Response by Allan a. Mills

140 Commentaries original. In summary; I have been able to reconstruct the shape and dimensions of Vermeer’s studio and all its furniture with considerable accuracy and have plotted the theoretical viewpoints of half a dozen pictures within this space. Those parts of the room that are visible in each painting are contained within a “visual pyramid” whose apex is at the viewpoint. If the sloping lines that form the edges of this pyramid are carried back through the viewpoint to meet the back wall of the room behind the painter, they define a rectangular area on that wall. In each of the six cases in question (and maybe more) this rectangle is the precise size of the respective painting. My explanation for this extraordinary geometrical coincidence is that Vermeer had a cubicle-type camera obscura at the back of the room with a lens that could be moved to each painting’s viewpoint (as in the 1989 BBC reconstruction). He used this arrangement to project the scene onto the back wall, which thus served as the camera’s screen. The camera explanation is simple and natural. Each of Vermeer’s six pictures is the same size as its “projected image” because he traced it. It is extremely difficult , on the other hand, to see how this strange geometrical phenomenon could arise from any use of conventional perspective techniques. If Allan Mills has an explanation in these terms, I should indeed be interested to hear it. PHILIP STEADMAN Faculty of Technology The Open University Milton Keynes MK76AA United Kingdom E-mail: References and Notes 1. Allan A. Mills, “Vermeer and the Camera Obscura: Some Practical Considerations,” Leonardo 31, No. 3 (1998) p. 218. 2. Athanasius Kircher, Ars Magna Lucis et Umbrae (Rome, 1646) plate 28. 3. See P. Steadman, “In the Studio of Vermeer,” in R. Gregory, J. Harris, P. Heard and D. Rose, eds., The Artful Eye (New York: Oxford Univ. Press, 1995) pp. 353–372. 4. J.M. Montias, Vermeer and His Milieu: A Web of Social History (Princeton, New Jersey: Princeton Univ. Press, 1989) pp. 183–187. 5. J. Verkolje, Portrait of Antony van Leeuwenhoek (1686), in the collection of the Rijksmuseum, Amsterdam. 6. A.A. Mills and M.L. Jones, “Three Lenses by Constantine Huygens in the Possession of the Royal Society of London,” Annals of Science 46 (1989) pp. 173–182. 7. J.M. Montias, “Vermeer and His Milieu: Conclusion of an Archival Study,” Oud Holland 94 (1980) pp. 44–62. 8. C. Huygens, Oeuvres Complètes I (The Hague: Société Hollandaises des Sciences, 1888) letters 202, 233 and 234. 9. See A.K. Wheelock, “Vermeer of Delft: His Life and His Artistry,” in Johannes Vermeer, exh. cat., A.K. Wheelock, ed. (1995/1996) pp. 15–29. 10. For biographies of Leeuwenhoek, see C. Dobell, Antony van Leeuwenhoek and His “Little Animals ” (London: John Bale, Sons and Danielsson, 1932) and A. Schierbeek, Measuring the Invisible World: The Life and Works of Antoni van Leeuwenhoek FRS (London: Abelard-Schumann, 1959). 11. B. Broos, “Un celebre Peijntre nommé Verme[e]r” in A.K. Wheelock, ed. [9] pp. 47–65. 12. Der Jeugd van Constantijn Huygens door Hemzelf Beschreven, A.H. Kan, ed. (Rotterdam: Donker, 1946), Appendix pp. 137–140; cited in R. Colie, “Some Thankfulnesse to Constantine”: A Study of English Influence Upon the Early Works of Constantijn Huygens (The Hague: Nijhoff, 1956) p.107. 13. B. de Monconys, Journal des Voyages de Monsieur de Monconys (Lyons: Boissat et Remeus, 1665). See also R.S. Clay and T.H. Court, The History of the Microscope (London: Charles Griffin, 1932) pp. 21–22. 14. The occasion is described in a letter from the Secretary of the Royal Society Henry Oldenbourg to Robert Boyle, quoted by A.E. Bell, Christian Huygens and the Development of Science in the Seventeenth Century (London: Edward Arnold, 1947) p. 53. 15. Two possible exceptions are the Allegory of Painting and Allegory of the Faith, which are much larger than of all of Vermeer’s other interiors. 16. See, for example, the early-eighteenth-century camera designs for copying prints by Georg Friedrich Brander and Nicolai Bion, illustrated in J.H. Hammond...