Al-Farisi's Revision of the Optics

The Tanqih al-Manazir is Kamal al-Din al-Farisi's critical revision of Ibn al-Haytham's optics. Russell explains that it does not merely simplify a predecessor: it distinguishes earlier statements from the reviser's voice, disputes conclusions and proposes replacements. Access to the book followed encouragement by Qutb al-Din al-Shirazi, who secured a distant copy ².

Russell describes seven revised books, a sequel and three appendices, with questions involving halos, rainbows, burning spheres, shadows, light and eclipses. The rainbow model belongs to the sequel: the whole work should not be reduced to one experiment, nor every appendix counted as another name for it. Eye investigations are also reported, not presented as modern anatomy ³.

A water-filled sphere and a dark room with one aperture model the drop. The primary bow has two refractions separated by one internal reflection, the secondary two reflections. The colour explanation nevertheless failed. MacTutor also describes the additional glass boundaries and the author's approximation. These limits are not erased to make the Tanqih a modern spectral theory ^{4 5}.

Russell records competing dates before1290 or after1302 and before the teacher's death in1311. A surviving copy's date does not settle composition. MacTutor reports Boyer's and Rashed's dispute over the teacher's and pupil's rainbow contributions; authorship of the book does not remove that historical question ^{6 7}.

Russell describes the work's circulation of optical material, with Taqi al-Din ibn Maruf among later readers. She finds no evidence of a Latin translation and places the Theodoric comparison within that limit. Similarity alone does not establish a transmission route to every European author ⁸.

She identifies Topkapi Ahmet III3340, dated716/1316, and the Hyderabad1928–1930 edition, warning of textual and diagram errors and its non-use of that manuscript. These are her descriptions, not a museum collation or inspection. The secondary articles, not the manuscripts or edition, were read here; museum schematics are not copied from them ⁹.