TARIKH-E ELM
Year:2008 | Volume:- | Issue:6|Papers Count:9

This article is devoted to two theorems on tangent circles, which were discovered by the Iranian geometer Ab Sahl K h (4th century A.H.). The two theorems were inspired by the Book of Lemmas (ma khūdhāt) attributed to Archimedes. Kūhī's original treatise is lost, but the two theorems are found in Nasīr al-Dīn Tūsī's edition of the Lemmas of Archimedes. They then appeared in Latin translations in 1659 in London, and again in 1661 in Florence, and in 1695 in a revised Dutch version in Amsterdam. The present article compares the original Arabic version of Kūhī's theorems (in the presentation of Tūsī ) with the revised Dutch version.

Al-Riyāḍ al-Kabīr, ascribed to Jābir ibn Ḥayyān, according to its introduction, was one of the most important basic texts for learning alchemy. The sixth chapter of this book is devoted to introducing different acid and alkaline solutions, their preparation and effects. On the basis of the sixth chapter of al-Riyāḍ al-Kabīr, this article investigates and analyzes Jābir’s method for preparing solutions, and explains chemical formulas and properties of reactants and products of his experiments.

The first section of Book I of al-Zīj al-Jāmi‘ (The Comprehensive astronomical tables) by Kūshyār ibn Labbān al-Jīlī (Gīlānī), the Iranian astronomer who lived around ten centuries ago, is dedicated to the subject of calendars. In this section, Kūshyār describes different types of calendars known in his time, their characteristics, and the methods for converting them into each other. Edition of an early Persian translation of this section, with introduction and commentary is provided in this article.

It is generally recognized that ‘zero’ as we understand the concept today originated in two geographically separated cultures: the Maya and Indian. However, if zero merely signified a magnitude or a direction separator, the Egyptian zero, nfr, dating back at least four thousand years, amply served these purposes. If zero was merely a place-holder symbol, then such a zero was present in the Babylonian positional number system before the first recorded occurrence of the Indian zero. If zero was represented by just an empty space within a well-defined positional number system, such a zero was present in Chinese mathematics a few centuries before the beginning of the Common Era. The dissemination westwards of the Indian zero as an integral part of the Indian numerals is one of the most remarkable episodes in the history of mathematics and the story is well-known.

The Islamic astronomy including the Persian astronomy was thoroughly introduced into India from the 14th century AD or so. Firstly, the astrolabe was introduced at the time of Fīrūz Shāh Tughluḳ, and a Sanskrit work entitled Yantra-rāja (1370 AD) was composed by Mahendra Sūri. At that time, some Sanskrit astronomical (or astrological) works were also translated into Persian. The astrolabe became quite popular in India, and Padmanābha wrote the second Sanskrit work on the astrolabe in 1423 AD. During the Delhi Sultanate period and the Mughal Empire period, Islamic astronomy and Hindu Classical astronomy influenced each other. I would like to discuss the introduction of the astrolabe into India and the development of astronomy in India in this period.

Dar Bayān-e Estekhrādj-e Djayb-e Yek Daradje is a Persian treatise by an anonymous author. The author’s purpose is to describe and explain a method for the determination of the Sine of one degree according to Ḳūshchī’s Persian commentary on Ulugh Beg’s Zīdj, and Ḳāḍīzāda’s Arabic treatise entitled Risāla fi Istikhrādj Djayb Daradjah Wāḥidah. Ḳāḍīzāda’s work, extant in several manuscripts, is, in fact, a revision of the lost work of the real inventor of the method, Kāshānī (al-Kāshī). Ḳūshchī in his commentary explains Kāshānī’s method, without mentioning his name. In this article, Dar Bayān-e Estekhrādj-e Djayb-e Yek Daradje is rewritten based on its unique manuscript, extant in Berlin, so that one can follow the traces of author’s citations from Ḳūsh chī and Ḳāḍīzāda’s works.

A total solar eclipse is one of the most beautiful celestial phenomena visible to the naked eye. It can inspire awe, and solar eclipses have sometimes been interpreted as omens. Despite their rarity, solar eclipses have had a large impact on society and sometimes they could change the course of history. In the Middle East the best-known solar eclipse affecting a historical event occurred during a war between the Lydians and the Medes on 28 May 585 B.C.Darkness fell in the middle of battle, so both sides became fearful and eager to make peace. The Greek historian Herodotus (I, 168) tells us that the year of the eclipse had been predicted by Thales of Milete. But the claim is vague and the contribution of Thales doubtful in the opinion of modern historians of astronomy; no theoretical framework for the prediction of such eclipses seems to have existed at the time (see Panchenko, 275)….

There are references to Aristotle’s viewpoints about meteorology in Asfizārī’s treatise entitled Āthār-i ʽUlwī that are not found in the Arabic translation of Aristotle’s Meteorologica. Ibn Biṭrīḳ, the Arabic translator, did not translate some parts of the book and there are mistakes in his translation. Asfizārī has also mentioned some points which cannot be found in the original work of Aristotle; so one could say that Asfizārī in addition to this Arabic translation, had access to some other sources connected with Aristotle’s original work. It seems that other composers of metrological works were not familiar with these sources, probably including Ibn Khammār’s al-Āthār al-Mukhayyala fi al-Djaww al-Ḥāditha ʽan al-Bukhār al-Māʼī. Later meteorological works are considerably affected by Asfizārī’s Āthār-i ʽUlwī.