Opus Majus of Roger Bacon, Vol. I (Bridges ed.)

PREFACE.

out an almost exact correspondence in their errors and in their variants. The Oxford MS. has therefore been taken as the foundation of the present edition, and is denoted by the letter O. It is, however, by no means perfect, especially in the second and third sections of the work: and recourse was had both by Jebb and by the present editor to various MSS. in the British Museum and elsewhere to supply the imperfections. Foremost among these are the two Cottonian MSS., Julius D.v., and Tiberius C.v. (designated here as Jul. and Tib.). The first of these, unfortunately much injured in the fire of 1731, gives the first three sections of the work and a large part of the fourth. The second gives the whole of the fourth.

For the geographical portion of the fourth section, I was allowed to consult the MS. in the possession of Corpus Christi College, Cambridge. It is not, however, believed to be of earlier date than the middle or later part of the fifteenth century. Occasional reference has been made to a MS. of the fifth section of the work (Perspectiva Optics) in the possession of Magdalene College, Cambridge, which I was permitted to examine. It is not, however, of earlier date than the Bodleian MS., and its variants are not of great importance.

Of the MSS. of the Perspectiva Optics and of the De Multiplicatione Specierum On the Multiplication of Species which appear to have been transcribed more frequently than other portions of the work, by far the most important is the British Museum MS. (Royal, 7 F. viii), already spoken of as contemporary, or nearly so, with Bacon. This, as I have said, was carefully collated by Jebb, who indeed has in certain places copied on the margin extracts from Combach's printed edition of the Perspectiva of 1614. The diagrams of this MS. are of special value. The