Producing Knowledge in Early Modern Rome: Concepts and Practices of Disegno in the Accademia di San Luca and the Accademia dei Lincei

This article offers new insights into the relationship between science and art in the early modern period by focusing on the concepts and practices of disegno (meaning a physical drawing or a mental design) in two Roman academies around 1600: the Accademia di San Luca and the Accademia dei Lincei. The first president of the Accademia di San Luca, Federico Zuccari, developed an elaborate theory of art that centered on the concept of disegno. More than other contemporary art theorists, Zuccari explicitly connected the process of artistic production to that of knowledge acquisition, and he described his theory of disegno as belonging to natural philosophy. The first part of the article provides a more profound interpretation of the relationship between the theoretical and the practical parts of Zuccari’s theory than has hitherto been given. His views of the relationship between knowledge acquisition and artistic production play a central role in this interpretation. The second part shows how his theory of disegno informed his ideas for the step-by-step training program of the Accademia di San Luca. In the third part, Zuccari’s theory of art is used to analyze the functions of the disegni (drawings, woodcuts, and engravings) and the artists the Accademia dei Lincei employed for its scientific projects in the first half of the seventeenth century. Seen through the lens of Zuccari’s theory, it is possible to understand the images as well as the artists themselves as instruments in the Lincean investigation of nature and to explain the different categories— academic or non-academic—used to distinguish among the different levels of proficiency that artists could attain.

Our understanding of the intimate relationship between the sciences and the visual arts in the early modern period has greatly improved over the past three decades. An ever growing number of publications by scholars working on the boundary between the history of science and art history have elucidated the various epistemic functions of images in processes of knowledge production and dissemination. 1 Sachiko Kusukawa and Lorraine Daston have shown, for instance, that early modern botanists, zoologists, and physicians used drawings and prints as visual narratives to prove an argument or the existence of a species, as substitutes for the objects described, or as mnemonic aids. 2 However, what have not hitherto received sufficient attention in this burgeoning interdisciplinary field are the roles of art theory, art education, and the division of labor within the science-art relationship in the early modern period. 3 This article addresses these points by offering an in-depth analysis of the concept 1 For a substantial but not exhaustive analytical overview of the literature, see Marr, "Knowing Images." 2 Kusukawa, "Uses of Pictures"; Dackerman, "Introduction"; Daston, "Epistemic Images." 3 For an analysis that includes early modern (Spanish) art theory, see Marcaída López, Arte e Ciencia, 180-92.
Jonker, Matthijs. "Producing Knowledge in Early Modern Rome: Concepts and Practices of Disegno in the Accademia di San Luca and the Accademia dei Lincei." Journal for the History of Knowledge 2, no. 1 (2021): 3, pp. 1-15. DOI: https://doi.org/10.5334/jhk.8 Cardinal Francesco Maria del Monte (1549Monte ( -1626, who was the official protector of the Accademia di San Luca from 1595-1626, included the Linceans Cesi, Johannes Faber (1574-1629, and Cassiano dal Pozzo (1588-1657) as well as academic artists, such as Antonio Tempesta (1555-1630), Filippo Napoletano (1589-1629), and Francesco Villamena (1566-1625. 12 More concretely, when Cigoli arrived in Rome to work for the pope in 1604, he joined the Accademia di San Luca and gave a lecture on disegno. 13 Eight years later, Cigoli advised the Lincei on how to improve the engravings for Galileo's book on the sunspots. 14 Such overlaps in academic networks make it highly likely that they were aware of Zuccari's theory of disegno.
The third and most important reason for connecting these academies with each other is the fact that the Lincei made extensive use of disegni and disegnatori (draftsmen) in their scientific projects. Federico Cesi and his colleagues Johannes van Heeck (b. 1579), Francesco Stelluti (1577-1652), and Fabio Colonna (1567-1640 were themselves able amateur draftsmen. 15 Moreover, they commissioned thousands of drawings and prints from professional artists, some of whom were members of or had connections to the Accademia di San Luca. This was the case, for instance, for Tempesta, Villamena, andGiovanna Garzoni (1600-1670). 16 Others, such as Vincenzo Leonardi (1589Leonardi ( /90-1646 and Giorgio Nuvolostella, do not seem to have had any relations with the Roman art institution.
The twofold aim of this article is, first, to provide a more profound interpretation of the relationship between the theoretical and the practical parts of both Zuccari's theory and his academic curriculum than has hitherto been given. His views on the relationship between knowledge acquisition and artistic production play a central role in this interpretation. The second aim is to use this interpretation for improving our understanding of the functions of both the images and the artists involved in the Lincei's knowledge practices. Seen through the lens of Zuccari's theory, it is possible to understand both as instruments in the Lincean investigation of nature and to explain why Cesi and his colleagues used different categoriesacademic or non-academic-of artists for different parts of their graphical production.

Disegno interno and esterno
Past interpretations of Zuccari's theory of art have focused almost exclusively on Idea and sought to determine his place within the history of art theory. This approach has led to the generally accepted view that Zuccari's theory is simultaneously derivative and innovative: although drawing heavily on Aristotelian-Thomistic faculty psychology and epistemology, his linking of these traditional doctrines to the concept of disegno marks an important moment in the history of art theory and in the social history of art. 17 The focus on Idea by previous scholars, however, has obfuscated how Zuccari envisioned the relation between disegno as an intellectual activity and a mental image (disegno interno) on the one hand, and as a material drawing or sketch created by an artist (disegno esterno) on the other. An analysis of Alberti's Origine allows us to more fully appreciate the centrality of this aspect of Zuccari's theory. Furthermore, Alberti's narrative makes it possible to come to a more profound understanding of the theory's practical consequences.
The first meeting of the Accademia di San Luca was held on 14 November 1593. On this occasion, Zuccari presented his proposal for the institution's educational program. It consisted of two parts: an hour of theory in which the academicians would give lectures on and hold debates about their arts and an hour of practice in which students would learn how to draw. 18 In the ensuing months, several artists gave lectures at the academy on topics related to their professions. Zuccari himself gave a lecture that, not surprisingly, was on disegno.
The central question Zuccari posed in his lecture for the Accademia di San Luca-as in his theory generally-was how disegno is formed. Like previous art theorists, such as Vincenzo Danti (1530Danti ( -1576 12 Solinas, "Pittura filosofica," 259; Jonker, "Accademia dei Lincei's network," 29-30. 13 Unfortunately, the description of the content of Cigoli's lecture by his nephew and biographer, Giovanni Battista Cardi (Cardi,Vita di Lodovico Cardi,33), is very brief. However, Cigoli's characterization of disegno as fundamental to all human activities is identical to Zuccari's general description of disegno in his lectures at the academy a decade earlier. 14 Gabrieli,Carteggio linceo,(no. 176). 15 Gabrieli,Carteggio linceo,); Tognoni, "Nature Described"; Solinas, "Cassiano dal Pozzo," 126; Solinas, "Osservazione," 231-32. 16 McBurney, "So Many Celestial Animals," 60-65. 17 The key publications on Zuccari's theory of art are Panofsky, Idea; Rossi, "Idea e accademia"; Kemp "Disegno"; Summers, Judgment of Sense; and Williams Art, Theory, and Culture. Exceptions to the purely theoretical interpretation of Zuccari's notion of disegno can be found in Pfisterer, "Entstehung des Kunstwerks"; Fowler, Drawing and the Senses, 90-97. However, neither author links Zuccari's theory of art to the curriculum in the early years of the Accademia di San Luca. 18 Alberti, "Origine," 16-17. and Giorgio Vasari (1511Vasari ( -1574, Zuccari based his explanation of the formation of disegno on Aristotle's De Anima. However, his explication was much more elaborate, consistent, and innovative than that of his predecessors. 19 In his lecture, he described how the human mind forms concepts and obtains knowledge about and understanding of objects in the external world and how it, in turn, imparts or causes one to act and produce any kind of object in the world. In this part of the lecture, Zuccari shows his adherence to an empiricist philosophy of knowledge. Zuccari first noted that there is nothing in the intellect that was not first in the senses, and he even calls the intellect a "blank slate" (tavola rasa). 20 He argued that an individual acquires knowledge or forms a concept of something through the help of his or her senses. He called these senses "our instruments or ministers." They contribute to the process of knowledge acquisition by receiving the "Form" of a thing and, subsequently, by transferring this Form from the external to the internal, or "secret," senses. In the internal senses, the Form is "illuminated" and given "colors" by the intellect, and a mental image or concept is constructed. 21 This is what Zuccari called the disegno interno speculativo (internal speculative design). 22 Here, the term speculativo refers to the knowing faculty of the human mind, and its goal is to understand universals (Figure 1). 23 Zuccari distinguished the disegno interno speculativo from the disegno interno pratico (internal practical design). The latter is also internal because it is the principle and the model in the mind that instigates the actions and the objects a person produces in the external world. 24 Zuccari again described the senses and the body as instruments, and in this case they are used for the production of the disegni esterni (external designs). The disegno esterno can be broadly defined as any visible shape or figure that expresses the inner Form, or essence, of a thing. Connecting it more specifically to the activity of drawing, Zuccari held that disegno esterno is created on paper by circumscribing a figure with a simple line-that is, without rendering the corporeal substance using shadows. 25 Thus, Zuccari contended that the process of artistic production was the exact reverse and counterpart of the process of knowledge acquisition (Figure 2). In the first process, the Form of an external object moves from the disegno esterno through the senses to the disegno interno speculativo (Figure 1); in the second process, it moves from the disegno interno pratico through the senses to the disegno esterno (Figure 2). In other words, the artist's understanding is necessary for rendering an accurate depiction, and the resulting depiction, in turn, augments his understanding.
The relation between the inner and the outer, the mind and the body was central to Zuccari's conception of disegno. Whereas disegno interno speculativo is both the active principle (primo motore) and the resulting mental image of the process of knowledge acquisition, disegno interno pratico is simultaneously the active 19 Danti, "Primo libro"; Vasari, Vite. For a discussion and comparison of these and other contemporary theoretical treatises written by artists, see Jonker, "Academization of Art," 315-75. 20 Alberti, "Origine," 33. Cf. Zuccari, "Idea," 172-73, 175-76, and 266, where Zuccari gives a similar description of the process and calls the intellect a "wide and clean canvas" (ampio, e polito quadro) instead of a tavola rasa. 21 Alberti, "Origine," 33-34. In fact, the matter is somewhat more complicated. Following Aristotle in De Anima, Zuccari distinguished the active from the potential intellect, i.e., the intellect as principle or cause from the intellect as model or mental image. In "Idea," 171-85, Zuccari discussed the processes of concept formation and artistic production in a more complex and detailed way but essentially in a similar fashion. According to Fowler (Drawing and the Senses, 86-90), this Aristotelian scheme regained popularity in the seventeenth century after the publication of Zuccari's Idea. 22 Alberti, "Origine," 34. See Zuccari, "Idea," 153-55 for Zuccari's conception of disegno as a mental image. 23 Alberti, "Origine," 31. Cf. Zuccari, "Idea," 163. 24 Alberti, "Origine," 31. Cf. Zuccari, "Idea," 167-71. 25 Alberti, "Origine," 31. principle and the mental model in the process of artistic production. 26 For instance-and elaborating on one of Zuccari's examples in Idea-after drawing several lions from nature, the universal concept, or disegno interno speculativo, of "the lion" is formed in the artist's mind. Subsequently, he can use this concept as the model, or disegno interno pratico, for drawing a particular lion-that is, disegno esterno-as a preliminary sketch for a work of art. Zuccari acknowledged that artistic products can also be based on mental images that are formed in the fantasy (fantasia) of the artist (for example, when he mixes concepts or construes images that have no counterpart in reality) and are thus not based on the direct observation of external reality. In Idea, Zuccari used the example of grotesques, painted decorations representing hybrid and mythological figures, for images formed in this way. 27 As Sergio Rossi and Robert Williams have pointed out, Zuccari's main theoretical achievement and innovation consisted in subsuming the processes of knowledge acquisition and artistic production under the artistic term disegno. 28 In doing so, he made Aristotle's theory not only applicable to visual artists, but he also hailed painters, sculptors, and architects as the professori-as he called them-who were the best equipped to carry out these processes of knowledge acquisition and artistic production. 29 In contrast to philosophers and theologians on the one hand, and to artisans on the other, Zuccari contended that artists combine and balance the equally necessary intellectual and practical sides of man. 30 What scholars have failed to illuminate until now, however, is how Zuccari's theory of disegno was connected to his outline and implementation of the Accademia di San Luca's curriculum during his presidency.

Zuccari's disegno and curriculum for the Accademia di San Luca
Zuccari specified his ideas for the practical training program of the Accademia di San Luca during its second meeting on 28 November 1593. 31 To make the most of the hour of practical training, the president ordered that four groups, or capate, be formed to teach the different stages of disegno, each associated with different skill levels. In ascending order of proficiency, Zuccari described each of the groups' exercises as follows. In the first group, the student would learn to copy (copiassero) the individual body parts, that is, the eyes, noses, mouths, etc. drawn by the academicians who functioned as teachers. 32 In the second group, he would learn to portray or retrace cartoons and reliefs (ritrare cartoni e rilievi). Zuccari believed that there already was a respectable collection of such objects in the academy. A document in the archive of the Accademia di San Luca containing the names of artists and the drawings, engravings, and plaster casts they donated for educational purposes confirms this. 33 In the third group, the student would learn to copy the works of the great masters (copiasse da opere di valent'huomini). In one of the speeches in which Zuccari presented 26 Ibid., 34. 27 Zuccari, "Idea," 240. See 153-54 for the example of the lion. 28 Rossi, "Idea e accademia," 48; Williams,Art,Theory,and Culture,148. 29 Zuccari, "Idea," 182 uses the term professori (or comprofessori) to refer to his fellow artists and, presumably, especially to those who are masters of disegno and have their own workshop. Moreover, he refers to painting, sculpture, and architecture as "professions" (professioni). 30 Thereby, Zuccari also implied that artists are the human beings who bear the closest resemblance to God insofar as their disegno reflects and resembles the unity of understanding and creation in God. However, he admitted that metaphysicians and theologians contemplate higher and more divine things. See Alberti, "Origine," 32-34 for Zuccari's comparison of God to the human soul in general and to that of the painter in particular. See Zuccari, "Idea," 297-99 for his remarks on the status of theologians and metaphysicians. 31 Alberti, "Origine," 22-23. 32 Ibid., 17. 33 AASL Inventari 1, 1. For a transcription of this document, titled "Cose donate all'Accademia 1594," see Lukehart, Accademia Seminars, 368.

Figure 2:
The process of artistic production according to Federico Zuccari.
his pedagogical ideas to the members at the academy, he cited Polidoro da Caravaggio as an example of a valentuomo whose work was worthy of being copied. 34 Since the institution appears not to have had an elaborate collection of completed masterpieces, 35 the drawing exercises in the third group must have taken place predominantly in churches, squares, and the collections of prelates and aristocrats in Rome rather than in the academy. In the fourth and final capata, the student would learn to create his own works and produce realistic compositions from his imagination without using a model. The levels through which students at the academy must pass to improve their mastery of disegno were set out in a particular order. Successfully completing the first capata meant that they were able to mimetically render two-dimensional images on a two-dimensional surface. Upon completing the second and third groups, they were able to render three-dimensional objects and compositions made by other artists in two dimensions. Finally, upon completing the fourth group, they could realistically create their own compositions on paper from his imagination. Once they arrived at this stage, they had completed their artistic training and acquired the skill level of a master artist. 36 At this point, they were ready to execute public commissions based on their own disegni or invenzioni for the Church or civic government. Pietro Roccasecca has noted that different terms were used to describe the drawing exercises in Zuccari's capate. 37 The beginners in the first group had to copiare the examples provided by the professors; students in the second capate learned to ritrare cartoni e relievi; those in the third group learned to copiasse da opere di valent'huomini; and, in the fourth level, students studied how to fare dissegni, & inventioni. Thus, the verbs copiare, ritrar[r]e, and disegnare (or fare un disegno) denoted the different skills learned at each level.
Relying on the contemporary Italian dictionary, the Vocabolario della Crusca (1612), Roccasecca has argued convincingly that these terms marked the cognitive differences among the stages of learning disegno. For example, copiare referred to the completely mechanical operation of making a copy of something-that is, of a text, drawing, sculpture, etc. Like copiare, the term ritrarre signified "making a copy" or "rendering something." But unlike copiare, ritrarre also denoted the act of observing and describing nature, which produces an impression of nature in the mind. 38 Finally, disegnare was described even more fully as an intellectual activity, the purpose of which was to create a composition, for example, for artistic, scientific, or technical projects.
Roccasecca's interpretation of the terms Zuccari used to refer to the different stages of the curriculum shows that, in the eyes of the first president of the Accademia di San Luca, one had to accumulate quite a lot of intellectual and cognitive skills to become an expert draftsman. Romano Alberti's descriptions of the meetings during the first years of the academy's existence as well as archival documents pertaining to its educational activities during the same period reveal that Zuccari's program was at least partially realized. 39 This means that students participating in the artistic-educational practices of the Accademia di San Luca would have progressed from learning mechanical skills to developing their cognitive abilities.
By connecting Zuccari's educational program to his double-layered notion of disegno, as described in Alberti's Origine, it is possible to take a further step and move beyond Roccasecca's interpretation. 40 For Zuccari, the goals of the theoretical education, that is, the lectures and debates, were to train, form, and improve the disegno interno-both intellectual and practical-of the artist. These goals, in turn, suggest that the first three stages of disegno-taught in the first three capate of the practical education-were designed to be a step-by-step training program in which students learned to extract the Forms of objects in the external world with the help of their drawing pens, which Zuccari described as extensions of their senses, especially, but not exclusively, sight. To reiterate, in the first three capate, students learned how to copy individual body parts, reliefs and plaster casts, and works by past masters, respectively. Through this process, students learned how to obtain the disegni esterni from the objects in the outer world by repeatedly copying them and turning them into disegni interni speculativi, thereby enhancing their understanding of the external 34 Alberti, "Origine," 19. 35 This can be inferred from the academy's inventories from 1624 and 1627. ASR, TNC, uff. 15, 1624, pt. 4, vol. 102, fol. 211v andASR, TNC, uff. 15, 1627, pt. 3, vol. 113, fols. 27r. 36 See Fowler, Drawing and the Senses, 79, for a similar conclusion about the goal of pedagogies of drawing in the early modern period. 37 Roccasecca,"Teaching, In his treatise on disegno from around 1565, Vincenzo Danti ("Primo libro," 235-36) gave a more mechanical interpretation of ritrarre in which he opposed it to the more intellectual drawing activity of imitare, which he described as perfecting nature where it is imperfect. 39 Roccasecca, "Teaching"; Jonker, "Academization of Art," 291-313. 40 The following interpretation of Zuccari's lectures as developing an artist's disegno interno and his drawing exercises, disegno esterno is hinted at-but not elaborated on-by Roccasecca in "Teaching," 125.
world. In the fourth and highest stage, students practiced exteriorizing the disegno interno pratico, often with the help of their imagination (fantasia). 41 Although similar graduated systems of practical training of disegno had existed since the fifteenth century, Zuccari was the first to ground these practices in a philosophical theory and epistemology in which the relation between theory and practice and between hand and mind occupied a central place. 42 Zuccari's theory was more developed than previous ones because it included the process of knowledge acquisition via the senses, hands, and instruments as a counterpart and preliminary process to that of artistic production. From Zuccari's perspective, the ability to render a realistic representation of an object or a scene in three dimensions attested to an artist's knowledge and understanding of nature. 43 Zuccari's conception of disegno and the academy's curriculum were also connected to existing social hierarchies. He described artists who had received praise for executing public commissions based on their disegni as valentuomini (worthy men) or accademici utili e honorati (useful and honorable academicians). At the opposite end of the socio-economic spectrum in early modern Rome were artists who earned modest wages as assistants in the workshops of others or sold mediocre works on the art market, often in series and based on disegni of others. This indicates that their skills corresponded to that which students learned in Zuccari's second and third capate. Contemporary sources described such artists as pittori grossi ("coarse painters"). 44 Zuccari would have agreed with this description although he did not use the term himself. These artists were not eligible for membership in the academy but were obliged to enroll in the Compagnia. However, many of them never joined either branch of the institution.

Disegno in the Accademia dei Lincei
The question now is if Zuccari's conception of disegno and his step-by-step curriculum for the Accademia di San Luca can help us understand the functions of both the images and the artists themselves in the knowledge practices of the Accademia dei Lincei. This section provides a general answer to this question by connecting Zuccari's ideas to the Lincei's visual epistemology and to their relationships with artists in the production and dissemination of knowledge. As such, it prepares the ground for more detailed and nuanced analyses-which lie outside the scope of this article-of the epistemic functions of the numerous images in the different Lincean projects through the lens of Zuccari's theory and practice of disegno.
The importance of images in the Lincei's projects is evident not just from the sheer quantity of graphic material produced but also from the testimonies in their correspondence, notes, and publications. The name "academy of the lynxes," or "lynx-eyed," is telling in this respect. It refers to the feline species that, according to legend, possessed vision so acute that it could see beneath the surface of things. In a programmatic lecture in 1616 in which Cesi presented the ideological and moral principles of his academy, he explained that this acute and penetrating vision should also-perhaps primarily-be understood as that of the mind's eye of the institution's members. According to the president, their keen vision allowed them to perceive "minutely and diligently, both inside and outside … all of the objects that present themselves in this great theatre of nature." 45 Cesi's explanation of the Linceans' vision as both corporeal and intellectual and directed towards both the surface and the interior of natural objects fits perfectly with Zuccari's conception of disegno as a process in which the senses and the intellect work together to obtain knowledge of Forms, or universals. However, in this explanation there is no link between the Linceans' vision and their use of images or artists.
Cesi, however, does make this connection in a letter to his colleagues written in 1605 in which he discussed the academy's goals and how these should be attained. One of his points relates to its use of artists and images: "The copper engraver (disegnatore in rame) will be most useful to our order, since in printing the Lincean writings the greatest expense will be in the figures, hence we will advance on this matter and we will be able to represent our every observation and capriccio." 46 There are three things that can be taken away from this passage. It shows first that at this early stage in the academy's existence, the Lincei were already aware of the importance of images for their scientific projects. Second, it demonstrates their commitment 41 Rossi, "Idea e accademia," 49-50. 42 Previously, Leonardo da Vinci (1452-1519) and Vasari advanced gradual teaching systems of drawing. See Vasari,Vite,[1][2][3][4][5][6][7][8][9][10][11][12][13][14][15] Fowler, Drawing and the Senses, 75 and 90-91. 43 Roccasecca,"Teaching," 149. 44 Cavazzini, Painting as Business, 26. 45 Cesi,Natural desiderio,. 46 Gabrieli,Carteggio linceo,67 (no. 24): "Utilissimo sarà il disegnatore in rame per il nostro ordine, poiché nel stamper i componimenti delli Lynceai la maggior spesa sarebbe nelle figure, onde avanzeremo questo et potremo figurare ogni nostra osservatione et capriccio." to hiring professional artists, or disegnatori, to produce these images. Third, it shows that these images should represent not only their observations but also their capricci, which can be translated as "fantasies," "whims," or "thoughts." In other words, the images produced by the Lincei should represent both the things experienced by their corporeal senses and the things perceived by their mind's eye-in Zuccari's terms, the objects formed by their disegni interni. 47 That the Lincei visually recorded their observations at this early date can be seen in an unpublished manuscript that consists of images and descriptions of the plants that Van Heeck encountered on his journey through northern Europe at the beginning of the seventeenth century (Figure 3). The manuscript contains images drawn with a pen and then colored with watercolor and varnished. The artist could have been Van 47 In this context, Cesi's interesting, albeit elliptical, remarks on what he calls pittura filosofica (philosophical painting) should be mentioned. With this notion, he expressed the idea that art can and should be used as an instrument in the understanding of nature. Baldriga, Occhio della lince, 13-15 and 259. Heeck himself or the draftsman he mentions in one of his letters to his colleagues in Italy. 48 For each plant he observed, Van Heeck recorded its Latin name at the top of the page and wrote (in Dutch) a description of its appearance and the precise location where it was collected. Together, the textual descriptions and the color drawings functioned as field notes that could later help him use his observations to identify a plant and, ultimately, construct a taxonomy. 49 The artistic skill level required for rendering these images corresponded to Zuccari's second capata in which students had to accurately copy or portray two-and three-dimensional figures. At this level, not much understanding of the objects depicted was required. On the contrary, it was the act of ritrarre dal naturale ("drawing from nature") itself that led to a more profound understanding of the objects. In other words, the drawings in Van Heeck's manuscript were supposed to help the Lincei extract the Forms of the plant species in question. For the exteriorization of the natural knowledge attained by the Lincei, we turn the publication that cost them the most effort, money, and time to realize-the Rerum medicarum Novae Hispaniae thesaurus (Treasury of the Medical Matters of New Spain), better known as the Tesoro messicano (Mexican Treasury). 50 A compendium of the natural history of Mexico, it was based on material collected by the Spanish Royal physician Francisco Hernández (ca. 1517Hernández (ca. -1587 in Mexico in the 1570s. The Lincei obtained an abridged version of Hernández's descriptions around 1610, and they spent the following four decades organizing, annotating, and illustrating them before publishing the completed work between 1648-1651. 51 The graphic material consists of a frontispiece and almost eight hundred woodcuts of Mexican plants and animals. The frontispiece is a copper engraving that was produced in several versions by Matthäus Greuter (1564-1638) and his son Johann Friedrich (1589-1660) (Figure 4). It is a complex composition with many iconographical elements placed on or against an architectural structure. The woodcuts were based largely on color drawings of the plants and animals that had been produced in Mexico by indigenous artists under Hernández's supervision and in some cases on exotic plants that were cultivated in Italian gardens. The names of two of the artists employed by the Lincei to produce these woodcuts are known. The first is Isabella Parasoli (ca. 1565/70-ca. 1625), who was mentioned by the painter and biographer Giovanni Baglione (1566Baglione ( -1643 as having executed prints for Cesi's Libro dell'herbe (Book of Herbs), which referred to the Tesoro messicano. 52 The second is an artist named Giorgio Nuvolostella (d. 1624). The archive of the academy contains a draft of the contract between the Nuvolostella and Cesi drawn up in October 1619 in the latter's palace in Acquasparta. It specified that he must complete eight figures per month for which he would receive 7 scudi and 25 baiocchi as well as a daily portion of bread and wine. 53 According to Zuccari's theory of disegno, the production of a complex composition with multiple iconographical elements-as in the case of the frontispiece of the Tesoro messicano-required more cognitive capacity and thus more disegno interno from the artists than the creation of woodcuts representing individual plants and animals. The difference in the cognitive capacity required to create works of varying complexity raises the issue of social difference among the artists who produced different types of works. For example, whereas Parasoli and Nuvolostella do not seem to have had a direct personal connection to the Accademia di San Luca, Johann Friedrich Greuter was one of the institution's teachers in the 1620s. 54 Moreover, between the socio-economic extremes of valentuomo and pittore grosso, the Greuters gravitated towards the former and Parasoli and Nuvolostella towards the latter. This difference can be seen, for instance, in Nuvolostella's contract, which earned him a modest salary and was not the kind of important public commission that valentuomini such as Zuccari and Cigoli were looking for.
Another indication of relationship between the social status and artistic ability of the artists the Lincei employed to produce the woodcuts of the Tesoro messicano is the involvement of the natural philosophers themselves in the production process. Since the artists would probably not have had the botanical knowledge required to distinguish the essential from the accidental features of a plant, the Lincei closely scrutinized them and their work. Such oversight is evident in the preparatory woodcuts of the plants dating from the early 1610s that are now in the Biblioteca Apostolica Vaticana. These prints contain the names of the plants in Nahuatl (the most important indigenous language of Central America), botanical annotations, 48 In a letter from December 19, 1604 Van Heeck wrote that he had taken in his service a young engraver to record the most notable things of his trip. Gabrieli,Carteggio linceo,46 (no. 18). 49 For the notational function of botanical images, see Dackerman, "Introduction," 20. 50 Hernández et al., Rerum medicarum. 51 Cadeddu and Guardo, Tesoro Messicano; Jonker, "Accademia dei Lincei's network." 52 Baglione,Vite,395;Tongiorgi Tomasi,"Femminil Pazienza, BANL, MS Archivio Linceo IV, 372r-v. 54 ASR, TNC, uff. 15, 1624, pt. 4, vol. 102, 247r andASR, TNC, uff. 15, 1625, pt. 2, vol. 105, 441r. and, in some cases, directions for the woodcutter. For example, a note in Cesi's hand on one of the prints reads: "these leaves have to be seen in the original, [because] I don't like them and they are unwrapped and striped in the length." 55 The woodcut to which Cesi was referring was subsequently redone, which is evidenced in the fact that it is represented in reverse in the Tesoro messicano. It was accompanied by another image of the same plant showing the leaves folded along their length in accordance with Cesi's instructions. 55 BAV, Stampe.I.81. The image cited can be found on 56 and represents the Tozcuilapil Xochitl (Nahuatl). It is described on page 282 of the Tesoro Messicano. The Italian reads: "queste foglie bisogna vederle al originale, che no(n) mi piacciono e vanno scartocciate e striate per il longo." Another example of the Lincei's scrutiny of the artists they employed can be found in their correspondence. When working on the annotations for his part of the Tesoro messicano in 1628, Fabio Colonna wrote from Naples to his colleague Stelluti in Rome about his concerns regarding the accuracy of one of the images: "[i]t is necessary to see if the painter of the leaf of the pepper plant has expressed what it says in my annotation." 56 Colonna was referring here to his annotation of the Piper rotundum (Black pepper), which was accompanied by a large image of the leaf of the plant (Figure 5). In focusing on a single part of the 56 Gabrieli, Carteggio linceo, 1117 (no. 974): "Bisogna veder se il pittore della foglia del Pepe ha espresso quel che si dice nell'annotazione mia." plant, this illustration is very different from another one of the same species in a part of the book that was prepared in the early 1610s by one of Colonna's colleagues (Figure 6). In this case, the plant is represented in its entirety, its leaves are much more crudely rendered than the one accompanying Colonna's text. In his annotation, Colonna mentioned that he had received some leaves of a pepper plant from a friend and that this had allowed him to examine the leaf closely and to see that it had five instead of three nerves along its length. The leaf's nerves are clearly visible in the woodcut adjacent to his annotation. Therefore, it appears that the artist had indeed adequately "expressed" what Colonna had written in his annotation and thereby exteriorized the natural philosopher's disegno interno. Thus, the skills the Linceans demanded from most of their artists corresponded to the skills acquired by students in the first two stages of Zuccari's training program. The examples discussed above have shown that the Lincean artists were supposed to portray faithfully single organisms, or parts thereof, from life or from existing drawings. Put into the terms of Zuccari's theory of disegno, in the process of knowledge acquisition, the Linceans used artists and artistic images to extract the disegni esterni from the organisms and to form disegni interni (speculativi) in their minds. In the act of publishing the resulting knowledge in the Tesoro messicano, they used the artists to transfer the disegno interno pratico from their minds to a sheet of paper or a woodblock. In other words, the artists functioned as the natural philosophers' instruments in analyzing and identifying plant, animal, and mineral specimens. They were aids to and, in a certain sense, improved versions of the natural philosophers' senses and hands. From Zuccari's perspective, most of the images produced in the Lincean scientific projects would not be considered true artistic products or the work of master artists because they only required the skill level attained by students in their second capata. In other words, such images required the skills used in the first part of the process of disegno, namely knowledge acquisition, not those used in the second part, namely artistic production. Zuccari expected more from the artists in the Accademia di San Luca. He urged them to take further steps and ultimately develop and exteriorize their own disegno interni without using any models or the aid of their fantasia. Of the examples discussed above, only the frontispiece by father and son Greuter falls within this category.

Conclusion
This article has sought to show that our understanding of the relationship between science and art in the early modern period can be improved by focusing on contemporary art theory, art education, and the division of labor between natural philosophers and artists in the production of knowledge. The analysis of Alberti's narrative has shown that Zuccari was not satisfied theoretically with only connecting the processes of knowledge acquisition and artistic production to each other but that he also sought to implement this central tenet of his conception of disegno in the practical training of artistic education.
By connecting Zuccari's theory to contemporary scientific activities of the Accademia dei Lincei, this paper has further illuminated its practical implications. In turn, Zuccari's double-layered notion of disegno in combination with his ideas for the Accademia di San Luca's curriculum have furthered our understanding of the functions of the images as well as the artists themselves in the the Lincei's knowledge practices. From the perspective of Zuccari's theory, both functioned as instruments in the processes of knowledge acquisition and dissemination. This conclusion can be used as the basis for further research on the relationship between science and art in the early modern period. In particular, one could focus on and compare the epistemic functions of the images produced and collected by the members of the Lincei in their various projects.