World-Maps for Finding the Direction and Distance to Mecca: Innovation and Tradition in Islamic Science.

• Author: Berggren, J. L.
• Position: Review

World-Maps for Finding the Direction and Distance to Mecca: Innovation and Tradition in Islamic Science. By DAVID A. KING. London and Leiden: AL-FURQAN ISLAMIC HERITAGE FOUNDATION and BRILL, 1999. Pp. xxix + 638.

This book is a personal account by one of the leading historians of Islamic science of his decade-long efforts to place into a historical context two highly sophisticated world maps that surfaced in the antiques trade in the 1980s. These operationally simple devices each allow a user, at any locality in the Islamic world of that time, to find the distance and direction to Mecca simply by rotating a narrow ruler around a central pivot on a brass disk. The devices work because their fabricators had access both to a sophisticated mathematical projection of the curved surface of the earth onto a fiat surface and to an extensive list of geographical coordinates (latitude and longitude) of localities in the Islamic world. The context for this sophisticated instrument turns out to be a fourth tradition in Islamic geography, one which King investigates with virtually every tool in the modern historian's armory.

The first two geographical traditions, with a long history of scholarly investigation, are those of Ptolemy's Geography and that of the Balkhi school, whose stylized maps formed from geometrical curves and straight lines are immediately recognizable. The third tradition is a sacred folk-geography, in which the world is centered on an edifice, the Ka'ba. It is unrelated to the first two traditions, and King was the first modern scholar, East or West, to investigate it seriously, in a series of papers published during the 1980s.

The fourth tradition is also a sacred geography and is centered on a city, Mecca. In the third Ka'ba-centered tradition, the orienting data were the orientation of the Ka'ba (which earlier work by King has shown is itself astronomically aligned), the rising and setting points of celestial luminaries, and wind directions. By contrast, in the fourth tradition, the orienting data are in the Ptolemaic tradition, the latitudes and longitudes of Mecca and the worshipper's locality, and the tools are mathematical methods that, ultimately, stem from Greek science. This Islamic tradition produced its own set of scientific works, including geographical tables and gazetteers in manuscripts and on astrolabes that provided, for a list of localities, the distances and directions from those places to Mecca. There were also...