Al-Biruni

For the lunar crater, see Al-Biruni (crater). For the university, see Al-Beroni University.

Al-Bīrūnī
An imaginary rendition of Al Biruni on a 1973 Soviet post stamp
Born	4 September 973 Kath, Khwarezm, Persia (modern-day Beruniy, Beruniy District, Karakalpakstan, Uzbekistan)
Died	9 December 1048 (aged 75) Ghazni, Ghaznavid Empire (modern-day Afghanistan)
Academic background
Influences	Muhammad, Aristotle, Ptolemy, Aryabhata, Brahmagupta, Abū Ḥanīfa Dīnawarī, Rhazes, al-Sijzi, Iranshahri, Abu Nasr Mansur, Avicenna, al-Battani, Al-Tamimi
Academic work
Era	Islamic Golden Age
Main interests	Geology, physics, anthropology, comparative sociology, astronomy, astrology, chemistry, history, geography, mathematics, medicine, psychology, philosophy, theology
Notable works	The Remaining Signs of Past Centuries, Gems, Indica, The Mas'udi Canon, Understanding Astrology
Influenced	Al-Sijzi, Avicenna, Omar Khayyam, al-Khazini, Zakariya al-Qazwini, Maragha observatory, Islamic science, Islamic philosophy

Abū Rayḥān Muḥammad ibn Aḥmad Al-Bīrūnī (Chorasmian/Persian: ابوریحان بیرونی Abū Rayḥān Bērōnī; New Persian: Abū Rayḥān Bīrūnī) (4 September 973 – 9 December 1048), known as Al-Biruni (Arabic: البيروني) in English, was a Turkish scholar and polymath from Khwarezm.

Al-Biruni is regarded as one of the greatest scholars of the medieval Islamic era and was well versed in physics, mathematics, astronomy, and natural sciences, and also distinguished himself as a historian, chronologist and linguist. He studied almost all fields of science and was compensated for his research and strenuous work. Royalty and powerful members of society sought out Al-Biruni to conduct research and study in order to uncover certain findings. He lived during the Islamic Golden Age, in which scholarly thought went hand in hand with the thinking and methodology of the Islamic religion. In addition to this type of influence, Al-Biruni was also influenced by other nations, such as the Greek, who he took inspiration from when he turned to studies of philosophy. He was conversant in Khwarezmian, Persian, Arabic, Sanskrit, and also knew Greek, Hebrew and Syriac. He spent a large part of his life in Ghazni in modern-day Afghanistan, capital of the Ghaznavid dynasty which was based in what is now central-eastern Afghanistan. In 1017 he traveled to the Indian subcontinent and authored Tarikh Al-Hind (History of India) after exploring the Hindu faith practised in India. He was given the title "founder of Indology". He was an impartial writer on customs and creeds of various nations, and was given the title al-Ustadh ("The Master") for his remarkable description of early 11th-century India. He also made contributions to Earth sciences, and is regarded as the "father of geodesy" for his important contributions to that field, along with his significant contributions to geography.

Life

He was born in the outer district of Kath, the capital of the Afrighid dynasty of Khwarezm (now a part of Uzbekistan, Kazakhstan, and Turkmenistan) (or Chorasmia). The word Biruni means "from the outer-district" in Persian, and so this became his nisba: "al-Bīrūnī" = "the Birunian". Al-Biruni's relatives also took interest in the studies of science as well, so he grew up in an environment encouraging to his interests. He even had ties to royalty as there are links in his family to the families of prestigious elites. In order to conduct his research, Al-Biruni used different types of methods to tackle the different fields he studied. People consider Al-Biruni to be one of the greatest scientists in history and especially of Islam because of his discoveries and methodology. He lived during the Islamic Golden Age, which promoted astronomy and encouraged all scholars to work on their research. Al-Biruni spent the first twenty-five years of his life in Khwarezm where he studied Islamic jurisprudence, theology, grammar, mathematics, astronomy, medics, philosophy and also dabbled in the field of physics and most other sciences as well. The Iranian Khwarezmian language, which was the language of Biruni, survived for several centuries after Islam until the Turkification of the region, and so must some at least of the culture and lore of ancient Khwarezm, for it is hard to see the commanding figure of Biruni, a repository of so much knowledge, appearing in a cultural vacuum. He was sympathetic to the Afrighids, who were overthrown by the rival dynasty of Ma'munids in 995. He left his homeland for Bukhara, then under the Samanid ruler Mansur II the son of Nuh. There he corresponded with Avicenna and there are extant exchanges of views between these two scholars.

In 998, he went to the court of the Ziyarid amir of Tabaristan, Shams al-Mo'ali Abol-hasan Ghaboos ibn Wushmgir. There he wrote his first important work, al-Athar al-Baqqiya 'an al-Qorun al-Khaliyya (literally: "The remaining traces of past centuries" and translated as "Chronology of ancient nations" or "Vestiges of the Past") on historical and scientific chronology, probably around 1000 A.D., though he later made some amendments to the book. He also visited the court of the Bavandid ruler Al-Marzuban. Accepting the definite demise of the Afrighids at the hands of the Ma'munids, he made peace with the latter who then ruled Khwarezm. Their court at Gorganj (also in Khwarezm) was gaining fame for its gathering of brilliant scientists.

In 1017, Mahmud of Ghazni took Rey. Most scholars, including al-Biruni, were taken to Ghazni, the capital of the Ghaznavid dynasty. Biruni was made court astrologer and accompanied Mahmud on his invasions into India, living there for a few years. He was forty-four years old when he went on the journeys with Mahmud of Ghazni. Biruni became acquainted with all things related to India. He may even have learned some Sanskrit. During this time he wrote the Kitab ta'rikh al-Hind, finishing it around 1030. Along with his writing, Al-Biruni also made sure to extend his study to science while on the expeditions. He sought to find a method to measure the height of the sun and created an early version of an astrolabe in order to do so. Al-Biruni was able to make much progress in his study over the frequent travels that he went on throughout the lands of India.

Mathematics and astronomy

An illustration from al-Biruni's astronomical works, explains the different phases of the moon.

Diagram illustrating a method proposed and used by Al-Biruni to estimate the radius and circumference of the Earth

Ninety-five of 146 books known to have been written by Bīrūnī were devoted to astronomy, mathematics, and related subjects like mathematical geography. His religion contributed to his research of astronomy, as in Islam, Muslim customs require knowing the directions of certain sacred locations, which can actually be found through this type of scientific study. Biruni's major work on astrology is primarily an astronomical and mathematical text, only the last chapter concerns astrological prognostication. His endorsement of astrology is limited, in so far as he condemns horary astrology as 'sorcery'.

In discussing speculation by other Muslim writers on the possible motion of the Earth, Biruni acknowledged that he could neither prove nor disprove it, but commented favourably on the idea that the Earth rotates. He wrote an extensive commentary on Indian astronomy in the Kitab ta'rikh al-Hind, in which he claims to have resolved the matter of Earth's rotation in a work on astronomy that is no longer extant, his Miftah-ilm-alhai'a (Key to Astronomy):

[T]he rotation of the earth does in no way impair the value of astronomy, as all appearances of an astronomic character can quite as well be explained according to this theory as to the other. There are, however, other reasons which make it impossible. This question is most difficult to solve. The most prominent of both modern and ancient astronomers have deeply studied the question of the moving of the earth, and tried to refute it. We, too, have composed a book on the subject called Miftah-ilm-alhai'a (Key to Astronomy), in which we think we have surpassed our predecessors, if not in the words, at all events in the matter.

In his description of Sijzi's astrolabe he hints at contemporary debates over the movement of the earth. He carried on a lengthy correspondence and sometimes heated debate with Ibn Sina, in which Biruni repeatedly attacks Aristotle's celestial physics: he argues by simple experiment that vacuum must exist; he is "amazed" by the weakness of Aristotle's argument against elliptical orbits on the basis that they would create vacuum; he attacks the immutability of the celestial spheres; and so on.

In his major extant astronomical work, the Mas'ud Canon, Biruni utilizes his observational data to disprove Ptolemy's immobile solar apogee. Not only did he perform research on theories, but he also wrote an in-depth analysis and explanation of an astrolabe and how it should work. He drew many different depictions of various instruments that are considered to be the precursors of more modern objects such as clocks and the astrolabe, in which other scientists were able to use to complete these inventions in the coming years. More recently, Biruni's eclipse data was used by Dunthorne in 1749 to help determine the acceleration of the moon and his observational data has entered the larger astronomical historical record and is still used today in geophysics and astronomy.

Physics

Al-Biruni contributed to the introduction of the experimental scientific method to mechanics, unified statics and dynamics into the science of mechanics, and combined the fields of hydrostatics with dynamics to create hydrodynamics. He came up with different methods in order to explore densities, weight, and even gravity. Along with those methods, Biruni went so far as to describe instruments that go along with each of those areas as well. Although he never entirely focuses just on physics in any of his books, the study of physics is present throughout many of his various works. Biruni also came up with different hypotheses about heat and light.

Geography

Four directions and Political divisions of Iran by Abū Rayḥān al-Bīrūnī

Bīrūnī also devised his own method of determining the radius of the earth by means of the observation of the height of a mountain and carried it out at Nandana in Pind Dadan Khan (present-day Pakistan). He was heavily interested in the workings of the earth and included research about the planet in many of his works. The result of his discovery of radius measurement was due to Biruni's arduous research about the earth.

See also: History of geodesy § Al-Biruni

Pharmacology and mineralogy

Biruni's most important work was a major pharmacopoeia, the "Kitab al-saydala fi al-tibb" (Book on the Pharmacopoeia of Medicine), describing essentially all the medicines known in his time. It lists synonyms for drug names in Syriac, Persian, Greek, Baluchi, Afghan, Kurdi, and some Indian languages.

Due to an apparatus he constructed himself, he succeeded in determining the specific gravity of a certain number of metals and minerals with remarkable precision.

History and chronology

Biruni's main essay on political history, Kitāb al-musāmara fī aḵbār Ḵᵛārazm (Book of nightly conversation concerning the affairs of Ḵᵛārazm) is now known only from quotations in Bayhaqī’s Tārīkh-e masʿūdī. In addition to this various discussions of historical events and methodology are found in connection with the lists of kings in his al-Āthār al-bāqiya and in the Qānūn as well as elsewhere in the Āthār, in India, and scattered throughout his other works. Al-Biruni's study of history was not limited to the aforementioned topics, he also touched upon the topic of the earth's creation. He elaborated upon the fact that the earth was created from the elements and not solely through divine creation. Even though Islam did influence his study, he did acknowledge the role of the elements.

History of Religions

Bīrūnī is one of the most important Muslim authorities on the history of religion. Al-Biruni was a pioneer in the study of comparative religion. He studied Zoroastrianism, Judaism, Hinduism, Christianity, Buddhism, Islam, and other religions. He treated religions objectively, striving to understand them on their own terms rather than trying to prove them wrong. His underlying concept was that all cultures are at least distant relatives of all other cultures because they are all human constructs. "What al-Biruni seems to be arguing is that there is a common human element in every culture that makes all cultures distant relatives, however foreign they might seem to one another."

Al-Biruni divides Hindus into an educated and an uneducated class. He describes the educated as monotheistic, believing that God is one, eternal, and omnipotent and eschewing all forms of idol worship. He recognizes that uneducated Hindus worshipped a multiplicity of idols yet points out that even some Muslims (such as the Jabiriyya) have adopted anthropomorphic concepts of God.

Indology

Bīrūnī’s fame as an Indologist rests primarily on two texts. Al-Biruni wrote an encyclopedic work on India called “Tarikh Al-Hind” (History of India) in which he explored nearly every aspect of Indian life, including religion, history, geography, geology, science, and mathematics. During his journey through India, military and political histories were not of Al-Biruni's main focus. Instead, he decided to document the more civilian and scholarly areas of Hindu life such as culture, science, and religion. He explores religion within a rich cultural context. He expresses his objective with simple eloquence:

I shall not produce the arguments of our antagonists in order to refute such of them, as I believe to be in the wrong. My book is nothing but a simple historic record of facts. I shall place before the reader the theories of the Hindus exactly as they are, and I shall mention in connection with them similar theories of the Greeks in order to show the relationship existing between them.(1910, Vol. 1, p. 7;1958, p. 5)

An example of Al-Biruni’s analysis is his summary of why many Hindus hate Muslims. Biruni notes in the beginning of his book how the Muslims had a hard time learning about the Hindu knowledge and culture. He explains that Hinduism and Islam are totally different from each other. Moreover, Hindus in 11th century India had suffered through waves of destructive attacks on many of its cities, and Islamic armies had taken numerous Hindu slaves to Persia which, claimed Al-Biruni, contributed to Hindus becoming suspicious of all foreigners, not just Muslims. Hindus considered Muslims violent and impure, and did not want to share anything with them. Over time, Al-Biruni won the welcome of Hindu scholars. Al-Biruni collected books and studied with these Hindu scholars to become fluent in Sanskrit, discover and translate into Arabic the mathematics, science, medicine, astronomy and other fields of arts as practiced in 11th century India. He was inspired by the arguments offered by Indian scholars who believed earth must be globular in shape, which is the only way to fully explain the difference in daylight hours by latitude, seasons and earth's relative positions with moon and stars. At the same time, Al-Biruni was also critical of Indian scribes who he believed carelessly corrupted Indian documents while making copies of older documents. He also criticized the Hindus on what he saw them do and not do, like their deficiencies in curiosity about history and religion. Al-Biruni's translations as well as his own original contributions reached Europe in 12th and 13th century, where they were actively sought.

One of the specific aspects of Hindu life that Al-Biruni studied was the Hindu calendar. His scholarship on the topic exhibited great determination and focus, not to mention the excellence in his approach of the in-depth research he performed. He developed a method for converting the dates of the Hindu calendar to the dates of the three different calendars that were common in the Islamic countries of his time period, the Greek, the Arab/Muslim, and the Persian. Biruni also employed astronomy in the determination of his theories, which were complex mathematical equations and scientific calculation that allows one to convert dates and years between the different calendars.

The book does not limit itself to tedious records of battle because Al-Biruni found the social culture to be more important. The work includes research on a vast array of topics of Indian culture, including descriptions of their traditions and customs. Although he tried to stay away from political and military history, Biruni did indeed record important dates and noted actual sites of where significant battles occurred. Additionally, he chronicled stories of Indian rulers and told of how they ruled over their people with their beneficial actions and acted in the interests of the nation. But, his details are brief and mostly just list rulers without referring to their real names. He did not go on about deeds that each one carried out during their reign, which keeps in line with Al-Biruni's mission to try to stay away from political histories. Al-Biruni also described the geography of India in his work. He documented different bodies of water and other natural phenomena. These descriptions are useful to today's modern historians because they are able to use Biruni's scholarship to locate certain destinations in modern-day India. Historians are able to make some matches while also concluding that certain areas seem to have disappeared and been replaced with different cities. Different forts and landmarks were able to be located, legitimizing Al-Biruni's contributions with their usefulness to even modern history and archeology.

The dispassionate account of Hinduism given by Al-Biruni was remarkable for its time. He stated that he was fully objective in his wrtitings, remaining unbiased like a proper historian should. Biruni documented everything about India just as it happened. But, he did note how some of the accounts of information that he was given by natives of the land may not have been reliable in terms of complete accuracy, however, he did try to be as honest as possible in his writing. Mohammad Yasin compares it to "a magic island of quiet, impartial research in the midst of a world of clashing swords, burning towns, and plundered temples.”

Biruni's writing was very poetic, which may diminish some of the historical value of the work for modern times. The lack of description of battle and politics makes those parts of the picture completely lost. However, Al-Biruni's work has been used by many in order to check the facts of history in other works that may have been ambiguous in meaning or had their validity questioned.

Works

Most of the works of Al-Biruni are in Arabic although he wrote one of his masterpieces, the Kitab al-Tafhim apparently in both Persian and Arabic, showing his mastery over both languages. Bīrūnī’s catalogue of his own literary production up to his 65th lunar/63rd solar year (the end of 427/1036) lists 103 titles divided into 12 categories: astronomy, mathematical geography, mathematics, astrological aspects and transits, astronomical instruments, chronology, comets, an untitled category, astrology, anecdotes, religion, and books of which he no longer possesses copies. His extant works include:

• Critical study of what India says, whether accepted by reason or refused (Arabic تحقيق ما للهند من مقولة معقولة في العقل أم مرذولة), also known as the Indica – a compendium of India's religion and philosophy
• The Book of Instruction in the Elements of the Art of Astrology (Kitab al-tafhim li-awa’il sina‘at al-tanjim).
• The Remaining Signs of Past Centuries (Arabic الآثار الباقية عن القرون الخالية) – a comparative study of calendars of different cultures and civilizations, interlaced with mathematical, astronomical, and historical information.
• The Mas'udi Canon (Persian قانون مسعودي) – an extensive encyclopedia on astronomy, geography, and engineering, named after Mas'ud, son of Mahmud of Ghazni, to whom he dedicated.
• Understanding Astrology (Arabic التفهيم لصناعة التنجيم) – a question and answer style book about mathematics and astronomy, in Arabic and Persian.
• Pharmacy – about drugs and medicines.
• Gems (Arabic الجماهر في معرفة الجواهر) about geology, minerals, and gems, dedicated to Mawdud son of Mas'ud.
• Astrolabe.
• A historical summary book.
• History of Mahmud of Ghazni and his father.
• History of Khawarezm.

Persian work

Biruni wrote most of his works in Arabic, as the scientific language of his age, however, his Persian version of the Al-Tafhim is one of the most important of the early works of science in the Persian language, and is a rich source for Persian prose and lexicography. The book covers the Quadrivium in a detailed and skilled fashion.

Legacy

Lunar crater Al-Biruni, on the far side of the Moon, as seen by Apollo 14

The lunar crater Al-Biruni and the asteroid 9936 Al-Biruni were named in his honour.

In June 2009 Iran donated a scholar pavilion to United Nations Office in Vienna which is placed in the central Memorial Plaza of the Vienna International Center. The Persian Scholars Pavilion at United Nations in Vienna, Austria is featuring the statues of four prominent Iranian figures. Highlighting the Iranian architectural features, the pavilion is adorned with Persian art forms and includes the statues of renowned Iranian scientists Avicenna, Abu Rayhan Biruni, Zakariya Razi (Rhazes) and Omar Khayyam.

The statue of Al-Biruni in Persian Scholars Pavilion, United Nations Office in Vienna, Austria

The statue of Al-Biruni in United Nations Office in Vienna as a part of Persian Scholars Pavilion donated by Iran

Notes and references

Notes

Citations

Bibliography

• C.E. Bosworth, "BĪRŪNĪ, ABŪ RAYḤĀN i. Life" in Encyclopædia Iranica [4] (accessed April 2011)
• David Pingree, ""BĪRŪNĪ, ABŪ RAYḤĀN ii. Bibliography", in Encyclopædia Iranica [5] (accessed April 2011)
• George Saliba, "BĪRŪNĪ, ABŪ RAYḤĀN iii. Mathematics and Astronomy" in Encyclopædia Iranica [6] (accessed April 2011)
• David Pingree, "BĪRŪNĪ, ABŪ RAYḤĀN iv. Geography" in Encycloapedia Iranica [7] (accessed April 2011)
• Georges C. Anawati, "BĪRŪNĪ, ABŪ RAYḤĀN v. Pharmacology and Mineralogy" in Encycloapedia Iranica [8] (accessed April 2011)
• David Pingree, "BĪRŪNĪ, ABŪ RAYḤĀN vi. History and Chronology" in Encyclpaedia Iranica [9] (accessed April 2011)
• François de Blois, "BĪRŪNĪ, ABŪ RAYḤĀN vii. History of Religions", in Encyclopædia Iranica [10] (accessed April 2011)
• Douglas, A. Vibert (1973), "Al-Biruni, Persian Scholar, 973–1048", Journal of the Royal Astronomical Society of Canada, 67: 209–211, Bibcode:1973JRASC..67..209D {{citation}}: Invalid |ref=harv (help)
• Bruce B. Lawerence, "BĪRŪNĪ, ABŪ RAYḤĀN viii. Indology", in Encyclopædia Iranica [11] (accessed April 2011)
• Yano, Michio (2007), "Bīrūnī: Abū al‐Rayḥān Muḥammad ibn Aḥmad al‐Bīrūnī", in Thomas Hockey; et al. (eds.), The Biographical Encyclopedia of Astronomers, New York: Springer, pp. 131–3, ISBN 978-0-387-31022-0| (PDF version)
• Kennedy, E. S. (2008) [1970–80], "Al-Bīrūnī (or Bērūnī), Abū Rayḥān (or Abu'l-Rayḥān) Muḥammad Ibn Aḥmad", Complete Dictionary of Scientific Biography, Encyclopedia.com
• Glick, Thomas F.; Livesey, Steven John; Wallis, Faith (2005), Medieval Science, Technology, and Medicine: An Encyclopedia, Routledge, ISBN 0-415-96930-1
• Abulfadl naba’I (1986), Calendar-making in the History, Astan Ghods Razavi Publishing Co.
• Abolghassem Ghorbani; Markaze Nashre Daneshgahi (1995), Biruni Name, ISBN 964-01-0756-5
• Kiple, Kenneth F.; Ornelas, Kriemhild Coneè (2001), The Cambridge World History of Food, Cambridge University Press, ISBN 0-521-40216-6
• Rashed, Roshdi; Morelon, Régis (1996), Encyclopedia of the History of Arabic Science, vol. 1 & 3, Routledge, ISBN 0-415-12410-7
• Saliba, George (1994), A History of Arabic Astronomy: Planetary Theories During the Golden Age of Islam, New York University Press, ISBN 0-8147-8023-7
• Dani, Ahmed Hasan (1973), Alberuni's Indica: A record of the cultural history of South Asia about AD 1030, University of Islamabad Press
• Samian, A.L. (2011), "Reason and Spirit in Al-Biruni's Philosophy of Mathematics", in Tymieniecka, A-T. (ed.), Reason, Spirit and the Sacral in the New Enlightenment, Islamic Philosophy and Occidental Phenomenology in Dialogue, vol. 5, Netherlands: Springer, pp. 137–146, doi:10.1007/978-90-481-9612-8_9, ISBN 978-90-481-9612-8
• Biruni, Abu al-Rayhan Muhammad ibn Ahmad al- (1910), E. Sachau (ed.), Al-Beruni's India: an Account of the Religion, Philosophy, Literature, Geography, Chronology, Astronomy, Customs, Laws and Astrology of Indiae, London: Kegan Paul, Trench, Trubner & Co.
• Rosenthal, F. (1976), E. Yarshter (ed.), Al-Biruni between Greece and India, New York: Iran Center, Columbia University
• Yasin, M. (1975), Al-Biruni in India, Islamic Culture
• Ataman, K. (2005), Re-Reading al-Biruni's India: a Case for Intercultural Understanding, Islam and Christian-Muslim Relations

Further reading

• On the Presumed Darwinism of Alberuni Eight Hundred Years before Darwin Jan Z. Wilczynski Isis Vol. 50, No. 4 (Dec., 1959), pp. 459–466 (article consists of 8 pages) Published by: The University of Chicago Press on behalf of The History of Science Society Stable URL: [12]

External links

• BĪRŪNĪ, ABŪ RAYḤĀN in Encyclopaedia Iranica
• Gomez, A. G. (2010) Biruni's Measurement of the Earth [online], http://www.academia.edu/8166456/Birunis_measurement_of_the_Earth
• Gomez, A. G. (2012) Biruni's Measurement of the Earth Geogebra interactive illustration.
• Richard Covington, Rediscovering Arabic Science, 2007, Saudi Aramco World
• "Al-Biruni (973–1048)." Encyclopedia of Occultism and Parapsychology. 2001. Encyclopedia.com. 5 Feb. 2015.
• Al-Bīr Complete Dictionary of Scientific Biography | 2008 | Copyright
• "Abu Rayhan al-Biruni." Encyclopedia of World Biography. 2004. Encyclopedia.com. 5 Feb. 2015

Works of Al-Biruni online

• Hogendijk, Jan: The works of al-Bīrūnī – manuscripts, critical editions, translations and online links
• Elliot, H. M. (Henry Miers), Sir; John Dowson (1871), "1. Táríkhu-l Hind of Bírúní", The History of India, as Told by Its Own Historians. The Muhammadan Period., vol. 2, London : Trübner & Co.{{citation}}: CS1 maint: multiple names: authors list (link) (At Packard Institute)
• Sachau, Dr.Edward C. (1910), ALBERUNI'S INDIA – An account of ... India about A.D. 1030, Volume 1, vol. 1, Kegan Paul, Trench Trubner & Co.Ltd., London
• Sachau, Dr.Edward C. (1910), ALBERUNI'S INDIA – An account of ... India about A.D. 1030, Volume 2., vol. 2, Kegan Paul, Trench Trubner & Co. Ltd., London
• Alberuni's India, in English, Volume I. Translated by Dr. Edward C Sachau, 1910
• "On Stones": Biruni's work on geology, medical properties of gemstones full text version + comments