Contributions to science

The expectation asks you to analyse, not only to name. Look for the problem a person worked on, what came before, and what they added. Notice whether a contribution is a whole theory or one precise fix.

Read one scene from the record of al-Biruni's mountain-and-horizon measurement. Al-Biruni writes in the first person about living at Nandana fort in the land of India. A nearby mountain stood west of the fort, with a broad plain south of the mountain; he thought it suitable for testing the method ². From its summit he observed the apparent meeting of earth and sky and surveyed the perpendicular representing mountain height. The account joins place, choice, observation and number, without supplying every detail of the observation day ². The record also keeps the book apart from the event: the date it gives dates the book, not an independently established day of observation ^3 4.

For al-Biruni the record preserves no sentence in which he says what moved him to try the method; what it shows is the book's aim. The book places Earth measurement within correcting distances between cities, and the advantage the passage names is avoiding long desert traverses to obtain the circumference ⁵. For Ibn al-Shatir a historian names the problem: Victor Roberts says Ptolemy's lunar theory exaggerated the changing distance, whereas Ibn al-Shatir's double-epicycle arrangement reduced that defect ⁶. Ibn al-Shatir worked in Damascus as head timekeeper at the Umayyad Mosque ⁷. The records read here report no preface in which either man states a religious purpose, and the museum does not supply one.

How did the lunar model relate to Copernicus? The record gives two attributed readings. Roberts finds Copernicus's lunar construction structurally identical apart from small parameter differences ⁸. On transmission, Roberts in the 1957 article leaves the question open and allows independent solutions, while King later regards the reappearance of model details as evidence of some transmission ^9 10. The record adds that no named translator or particular Latin witness connecting this lunar theory with Copernicus has been established, and that Earth remains central in Ibn al-Shatir's model ^9 10. The museum decides nothing between the two readings.

The record is careful about what al-Biruni is credited with. It says the documented contribution is exposition, proof and numerical application, not the first recognition that Earth is spherical ^11 12. His own text reports Sanad ibn Ali accompanying al-Ma'mun on a campaign against the Byzantines, and the caliph ordered him up a mountain near the sea to measure the sun's dip, from which he derived Earth's circumference ¹³. The translator's preface calls the method the author's invention, so the record is marked "contested attribution" while retaining al-Biruni's specific contribution ¹⁴.

The witness actually read for al-Biruni is an illustrated English translation by Jamil Ali, published by the American University of Beirut ¹⁵. The preface itself warns about computational and figure-letter problems, sometimes difficult to assign to author or copyist ¹⁶. The record states that the museum has not inspected the original manuscript or read the whole book, and that only the abstract of Maslikov's article was read ^16 4 12. For Ibn al-Shatir, King distinguishes the surviving treatise from the observational work with no known copy ¹⁷. A manuscript copied within the author's lifetime, as Roberts describes it, is not thereby an autograph ¹⁸.

The translator's preface calls al-Biruni's method the author's invention, while the book's own text reports an earlier man, Sanad ibn Ali, doing the same thing under al-Ma'mun. Which would you trust more on who used the method first, a modern translator's preface or the author's report of a predecessor, and what further evidence would make you change your mind, and why?

• Al-Biruni's mountain-and-horizon measurement: the geometry, the sexagesimal numbers and the question of who used the method first.
• Ibn al-Shatir's lunar model: the two small circles, the numbers, and the comparison with Copernicus.
• Al-Biruni: his life and the discussion of how researchers read his affiliation.
• Ibn al-Shatir: the Damascus timekeeper and his works.