HISTORY OF SPAIN: AL-ANDALUS WISEMEN: Ibn-al-Samh or al-Muhandis

INTRODUCTION

He was born in Cordoba, al‐Andalus, (Spain), 979, and he died in Granada, al‐Andalus, on the 29th May 1035, on the 18th of the Rayab month in the Muslim calendar, at the age of 56.

Ibn al‐Samḥ, known also as al‐Muhandis (the geometer), was a noted mathematician and astronomer in Andalusia and an important member of the school of Maslama al‐Majrīṭī ,el Madrileño, settled in Cordoba. Because of political unrest, Ibn al‐Samḥ fled to Granada, where he lived (out) for the rest of his life. There he worked in the service of the local chief, the Berber Ḥabbūs ibn Māksan, whose Jewish Minister, Samuel ben Nagrella, was also interested in mathematics and astronomy.

When he moved to Granada with his family, in this city he opened his own academy, where he explained mathematics and astronomy. He came to know and study well the books of Ptolemy.

Ibn al‐Samḥ worked in the fields of astronomy, mathematics, and, possibly, medicine. The 14th‐century historian Ibn al‐Khaṭīb states that Ibn al‐Samḥ wrote an essay on history, but there is no other evidence for this assertion. Ibn al‐Nāshī, one of Ibn al‐Samḥ's most important disciples, gives a list of nine books written by his teacher.

Manuscription in the zīj, an astronomical handbook with tables

In astronomy, Ibn al‐Samḥ, like his teacher Maslama al‐Majrīṭī, composed a zīj (an astronomical handbook with tables) based on Khwārizmī's Sindhind, which had been composed in 9^th‐century Baghdad. Ibn al‐Samḥ also composed a treatise on the construction of the astrolabe and another on its use. Although Ibn al‐Ṣaffār's treatise on the astrolabe gained more popularity, this long book (129 chapters on the use of the instrument) is the most complete treatise written in the Iberian Peninsula during the Middle Ages. The text is especially interesting because it deals with questions not usually analyzed in works of this kind, such as the visibility of the Moon and its latitude and longitude. His Kitāb al‐ʿAmal is also important; in it we can find a text that shows that the school of Maslama knew and used the works of Battānī. The Kitāb al‐ʿAmal was the source of a treatise on the use of the spherical astrolabe composed at the court of Alphonse X. Since the king's astronomers did not have an Arabic text on the spherical astrolabe from which to make the Castilian translation, they took Ibn al‐Samḥ's treatise and made an adaptation of it. His treatise on the construction of the equatorium – an instrument originally conceived in Al-Andalus and later developed in Latin Europe – is another of Ibn al‐Samḥ's major contributions to astronomy.

Ibn al‐Samḥ is well known for his many compositions in mathematics. His range of subject matters includes calculation, numbers, commercial arithmetic, theory of proportions, arithmetical operations, and the solution of quadratic and cubic equations. His work in geometry includes a commentary on the book of Euclid, and a general treatise that includes an important study of straight, curved, and broken lines.

According to sources that mention him, Ibn al-Samh was the author of numerous articles and books. At least, there is reference about ten books that belong to him.

HIS WORKS

1. A commentary on Euclid's work as an introduction to the geometry (Kitab al-ila-Madkhal Handasa Uklidus Kitab fi tafsir).

2. Mu'amalat, a book about the nature of the figures (Kitab al-'adad Timar).

3. A history of physics (Kitab al-'adad Tabi'at).

4. A book of higher geometry (Kitab al-kabir fi-l-Handasa).

5. A treatise, in two parts, about the construction of the astrolabe.

Dismantle astrolabe before being built

6. A second book about the astrolabe, this time on employment and use. In this work, the manuscript is preserved in the British Museum.

An astrolabe, its parts and the things they are refered to

7. Some astronomical tables which were highly praised by the Toledo’s astronomer Azarquiel (Kitab al-Ziy).

Toledo's astonomer Azarquiel

8. A letter about the art of calculation, there is a copy in El Escorial and another copy in Berlin’s Library. It is a short treatise of arithmetic. Its content is divided into ten chapters (Kafiya Risala fi 'ilm al-hisab).

9. A book about the Art of calculation (Kitab al-kamil fi-l-al-Hawa'i hisab).

10. A book called Book of the planet that was written around the year 1026 and which Alphonse X ordered to fix and translate under the title of Book of the instruments of the sheets of the seven planets. This same work was continued by Azarquiel, circa 1081.