CONTRIBUTIONS OF EARLY MUSLIMS TO THE FIELD OF EARTH SCIENCES

By: Dr. / Zaghloul El-Naggar

Despite the magnificent contributions of Early Muslims to the field of Earth Sciences, it has been wrongly assumed that the birth of such sciences did actually take place in 1830 A.C. by the publication of Charles Lyell’s book “Essentials of Geology”. It is true that the field has since been broadened to accommodate many specializations, has gradually advanced with big leaps and great strides, has been met with world-wide recognition and placed to widespread economic applications, but contributions

of generations before Lyell cannot be ignored. Some knowledge of the earth and of its resources must have been flourishing long before Lyells time, as quarrying for building and decorative stones, ore-mining and metal extraction, exploration for gems and gemstones as well as their industries were developed in all ancient civilizations. The techniques used must have been simple and primitive, but were definitely based on some knowledge and experience, particularly with miners gemologists, quarrymen, professionals in ore prospection and extraction, specialists in other industries and trades dealing in minerals and rocks, scientists, philosophers and even clergymen. As mentioned above, most of the civilizations prior to the advent of Prophet Muhammad (PBUH) had already lost their divine guidance, and hence, deviated to irrational thoughts and misconceptions, and their legacies were flooded with such as methologies, magic, mysticism, superstitious and skeptic views about the universe, peculiar ideologies, queer dogmas and strange beliefs. Consequently, the synthesis and theorization of the collected information about the earth were distorted by such strange beliefs, despite marked successes in the applied field. Tracing the origin of Geological knowledge in such peculiar explanations of classic times, or jumping from there to Renaissance, overlooking the “Golden Age” of the Islamic civilization is a gross historical and scientific mistake. Ancient Greek and Roman writers - like their predecessors in ancient Egypt, Mesopotamia, India and China - pondered about the origin of the earth and of the rest of the universe, but their conclusions were nothing more than a number of facts borrowed from previous revelations, highly twisted and corrupted by conjectural speculations and presumptions, without much observational or experimentational deductions. Luckily enough most of their writings are lost and-indeed-what is left makes such a loss unregretable. It was described by Schwarz ( 1968) under the

correct title “The Failure Of Geological Attempts By The Ancient Greeks From Old Ages To The Reign Of Alexander". Indeed some ancient Greek and Roman writers assumed the presence of fire at the earth’s center and recognized the remains of animals and plants in rocks of the earth’s crust, the rise and subsidence of land areas and a number of other geological phenomena, but failed to rationalize their explanations for such assumptions and observations as myths normally pre-occupied any systematic thinking in their minds.

Consequently, their contribution to Earth Sciences is, indeed scanty and of little worth. Zittel mentioned this in what is translated in the following lines: Not a single writer on these subjects in the ancient world had examined the rocky crust of the earth with a view to ascertain its composition, nor conceived that fossils in the sedimentary succession can afford clues to the history of the earth. The aims and objectives of modern geological and paleontological studies were

absolutely unknown to the ancients, for baseless hypotheses and haphazard observations cannot be considered as a foundation for scientific achievement. However, if such generalization applies to the legacy of the Greco-Roman civilization, it definitely does not apply to the contributions of the Early Muslims. These contain a wealth of scientific knowledge experiences and procedures for the identification of minerals and rocks, including physical and chemical properties (such as specific gravity, colour luster, transparency, impurities, streak, hardness, fractures, cleavage, fusibility, refractivity, crystallinity and crystal form, reaction to both heat and acids, etc.); as well as certain pertinent information about the occurrence, association, genesis, classification, extraction and uses of economic minerals and rocks ( such as gems and gemstones, gold, silver copper mercury; , lead and zinc, iron, borax, alum, rock salt, corals; crude oil and oil seeps, tar, coal, asbestos etc. The tables constructed by Muslim scholars for the classification and physical properties (such as specific gravity) of minerals and rocks hardly differ from modern readings. Muslim scholars also carried elaborate experimentation in chemical reactions, acid treatment, heating and calcinations, etc. And hence were pioneers in introducing experimentation in the examination and extraction of minerals and ores. Early Muslims’ contributions to Earth Sciences also include the description of the shape of the earth, proving its sphericity and rotational movements; the measurement of its dimensions (radius, circumference and volume with an error of no more than 3% ), the notion to the presence of most of its mass at its center; description of the geomorphological features of its surface and the processes shaping such features; the distribution of land and sea and the description of many oceanographic characteristics (such as shoals and shoal deposits, islands and peninsula, coral reefs, tides and tidal effects, etc.) ; the rational description of both internal and external forces of the earth and their associated processes and phenomena ( e.g. earthquakes, volcanic eruptions, orogenic movements, faults and surface collapses, other catastrophic events, the processes of both weathering and erosion and their products etc.); the rising of temperature towards the center of the

earth and the rising of mountains from within oceans and seas (an early notion to the ocean/continent’ cycle); the recognition and classification of both meteors and meteorites; the suggestion of a scale of hardness for determining the relative hardness of minerals [ 8 centuries before Fredrich Mohs ( 1773-1839) introduced his scale] ; the rock cycle or the formation of igneous rocks from molten magma and their disintegration by weathering into sediments and sedimentary rocks, the precise definition for the textural characteristics of both sediments and the later compaction of such. Sediments into sedimentary rocks; the recognition of beds, bedding planes and the law of superposition of strata [ centuries before both James Hutton ( 1726 - 1797) and William Smith ( 1769 - 1839) who are wrongly acclaimed as the fathers of Geology]; the understanding of metamorphism and its processes; the rational explanation of a large number of geological phenomena ( e.g. the transgression and regression of seas and oceans; the water cycle and the gushing of fresh, saline and hot-water springs; the formation of sabkhas, salt pans and playas; evaporation of water from the earth’s surface, cloud formation, and condensation, rain, hail, snow, lightening, thunder storms, rainbow formation, and other meteorological observations; the river cycle, desertification, etc.); the correct interpretation of the true nature of fossils and the process of fossilization, as well as the use of such information for paleogeographic reconstructions and paleoecologic interpretations; the recognition of the very slow pace of the geologic processes and the gradual development of creation with time from matter to plant life, then animal life and finally humans; recognition of the antiquity of the earth and providing a sound basis for the estimation of its age; the development of instruments of such extraordinary power such as the telescope, the microscope, the alidade, the compass etc., which opened the gates of knowledge in front of the human eye; precise geographic descriptions, measurements and mapping, geodetic surveying techniques, etc. All this wealth of information was written in a superb language where scientific terms are precisely defined to the extent that linguistic dictionaries such as that of Ibn Sayydeh (D. 458 A.I-I. = 1066 A.C.) contained a whole chapter on geologic terminology. These contributions are well within the core of Earth Sciences, and hence cannot be overlooked or credited to others, as wrongly practiced by European scholars who have - undoubtedly - made some use of this sound scientific knowledge, and ascribed it to Greek authors. Such wealth of geologic information is not only ignored in writings about Earth Sciences or about the History of Sciences, but the names of eminent Muslim scholars have been Latinized to mystify their identity. Indeed, numerous Arabic manuscripts have been translated into Latin and Greek, and referred to other European authors. The case of Ibn Sina’s section on “Minerals” in his famous book “Al-Shifaa” (or the Book of Remedy) is only one of the many shameful practices by Europeans during Renaissance. This chapter was partly translated and partly abridged under the Latin title “De Mineralibus” and wrongly attributed to Aristotle. Another manuscript in the same field by Jaber bin Hayyan was also translated into Latin under a similar title and attributed to Garlandius. For the names of distinguished Muslim scholars who have contributed elaborately to the field of Earth Sciences, for the titles of their works and to the

analysis of their contributions reference is made to Al-Sukkary (1973), Ahamd (1978), E1-Naggar & Al-Daffaa (1988) and other references on the history of sciences, but the names in the following list are only given as selected examples: SELECTED EXAMPLES OF MUSLIM SCHOLARS DISTINGUISHED IN THE AREA OF EARTH SCIENCES

1- Imam J’aafar Al-Sadeq (died 148 A.H - 765 A.C.) who wrote a manuscript on mineralogy, that was published by Ruska (1924). Original Arabic Name Latinized Name Ibn Rushde Ibn Bajah Ibn Zuhre Ibn Sina Ibn al-Haytham Jaber bin Hayyan Al-Razy Al-Zerqaly Abu Ma’ashar Al-Khuwarazrny Al-Farghany A1-Battany Al-Bitujy Bin Maymoun Al-Faraby Averroes Avempace Avenzoar Avicena Al-Hazan Geber Rhazes Arzachel Albumasar Algorithm

Alfraganus Albertagnius Albetragnius Maimonides Al pharahius : Examples of Muslim Scholars’ names which have been Latinized by Westerners in an attempt to mystify their identity. 2- Jabir bin Hayyan (died 160 A.H. - 776 A.C.) who was basically a chemist, and a medical scientist, was the first to synthesize minerals from natural ingredients (e.g. Cinnabar from mercury and sulphur), and to classify them on the basis of their physical properties. He suggested the possibility of transformation of base metals such as tin, lead and iron into precious metals such as gold and silver, and described in a professional manner the operations of calcinations, oxidation, evaporation, filtration, sublimation, melting, distillation and crystallization, as well as the solubility of gold in a mixture of acids (aqua regia). Jabir innovated a theory on the geological formation of metals, observed the imponderability of magnetic force, and emphasized the importance of experiment in scientific research. He wrote a number of treatises on chemistry and mineralogy of which we know at least 3, selections of which have been translated by Julius Ruska & Paul Kraus (1935). Many of his works were also translated into Latin and referred to Greek authors such as his manuscript on minerals (Mineralibus) which was wrongly ascribed to Garlandius. 3- Al-Haseb (died 206 A.H - 821 A.C.) who wrote a book on the uses of rocks. 4- Ibn Masaweeh (died 215 A.H. - 830 A.C.) who wrote a book on rocks. 5- Al-Khuwarizme (died 235 A.H. - 852 A.C.) who wrote 3 treatises on the shape of the earth and its geography. A manuscript copy of his book “The Image Of The Earth” is preserved at Strassbourg, France and was edited and translated into Italian by Nallino and into German by Hans Mzik.

6- Al-Kindy (died 252 A.H. - 866 A.C.) who wrote 7 treatises on geological issues including one on gems and semi-precious stones, a second on tides and a third on thunder storms, lightening, snow, hail and rain. 7- Al-Razy (died 320 A.H. - 932 A.C.) who wrote 7 treatises on minerals, rocks and the origin of the earth. His book ” The Secret of Secrets” was fully translated by Ruska and reviewed by Mieli (1938). 8- Al-Hamadany (died 334 A.H. - 945 A.C. ) who wrote a treatise on gold and silver that was revised and published in Uppsala, Sweden by C. Toll (1968), another on “The Description Of the Arabian Peninsula, And A Third On Routes and Kingdoms”. 9- Al-Masaudy (died 346 A.H. - 957 A.C.) who wrote 4 treatises on subjects related to the earth, including one on gold and gemstones, that was translated into English by Springer (1841) and into French by Barbier de Meynard & Pavet de Corteille ( 1861-1877). 10- Al-Maqdisy (died 381 A.H. - 992 A.C.) who wrote a wonderful book on geographic provenance. 11- Ikhwan Al-Safa (4th century A.H. - 11th A.C.) who wrote three theses on Earth Sciences out of a collection of 52 (the 4th, the 5th and the 19th). These theses were translated completely into Persian, Hindostani and Turkish and partly into German and French by Dieteric (1861- 1886) and Forbes & Rieu (1861), respectively. 12- Al-Yanbuay, Abou Dilfe (4th Century A.H. - 11th A.C.) who wrote a treatise on minerals that was revised by Minorsky and published in Cairo (1955). 13- Ibn Al-Jazzar (died 400 A.H. - 1009 AC.) who wrote a book on rocks. 14- Ibn Sina (died 428 A.H. - 1037 A.C.) who wrote 3 chapters on geological subjects in his treatise entitled “The Book of Remedy”, one on minerals and meteorological phenomena, a second on natural forces and a third one on properties of the equator. The chapter on minerals was translated into Latin and ascribed wrongly to Aristotle. It was translated into German by Ruska (1912) and into French by Holmyard & Mandeville (1927). 15- Al-Bayrouny (died 443 A.H. - 1051 A.C.) who wrote at least 13 treatises on subjects related to the earth, including: gems and gemstones, minerals, specific gravity of minerals and precious stones, the relationship between metals and gems, shadows, the determination of the direction of Qiblah, the determination of locations by means of the intersection between latitudes and longitudes and a scientific discussion on both the formation of mountains and the estimation of the

age of the earth. His book on gems and gemstones was reviewed by Clement -Mullet ( 1858), revised and published by Stapleton (1905), Kramkov (1907), Sachau (1898, 1910), and was translated into German by Wiedemann and published serially since the beginning of the 20th century A.C. The book was also translated into Persian by an anonymous person and this translation was rendered into English by Ahmad (1929). This last translation was reviewed by Lippmann (1931). The book was also translated into Russian by Byelenskiy. 16- Al-Jirjany (died towards the end of the 5th century A.H. - beginning of the 11th century A.C.) who wrote a book on rocks that was reviewed by Ritter (1935). 17- Al-Bakry (died 487 A.H. - 1095 A.C.) who wrote an encyclopedic work on the geography of the earth and a glossary to explain the necessary terminology. 18- Al-Tughr’aiy (died 515 A.H. - 1121 A.C.) who wrote two treatises on the transformation of minerals, that were translated into Latin. 19- Al-Zamakhshary (died 538 A.H. - 1151 A.C.) who wrote a treatise on “Mountains, Places and Water”. 20- Al-Idreesy (died 560 A.H - 1164 AC.) who wrote 4 treatises on the earth, its shape, morphologic features, maps, routes and kingdoms. 21- Al-Hamawi Al-Baghdady (died 627 A.H. - 1230 A.C.) who wrote two geographic glossaries, one on countries and the other on places. 22- Al-Demashquy, Al-Misri, Ibn Al-Awwam (the last half of the 6th century A.H. - 12th A.C.) who wrote elaborately on minerals, rocks and soils; most of their original writings could not be located but has been reviewed by a large number of subsequent writers. 23- Al-Sweedy (died 601 A.H. - 1291 A.C.) who wrote a book on gems and gemstones. 24- Al-Teefach (died 651 A.H. - 1253 AC.) who wrote two elaborate treatises on geology, one dealing with minerals and rocks ( mainly with gems and gemstones) and the other on the observations of natural phenomena. The mineral book was abridged and published by Raphius (1784) in Utrecht, Holland. The book was previously translated into Latin and a number of other European languages since the early days of the Renaissance. A copy of the Arabic text with an Italian translation was published in Florence, Italy in the year 1818 A.C. under the auspices of Count Antonio Reineri, and was reprinted in Bologne, Italy in 1906 A.C. Copies of the manuscript are kept in Leiden, Paris, Guteh, Cairo and Kuwait. 25- Al-Khaziny (died in the 6th century A.H. l2the century A.C.) who wrote a book on mechanical contrivances, but it contains tables and methods of determinations of

specific gravity for a large number of gems, minerals and rocks, with great precision. The book was reviewed by Koenikoff (1879), Wiedemann (1911) and by Mieli & Brunet (in Mieli, 1938). 26- Al-Toosy (died 672 A.H. - 1274 A.C.) who wrote a book on rocks. 27- Al-Qabajaky (died towards the end of the 7th century A.H. - 13th century A.C.) who wrote a book on rocks, recognizing the magnetite mineral and advocating the use of the magnetic needle. 28- Al-Qazweeny (died 682 A.H. - 1283 A.C.) who wrote at least 6 treatises in areas related to Earth Sciences including: gold and gemstones; on the geologic profession; on the order of the universe; countries and geographic provinces; archaeology and history; strange creatures and peculiar creations. The latter is an encyclopedic work that discusses many things on Earth and in the universe. It was published by Wustenfeld (1848) in Germany, was partly translated into German by Hermann Ethe (1878), by Ruzka (1896) and by Wiedmann (1911), and into French by Mercier, and by both Chezy & De Sacy. 29- Al-Iraquy ( the 7th century A.H. - the 13th A.C.) who wrote elaborately on geological topics including two manuscripts, one on precious stones and the other on gold. His works were reviewed by Ruska (1929) and translated into English by Holmyard (1923). 30- Al-Kamily (the 7th century A.H. - the 13th A.C.) who wrote monumental work on minting the Egyptian coins, where various metallurgical aspects are discussed. The book was reviewed by Holmyard (1931). 31- Al-Kashany (died 700 A.H. - 1301 A.C.) who wrote a manuscript on precious stones, essences, pottery ceramics and china, where a large number of minerals and rocks are discussed. The book was reviewed by Mieli (1938). 32- Al-Demashquy, Al-Soufy (died 726 A.H. - 1326 A.C.) who wrote a selection on peculiarities of both land and sea, where 700 minerals and rocks are described. 33- Al-Jaldaki (died 743 A.H. - 1342 A.C.) who wrote a manuscript on rocks. 34- Ibn Al-Akfany (died 749 A.H. - 1348 A.C.) who wrote a treatise on gems and gemstones. 35- Al-Telemsany Al-Miqury (died 1041 A.H. - 1631 A.C.), who wrote a book on minerals in Andalusia. These names are only a selection from a long list that cannot possibly be included here. Other scholars mentioned under Astronomy, as most of the Muslim astronomers had interest in the Earth, and their names need not to be repeated. Each of these authors also quoted, in his preserved manuscripts, a much larger list of references and of authors of whose works we know absolutely nothing

today, either due to their loss during the sacking of Baghdad and of many other centers of learning throughout the Islamic World, or due to the fact that such manuscripts are still lying in the darkness of library cellars in both Western and Eastern countries. However, this modest list shows clearly the great interest of Muslims in sciences of the earth and its applications for exploring, prospecting and exploiting its wealth, as well as for discovering the properties of our planet and forces influencing it.

CONTRIBUTION OF EARLY MUSLIMS TO THE FILED OF ASTRONOMY

By: Dr. / Zaghloul El-Naggar

Out of numerous contributions by Early Muslim scholars to the field of astronomy, the following can be listed: Early Muslims precisely defined astronomy as a definite field of scientific research; translated available information and critically reviewed it; developed observing equipments (such as the telescope, the celestial mirror or armillary sphere, the quadrant, the

astrolabe, etc.), astronomical tables, calculations and techniques; established a large number of observatories; innovated algebra and introduced applied mathematics for the first time to astronomy; invented the sciences of trigonometry, spherical trigonometry, algorithm, geometrical optics, spherical graphics and its applications in celestial observations; proved the spheroidal and the rotational movement of the Earth; invented longitudes and latitudes and very precisely measured the distance of a longitudinal degree; calculated the circumference, diameter and size of each of the Earth, the Moon, Mars, Jupiter and Saturn with great precision; introduced the Helio-centric of our solar system; estimated the mean orbit and the different altitudes of the sun; defined the nature and movements of many celestial bodies, calculated the degree of obliquity of the ecliptic; catalogued and named many stars and constellations, giving their coordinates and magnitudes, discovered the nebula Andromida, determined with wonderful accuracy the precession of equinoxes and the movements of both the solar apogee and the summer solstice, demonstrating that it is subject to the precession of the equinoxes and that, in consequence, the equation of time is subject to a slow secular variation; recorded the movements of the planets, and the condition of visibility of ~he new moon, and its distance from the earth, described the eclipses, the apparitions of comets; defined the exact movement of the sun with respect to other celestial bodies; marked for the first time the variations in the lunar altitudes in its orbit around the earth; calculated the length of both the solar and lunar years, of the seasons, the month and the day; named the constellations and the position of the Sun with respect to each one of

them, designed various chronometers (sundials, sand glasses, candle-water - mercury - and mechanical - clocks), constructed elaborate astronomical tables and treatises, described and explained many phenomena such as the Zodiacal light, rainbows, lightening and thunder storms; constructed calendars 600 years before the Gregorian calendar, and are said to be even more accurate, introduced many Arabic names to the science of Astronomy which are still in use, etc. The names of distinguished Muslim astronomers and the titles of their works and analyses of their contributions can be found in books dealing with the “History of Science”, but I quote the following as example: SELECTED EXAMPLES OF DISTINGUISHED MUSLIM ASTRONOMERS 1- Al-Fazzari Ibrahim (D. 160 A.H.) and his son Muhammad (D.180 A.H.) who constructed the first Astrolabe wrote on the use of the armillary sphere and prepared tables according to the Hijri Calendar. At least six treatises written by Ibrahim Al-Fazzari in Astronomy are still intact. 2- Al-Baghdady (2nd Century A-H.). 3- Ibn Hayyan (D. 197 A.H.) who wrote 19 treatises about celestial bodies and 16 in astronomy. 4- Sanad bin Aly (3rd Century A.H.) who wrote 5 books on mathematical astronomy. 5- Al-Firghany (3rd Century A.H.) who developed and modified the sundial, and calculated the diameters of each of the Earth, the Moon, the Sun, Mars, Jupiter and Saturn with great precision... At least 3 of his written manuscripts on astronomy are still intact. 6- Al-Khuwarizmy (D. 235 A.H.) The great astronomer, mathematician, geographer, historian, and the innovator of the science of ‘Algorism'. His book entitled Hisab AI-Jabre wa Al-Muqabalah” was translated into Latin by Gerard of Cremona, Robert of Chester and Adelard Bath and much later into English by F.Rosen (1831). This book introduced the science of Algebra to the Europeans and was used as the principal textbook for mathematics in their universities until the end of the 16th century A.C. Al-Khuwarizmy wrote 7 treatises on astronomy which have all been translated into Latin. 7- Al-Marwazi (D. 250 A.H.) who wrote many treatises in astronomy, of which only 11 have survived. 8- Al-Kindi (D. 252 A.H.) who wrote more than 265 manuscripts on different subjects, including astronomy and mathematics. At least 20 treatises on astronomy are still intact including one on calculating the distance between the Earth and the

Moon, another on telescopes, a third on the engineering of the Astrolabe, a fourth on the Zodiacal light and a fifth on moving bodies and the true nature of light and darkness. 9- Abou Ma’ashar (D. 264 A.H.) who wrote a tabulated astronomical treatise which remained for centuries one of the main sources of astronomical knowledge. Four of his works were translated into Latin by Johannes Hispatensis and Adelard of Bath. 10- Al-Sarkhasi, lbn Al-Tayyeb (D. 286 A.H.) who wrote an astronomical treatise entitled “The Introduction to the profession of stellar observation". 11- Thabit bin Qurrah (D. 287 A.H.) who wrote more than twenty memoirs on astronomy and geometry, invented the sundial, the balance and wrote elaborately on the altitude of the Sun and the length of the solar year. His treatise on the balance was translated into Latin by Gerard of Cremona. He was followed in his profession (Astronomy, Geometry and Mathematics) by his Sons Ibrahim and Sinan, his grandsons Thabit bin Sinan and Ibrahim bin Sinan, and great-grandson Abou Al-Faraj. Besides his interest in Astronomy, Geometry and Mathematics, Thabit was a skillful physician, while Ibrahim showed his distinction in geometry. His quadrature of the parabola was the simplest ever made before the introduction of integral calculus. 12- Al-Balancy (D. 296 A.H.) who wrote a large number of astronomical tables. 13- Banu Musa Bin Shakir (Muhammad, Ahmad & Hassan) who lived during the 3rd Century A.H. and were outstanding researchers in the field of astronomy, geometry, mechanics and engineering. They calculated the mean movement of the Sun and other celestial bodies, ascertained with remarkable precision the obliquity for the ecliptic, and marked for the first time the variations in the lunar altitudes. They also determined with great accuracy the precession of the equinoxes and the movement of the solar apogee, calculated the size of the earth, invented the telescope, recorded the movements of heavenly bodies and wrote about the measurements of plane and spherical surfaces. This last work of theirs was translated into Latin by Gerard of Cremona, and their treatise on mechanics is still preserved in the Vatican. 14- Al-Baalabakky (D. 300 A.H.) who has at least 2 preserved manuscripts on astronomy and orbits and the other on “the use of the armillary sphere”. 15- Al-Tibreezy (D. 310 A.H.) of whose works at least 5 manuscripts on astronomy are still intact. 16- Bin Hameed (Al-Aadamy) who lived towards the end of the 3rd and the beginnings of the 4th centuries A.H., and of whose works we know at least one astronomical treatise with tables (Zeej).

17- A1-Madainy (Al-Alawi) who also lived towards the end of the 3rd and the beginnings of the 4th centuries A.H. and also has a large astronomical treatise with tables (Al-Zeej Al-Kabeer). 18- Al-Battany (D. 318 A.H.) was the greatest astronomer of this time, and lived at Al-Raqqah (on the left bank of the Euphrates). His works on astronomy and spherical trigonometry influenced the whole of Europe during the middle Ages and the Renaissance and were repeatedly quoted by Copernicus in his book “De Revolutionibus Orbium Coelestium". According to Ibn Al-Nadeem (1871-1872) we only know one of his numerous works that is still intact which is a treatise on astronomy with detailed tables (al-Zeej). This work was translated into Latin by both Robertus Retinensis and Plato Tiburtinus (in the first half of the 12th Century A.C. and was published in Nuremberg in 1537). It was later edited and translated into Italian by C.A. Nallino and J.M. Millas. In this book, Al-Battany determined with great accuracy the inclination angle of the ecliptic and the possibility of the annular eclipse, , die length (If the tropic year and of the seasons, the true and mean orbits of the sun; discovered the mobility of the solar apogee, as a result of the precession of the equinoxes which he accurately measured ( and mentioned that, in consequence, the equation of time must he subject to a slow secular variation), calculated the variation of the apparent angular diameter of the Sun, rectified orbits of the Moon and planets, and suggested a new, ingenius theory for the determination of the conditions of visibility of the new Moon. His excellent observations on lunar and solar eclipses were used by Dunthome 1749 A.C to determine the secular acceleration of motion of the Moon. 19- Al-Harrany Al-Sabi’ey (D. 384 A.H.) of whose works we only know one tabulated treatise on astronomy. 20- Al-Balkhy (D. 323 A.H.) who wrote more than 70 treatises on astronomy and geography. 21- Al-Jealy (D. 350 A.H.) who wrote 6 known treatises and tables on astronomy. 22- Al-Shareef AI-Baghdady (D. 375 A.H.) of whose astronomical works we only know one treatise with tables. 23- Al-Soufy (D. 364 A.H.) who wrote an illustrated treatise on fixed stars, giving their magnitudes and coordinates, based on his own observations. It is considered the first star atlas to take cognizance of the nebula in the constellation Andromeda, and was translated into French. The book is of great importance even today, as it reveals the changes in magnitude undergone by a number of prominent stars in the course of ten centuries. 24- Abou Al-Wafaa Al-Buzjany (D. 376 A.H.) who wrote extensively on algebra, mathematics, geometry, spherical trigonometry, and astronomy, introduced the use of the secant and the tangent in astronomical observations, and defined methods for

finding the value of chords of arcs, and for constructing sine tables. At least 4 of his valuable works are still available, including a large treatise on astronomy. 25- Abou Saqre Al-Qubaissy (D. 380 A.H.) who revised AlFirghanys work and wrote at least three astronomical treatises. 26- Al-Majreety (D. 385 A.H.) who was one of the most eminent astronomers of Cordova. He revised and edited the works of both Al-Khuwarizmy and Al-Battany, and left at least 3 valuable works on astronomy. 27- Ibn Younus Al-Sadafi (D. 399 A.H.) who wrote a tabulated treatise on astronomy that was translated into Persian, Greek, Mangolian and Chinese languages. He also invented the pendulum which was successfully used in measuring time during his celestial observations and in constructing mechanical clocks. 28- A1-Kouhy (D. 405 A.H.) who wrote elaborately on the astrolabe geometry, spherical geometry and astronomy. He studied the movements of the planets, discovered the summer solstice and the autumnal equinox, and left at least 3 valuable works. 29- Ibn Al-Samhe Al-Ghirnaty (D. 426 A.H.) who left behind 3 treatises on astronomy. 30- Abou Al-Qasim Bin Al-Saffar (D. 426 A.H.) of whose work we know two major treatises on astronomy. 31- Al-Kirmany, Abu Al-Hakam (D. 458 A.H.), who was an eminent mathematician, astronomer, engineer and surgeon. He studied astronomy at the hands of A1-Majreety and left a number of manuscripts in that area. 32- Ibn Iraq (who lived during the late 4th and the early 5th centuries A.H.) and left a wealth of literature on astronomy of which we know at least 9 treatises. 33- Al-Bayrouni (D. 443 A.H.) who is considered the most profound and original scientist in human history, with contributions in very many disciplines that were centuries ahead of his time. Among his astronomical contributions is the precise determination of the magnitude of both the earth’s radius and circumference, the scientific discussion of the then controversial rotation of the earth on its own axis, the accurate definition of latitudes and longitudes, the correct explanation of numerous astronomical phenomena like the Zodiacal light, the excessive speed of light as compared to sound and the much greater radius of the sun as compared to both moon and earth, among his comprehensive treatises are the one entitled “Al-Qanoun Al~Masa’udi Fi Al-Haya’at Wa Al-Nujoum”, and “Kitab Al-Tafheem Li Aw’ail Sanat Al-Tanjeem”. An English translation of the latter book, facing the Arabic text was published 1939 in London by Ramsay Wright. (His written works

amount to about 180 manuscripts, some of which has been translated into many languages. 34- Ibn Hayy (D. 456 A.H.) who wrote a tabulated treatise on astronomy. 35- Al-Zarqaly (D. 480 A.H.) who was reputed for his talent in inventing and constructing astronomical equipments and tables, as well as contributions to the field of astronomy. He correctly determined the degree of inclination of the ecliptic within one minute of arc, and his works were translated into Latin, and were quoted by Copernicus in his book De Revolutionibus Orbium Coelestium. 36- Al-Isfizary (D. 480 A.H.) who critically reviewed the works of Euclid and of Banu Musa Bin Shaker and wrote 3 manuscripts on geometry, surveying and mechanical contrivances. 37- Bin Aflaj (who lived during the later years of the 5th and the earlier years of the 6th centuries A.H.) and wrote 9 manuscripts in the area of Astronomy. 38- Omar Al-Khayyam (D. 516 A.H. 1123 A.C.) who together with Abd Al-Rahman Al-Khazini supervised the Nishapur observatory, collaborated in the reformation of the Persian calendar (which preceded the Gregorian calendar by 600 years and is said to be even more exact), and was one of the greatest mathematicians, astronomers and poets of his time. 39- A1-Hakeem A1-Dany (D. 529 A.H.) who wrote on geometry (2 manuscripts), astronomy and astronomical equipments (2 manuscripts). 40- Ibn Bajah (D. 530) who was an outstanding physician, philosopher, mathematician, botanist and astronomer. Some of his works are translated into both Spanish and English. 41- Al-Badeea Al-Astrolaby Al-Baghdady (D. 534 A.H.) who wrote on astronomy and astronomical equipments two manuscripts at least. 42- AI-Batroujy (D. 582 A.H.) who wrote a treatise on astronomy that was translated into Latin by Kalonymos ben David and into Hebrew by Moses bin Tibbon. Some of his original contributions were the discovery of the spinning movements of the planets. 43- Al-Mosely (D. 639 AM.) of whose work we know two manuscripts on astronomy. 44- Al-Asfouny (D. 649 A.H.) who wrote on both geometry and astronomy invented both the armillary sphere and the water-wheel and wrote in other fields.

45- Al-Morrakeshy (D. 660 AM.) of whose astronomical writings we have at least two manuscripts: one on viewing the moon and the other on the measurement of time. 46- Al-Saheb Al-Labboudy, Najm Al-Deen (D. 670 A.H.) who wrote two lengthy treatises on astronomy. 47- Al-Tousi (D. 672 A.H. -1274 A.C.) the famous astronomer, mathematician, physicist, geologist, natural scientist, physician, philosopher and theologian, who wrote the "Al-khanian Astronomical Tables”, constructed the famous Maraghah Observatory and the one at Samarqand These were equipped with the best available instruments of the time, e.g. ecliptical, solisticial and equatorial armillary spheres, Mural quadranis, etc. The Maraghah Observatory also housed a very big library, which was described to contain more than 4,000,000 manuscripts. He wrote a number of astronomical treatises of which the most important is “Kitab Al--Tathkirah Fi ‘Ilm Al-Haya’ah” or “The Memoir of Astronomy”, which is a complete survey of astronomical knowledge until his time. This manuscript was a landmark in the development of astronomy, and hence was reviewed by a large number of authors and translated into several Eastern as well as Western languages. In the field of astronomy, Tousi also wrote:

(i) “The Cream of Astronomy” which is still extant in both Arabic and Persian. (ii) “The Stars Made Easy”. (ii) “On the Trajectory, Size and Distance of Mercury". (iv) “Rising and Setting”. (v) “On The Moving Sphere”.

(vi) “On the size and distances of the Sun and the Moon". (vii) “On the ascension of Stars”. (viii) “Spherics”. (ix) “Days and nights”. (x) “Tazheer Al-Majesty”. (xi) “Research on the reflection and deflection of light rays". (xii) "The Book of optics".

48- Al-Hakeem Al-Maghriby (D. 680 A.H.) who wrote elaborately on astronomy, and left at least 10 manuscripts in that area. 49- Al -Shirazi (D. 709 A.H. - 1311 A.C.) who was Al-Tousi’s student and wrote a manuscript on Astronomy with the title “Nihayat Al-Idrak Fi Dirayat Al-Aflak” (or The Latest Knowledge in the Science of Planetary Orbits). Besides its main theme, astronomy, the book contains a wealth of knowledge on geometrical optics, like the nature of vision and the formation of the rainbow. 50- Ibn A1-Shater (D. 777 A.H.) who wrote an elaborate, tabulated treatise on astronomy (Al-Zeej Al-Jadeed) from which Copernicus drew most of his information without acknowledging that. He is also credited for measuring the angle of inclination of the Zodiacal Sphere with great precision, and inventing a chronometric instrument for defining the exact time of prayer. 51- Al-Majdy (D. 850 A.H.) who wrote 15 manuscripts on astronomy and elaborated on sighting the Moon, on Saturn, the luni-solar calendar, and the application of geometry in astronomy. 52- Ulugh Beg (D. 853 A.H. - 1440 A.C.) who was interested in astronomy, published a stellar catalogue and tables, comparing his observations with those of previous workers such as AI-Sufi, and erected a large observatory at Samarquand, where a group of distinguished astronomers did work. 53- Badre Al-Deen (D. 907 A.H.) who wrote 6 manuscripts on astronomy and geometry. 54- Salah Al-Deen Qadhi Zadeh (D. 940 A.H.) who revised the astronomical work of Ulugh Beg and published his astronomical tables. 55- Al-Kaslii (D. 851) LII. - 1436 At.) Who was the first director of the observatory at Samarquand, a great astronomer and mathematician, prepared a number of astronomical tables and maps including “Zeej Al-Khaqani”. 56- Al-Qashji (D. 878 A.H. - 1474 A.C.) who prepared the astronomical tables of Ulugh Beg. These tables were edited, translated and published into both the Persian and Latin languages by J. Greaves & T. Hyde (1650-1665), and its introduction was translated into French by Sedillot (1846). Such work was highly treasured in Europe as an excellent source for astronomical information until the mid-nineteenth century A.C.