The Cover Design THE ENIGMA OF EARLY LENS USE JAY M. ENOCH Surprisingly little is known about the origins and early uses of lenses.1 Lens-shaped (lenses take their name from the bulging, double-convex shape of the lentil bean), near-transparent objects Dr. Enoch is Professor of the Graduate School and dean emeritus at the School of Optometry at the University of California at Berkeley, as well as professor ofphysi ological optics at the Department of Ophthalmology at the School of Medicine, University ofCalifornia at San Francisco. He wishes to express his appreciation to Ian Bailey (School ofOptometry, University of California, Berkeley) ; Wolfgang Heimple (Department of Ancient Near Eastern Studies, University of California, Berkeley); George Sines (Department of Materials Science, University of California, Los Angeles); and G. L’E. Turner (Museum of Scientific Instruments, Oxford Univer sity) for their constructive criticisms of this manuscript. 'Examples of pertinent papers areJay M. Enoch, “It is Proposed that the Cornea of the Eye of the Bull’s Head Rhyton from the Little Palace of Rnossos (Artifact Dated 1550-1500 b.c.) is a True Lens,” in Advances in Diagnostic Visual Optics, ed. A. Fiorentini, D. L. Guyton, I. M. Siegel (New York, 1987), andJay M. Enoch, “Early Lens Use: Lenses Found in Context with Their Original Objects,” Optometry and Vision ScienceTi (1996): 707-15. This article and Enoch, “Early Lens Use,” overlap to some degree but differ significantly in content. G. Sines and Y. Sakellarakis, “Lenses in Antiquity,” American Journal of Archeology 91 (1987): 191-96; G. Sines, “Precision of Engraving of Etruscan and Archaic Greek Gems,” Archeomaterials 6, no. 1 (1992): 53-68; L. Gorelick and A. J. Gwinnett, “Close Work without Magni fying Lenses?” Expedition 23 (winter 1981): 27-34; D. C. Lindberg, Theories of Vision from Al-Kindi to Kepler (Chicago, 1976) and Studies in the History of Medieval Optics (London, 1983). G. L’E. Turner, “Animadversions on the Origins of the Micro scope,” in The Light ofNature: Essays in the History and Philosophy of Science Presented to A. C. Crombie, ed. J. D. North and J. J. Roche (Dordrecht, 1985). Also see the publications ofA. C. Crombie; T. H. Martin, “Sur les Instruments d’Optique Fausse mentAttribues aux Anciens par Quelques Savants Modernes,” Bulletino di Bibliografía e di Storia della Scienza Matematiche e Eisiche 4 (Rome, 1871): 165-238, or Impr. des Sciences Mathématiques et Physiques, 1871; E. Rosen, “The Invention of Eyeglasses,” Journal of the History of Medicine and Allied Sdences 11 (1956): 13-53 and 183-218. C. W. King, Antique Gems and Rings, 2 vols. (London, 1872), 32-34. J. R. Baker, “Experiments on the Function of the Eye in Light Microscopy,” Journal ofthe Royal Microscopical Society 85, pt. 3 (June 1966): 231-54.© 1998 by the Society for the History of Technology. All rights reserved. 0040-165X/98/3902-0004$02.00 273 274 Jay M. Enoch made from naturally occurring crystals2 and from glass have been used for thousands of years in jewelry, as building decoration and objets d’art, and as parts of items venerated as religious symbols; many early examples of lens-like objects can be seen in museums around the Mediterranean and in the Near East, as well as in major art and archaeological centers elsewhere (for example, the British Museum). Early lenses were shaped double-convex, or, alternatively, convex on one side and near flat (piano) on the other side (plano convex). On occasion, hollowed-out concave surfaces also appear in a variety of settings. However, concave surfaces were not used for early lenses, per se. The craft ofglassmaking has been practiced at least since Egyptian times. Artisans fabricating or blowing glass objects had ample oppor tunity to encounter lens qualities in their material. Some individuals, perhaps artisans making lens-shaped objects, must upon looking through them have detected their ability to magnify and may have appreciated other lens properties. But when, where, and by whom were lenses first appreciated? So little is known about early lens history in part because lenses, made by artisans, did not arise within the scientific establishment, and there is virtually no written record of their invention and devel opment.3...