(fl. Cairo, Egypt, ca. 1250)
mineralogy, probably also mathematics, technology.
Baylak’s period of activity is determined from his signature, dated 1282, in the Kanz al-tujjār. An autobiographical note there states that in 1242/1243 he undertook a trip by sea from Tripoli, Syria, to Alexandria. He must have had connections at the court of Ḥamā, Syria, for the Kanz is dedicated to either the Ayyübid ruler al-Malik al-Muẓaffar II (1229–1244) or his son al-Malik al-Manṣür II (1244–1284). If Baylak is identical with the mathematician—and this can be assumed—who in 1260 prepared a copy of a work on the knowledge and use of the clocks of Riḍwān al-Khurāsānī, and if he is also the one who made a handwritten mark of ownership on another mathematical manuscript (1269/1270), both preserved in Istanbul, then he was concerned with at least three areas of mathematics and natural science. However, in the Kanz his father apparently is named Muḥammad, and in the manuscript on clocks he is definitely ʿAbdallāh. The authenticity of these details is open to investigation, but in any case, all dates mentioned fall within the lifetime of one particular mature man.
Baylak’s only known book is his mineralogical work Kanz al-tujjār [or al-tijār] fī maʿrifat al-aḥjār (“Treasure of the Merchants on the Knowledge of Minerals”). If this was dedicated to al-Malik al-Muzaffar II, then the autograph of 1282 must be a copy of the original prepared by the author himself, for by 1282 al-Malik al-Manṣūr II was the ruler of Hamā. Apparently, however, 1282 was the year in which the original was written, for the note on the sea voyage is composed in such a manner that the Kanz can hardly have been written before 1244, the year of al-Malik al-Muẓaffar’s death. If one is to judge by excerpts of the book published by Clément-Mullet, in 1868, the book contains little that is original; and this little is further reduced if one compares it with other texts additional to those preserved in the Paris manuscripts used by Clément-Mullet, and especially if it is compared with the older mineralogical books that have been discovered and published within the past hundred years.
Baylak was the first author writing in Arabic to treat the use of the magnetic needle as a ship’s compass. On the trip to Alexandria, he watched one starless night as the captain stuck a needle through a straw so that the two objects formed a cross. This apparatus was then floated in a vessel of water. The needle responded to the circular movement of a nearby magnet. At the sudden removal of the magnet, the needle came to rest with a north-south orientation. Baylak had also heard that seamen in the Indian Ocean used hollow iron fish as compasses. His report on the magnetic needle was translated into French by Klaproth, then by Clément-Mullet (with the original Arabic text), and finally by De Saussure; Ferrand emended the latter translation at the time of its reprinting. Wiedemann translated the report into German in 1904.
C. Brockelmann, Geschichte der arabischen Literatur, I (1898), 495; Supp. I (1937), 904; 2nd ed., I (1943), marginal 495—with contradictory details in each place; J. Clément-Mullet, “Essai sur la minéralogie arabe,” in Journal asiatique, 6th ser., 11 (1868), 5–81, 105–253, 502–522, esp. 13 f., 146 ff., also published separately (1869); L. De Saussure, “L’origine de la rose des vents et l’invention de la boussole,” repr. in Gabriel Ferrand, Introduction à l’astronomie nautique arabe (1928), pp. 80 ff.: F. Kern, in Mitteilungen des Seminars für orientalische Sprachen in Berlin, Westasiatische Studien, 11 (1908), 268 f.: Jules Klaproth, Lettre à A. de Humboldt sur l’invention de la boussole (1834), p. 59; M. Krause, “Stambuler Handschriften islamischer Mathematiker,” in Quellen und Studien zur Geschichte der Mathematik, Astronomie und Physik, Abt. B, 3 (1936), 490 f.; G. Sarton, Introduction to the History of Science, II (1931), 1072, with several mistakes; MG. de Slane, Bibliothèque Nationale, Catalogue des manuscrits arabes (Paris, 1883–1895), MS No. 2779; G. Vajda, Index général des manuscrits arabes musulmans de la Bibliothèque Nationale de Paris (1953), p. 420, which differs from de Slane; and E. Wiedemann, “Beiträge zur Geschichte der Naturwissenschaften (II),” in Sitzungsberichte der physikalisch-medizinischen Sozietät in Erlangen, 39 (1904), 330 f. (the quotation from an Arabic author of 854 does not refer to the naval compass), and “Maghnaṭīs,” in Encyclopaedia of Islam, III (1936).