Scientists of the Islamic world and their fields

Look at the expectation's verb: it asks you to describe, not to rank. For each scientist, separate what the sources document from what later tradition adds, and note who came before.

Choose two or three points to compare, such as the field, the method and the kind of evidence, and use the same points for every scientist, whether Canadian or not.

Read one passage slowly. Al-Biruni writes in the first person about living at Nandana fort in the land of India ². 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 ². The record of the measurement says to read the figures carefully: the dip is 0;34 degrees, meaning 34 arcminutes, not 0.34 degrees, and the height is 652;3,18 regional cloth-measuring cubits ². It retains the numbers in their unit rather than selecting a modern cubit length to obtain an impressive answer ².

The museum's records hold no passage in which al-Biruni says why he measured the Earth, and they do not supply a motive for him. What they show is that his book is titled the Determination of the Coordinates of Positions for the Correction of Distances between Cities, that it places Earth measurement within correcting distances between cities, and that the passage's explicit advantage is avoiding long desert traverses to obtain circumference ³. The preface of his other book, al-Qanun al-Mas'udi, is quoted by its editor: he did not follow earlier zij-makers, who confined themselves to tabular settings and concealed how they had founded their rules, but joined to every procedure its reasons, so that the reader could approve or correct rather than imitate ^4 5. He opens that book with praise of God and of the sultan Mas'ud, and says that the rank of learning is the noblest in his eyes ^6 7.

Who first used the method? The translator's preface calls deriving the circumference from horizon dip the author's invention: Jamil Ali's reading ⁸. The main text reports Sanad ibn Ali accompanying al-Ma'mun on a campaign against the Byzantines; the caliph ordered him up a mountain near the sea to measure the sun's dip, from which he derived Earth's circumference ⁹. This is al-Biruni's transmitted account, not Sanad's field record independently inspected here; the record is marked "contested attribution" while retaining al-Biruni's specific contribution ⁸.

Researchers also differ on his school affiliation. Britannica explicitly identifies him as a Muslim scholar, and Günay Tümer discusses his commitment to Islam. Tümer's reading, which challenges a settled Shia classification, comes first, followed by the Shia and Zaydi classifications he reports from other researchers, without a museum verdict ^10 11.

It is easy to suppose that al-Biruni was the first to know that the Earth is round. The documented contribution is exposition, proof and numerical application, not the first recognition that Earth is spherical ¹². The passage begins with a method in Ptolemy's Geography, and the contrast is not between a flat Earth and a newly discovered sphere, but between ways to determine the size of the sphere already assumed in the calculation ¹³. A date is also misread: 416 AH/1025 CE belongs to the book reporting the experiment, not to the experiment itself ^14 15.

The witness actually read is an illustrated English translation by Jamil Ali, published by the American University of Beirut, with a February 1967 preface ¹⁶. Tümer identifies the book's manuscript in the Fatih collection, 3386, and Bulgakov's 1962 Cairo edition; Ali's preface says his translation used that edition ^17 18. The preface warns about computational and figure-letter problems, sometimes difficult to assign to author or copyist ¹⁸. The record has not inspected the original manuscript or read the whole book ^18 17. On accuracy, MacTutor offers a favourable 6339.6 km assessment, while Maslikov's abstract cautions about accuracy and the conversion of the historical unit; only the abstract was read ^19 20.

Jamil Ali's preface calls deriving the circumference from horizon dip the author's invention, while the text reports that Sanad ibn Ali applied the same principle under al-Ma'mun. Take a position on whether the museum should call al-Biruni the originator of the method, and answer the strongest objection to it: can someone who left a detailed exposition and application be an originator of a method that another is reported to have used first?

• Al-Biruni's mountain-and-horizon Earth measurement: the geometry, the sexagesimal figures, Sanad ibn Ali and the limits of the evidence.
• Al-Biruni: his life and works, and the disagreement over his affiliation as the record reports it.
• Al-Qanun al-Mas'udi: its preface and method, as the editor of the edition reports them.