In this large map, many of Piranesi’s goals in this volume of Le Antichità Romane coalesce. Visual illusions, however, risk obscuring those goals. Sheets of paper and blocks of stone seem to rest on top of a single marble slab, in a combination of media that invokes both the fragments of the Marble Plan, which he assembles around the edges of his “Pianta di Roma,” and his own medium of print (Pinto 2012, 134). This large, solid block also suggests a sense of totality that is possible only through Piranesi’s illusionistic archaeology. On its surface, shaded structures are labelled as circuses, amphitheaters, and baths. The most recognizable natural feature is, appropriately, the Tiber River, which winds from the upper right to the lower left, since the subject of the image is, of course, water. This map was in fact the first to trace Rome’s ancient aqueduct system within the contemporary city. As such, Piranesi’s efforts to reveal the unique achievements of ancient Rome’s water management here see their full expression. Additionally, his aims to convey tremendous amounts of information within a single visual field are also at play in this map, which includes three inset images, each with their own annotations, and alphabetic and numerical markers in the central cartographic image that are explained within and beyond it. This map is, to say the least, hard to follow. Once oriented within the image, a viewer can trace not only the Tiber but also the narrow, dark, meandering lines that indicate, for example, the Acqua Vergine or the Acqua Appia. Tracing Piranesi’s networks of information, though, remains a challenge. 

At 840 x 600 mm, the image is roughly eight times the size of the vedute in the volume. Although it was originally a foldout, the image is divided in half and appears across two pages in the Didot edition. As a foldout, and, to a different degree, as an image divided across two pages, it requires users to manipulate pages in such a way that the rest of the book becomes inaccessible. The legend, on a curling piece of paper below the map’s title, explains the lines and blocks used to represent specific aqueducts and notes that all annotations, besides “A” and “B,” are described in an explanation that follows. The image’s full title refers to two other texts: Piranesi’s commentary on an ancient treatise about water management, and his observations on the circumference of Rome’s ancient regions and streets. The numbers and letters throughout the map are identified primarily in the notes to the “Explanation of the Map of the Aqueducts” mentioned in the legend, but some are also explained in the “Observations on the Limits of the Campus Martius,” and a few are mentioned incidentally in the “Index to the Map of Rome.” The digital annotations above locate this information, drawn from three texts, within the image, but, as a printed image, the map presumes that readers will consult his written texts first and then proceed to the image.  

The “Explanation of the Map of the Aqueducts” is in fact a selective translation of De aquaeductu urbis Romae, a treatise on water management by Sextus Julius Frontinus (c. 40-130 CE) that was considered on par with De architectura by Vitruvius (c. 80-70 BCE – c. 15 BCE) for the knowledge it conveys about ancient architecture and building methods. Frontinus praises aqueducts at the expense of other ancient marvels, dismissing Egyptian pyramids and Greek monuments as useless (Hodge 1, Evans 20). Understanding ancient Rome’s water management can, for Piranesi, reinstate its glory.  

The map is a visual expression of information that is found primarily in footnotes and index entries rather than an annotated image of the sort that comprises most of this volume, in which numbers or letters in an image “point” to a caption below. The position of this map as an illustration of Piranesi’s footnotes to De aquaeductu, as Lola Kantor-Kazovsky suggests, makes the map and its related text resemble “a humanist commentary on a classical source” (104). This commentary, though, involves moving from text to image and, presumably, back again. It entails transitions in media and, to put it simply, quite a lot of work. Users of the map might be tempted to conclude that Piranesi’s reach exceeds his grasp: it is unlikely if not impossible for users to read his texts, search out their annotations in the map, and then return to the text to continue reading and seeking annotations. As Sarah Buck has argued of this map, the material form of Piranesi’s pattern of cross-references—from a text’s footnotes to a fold-out etching—makes following this pattern virtually impossible. Piranesi “traps” his reader between consulting only the map and accepting its arguments about the locations of certain aqueducts, or reading his claims without unfolding the map (Buck 32). This structure, however impractical it may be, also demonstrates Piranesi’s boldest ambitions for conveying information about water management through the conventions of cartography and the structures of books. (JB)