Part of the Third Work (Opus Tertium)

xi

INTRODUCTION

Roger Bacon (Quaracchi). This fragment was hidden in a manuscript in the National Library of France original: "Bibliothèque Nationale"¹ under the title The Third Book of Alpetragius original: "Tertius liber Alpetragii"; Alpetragius refers to the astronomer Al-Bitruji. It contained the summary of Part 5 of the Great Work original: "Opus Majus". This includes a long side discussion on the movements of celestial bodies. It also covers Part 6, which contains a discussion on the halo and its relation to the rainbow. Finally, it covers Part 7, including the last two previously unknown sections. This is followed by a brief summary of the Lesser Work original: "Opus Minus", three chapters on alchemy, and the beginning of a treatise titled On the Generation of Natural Things original: "De rerum naturalium generatione".

Professor Duhem pointed out that a gap remained between the end of the fragment edited by Brewer and the start of the fragment he discovered. We still lacked the summary and commentary in the Third Work original: "Opus Tertium" for the last two sections of Part 4 of the Great Work. These sections deal with geography and astrology; or, as Bacon describes them, the value of mathematics in state affairs. The missing portion has now been discovered. It is printed on pages 1 to 19 of this volume for the first time.

The Manuscripts. 1. Winchester College Manuscript 39.
Dr. M. R. James drew my attention to this manuscript. I had failed to note it in my List of Roger Bacon's Works. I thank the College authorities, especially Mr. Hardy, the Acting Librarian, and Mr. Chitty, the Bursar. They allowed me free access to the manuscript and sent it to the British Museum for my use.
The manuscript was apparently² presented to the College

¹ No. 10264, Latin collection original: "fonds latin".
² This is not quite certain. The inscription "from the gift of William Mory, formerly an alumnus of this college, 1543" original: "ex dono Willelmi Morȳ quondam huius collegii alumni—1543°" occurs on the first leaf of the volume. However, the contents of the volume appear to have been bound separately at one time. The old catalogue printed by Bernard in his Catalogues of Manuscript Books of England and Ireland original: "Catalogi Librorum MSS. Angliae et Hiberniae", Oxford, 1697, Volume 2, Part 1, page 30, mentions: "24. Book on the Service of Evangelical Philosophy" original: "Liber de Famulatu Philosophiae Evangelicae". This is another name for the Treatise on the Consideration of the Quintessence original: "Tractatus de Consideratione Quintae Essentiae", which is the first treatise in the volume now numbered 39. It also mentions: "26. Roger Bacon's treatise on the multiplication of species. Various treatises by the same author on Divine Wisdom, showing how Mathematics, Grammar, etc. serve Theology" original: "Rogeri Bacon tractatus de multiplicatione specierum. Ejusdem varii tractatus de Sapientia Divina, ostendentes quomodo Mathesis, Grammatica, &c. inserviunt Theologiae". These refer to the remaining treatises in the volume now numbered 39. All the treatises belong to the same period and are written on paper of the same size.