Al-Nayrizi

Abū’l-'Abbās al-Faḍl ibn Ḥātim al-Nairīzī (Template:Langx; Template:Langx; Template:Langx, c. Template:TrimTemplate:Sndc. Template:Trim) was a Persian mathematician and astronomer from Nayriz, now in Fars province, Iran.

Life

Little is known of al-Nairīzī, though his nisba refers to the town of Neyriz. He mentioned al-Mu'tadid, the Abbasid caliph, in his works, and so scholars have assumed that al-Nairīzī flourished in Baghdad during this period.Template:Sfn Al-Nairīzī wrote a book for al-Mu'tadid on atmospheric phenomena. He died in c. Template:Trim.Template:Sfn

Mathematics

Al-Nayrizi wrote a commentary to the translation in Arabic by Al-Ḥajjāj ibn Yūsuf ibn Maṭar of Euclid's Elements. Both the translation and the commentary have survived, as well as a 12th-century Latin translation by Gerard of Cremona. Al-Nayrizi's commentary contains unique extracts of two other commentaries on the Elements, produced by Hero of Alexandria and Simplicius of Cilicia.Template:Sfn

Al-Nairīzī used the , the equivalent to the tangent, as a genuine trigonometric line, as did the Persian astronomer al-Marwazi before him.Template:Sfn He gave a proof of the Pythagorean theorem using the Pythagorean tiling.Template:Sfn

Al-Nayrizi gave a mathematical proof of the parallel postulate based on the assumption that parallel lines are equidistant. He wrote a treatise on an exact method for the numerical determination of the kibla and a text about a device for measuring the heights, widths, and depths.Template:Sfn

Astronomy

Al-Nairīzī wrote a treatise on the spherical astrolabe, an elaborate work that seems to be the best Persian work on the subject. It is divided into four books:Template:Sfn

1. An historical and critical introduction of the astrolabe;
2. A description of the instrument; and a comparison with other astronomical instruments;
3. Applications of the instrument;
4. Applications of the instrument.

Ibn al-Nadim mentions Nayrizi as a distinguished astronomer with eight works by him listed in his book al-Fihrist.

Al-Nayrizi's most important astronomical works, his commentary on Ptolemy's Almagest and both his zijes, are lost. He produced treatises on the spherical astrolabe and astrological conjunctions, both of which are extant.Template:Sfn

Further reading

• (PDF version)

External links

• Al-Nairizi's Commentary on Euclid's Elements – Codex Leidensis 399: Euclidis Elementa cum Commentariis al-Nairzii (Bestorn, Heiberg) – ابو العباس الفضل بن حاتم النريزى كتاب اوقليدس المختصر فى علم الاصول المقدمة from Joseph G. Leichter (sel-published)
• Texts relating to al-Nayrizi from the Bibliothèque nationale de France