The National Library of Medicine has a manuscript (MS A 27) preserving a chapter titled Bāb khawḍ al-ṭaruq al-aqrab (Chapter on the Examination of the Closest Methods) stated to be taken from a treatise titled from Kitāb al-‘Ilm al-makhzūn fī mufāriḍah (The Book of Accumulated Knowledge on Suppositions) by Jābir.
No treatise of such a title is recorded amongst the writings attributed to Jābir ibn Ḥayyān, yet the NLM copy is specific in giving Jābir as the author.
No other copy has been identified.
Bāb khawḍ al-ṭaruq al-aqrab (MS P 27, item 5)
Arabic. 1 leaf (fol. 41b). Dimensions 21.4 x 16.6 (text area 16.3 x 9.8) cm. The chapter title is given in the first line of text. On fol. 41b line 2 it is stated to be from Kitāb al-‘Ilm al-makhzūn fī mufāriḍah by Jābir.
The copy was completed by the same hand as transcribed the previous, fourth, item in the volume. Both items were probably added to the volume after the first three items, which were transcribed at Kashan in the month of Rajab 1133 (= 28 April-27 May 1721).
The beige paper is nearly matte-finished and has no laid lines or chain lines visible; the edges have been trimmed from their original size. The paper is grease and damp stained and soiled through thumbing.
The volume consists of 41 leaves. Fol. 1a is blank except for penciled note (Collection: Risalat Jābir) attributing the volume to Jābir ibn Ḥayyān and an undeciphered phrase in Persian script. Fols. 1a-39a (item 1) contain Kitāb Nihāyat al-ṭalab fī sharḥ Kitāb [al-‘ilm] al-Muktasab dar zirā‘at-i dhahab by al-Jaldakī (MS P 27, item 1); fols. 39b-40a (item 2) a Persian treatise on the smelting of iron, attributed to Jābir ibn Ḥayyān (MS P 27, item 2); fols. 40a-40b an untitled short anonymous Persian essay on winds and rain (MS P 27, item 3); fols. 40b-41b are an Arabic untitled treatise on numerology whose author is given as Zosimos (MS P 27, item 4); and fol. 41b, lower two-thirds, contains the Arabic alchemical chapter taken from Kitāb al-‘Ilm al-makhzūn fī mufāriḍah here catalogued.
There is an owner's stamp on fol. 41b (not legible).
The volume was purchased in 1941 by the Army Medical Library from A.S. Yahuda (ELS 2357 m. 127).
Schullian/Sommer, Cat. of incun. & MSS., entry P 27 item 1, p. 339.
NLM Microfilm Reel: FILM 48-137 no. 2