The Arabic Origin of
Summa perfectionis magisterii
And the Other Geber Latin Works
Jabir’s Latin Names
In our present investigation about Geber’s Latin works any information about Jabir in Latin literature will be useful. We shall discuss here the different forms of Jabir’s name in Latin. Our survey is not exhaustive and if more Latin variants of the name are revealed in future they will be indicated in the coming articles.
Latin translators did not follow any system of transliteration for Arabic names or words. There were inconsistencies in transliteration to a rather high proportion. Thus Ibn Sina is Avicenna in Latin and Ibn Rushd is Averroes. Fortunately the name of Jabir is simpler and it was not deformed to a high degree. We shall try to make sense in discussing the various Latin forms of this name
The word “Geber” became the standard Latin name for Jabir. In Latin the ‘G” followed by “E” is pronounced as a soft “G” as in the English word “GEM’. Therefore the Latin translators used “GEBER” with a soft “G” to denote Jabir. If they wrote it as “GABIR” it will be a hard “G”. “J” is not used in Latin.
We meet the word “GIABER” in Latin to denote Jabir. Here the “G” is soft because it is followed by “I” and it is the nearest form to Jabir.
In English the word “GEBER” is pronounced with a hard “G” unlike its pronunciation in Latin. Nevertheless the word “GEBER” was adopted in English literature. Since “J” is pronounced in English one would expect to see the word “JEBER”, and actually we find this word in one Cambridge MS:
Cambridge, Trinity College MS. O.7.35, Vellum, 15th Century
Jeber libro 15.
There is no “J” in Latin and “I” is used instead. As a consonant “I” was probably pronounced as “Y” rather than “J”. So Jeber becomes “YEBER”. We find this word in one of the important early manuscripts of the Summa in the B. N. of Paris:
MS. Lat. 6514. 13th - 14th Centuries A.D., Parchment.
7. f61-83v Incipit liber Yeber de summa colectionis complementi oculte secretorum nature. Prohemium perfectionis in arte.
As mentioned above “I” is used instead of”J”. Therefore we should expect to find “IEBER” being used instead of “JEBER”.. “I” as a consonant is pronounced as a “y” in “year”, and it is therefore pronounced as “YEBER” We find this form in a Florence MS.
Biblioteca Nazionale MS. Magl.
14th and 16th Centuries.
1. f1-27 Ieber [Geber] perfecti magisterii hec dicta sufficiant... Explicit liber Ieber perfectionis in arte.
2. f27 Incipiunt excepta libri Ieber quem fecit ad filium et dicitur liber regni quia regum spondet... Explicit liber regis Ieber quem abreviavit ad filium suum solum.
Geber ebn Haen
A complete name occurs sometimes such as Geber ebn Haen  Now ebn Haen is clearly a crude transliteration of the Arabic ibn Hayyan,
Gebir filius hegen ezahufy
In a thirteenth century MS at Florence (Codex Riccardiana 933) Darmstaedter had found a Latin translation of Kitab al-Rahma, entitled Liber Misericordiae. It begins "Dixit qui compilavit librum istum. Ista est reformatio libri gebir filii hegen ezahuphi. Et est nominatus liber misericordie. Dixit gebir filius hegen ezahufy. Postquam vidi," etc
This is clearly the name of Jabir ibn Hayyan al-Sufi. جابر ابن حيان الصوفي
This form of the name Jabir ibn Hayyan occurred in Liber de Anima in arte alchimiae attributed to Avicenna. 
In modern times the word Geber is used almost exclusively to denote the Pseudo-Geber to distinguish it from Jabir. In modern English Jabir is written also as Djabir. In French it is often Djàber and in German it is written as Dschabir. Ruska who was well known by his habit of casting doubts about the authorship of Arabic Latin works and by attributing some of them to pseudo Latin authors, distinguished in his writings between the Arab Dschabir and the Latin Pseudo-Geber.
We conclude that all these variations in Latin refer to one person: he is Jabir ibn Hayyan. Usually in the Latin translations of Arabic works one word only is used to indicate the author. Thus in the case of Abu Bakr Muhammad ibn Zakariyya al-Razi the word Rhazes was used and for Jabir ibn Hayyan the word Geber was adopted.
 Darmstaedter, Ernst, Die Alchemie Des Geber, Reprint, Berlin, 1978, p. 134
 Cassell’s Latin Dictionary, New York, 1968, “J:”, p. 332
 Holmyard, E. J. , « The Present Position of the Geber Problem », Science Progress, Jan. 1925, XIX, No. 75, pp. 414-426,
 Darmstaedter, E, :“ Liber Misericordiae Geber. Eine lateinische Übersetzung des grösseren Kitâb alrahma.“, Sudhoff’s Archiv für Geschichte der Medizin, Bd. xvii, Heft 4, 1925
 Ruska, op. cit. pages 18 and 60.. Ruska attributed the authorship of the Khalid-Morienus dialogue Liber de compositione alchimiae to a pseudo-Latin author despite the many indications that were at his disposal pointing to the contrary. See the article on the Origin of Liber de compositione alchimiae at this web site.