The Fragment of Al-Kindī's Lost Treatise on Observations of Halley's Comet in A.D. 837

Abstract

1. IntroductionIn the first half of the ninth century, a generation of Muslim scholars emerged under the support of the Abbasid Caliphs in Baghdad, among whom the great polymath al-Kindl stands tall. There is an astrological work written by him (on the duration of the reign of the Arabs), in which he mentions an uprising in a.d. 866, and so he must have died later than that date,' most likely around 870. He started his work under al-Ma'mun (reigned 813-833) but served mostly under the caliphate of al-MuTasim (reigned 833-842), during which his career reached to its peak.2 Since he was still alive in the late 860s and most likely an active scholar around 830, he probably was bom about 800.3The most important feature of al-Kindl's wider historical context is that he worked during the translation movement that was encouraged by the Abbasid Caliphs.4 Al-Kindl's scientific works had a two-fold influence on the development of the sciences in the early stage of the Islamic period: they expounded the newly translated Greek texts, and then promoted them by discussing their authenticity.Ibn al-Nadlmin his al-fihrist devotes several sections to al-Kindl's scientific works, such as arithmetic, geometry, music, astronomy, meteorology, and spherics.5 The list of Al-KindT's meteorological works includes two lost treatises, entitled His treatise on what was observed of the great atmospheric phenomenon in 222 a.h. (Kitab risalatih fima rasada min al-athar al-cazim fisanat ithnatayn wa cishnn wa mi 'atayn li- 'l-hijra) and His treatise on a comet that appeared and [al-Kindl] observed it for some days until it faded out (Kitab risalatih fi kawkab alladhi zahara wa rasadahu ayyaman hatta idmahalla).6The title of the first treatise indicates that it concerns al-Kindl's observation of an 'atmospheric' phenomenon that appeared in 222 a.h./a.d. 837 and which we can probably identify as a comet.7 Rada supposes that this would have been al-Kindl's treatise on observations of Halley's Comet which appeared in that year.8 In this article, I will demonstrate that this conjecture is definitely correct. Moreover, it is quite possible that the second treatise was associated with the same topic.9Recently, I came across a treatise entitled Nayazik,'0 during my research into a collection of manuscript images from Princeton University Library. This treatise is said to be an Arabic commentary on Aristotle's lost treatise on comets, written by Hunayn ibn Ishaq al-clbadl from the ninth century.12 Hunayn, who was contemporary to al-Kindl, translated numerous Greek scientific texts into Arabic.13 However, Hunayn's commentary on Aristotle's treatise has not come down directly to us in the original form although a recension (with later additions) is currently at our disposal. Much of the text concerns the implications of for judicial astrology.14 The recension was certainly written after 299 a.h./a.d. 912 (see below), and as a whole it still awaits a detailed study. However, there is a passage in it dealing with al-Kindfs observational report of a comet that appeared in 222 a.h7a.d. 837.15 This passage (with some hiatuses) also appears in another treatise regarding prognosis of entitled 'The gift of sages on description of the prognosis of comets (Tuhfat al-albab fibayan hukm al-adhnab) written by al-Maqdisiwho lived c. 1675, probably in Cairo.16 Further research shows that the report is very likely a summary or a fragment of al-Kindfs lost treatise on observations of Halley's Comet in a.d. 837 (see below).17 Only one other description of Halley's Comet's appearance in 837 has previously been known from Islamic sources, to be found in the voluminous History of Ibn al-Athlr; this has been examined by Rada and Cook.18The return of Halley's Comet in a.d. 837 marks its closest known approach to Earth and has been among the closest ones for any comet ever seen in history. It was also the most thoroughly documented account of Halley's Comet during the first millennium. …