Introduction

Abstract

Halley’s announcement came at the end of a paper discussing the ancient city of Palmyra in Syria and the inscriptions that had been found there. After outlining the history of the city from Classical sources, Halley made some remarks on the inscriptions, noting, for example, that before A.D. 500 none of the individuals referred to in the inscription had Roman names whereas after that date forenames taken from Roman Emperors such as Julius, Aurelius and Septimus, become common. He then turned to the geography of the region identifying Aleppo, Andrene and Efree with the ancient cities of Berrhæa, Androna and Seriane respectively and stating that Ptolemy and more recently Kepler in the Rudolphine Tables (followed by Bullialdus and others) gave incorrect latitudes and longitudes for these cities. More importantly, Halley said, he had identified the ancient city of Aracta with the city now known as Racca (al-Raqqa) on the Euphrates. It was in this city that al-Battānī made his observations. If an accurate latitude and longitude for this city were known, Halley said, it would be possible to use al-Battānī’s observations to resolve the question of whether there has been any change in the axis of the Earth’s rotation and to determine the size of the acceleration of the moon’s motion.