INTRODUCTION.

THE treatise here printed is found in Royal MS. 7 F. vii. in the British Museum, a folio vellum MS., written at the end of the thirteenth century. On page 13 of the volume in which it is included is the following (erased) inscription: “Iste liber est de ordine fratrum minorum concessu W. Herebert qui eum ad ordinem procuravit”. The MS. (with 7 F. viii., which also contains writings of Roger Bacon) was in the Lumley Library, and afterwards came into the possession of Prince Henry’s chaplain, John Prideaux, Bishop of Worcester (1641-50), whose name occurs in a note (7 F. vii. fol. 46), and thence into the Theyer collection. It bears the name of John Theyer, with date 1651. A MS. belonging to University College (No. 47) is a transcript of this MS. made by Prideaux. He has sometimes dealt freely with his text, and occasionally omits passages which he found it difficult to read. My text is that of the Royal MS. (R.), except where I have noted the fact that I have adopted the reading of the University College MS. (O.) or have altered it conjecturally. The MS. is in places very much contracted and hard to read. It was evidently written by a scribe who very imperfectly followed what he was writing.

The MS. contains the following works:—

(1) Pars Quarta Compendii Studii Theologie (i.e. the sections on mathematics and geography which now make part of part iv. of Roger Bacon’s Opus Majus as printed by Bridges).

(2) Tractatus de Visu et Speculis (a fifteenth-century title), [probably not by Bacon].

(3) A Letter of Henry of Southwark to ——, Bishop of Constantia (? Coutances) on Optical Problems.

(4) Tractatus de Corporibus Celestibus (fifteenth-century title),