO, B4/1 (34), p. 396), and, like any astronomical observation, it was entirely dependent on good meteorological conditions. These two drawings thus suggest that Cassini had a particular interest in getting a correct representation of the figure.

Moreover, in a manuscript draft, Cassini detailed the “disheveled girl” with her hair like “a chain of very high mountains, whose summits represent the curls”. He seemingly made many observations of the phenomenon since he noticed that “one can see in this head several transformations year after year”, so that “the face which was formerly very well shaped is currently very disfigured”.<fnref n="40" /> This observation led

<footnote n="40">⁴⁰ “Il y a aussi quelque [apparence] dans le promontoire appelé Hélicon qui représentoit la teste d’une fille déchevelée dont la chevelure, qui est une chaîne de montagnes fort élevées, dont les sommets représentants les boucles sont éclairez du Soleil longtemps avant que le pied sort hors de</footnote>
him to discuss, in quite a convoluted language, that such changes might have been
due “to the various illuminations that the phases of the moon receive, depending on
the various exposures to the sun, [these] being very difficult to meet once again
exactly because of the apparent libration which slightly turns [the moon] when the
latter is at the same distance to the sun”.<fnref n="41" /> Here, the figure was thus a way to
introduce a problem regarding the interpretation of the visual cues provided by
lunar observations.

It is likely that the reproduction of the profile in print also served a didactic
purpose, the same way its description in Cassini's manuscript did. It can indeed be
related to a well-known discourse on visual perception that Fontenelle developed
in the second edition of his *Entretiens de la pluralité des mondes* (1687) by referring
to the female profile. By using this example, Fontenelle aimed to show the way
pareidolia works in general: he indeed claimed that “everyone conveys on the
objects the ideas that he is filled with”, so that “our astronomers see on the moon
the faces of ladies, while it is likely that a woman [...] would see a man’s handsome
face” (p. 280–281). Under his pen, the lady on the moon thus became a telling
example of the way visual perception might be deluded by mental projections.

<footnote>la section de la Lune [...] ce qui arrive le dixième ou onzième jour de la Lune. On voit donc dans cette teste quelque transformation d'une année à l'autre : le visage qui estoit autrefois fort bien formé estant présentement fort défiguré" (AO, B4/1 (34), p. 396).</footnote>

<footnote n="41">⁴¹ “On pouvoit attribuer ces changements à différents jours que ces phases de la Lune reçoivent [...] selon la diverse exposition au Soleil, qu’il est très difficile de rencontrer précisément la mesme et particulièrement à cause de la libration apparente qui la tourne un peu diversement lorsqu’elle à la mesme distance du Soleil” (AO, B4/1 (34), p. 396–397).</footnote>
Fontenelle certainly followed Cassini’s observations, as his description echoes the astronomer’s one: he explained that the “young lady seen on the moon with a telescope [...] considerably aged”: she had “a fairly beautiful face” but then “her cheeks became hollow, her nose lengthened, her forehead and her chin moved forward so that all her charms have waned” (ibid., 279). The connection between his description and Cassini’s print is moreover suggested by Bernard Picart’s small vignette published in his 1728–1729 lavish edition of Fontenelle’s *Œuvres diverses*, which clearly represent the *Grand Selenography* with the little female profile (Figure 17).

One may thus suggest that Cassini already thought about the little profile’s potential meaning when he asked Patigny to include it on the copperplate. Indeed, Fontenelle’s discourse was not wholly original; it was, in fact, closely connected to a tradition that the astronomer himself could not have ignored. When the moon is seen with the naked eye, it vaguely resembles a human face, and this appearance was at the core of one of the most famous ancient astronomical treatises, Plutarch’s *De facie quæ in orbe lunæ apparet*. In Cassini’s time, the text had been translated several times from Greek to Latin – notably by Kepler – while the first French version by Pierre Amyot was already a century old (Lesage Gárriga, 2021, 1–22). Following Plutarch’s model, the face on the moon had become a paradigmatic way to exemplify the fallibility of human senses in late seventeenth-century France. The most remarkable reference to the phenomenon may be found in the first volume of Nicolas Malebranche’s *Recherche de la vérité* (1674). Malebranche indeed mentioned that when some people, especially short-sighted ones, “look at the moon,
they ordinarily see two eyes, a nose, a mouth, in a word, they seem to see a face".

He then set forth the illusion by the hypothesis that one is so used to seeing faces that those have deeply impressed their "traces" into the brain (Malebranche [1674] 1997, 135). In his poem *Un animal sur la lune*, La Fontaine provided the same example to express a similar yet less sophisticated view: the "woman's head" which appears "on the moon" is only due to some "irregular places that look like that from afar". La Fontaine simply emphasized that the illusion may be quickly dispelled by the use of reason: thanks to the latter, the eyes "can never deceive" since they "always lie" (La Fontaine 1991, 1: 284).42 This epistemological optimism was shared by Malebranche himself:

> And those who believe the moon really is as it seems to them will be easily corrected if they look at it through a telescope, no matter how small, or if they consult the descriptions that Hevelius, Riccioli, and others have given to the public.
>
> (Malebranche [1674] 1997, 135)

It seems that Cassini chose to transfer La Fontaine's and Malebranche's discursive use of the face on the moon onto the small profile so that he could have visually stressed how delusive perception might be. Indeed, because of the difficulties that the astronomer and his engraver faced when trying to interpret the visual cues they observed and recorded, the lady on the moon might have appeared

<footnote n="42">42 In fact, it is not entirely clear whether La Fontaine refers to the face on the moon seen with the naked eye or to the small profile seen through a telescope, but this ambiguity does not impact the argument presented here.</footnote>
as a way to warn beholders about the very limits of the figure itself<fnref n="43" />. Compared to Malebranche, La Fontaine, and even Fontenelle, Cassini thus advocated for a much more modest epistemological position: reason could not always dispel the illusions of the senses, and the genuine nature of things beyond their appearances was not always accessible. Despite all efforts, the proper interpretation of the lunar relief by observing the variations in the shadow pattern remains uncertain because the empirical data were too limited. A few years earlier, one could have hoped that the magnifying power of refracting telescopes would indefinitely grow and allow observations of tiny details on the moon, such as hypothetical buildings or even animals. However, when Cassini made his print, this hope had already vanished within the Académie: such telescopes would be so long and their lenses so wide that there were completely unrealizable. The idea that knowledge on lunar topography could constantly improve thanks to technological advances thus appeared fallacious.<fnref n="44" />

Hooke was optimistic enough to think that the “many examinations in several lights” could provide all the information that the mind requires to “discover” the “true form” of microscopical elements because these examinations were always possible – they were just time-consuming. On the contrary, the limited conditions in which the moon can be observed led Cassini to acknowledge that its “true form”

<footnote n="43">⁴³ While such a metapictorial use of the figure remains hypothetical, it is not implausible in regard to some contemporary highly intellectual uses of pictures (as explored by Berger 2017) and the broader development of metapictorial elements in seventeenth-century painting (Stoichita 2015).</footnote>

<footnote n="44">⁴⁴ On this question, see the debate between Adrien Auzout and Hooke related in Hamou 1999-2001, 2:194–195.</footnote>
could only be *reconstructed*. Hence, the *Grand Selenography* was to remain
essentially imperfect because it resulted from a subjective process whose delusive
potential was recognized. In other words, the making of the print led Cassini to
acknowledge that getting the “true form” of an object whose appearances were
limited was illusory: to some extent, the maker had to project what he thought there
was, without having any evidence that his mental image matched the properties of
the real object. It is at this point that Cassini might have decided to add the small
figure of a lady in order to convey his epistemological doubts.

At first, this warning might have been considered good enough, but it soon
proved to be insufficient. The fact that the print was never completed indeed
suggests that, despite the small figure, it was still regarded as a failure. In 1699,
Cassini planned to execute another “exact description of the moon, with the use that
one can draw for astronomy and geography” (AAS, *Registres*, 18, fol. 135v) While
the exact nature of this project – if ever achieved – is unknown, the fact that he
considered it two decades after he conceived the *Grand Selenography* attests that
he was unsatisfied with the later. Moreover, it seems that La Hire finally came up
with a much more efficient way to represent the moon: after having tried to surpass
Cassini with a huge painting of the moon, he endeavored to execute a three-
dimensional model (La Lande 1792, 3/1:310). During a joint meeting with the
Académie des inscriptions, La Hire discussed the various appearances of the moon:
according to Jean-Paul Bignon, the success of the talk urged him “to make a globe
of the moon in relief” (BnF, Mss., Clairambault 566, fol. 231v). This was not the
first time such a project was completed, since Christopher Wren had made one a
few decades earlier (see p. ##). However, in this context, La Hire's globe was a way to solve the main issue raised by the *Grand Selenography*: it could provide a view of the lunar relief that was at the same time true and verisimilar.

The abandonment of the print might thus be due to the fact that Cassini progressively realized its inability to offer a proper representation of the moon. However, there might have been a further reason. When the astronomer planned to produce an “exact description of the moon” in 1699, he stressed the latter’s usefulness “for astronomy and geography”. This was not a trivial mention: indeed, it will now appear that the most serious criticism leveled against the *Grand Selenography* was not related to its appearance but to its very purpose.

Moon-mapping and the determination of longitudes: the utilitarian justification and its limits

In a 1692 article, Cassini claimed that maps of the moon were used “to mark the exact position of the places on earth and improve geographical and hydrographic maps, without which it is impossible to travel afar and trade with people far away” (Cassini 1692b, 134). The explanation might be surprising but is actually sound. As its title indicates, Cassini’s article focuses on the “method to determine longitudes through several observations of the same eclipse made in different places”. Lunar eclipses were indeed one of the most widely acknowledged methods for measuring longitudes, as Peiresc and all subsequent selenographers had already noticed: it enabled different observers situated far away from one another to synchronize their observations and thus to obtain the meridian difference
by the time difference.<fnref n="45" /> Since the determination of longitudes was undoubtedly the
most crucial issue for improving travels by land and sea, Cassini could have easily
appealed to such an argument to justify the usefulness of moon mapping.

However, such an explanation also attests to Cassini’s discomfort with the
original purpose of the *Grand Selenography*: obviously, the latter was of no help
for determining longitudes since it could not have been used for eclipse
observations. Cassini apparently felt compelled to explain the purpose of pictures
of the moon because some people, “who do not consider things thoroughly, deemed
[them] to be useless descriptions of an imaginary land”. He then reported that those
people “were astonished that someone who has wit and common sense, would
amuse himself making such exact maps of the moon, where no one would ever go
as if he planned to conquest it and establish colonies there” (Cassini, 1692b, 134).
In the absence of any other hint, it is impossible to ascertain who were his
detractors, but one can reasonably assume that their target was indeed Cassini’s
large print and perhaps La Hire’s painting since both were by far the most detailed
representations of the moon completed by this time.

<footnote n="45">⁴⁵ It has been claimed that the observation of the eclipses of the satellites of Jupiter, already used by Galileo, was widely recognized as more efficient than the observation of lunar eclipses, even by Cassini himself (Van Helden 1996, 93–97; Mallon 1983, 107–108). It is indeed true that the motion of the earth’s shadow is difficult to measure precisely because of its slow path and because of the fuzziness of the penumbra-umbra boundary (I am grateful to William Tobin for this information) and it seems that Cassini recognized this issue (AAS, *Registres*, 9, fol. 105v). However, the Academicians’ frequent observations of lunar eclipses in various places on the globe clearly attest that the method was still deemed valuable (see, for example, *Journal des savans* 1686, 317–324).</footnote>
One should now question why Cassini had to counterfeit a utilitarian argument to defend the value of his work. Indeed, it is far from evident that utility had ever been the primary motivation to depict the moon. After all, Mellan's prints might have been driven by Peiresc's large-scale project on the determination of longitudes, but when Gassendi related the origin of the project, he simply confessed his own "ardent desire [...] of having the several Appearances of the Moon, and the varieties appearing in each of them [...] in their just proportions and scituations [sic]". He then explained that Peiresc immediately agreed that such pictures would be "very considerable, both in natural Philosophy, and in Astronomy" (Gassendi 1657, 123-124), without mentioning their potential function for improving geographical maps. In Gassendi's view, there was no better justification than disinterested curiosity.

It must be stressed that the context in which the purpose of the picture was formulated plays a significant role. In the case of Van Langren, his map was explicitly advertised as being of the "greatest utility for mankind" (*humano maxime utilia*), but such a discourse was probably due to his need to convince a powerful patron.<fnref n="46" /> Van Langren indeed explained that the Infanta Isabella Clara Eugenia had introduced him to Philip IV in order to provide the King with "an astronomical method for the determination of longitudes".<fnref n="47" /> And indeed, in his request to Isabella, Van Langren stressed that the determination of longitude "was desired by many princes and especially by His Majesty [Philip IV], as it clearly appears from

<footnote n="46">⁴⁶ About the relationship between utility and courtly science, see the essays gathered in Moran 1991.</footnote>

<footnote n="47">⁴⁷ See also the French translation in Bosmans 1910, 251.</footnote>
the prize with which His Majesty wants to reward the one that would find the invention of the longitude" (cited in Bosmans 1903, 134).

Cassini's development of a utilitarian rhetoric might have been due to similar reasons. In his *Mémoires*, he relates that he often met with the King and talked "about [his] projects to use astronomy for the improvement of geography and navigation" (Cassini 1810, 291). Louis XIV was undoubtedly pleased to hear that astronomical research could have directly impacted the commercial development of the kingdom. However, it does not necessarily mean that the *Grand Selenography* needed to be useful: the print's lavish appearance and symbolic power were certainly sufficient for the King. Let us recall that Colbert had initially planned to establish a "*Grande académie*" which would have unified the cultural elite in service of the King's glory (Lux 1990). Despite the failure of this project which partly led to the foundation of the Académie des sciences, the making of the King's glory was still, in Colbert's view, the savants' primary task – and it undoubtedly remains as such for the marquis de Louvois.<fnref n="48" /> It is worth stressing that both utility and curiosity were emphasized as the two purposes of the academicians' work in the *règlement* of 1699 (art. XXII transcribed in Aucoc 1889, lxxxvii).

In fact, the utilitarian trend was rather the affair of the savants themselves: even before Cassini arrived in France, several academicians shared a Baconian ideal of

<footnote n="48">⁴⁸ About Louvois's management of the Académie, the most detailed accounts remain Saunders 1980, 11–130 and Mallon 1983, 168–246. However, they both stress Louvois's utilitarian view by relying on a very specific document connected to Samuel Duclos's alchemical research, which cannot be applied to the academicians' other research areas, as demonstrated in Meynell 2000. Moreover, the traditional emphasis on the early Academy's utilitarianism (for example Stroup 1987, 53–60) has been convincingly nuanced in Briggs 1991.</footnote>
science as a way to improve human welfare. The initial project of a *Compagnie des arts et des sciences* presented to Colbert in 1664 and Adrien Auzout's plea to the King to build an observatory in Paris both indicate the profoundly utilitarian rhetoric developed in informal scientific circles during the 1650s and early 1660s.<fnref n="49" /> Furthermore, in the record of the eclipse observation performed by future academicians at Colbert's house on 2 July 1666, it was already stated that such observations "are so useful and their usefulness so well known that one should not be surprised that all astronomers take care to observe them with as much accuracy as possible" because they can serve "to know the difference in meridians, that is the longitude, without which geography and navigation remain uncertain" (AAS, *Registres*, 2:20, cited in Sturdy 1995, 74).

However, in the case of the *Grand Selenography*, it seems very unlikely that the Académie avowedly pressured Cassini. While the official discourses were clearly driven by a utilitarian concern, the academicians' practices were far from being reducible to such a view (Briggs 1991). We saw that Huygens and La Hire did not really care about the practical applications of lunar topography. Moreover, in *De l'origine et du progrés de l'astronomie et de son usage dans la geographie et dans la navigation* written in early 1684, Cassini argued that pictures of the moon could also enable the recognition of changes that might later occur on the moon's

<footnote n="49">⁴⁹ About these projects (transcribed in Huygens 1888–1970; 4:325–329; Wolf 1902, 3–4) and the origin of the Baconian trend in the Académie, see especially Brown 1934, 145–48; Taton 1966, 29–34; Hirschfield 1981, 9–12; Perkins 1985.</footnote>
surface (Cassini 1693, 34).<fnref n="50" /> This non-utilitarian explanation contrasts with the rest of the treatise which precisely aims to emphasize the numerous uses of astronomy for the improvement of human welfare throughout history. That La Hire himself and the future academician Nicolas Hartsoeker then repeated Cassini’s explanation (La Hire 1706, 113; Hartsoeker 1694, 182) attests that the latter was unproblematic: there was no need to appeal to utility in such a matter.

Thus, it seems that the charges against the uselessness of exact pictures of the moon that Cassini reported could only be ascribed to some savants who were not directly related to the Académie. Indeed, many criticisms were apparently leveled against the Academicians during this period: for example, the scholar Henry Justel reported to Oldenburg that some people just sought “to make fun of” the academicians’ works (Oldenburg 1965–1986, 4:29, 31, cited in Stroup 1990, 205) while Huygens reported that others accused him of having stolen their inventions (Huygens 1888–1970, 7:253–254 cited in Stroup 1990, 210). Interestingly, some of them were based on a utilitarian rhetoric. Already in the mid 1670s, the engineer Bertrand de La Coste accused the academicians of spending the crown’s money without doing anything useful for the public (Hahn 1971, 143). Two decades later, Fontenelle complained that people were prone to condemn the lack of “usefulness” (*utilité*) of the institution’s projects (Fontenelle 1699, iii–iv). In this sense, it has

<footnote n="50">⁵⁰ This treatise was read at the beginning of 1687 (AAS, *Registres*, 12, fol. 32v, AAS), but it seems to have been already completed in 1685 (ibid., 11, fol. 134r, AAS) on the basis of a previous discourse entitled *De l'origine et progrez de la geographie et de l'usage de l'astronomie dans la geographie*, read in August 1684 (ibid., 11, fol. 112r-v).</footnote>
been rightly pointed out that royal patronage influenced not only its beneficiaries
but also those it neglected: without doubt, the reactions against the academicians
can partly be ascribed to the envy generated by their specific status and financial
resources (Stroup 1992, 221), but also because the very purpose of the institution
remained entirely blurred before it was more or less settled in the *règlement* of 1699
(transcribed in Aucoc 1889, lxxxiv–xciii).

Those criticisms were not ignored by the academicians who generally
attempted to provide adequate replies, as proven by Cassini's reaction to an
argument leveled against the use of eclipse observations for determining longitudes.
In the preface of his *Elements de l'histoire* (1696), the antiquarian and polymath
Pierre Le Lorrain de Vallemont explicitly criticized this procedure, bragging that
one should "not blindly receive a method" only because "the academicians received
it themselves and praised it in any circumstance". While some of the inconsistencies
he pointed out are correct, he naively argued that "it would seem odd that one
should search in celestial observations for the distance from one place on Earth to
another, [since] astronomy is still perhaps more imperfect and less certain than
geography" (Vallemont 1696, n.p. [preface]). In other words, Vallemont's
arguments were not a real threat. However, only five days after their publication in
the *Journal des savans* on 19 November 1696 (p. 446–448), Cassini read the article
in the Académie; he then presented a short reply to it, and everybody agreed that it
should be published in the *Journal* (AAS, *Registres*, 15, fol. 207r–207v). Although
the project was then dropped, Cassini's prompt reaction attests that he felt necessary
to defend his work against any criticism, however trivial it might be.
Unlike Vallemont's argument, the attack against the *Grand Selenography* potentially endangered a whole area of the Académie's research. While Cassini – like Fontenelle later did – bitterly decried his critics' lack of knowledge, he was however compelled to rely on a utilitarian rhetoric instead of defending the value of his initial motivations. It suggests that curiosity might have become morally reprehensible in this very context, not on the ground of Augustinian precepts, but more simply because it was to some extent incompatible with the new status of academicians. While the gentlemen of the Royal Society pursued scientific investigations for leisure, the academicians rely on a plurality of resources provided by the crown, establishing them as professional men of science (Stroup 1987, 10–31; Stroup 1990, 35–46). For this very reason, they could not have been ascribed similar motivations.<fnref n="51" /> Indeed, pleasure driven by disinterested curiosity could be regarded as the most truthful way to gain knowledge, but it could also be easily assimilated to a kind of entertainment distinct from the pursuit of truth.<fnref n="52" /> The latter view was notably expressed by the scholar Dominique Bouhours in his famous *Entretiens d'Ariste et d'Eugène* (1671): Ariste admits that he “craves to know what savants have said [about the tides], even if it is only for entertainment since most of them use to say pleasant things on subjects they do not understand” (Bouhours 1671, 11). At a time when academicians were striving to get public recognition of

<footnote n="51">⁵¹ It does not mean that the discourses held within the Royal Society were devoid of references to utility (Daston 1995, 403; Harrison 2001, 289), but it must be stressed that there is no development of a broader utilitarian trend comparable to what happened in France.</footnote>

<footnote n="52">⁵² This issue had already been stressed by Descartes (Garrett 2009, 48–51) and echoes the later criticisms in the eighteenth century (Daston and Park 1998, 329–363).</footnote>
their new specific status, they obviously could not have tolerated being assimilated
to such pleasurable and meaningless practices. Moreover, because of their seducing
power, pictures would have easily raised such wariness even among those who
supported their use.<fnref n="53" /> It seems that Cassini’s print was thus especially vulnerable:
its monumental size and lavish aspect made it an ideal proof to accuse the
academicians of having failed to keep a virtuous path.

In this respect, the criticisms leveled against the *Grand Selenography* could
have been highly detrimental to Cassini: according to the astronomer’s relation, the
print was seen as a description “of an imaginary land” as if one would have
“planned to conquest and establish colonies there” (Cassini 1692b, 134). Strikingly,
this quip echoes the rhetorical strategy that the astronomer might have used in this
very context, as he did for the satellites of Saturn. Two levels of criticism may thus
be identified here. Firstly, the making of such “maps” was accused of being
ultimately driven by some foolish dream of visiting the moon – echoing a fictional
literature that had developed during the previous decades (cf. Ait-Touati 2011).
And indeed, such a fantasy might have been unwittingly spread by those who
supported Cassini’s research: for example, Fontenelle noticed in his *Entretiens* that
“the description of the moon is now so exact that a savant who would be there could
not go astray any more than [he] would in Paris” (Fontenelle 1687, 86). In this case,
Fontenelle’s praise of the recent developments in lunar topography might have been
easily used against such works. Disinterested curiosity was thus turned into a pure

<footnote n="53">⁵³ As Felicity Henderson (2019) has shown in the case of the Royal Society, the most enthusiastic users of pictures still remained wary of their potential pitfalls.</footnote>
whimsy which makes the enterprise not only useless but also devoid of epistemic
value. On the contrary, since the academicians received gratifications that were *not*
commensurate to the utility of their research, utility itself could have potentially
become more disinterested and thus more virtuous than it was before.

Secondly, the underlying idea of a “conquest” associated with the extreme
lavishness of the *Grand Selenography* might have raised the suspicion that the print
was solely conceived as an object of prestige. This view became incompatible with
the purpose of the Académie: of course, the academicians’ achievements should
contribute to the King’s glory, but precisely because their primary purpose was
epistemic and not encomiastic (cf. Licoppe 1994, 224–229) – the same way the
Académie française’s task was to create a proper language to celebrate the King
and not directly to write eulogies (Zoberman 1998, 105–125). Even for the *Histoire
des animaux* – without doubt the most successful publication of the young
institution – the conflation between epistemic and encomiastic purposes worked
well as long as the latter did not subsume the former.<fnref n="54" /> Unlike Cassini, Claude
Perrault seems to have been well aware of this potential issue. In his *Projet pour
les experiences et observations anatomiques* presented to the Académie on
15 January 1667, he precisely chose to enhance the usefulness of natural history in
order to diminish the encomiastic function of the project:

<footnote n="54">⁵⁴ The fact that copies of the book were only intended to be used as royal gifts became considered highly detrimental to the diffusion of their content. It was only four years after the publication of the first volume of the *Histoire des animaux* that Pierre de Carcavy was finally able to send two copies to the Royal Society (Oldenburg 1965–1986, 12:120). See also Guerrini 2015, 163.</footnote>
The truths on which the King wants the academicians to work are not the most remarkable, [...] but one can say that they are the soundest ones because they belong to what must be the basis for all the sources of human well-being. (AAS, *Registres*, 1:22)

Because Cassini's print could not have been seen as the result of a purely disinterested intention, it could have easily been related to the astronomer's ambitions – let us recall that, when Cassini arrived in France, he quickly got into a dispute with Claude and Charles Perrault about the plan of the Paris observatory (Wolf 1902, 19–27 and Petzet 2000, 370–391), a situation that probably did not help with his reputation. At the time when panegyrists became so prone to develop hyperbolic figures to celebrate the King, men of letters such as Nicolas Boileau or Jean La Bruyère began to show awareness of the inadequacy of overly flattering encomiastic practices (Ferrier-Caverivière 1981, 204–209, 246–249). On similar grounds, the criticisms toward the *Grand Selenography* might have been due to the *excessiveness* of the print: the latter being too expensive, too large, and too detailed, it would have reflected, in the eyes of its detractors, the excessiveness of Cassini's own ambitions. For the astronomer to undermine such an idea, the only remaining solution was to offer a convincing counter-argument: by asserting that maps of the moon were essential to the improvement of trade, he could have claimed how self-disinterested he had always been while concealing at the same time the fallacy of his argument. As Fontenelle unintentionally made clear when he related the King's visit in 1682, the *Grand Selenography* indeed had to be relegated to a common tool drowned among other pictures of the moon.
Conclusion

As soon as one considers the *Grand Selenography* as a partial failure, not only does the print become far less mysterious, but it can also provide new insight into the changing epistemic values within the early Académie. When reconstructing the complex history of this peculiar object, I have attempted to shed light on the range of motives that drove Cassini and the specific issues he encountered during the making of the picture as well as after it was completed. The way his initial intentions were thwarted could reveal two distinct phenomena.

The astronomer's first problem resulted from the nature of his expectations. The *Grand Selenography* was a highly promising project, supported by an adequate encomiastic function combined with Cassini's growing interest in the physical nature of celestial bodies. Through the meticulous reproduction and recombination of minute details of the lunar relief based on *autopsia*, the synoptic figure aimed to be at the same time truthful and complete: its examination was intended to provide more knowledge of the lunar object than could be gleaned from the examination of the object itself. Such a way of using pictures was not only meaningful in the specific case of the moon – since the latter's appearances were always partly veiled – but it was also considered, although differently, by another academician, Joseph-Guichard Duverney, in the field of animal anatomy (Gallay 2023). In a seemingly paradoxical way, one may suggest that some of the pictures produced within the early Académie were not simply conceived as substitutes for textual descriptions – as they were traditionally (Kusukawa 2012, 111–113) – but as direct substitutes for the objects themselves.
The way Cassini conducted the making of the print by selecting some elements and dismissing others might echo to some extent the work of savants who, in the field of natural history, attempted to represent the *type* of a species by selecting, in the various specimens they observed, what they considered to be essential to the species (Daston and Galison 2007, 69–136). However, while the latter process was considered epistemically virtuous by the naturalists who used them, Cassini appeared to have grasped the crucial issue raised by this process: the peculiar viewing conditions of the moon made clear that its synoptic representation was the result of a *construction* and not a *discovery* – something that was not obvious, as we have seen, even for Robert Hooke. In other words, it means that the process – both mental and manual – by which the representation of the lunar relief was made possible was not transparent: it cannot naturally lead to the “true form” of the moon.

By possibly turning the small profile of the lady into a warning sign, Cassini not only attempted to show that visual perception can be deceived, but also that the correction of sensory delusion by the use of reason was not always possible. Such a pessimistic view contrasts with the philosophical attitude exemplified by Malebranche and La Fontaine, and could be related to a skeptical position – except that, contrary to most early modern proponents of skepticism (cf. Popkin 2003), Cassini’s position was precisely not built upon literary culture but was rather due to the problems he met in a very concrete situation. The failure of the print was thus partly due to the discrepancy between the astronomer’s initial expectations and the result he eventually obtained. In all likelihood, the three-dimensional representations of the moon developed by La Hire during the same period, could
have presented a more promising alternative to investigate the nature of the lunar
relief.

While those problems were connected to the way the print was made, the issues
regarding its function have brought us to another range of questions. The fact that
the astronomer came up with a utilitarian argument to justify the existence of the
*Grande Selenography* reveals a change of attitude toward the purpose of scientific
inquiry. When Cassini initially conceived the picture, he considered his motives to
be virtuous: although his curiosity might have been partly fashioned by the broader
fascination raised by the moon during the previous decades, it remained a valuable
motive. Besides, the fact that the print should have served the King's glory was not
to undermine Cassini's virtuous intentions – after all, the plates for the early
projects on botany and anatomy had already been integrated within the Cabinet du
Roi. What happened then is the result of a conjunction of different factors. Since a
utilitarian trend was already well-spread in Parisian scientific milieus, it had
become easy to point out the lack of usefulness of someone's work in order to
question its value. Moreover, because the academicians were granted special
privileges and were gathered into a specific institution whose purpose remained
little defined at this time, they were potentially more threatened than any other
savants by such arguments. It is plausible that Cassini was even more vulnerable
than any other academician because he was a highly paid foreigner. But more
importantly, because of its extraordinary aspect and ambiguous function, the *Grand
Selenography* might have raised questions about its maker's intentions, which could
have been easily established as egoist ones. This specific case study thus shows
how the rise of utilitarian research in the Académie was not only the result of a
dialectical relationship between the crown and the academicians: the role of savants
outside the institution and the pressures they might have exerted should also be
taken into consideration.
Reference list

Manuscripts

Paris, Archives de l'Académie des sciences (AAS)

Registres des procès-verbaux des séances de l'Académie royale des sciences

Paris, Archives de l'Observatoire de Paris (AO)

B4/1 (34). Giovanni Domenico Cassini, “Les premiers essais des observations correspondantes de l’Académie Royale des Sciences pour déterminer la différences des longitudes des plus célèbres villes d’Europe”.

B4/1 (35). Giovanni Domenico Cassini, “De la determination des longitudes par les eclypses des satellites de Jupiter”.

D1/1. Giovanni Domenico Cassini, “Journal des observations faites à l'Observatoire royal de Paris, 14 September 1671 – 30 January 1672”.

D1/11 (B24–32). Giovanni Domenico Cassini, “Preparations a faire presentement pour les observations a conferer avec celle d'Uraniborg”.

Paris, Bibliothèque nationale, Département des estampes et de la photographie (BnF, Est.)

Ye-144. “Registre des Planches gravées qui ont esté receues depuis l’Inventaire fait avec Mr. l’Abbé Varés, au moi d’aoust 1684”

Ye-160. “Memoire de toutes les Planches gravées pour le Roy depuis l’année 1670 jusqu’en 1683”.

Paris, Bibliothèque nationale, Département des manuscrits (BnF, Mss.)

Clairambault 566. Documents about the royal academies

Printed works
Aït-Touati, Frédérique. 2011. *Fictions of the Cosmos: Science and Literature in the Seventeenth Century*. Chicago: University of Chicago Press.

Ashworth, William B. Jr. 1994. "The Map of the Moon of Gassendi, Peiresc and Mellan." In *Quadricentenaire de la naissance de Pierre Gassendi, 1592-1992: Actes du colloque international Pierre Gassendi, Digne-Les-Bains, 18-21 Mai 1992*, vol. 2, 341-352. Digne-Les-Bains: Société scientifique et littéraire des Alpes de Haute-Provence.

Ashworth, William B. Jr. 1985. "The Persistent Beast: Recurring Images in Early Zoological Illustration." In *The Natural Sciences and the Arts: Aspects of Interaction from the Renaissance to the 20th Century: An International Symposium*, 46-66. Stockholm: Almqvist & Wiksell.

Aucoc, Léon. 1889. *L'Institut de France: lois, statuts et règlements concernant les anciennes académies et l'Institut, de 1635 à 1889. Tableau des fondations*. Paris: Imprimerie nationale.

Ayala, Lucía. 2014. "Cosmology after Copernicus: Decentralisation of the Sun and the Plurality of Worlds in French Engravings." In *The Making of Copernicus: Early Modern Transformations of the Scientist and His Science*, edited by Wolfgang Neuber, Thomas Rahn, and Claus Zittel, 201-226. Brill: Leiden.

Balfe, Thomas and Joanna Woodall. 2019. "Introduction: From Living Presence to Lively Likeness – the Lives of Ad Vivum." In *Ad Vivum?: Visual Materials and the Vocabulary of Life-Likeness in Europe before 1800*, edited by Thomas Balfe, Joanna Woodall, and Claus Zittel, 1-43. Leiden: Brill.

Bennett, Jim A. 1982. *The Mathematical Science of Christopher Wren*. Cambridge: Cambridge University Press.

Berger, Susanna. 2017. *The Art of Philosophy: Visual Thinking in Europe from the Late Renaissance to the Early Enlightenment*. Princeton: Princeton University Press.

Biagioli, Mario. 2007. *Galileo's Instruments of Credit: Telescopes, Images, Secrecy*. Chicago: University of Chicago Press.
Biagioli, Mario. 1995. "Le prince et les savants: la civilité scientifique au XVIIᵉ siècle." *Annales. Histoire, Sciences Sociales* 50:1417-1453.

Boinet, Amédée. 1924. *Catalogue des oeuvres d'art de la bibliothèque Sainte-Geneviève*. Paris.

Bosmans, Henri F. 1910. "La carte lunaire de Van Langren conservée à l'Université de Leyde." *Revue des questions scientifiques* 67:248-264.

Bosmans, Henri F. 1903. "La carte lunaire de Van Langren conservée aux Archives générales du Royaume, à Bruxelles." *Revue des questions scientifiques* 54:108-139.

Bouhours, Dominique. 1671. *Les entretiens d'Ariste et d'Eugene*. Paris: Sébastien Mabre-Cramoisy.

Bouyre, Claire. 2014. "Vivre et Aller sur la Lune en 1640? Les sciences du vivant dans le discours sur la pluralité des Mondes, à partir de l'œuvre de John Wilkins: *The Discovery of a New World* (1640)." *Bulletin d'histoire et d'épistémologie des sciences de la vie* 21 (1):7-37.

Briggs, Robin. 1991. "The Académie Royale des Sciences and the Pursuit of Utility." *Past & Present* 131 (1):38-88.

Brown, Harcourt. 1934. *Scientific organizations in seventeenth-century France: 1620-1680*. Baltimore: Williams and Wilkins.

Burke, Peter. 1992. *The fabrication of Louis XIV*. New Haven: Yale University Press.

Cassini, Anna. 2003. *Gio. Domenico Cassini: uno scienziato del Seicento: testi e documenti*. Perinaldo: Comune di Perinaldo.

Cassini, Giovanni Domenico. 1693. "De l'origine et du progrés de l'astronomie et de son usage dans la geographie et dans la navigation." In *Recueil d'observations faites en plusieurs voyages par ordre de Sa Majesté, pour perfectionner l'astronomie et la geographie, avec divers traitez astronomiques*, 1-43. Paris: Imprimerie royale.

Cassini, Giovanni Domenico. 1692a. "Avertissement touchant l'observation de l'éclipse de Lune, qui doit arriver la nuit du 28 Juillet prochain." In *Memoires de*
*mathematique et de physique, tirez des registres de l'Académie Royale des Sciences*, 111-112. Paris: Imprimerie royale.

Cassini, Giovanni Domenico. 1692b. "Observations de l'éclipse de Lune du 28 Juillet dernier, avec une Methode pour déterminer les longitudes par diverses observations d'une même éclipse interrompuës & faites en différens lieux." In *Memoires de mathematique et de physique, tirez des registres de l'Académie Royale des Sciences*, 129-134. Paris: Imprimerie royale.

Cassini, Giovanni Domenico. 1673. *Découverte de deux nouvelles planetes autour de Saturne*. Paris: Sébastien Mabre-Cramoisy.

Cassini, Jean-Dominique. 1810. *Mémoires pour servir à l'histoire des science, et à celle de l'Observatoire Royal de Paris*. Paris: Bleuet.

Castex, Jean-Gérald, ed. 2019. *Graver pour le roi: collections historiques de la chalcographie du Louvre*. Paris: LienArt; Louvre éditions.

Chapin, Seymour L. 1957. "The Astronomical Activities of Nicolas Claude Fabri de Peiresc." *Isis* 48:13-29.

Cohen, I. Bernard. 1980. "The Influence of Theoretical Perspective on the Interpretation of Sense Data: Tycho Brahe and the New Star of 1572, and Galileo and the Mountains on the Moon." *Annali dell'Istituto e Museo di storia della scienza di Firenze* 5:3-14.

Colbert, Jean-Baptiste, 1861-1882. *Lettres, instructions, et mémoires de Colbert*. 10 vols. Edited by Pierre Clément. Paris: Imprimerie impériale.

Daston, Lorraine. 2015. "Epistemic Images." In *Vision and Its Instruments: Art, Science, and Technology in Early Modern Europe*, edited by Alina Payne, 13-35. University Park: Penn State University Press.

Daston, Lorraine. 2014. "The Synoptic Scientific Image in Early Modern Europe." *Archives des sciences* 67:159-174.

Daston, Lorraine. 1995. "Curiosity in early modern science." *Word & Image* 11:391-404.

Daston, Lorraine and Peter Galison. 2007. *Objectivity*. New York: Zone Books.

Daston, Lorraine and Katherine Park. 1998. *Wonders and the order of nature: 1150-1750*. New York: Zone Books.
Deias, Dalia. 2024. "Portrait d'un savant royal au fil des siècles: essai biobibliographique sur Giovanni Domenico Cassini (1625-1712)." *Archives internationales d'histoire des sciences* (forthcoming).

Deutsch, Kristina. 2015. *Jean Marot. Un graveur d'architecture à l'époque de Louis XIV*. Berlin: De Gruyter.

Ditzen, Stefan. 2015. "Instrument-Aided Vision and the Imagination: The Migration of Worms and Dragons in Early Microscopy." In *The Technical Image*, edited by Horst Bredekamp, Vera Dünkel, and Birgit Schneider, 130-137. Chicago: University of Chicago Press.

Doherty, Meghan C. 2022. *Engraving Accuracy in Early Modern England: Visual Communication and the Royal Society*. Amsterdam: Amsterdam University Press.

Doherty, Meghan C. 2012. "Discovering the 'true form:' Hooke's Micrographia and the visual vocabulary of engraved portraits." *Notes and Records of the Royal Society* 66:211-234.

Duverney, Joseph-Guichard. 1761. *Oeuvres anatomiques*. Paris: Charles-Antoine Jombert.

Ferrier-Caverivière, Nicole. 1981. *L'image de Louis XIV dans la littérature française de 1660 à 1715*. Paris: Presses universitaires de France.

Findlen, Paula. 1990. "Jokes of Nature and Jokes of Knowledge: The Playfulness of Scientific Discourse in Early Modern Europe." *Renaissance Quarterly* 43:292-331.

Flammarion, Camille. 1891. "Une tête de femme dans la lune." *L'Astronomie: Revue d'astronomie populaire* 10:454-459.

Flamsteed, John, 1995-2002. *The Correspondence of John Flamsteed, The First Astronomer Royal*, 3 vols. Edited by Eric G. Forbes, Lesley Murdin, and Frances Willmoth. Bristol: Bristol Institute of Physics.

Fontenelle, Bernard Le Bouyer de. 1733. *Histoire de l'Académie royale des sciences. Depuis son établissement en 1666 jusqu'en 1686* [vol. 1]. *Depuis 1686 jusqu'à son renouvellement en 1699* [vol. 2], 2 vols. Paris: Gabriel Martin; Jean-Baptiste Coignard; Hippolyte-Louis Guerin.
Fontenelle, Bernard Le Bouyer de. 1699. "Preface." *Histoire de l'Académie royale des sciences. Année MDCXCIX. Avec les Memoires de Mathématique & de Physique pour la même Année tirez des registres de cette Académie*, i-xix.

Fontenelle, Bernard Le Bouyer de. 1687. *Entretiens sur la pluralité des mondes*. Nouvelle edition, augmentée d'un nouvel entretien*. Paris: Michel Guerout.

Freedberg, David. 2002. *The Eye of the Lynx: Galileo, his Friends, and the Beginnings of Modern Natural History*. Chicago: University of Chicago Press.

Gallay, Antoine. 2024. "The Supervision of Draughtsmen and Printmakers in the Early Académie Royale des Sciences in Paris". In *Images and Institutions: The Visual Culture of Early Modern Scientific Societies*, edited by Matthijs Jonker and Katherine M. Reinhart. Turnhout: Brepols (forthcoming).

Gallay, Antoine. 2023. "Un nouveau regard sur la nature? La professionnalisation des dessinateurs de l'Académie royale de sciences et l'évolution des modes de représentation en histoire naturelle (1670-1710)". In *Faire et défaire les savoirs. Frontières épistémiques sur le métier (XVIe-XVIIe siècles)*, edited by Yasmine Atlas, Adrien Mangili, and Dorine Rouiller, 155-180. Genève: Droz.

Gallay, Antoine. 2021. "Sébastien Le Clerc (1637-1714). Entre arts et sciences: les ambitions d'un graveur au siècle de Louis XIV." PhD diss., University of Geneva; University Paris-Nanterre.

Garrett, Brian J. 2009. "Wonder Among Cartesians and Natural Magicians." In *Topics in Early Modern Philosophy of Mind, Studies in the History of Philosophy of Mind*, edited by Jon Miller, 39-55. Dordrecht: Springer.

Gassendi, Pierre, 1657. *The Mirrour of True Nobility and Gentility, Being the Life of the Renowned Nicolas Claudius Fabricius, Lord of Peiresk*. Translated by William Rand. London: J. Streater.

Grivel, Marianne. 2010. "Ouvrages, volumes ou recueil? La constitution du recueil du Cabinet du Roi." In *À l'origine du livre d'art: les recueils d'estampes comme entreprise éditoriale en Europe, XVIe-XVIIIe siècle*, edited by Cordélia Hattori and others, 65-79. Milan: Silvana.

Grivel, Marianne. 1985. "Le Cabinet du Roi." *Revue de la Bibliothèque Nationale* 18:36-57.
Guerrini, Anita. 2019. "Counterfeit Bodies: Sébastien Leclerc, Anatomy, and the Art of Copying at the Paris Academy of Sciences." *Word & Image* 35:277–295.

Guerrini, Anita. 2015. *The Courtiers' Anatomists: Animals and Humans in Louis XIV's Paris*. Chicago: University of Chicago Press.

Guerrini, Anita. 2010. "The King's Animals and the King's Books: The Illustrations for the Paris Academy's *Histoire des Animaux*." *Annals of Science* 67:383–404.

Guiffrey, Jules J., ed. 1881–1901. *Comptes des bâtiments du roi sous le règne de Louis XIV*, 5 vols. Paris: Imprimerie nationale.

Haddad, Thomas A. S. 2019. *Maps of the Moon: Lunar Cartography from the Seventeenth Century to the Space Age*. Leiden: Brill.

Hahn, Roger. 1971. *The Anatomy of a Scientific Institution: The Paris Academy of Sciences, 1666-1803*. Berkeley; Los Angeles: University of California Press.

Halley, Edmund. 1932. *Correspondence and Papers of Edmond Halley, Preceded by an Unpublished Memoir of his Life by One of his Contemporaries and the “Eloge”, by d’Ortous de Mairan*. Edited by Eugene Fairfield McPike. Oxford: Clarendon.

Hallyn, Fernand and William Shea. 2000. "Looking at the Moon as another Earth. Terrestrial Analogies and Seventeenth-Century Telescopes." In *Metaphor and Analogy in the Sciences*, edited by Fernand Hallyn, 83–104. Dordrecht: Kluwer Academic Publishers.

Hamou, Philippe, 1999-2001. *La mutation du visible: essai sur la portée épistémologique des instruments d'optique au XVIIe siècle*, 2 vols. Villeneuve-d'Ascq: Presses universitaire du Septentrion.

Harrison, Peter. 2001. "Curiosity, Forbidden Knowledge, and the Reformation of Natural Philosophy in Early Modern England." *Isis* 92:265–290.

Hartsoeker, Nicolas. 1694. *Essay de dioptrique*. Paris: Jean Anisson.

Heilbron, John L. 1999. *The Sun in the Church: Cathedrals as Solar Observatories*. Cambridge, MA: Harvard University Press.

Henderson, Felicity. 2019. "Robert Hooke and the Visual World of the Early Royal Society." *Perspectives on Science* 27:395–434.
Hevelius, Johannes. 1647. *Selenographia, sive Lunae descriptio*. Danzig: Hünefelde.

Hirschfield, John M. 1981. *The Académie Royale des Sciences, 1666–1683*. New York: Arno Press.

Hooke, Robert. 1665. *Micrographia, or Some Physiological Descriptions of Minute Bodies Made by Magnifying Glasses: with Observations and Inquiries thereupon*. London: John Martyn and James Alestry.

Humbert, Pierre. 1931. "La première carte de la Lune." *Revue des questions scientifiques* 100:193-204.

Hunter, Matthew C. 2013. *Wicked Intelligence: Visual Art and the Science of Experiment in Restoration London*. Chicago: University of Chicago Press.

Hutchinson, Keith. 1987. "Towards a Political Iconology of the Copernican Revolution." In *Astrology, Science and Society. Historical Essays*, edited by Patrick Curry, 95-141. Woodbridge: Boydell Press.

Huygens, Christiaan. 1888-1950. *Œuvres complètes de Christiaan Huygens*, 23 vols. The Hague: M. Nijhoff.

Janson, Horst W. 1961. "The 'Image made by Chance' in Renaissance Thought." In *Essays in Honor of Erwin Panofsky*, edited by Milliard Meiss, 55-74. New York: New York University Press.

Joblot, Louis. 1718. *Descriptions et usages de plusieurs nouveaux microscopes tant simples que composez, avec de nouvelles observations faites sur de multitude innombrable d'insectes, et d'autres animaux de diverses espèces qui naissent dans des liqueurs préparées, et dans celles qui ne le sont point*. Paris: J. Collombat.

Kemp, Martin. 1993. "The Mark of the Truth: Looking and Learning some Anatomical Illustrations from the Renaissance and Eighteenth Century." In *Medicine and the Five Senses*, edited by William F. Bynum, 85-122, 294-297. Cambridge: Cambridge University Press.

Kopal Zdeněk and Robert W. Carder. 1974. *Mapping of the Moon: Past and Present*. Dordrecht: Reidel.

Kusukawa, Sachiko. 2019. "The Early Royal Society and Visual Culture." *Perspectives on Science* 27 (3):350-394.
Kusukawa, Sachiko. 2015. "Drawing as an Instrument of Knowledge: The Case of Conrad Gessner." In *Vision and Its Instruments: Art, Science, and Technology in Early Modern Europe*, edited by Alina Payne, 36–48. University Park, Pennsylvania: Penn State University Press.

Kusukawa, Sachiko. 2012. *Picturing the Book of Nature: Image, Text, and Argument in Sixteenth-Century Human Anatomy and Medical Botany*. Chicago: University of Chicago Press.

Kusukawa, Sachiko. 2000. The *Historia Piscium* (1686). *Notes and Records of the Royal Society of London* 54:179–197.

La Fontaine, Jean de. 1991. *Oeuvres complètes*, 2 vols. Edited by Jean-Pierre Collinet and Pierre Clarac. Gallimard, Paris.

La Hire, Philippe de. 1706. "Reflexions sur les apparences du corps de la Lune." *Histoire de l'Academie royale des sciences. Année MDCCVI. Avec les Memoires de Mathématique & de Physique pour la meme Année tirez des registres de cette Academie*, 107–113.

La Lande, Jérôme de. 1792. *Astronomie*, 3 vols. Paris: Veuve Desaint.

Launay, Françoise. 2003. "La tête de femme de la carte de la Lune de Cassini : une déclaration d'amour de Jean-Dominique Cassini (1625-1712) à son épouse Geneviève de Laistre (1643-1708)?" *L'Astronomie: bulletin de la Société astronomique de France* 117:10–19.

Launay, Françoise and William Sheehan. 2010. "The Mysterious Lady on the Moon. Is the Moon Maiden on Cassini's famous 1679 Moon Map an Astronomer's Secret Declaration of Love?" *Sky & Telescope* 120:26–30.

Le Lorrain de Vallemont, Pierre. 1696. *Les Élémens de l'histoire, ou Ce qu'il faut savoir de chronologie, de géographie, de blazon, de l'histoire universelle, des monarchies anciennes et des monarchies nouvelles, avant que de lire l'histoire particulière*. Paris: Jean Anisson.

Leibniz, Gottfried Wilhelm. 1923–[ongoing]. *Sämtliche Schriften und Briefe*. Darmstadt: O. Reichl; Berlin: Akademie Verlag.
Lesage Gárriga, Luisa. 2021. *Plutarch: "On the Face which Appears in the Orb of the Moon": Introduction, Edition, English Translation, and Commentary to the Critical Edition*. Leiden: Brill.

Licoppe, Christian. 1994. "The Crystallization of a New Narrative Form in Experimental Reports (1660–1690): The Experimental Evidence as a Transaction between Philosophical Knowledge and Aristocratic Power." *Science in Context* 7:205–244.

Lüthy, Christoph. 2006. "Where Logical Necessity Becomes Visual Persuasion: Descartes's Clear and Distinct Illustrations." In *Transmitting Knowledge: Words, Images, And Instruments in Early Modern Europe*, edited by Sachiko Kusukawa and Ian MacLean, 97–133. Oxford: Oxford University Press.

Lux, David S., 1990. "Colbert's Plan for the Grande Académie: Royal Policy Toward Science, 1663–67." *Seventeenth-Century French Studies* 12:177–188.

Maindron, Ernest. 1888. *L'Académie des sciences*. Paris: F. Alcan.

Malebranche, Nicolas. [1674] 1997. *The Search after Truth*. Translated and edited by Thomas M. Lennon and Paul J. Olscamp. Cambridge: Cambridge University Press.

Mallon, Andrew. 1983. *Science and Government in France, 1661–1699. Changing Patterns of Scientific Research and Development*. Belfast: Queen's University.

Marr, Alexander. 2016. "Knowing Images." *Renaissance Quarterly* 69:1000–1013.

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Figures

<figure><img src="image_1.png" /><figcaption>Figure 1. Giovanni Domenico Cassini, *Grand Selenography*, 1679. Engraving, 560 × 730 mm. Paris, Bibliothèque de l'Observatoire de Paris, Inv.I.1576 (© Observatoire de Paris)</figcaption></figure>
<figure><img src="image_2.png" /><figcaption>Figure 2. The female profile in the Promontorium Heraclides (detail of Figure 1)</figcaption></figure>
<figure><img src="image_3.png" /></figure>

Figure 3. Jean Patigny, drawing of the oriental part of the moon based on several observations between 1677 and 1678. Black chalk and white chalk on blue paper, 17 × 12 mm. Paris, Bibliothèque de l'Observatoire de Paris, D6/40, fol. 27 (© Observatoire de Paris).
<figure><img src="image_4.png" /><figcaption>Figure 4. Jean Patigny, drawing of the crater Kepler made on 22 September 1673. Black chalk and white chalk on blue paper, 1573 × 22 September mm. Paris, Bibliothèque de l'Observatoire de Paris, D6/40, fol. 6 (© Observatoire de Paris).</figcaption></figure>
<figure><img src="image_5.png" /></figure>

Figure 5. Jean Patigny, drawing of the Promontorium Heraclides based on several observations made in 1676. Black chalk and white chalk on blue paper, 6 × 7 mm. Paris, Bibliothèque de l'Observatoire de Paris, D6/40, fol. 13 (© Observatoire de Paris).
<figure><img src="image_6.png" /></figure>

Figure 6. Jean Patigny, drawing of the Promontorium Heraclides made in 1678. Black chalk and white chalk on blue paper, 11 × 16 mm. Paris, Bibliothèque de l'Observatoire de Paris, D6/40, fol. 22 (© Observatoire de Paris).
<figure><img src="image_7.png" /></figure>

Figure 7. Jean Patigny, drawing of the full moon made in 1675. Black chalk and white chalk on blue paper, 16 × 12 mm. Paris, Bibliothèque de l'Observatoire de Paris, D6/40, fol. 56 (© Observatoire de Paris).
<figure><img src="image_8.png" /><figcaption>Figure 8. Claude Mellan, *A Waxing Gibbous Moon Observed on 7 October 1635*. Engraving, 234 × 173 mm. Abbeville, Musée Boucher-de-Perthes, M378 (© Musée Boucher-de-Perthes, Abbeville).</figcaption></figure>
<figure><img src="image_9.png" /><figcaption>Figure 9. Michael Van Langren, *Map of the Moon*, 1645. Engraving, 500 × 380 mm. Paris, Bibliothèque nationale, Cartes et plans, GE D–17925 (© BnF).</figcaption></figure>
<figure><img src="image_10.png" /><figcaption>Figure 10. Unknown artist after Francesco Maria Grimaldi, *Map of the Moon* for Giovanni Battista Riccioli’s *Almagestum Novum* (Bologna, 1651). Engraving, 10 × 8 mm. Zurich, ETH Library, Rar 9471 (© ETH Zurich).</figcaption></figure>
<figure><img src="image_11.png" /><figcaption>Figure 11. Johannes Hevelius, *Map of the Moon* for his *Selenographia* (Danzig, 1647). Engraving, 10 × 8 mm. Paris, Bibliothèque nationale, Impr., Rés., G-V-508 (© BnF).</figcaption></figure>
<figure><img src="image_12.png" /><figcaption>Figure 12. Unknown artist, after Giovanni Domenico Cassini, *Full Moon for the Memoires de mathematique et de physique tirez des registres de l'Académie Royale des Sciences* (Paris, 1692). Engraving, 7 × 5 mm. Munich, Bayerische Staatsbibliothek, 4 Math.u. 70-1692/93 (© BSB).</figcaption></figure>
<figure><img src="image_13.png" /><figcaption>Figure 13. Unknown artist, after Giovanni Domenico Cassini, *Schematized Figure of the Full Moon* for the *Memoires de mathematique et de physique tirez des registres de l'Académie Royale des Sciences* (Paris, 1692). Engraving, 2 × 3 mm.
Munich, Bayerische Staatsbibliothek, 4 Math.u. 70-1692/93 (© BSB).</figcaption></figure>
<figure><img src="image_14.png" /><figcaption>Figure 14. Unknown artist, after Robert Hooke, *The Figures of Hipparchus*
*Observed by Hooke, Hevelius (Fig. X) and Riccioli (Fig. Y) for the Micrographia*
(London, 1665). Engraving, 1 × 1 mm. Bethesda, National Library of Medicine,
inv. 2366075R (Courtesy of the National Library of Medicine).</figcaption></figure>
<figure><img src="image_15.png" /><figcaption>Figure 15. Abraham Bosse, *Mandragora*. Etching, × 1 mm. London, Wellcome Collection, EPB/F/837 (B 380) (public domain license).</figcaption></figure>
<figure><img src="image_16.png" /><figcaption>Figure 16. Unknown artist, *Figure of an Animalcule with a Human Figure* for Louis Joblot's *Descriptions et usages de plusieurs nouveaux microscopes tant simples que composez* (Paris, 1718). Etching and engraving, 7 × 5 mm. Paris, Bibliothèque nationale, Impr., Rés., V-7411 (© BnF).</figcaption></figure>
<figure><img src="image_17.png" /><figcaption>Figure 17. Bernard Picart, *The globe of the moon*, for Fontenelle’s *Œuvres diverses* (The Hague, 1728–1729). Etching and engraving, 10 × 7 mm, Paris, Bibliothèque nationale, Est., AA–2 (Picart, Bernard) (© BnF).</figcaption></figure>