simply meant to extrapolate from what came before. Although Pozzo’s European readers would have been familiar with the examples of classicizing Doric, Ionic, and Corinthian capital decoration illustrated in this section, it is difficult to imagine that an eighteenth-century Chinese reader would have been equally familiar with them, much less have understood
their simplified illustration in The Study of Vision. Throughout the treatise, only in very rare cases do Nian’s instructions identify the subjects of the illustrations; instead, they presume that the reader recognizes them, and therefore focus on the method necessary to create those subjects. But methods are presented in only a minority of the illustrations, leaving the reader to infer the method based on the previous forms, and they are far from transparent, requiring not only advanced mathematical knowledge, but also familiarity with and willingness to use technical drawing tools. What Nian’s concluding comment in this passage and the significantly higher number of illustrations than explanations in the treatise do show, however, is that Nian believed images conveyed more information than text. He thus provides the very methodology with which to engage The Study of Vision.
The second section of The Study of Vision (19r–23v) includes thirty-four individual illustrations depicting the use of distance-point perspective to create a variety of architectural forms, including rooms with paved floors in the European pavimento treatment of perspective (figure 2.4), also seen in the scenic illusion version of Spring’s Peaceful Message. Unlike the central-point method of perspective, the distance-point method creates perspectival images by triangulating the vanishing point (which Nian commonly refers to as the toudian or zhengtoudian, “head point” and “main head point,” respectively) from two lateral distance points (lidian, literally “distance point”), the distances between which are equivalent to the original viewing distance from the eye’s viewpoint and the picutre plane.50 Viator (Jean Pelerin, c. 1425–before 1524) first described the distance-point or “third-point” (tier point) system in a series of diagrams without significant text in De artificiali perspectiva (Toul, 1505), the first illustrated perspective treatise. It informed subsequent authors such as Jean Cousin the Elder (1500–93) and Jacopo Barozzi da Vignola (1507–73), who further developed both the theory and the praxis of distance-point perspective. Viator, Cousin, and Vignola were among the authors of the numerous perspective treatises held in the eighteenth-century Jesuit library in Beijing.51 The illustrations in many of these treatises, including Guidobaldo del Monte’s (1545–1607) Perspectivae librae sex (Pisa, 1600) and Sebastiano Serlio’s (1475–1554) Architeturae liber septimus (1537–75), have been linked to those in The Study of Vision.52 These visual connections imply that Nian enjoyed significant access to the Jesuit library, although someone (almost certainly a Jesuit) must have translated or at least explained the texts to him, as Nian neither spoke nor read any Western languages. The Jesuit library does not seem to have held a copy of Jean Dubreuil’s (1602–70) La perspective pratique (1642), yet several of the illustrations from this second section of The Study of Vision closely resemble some in this French treatise.53 European authors of perspective treatises freely and frequently borrowed both images and text from other treatises, often without crediting their sources.54 It is quite likely that Nian encountered variations on Dubreuil’s images in other treatises, but by never mentioning the fact that he had studied and borrowed from them, he unwittingly followed in this tradition.
2.4Four rooms created using the distance-point method of perspective. From Nian Xiyao, The Study of Vision. The Bodleian Libraries, University of Oxford, Douce Chin. B. 2, p. 20r.
Consequently, precisely sourcing Nian’s obviously European images from Western perspective texts is not as productive as noting where and how The Study of Vision diverges from its European models. For example, European treatises commonly include a human figure in profile with rays or lines from his or her eye (marking the distance point) that extend obliquely toward the image, which directly faces the reader. In contrast, Nian’s diagrams for constructing the distance point omit this figure, which represents “both the mathematics of perspective and the illusion of space that is one of perspective’s putative goals,” but also results in an indeterminate view of the scene by splitting the viewpoint of the illusion between the text reader/image viewer located outside the picture plane and the profile figure inside the picture plane.55 In his distance-point illustration depicting rooms with tiled floors, rather than relating the vanishing point and the distance point as two representations of the same human viewpoint, Nian simply employs a single en face view of both the technical process and the illusionistic final result of representing
2.5Diagram demonstrating the method for depicting rectilinear forms. From Nian Xiyao, The Study of Vision. The Bodleian Libraries, University of Oxford, Douce Chin. B. 2, p. 27v.
a three-dimensional projection of a receding space on a two-dimensional surface. The vanishing point of all four examples in this illustration is marked with the character jia (which corresponds to A as the first in a series), and this point is also presented as the eye level of the reader looking at the illustration and the viewer looking at the room. Using diagram number 9 (the simple tiled floor at the top right) as the basis, Nian defines these illustrations as the “method of creating things on a ground plane” (diping shang qi wujian fa) and explains how to construct this space according to distance-point perspective. He then leaves the remaining three diagrams for the reader to extrapolate, merely noting that the measurements for all four diagrams are the same. The vanishing and distance points in the illustration at the bottom right (marked as figure 10 in Chinese) are both accompanied by a semicircular array of lines, which are not light rays but a suggestion of the orthogonals that converge on these points. Although this figure and those marked as 11 and 12 (the two on the left side of the image) all have their vanishing points and distance points labeled as the Chinese equivalents of A and B, these are the only concessions to
2.6Diagram demonstrating the method for depicting windows. From Nian Xiyao, The Study of Vision. The Bodleian Libraries, University of Oxford, Douce Chin. B. 2, p. 32r.
method he makes in the last two images, otherwise emphasizing result over process but not producing anything closer to a painting than a colorless draft sketch.
The third section (24r–29v) of The Study of Vision illustrates how to draw rectilinear forms set at various angles in three dimensions (figure 2.5), often using the same multiview approach as he did in at the beginning of the treatise in figure 2.3. The fourth section (29v–32r) discusses how to create open doors and windows in architectural spaces, the culmination of which comes in figure 2.6. However, with the exception of the A, B, C, D points, the grid marked on the floor in figure 2.6 could also be read as a simplified shadow cast by the open latticed window on the floor of the room, the ambiguity of this element again minimizing the method necessary to create it. Together, these two sections of the treatise generally present how objects occupy space in a representation and affect their surroundings as they do just as in real life, particularly those in section 4.
The fifth section (32v–42v) presents instructions for representing a variety of three-dimensional objects, most of which (36v–38r, 39r–41r) are rounded ceramics. Beginning
