Harley MS 80, ff 1r-57r, ff 1r-33r

De Scientia Perspectiva, treatise on optical science and phenomena by Roger Bacon (circa 1214-1292), philosopher and Franciscan friar. It is copied in cursive script (Anglicana) by two English hands, datable respectively to the second half of the 14th century (ff. 1r-8v, and 15th century (ff. 9r-33r).

Title (upper margin) 'Scientia perspectiva Bacon', prologue 'Tractatus perspective habet 3: partes … habens quinque capitula cum distinctiones', rubric 'Capitulum primum distinctionis prime de proprietatibus huius conscientie', incipit: 'Propositis radicibus sapientie', explicit 'non posset sustinere. Deo gratia'. Includes contemporary marginal notes (esp. ff. 1v-4r).

A revised version of the treatise was sent by Bacon to pope Clement IV as part of his Opus maius, which may explain the different preambles and opening lines of the text occurring in the manuscript tradition. The thirty-nine extant medieval manuscripts of the text have been divided by D. C. Lindberg into five families according to their openings. The present manuscript (H) belongs to the first family: see Lindberg 1996.

Other copies of the text in Additional MS 8786 (ff. 84r-107v, fourth family), Royal MS 7 F. viii (ff. 47r-98r, fifth family), Sloane MS 2156 (ff. 2r-41v, dated 1428, fifth family), and Slone MS 2542 (ff. 1r-55r, imperfect at beginning); a fragment in Cotton Fragments iv (ff. 23r-26v). First edition by Johannes Combach, Frankfurt, 1614; published as part v of the Opus maius of Roger Bacon, ed. by J. H. Bridges, 2 vols. (Oxford, 1897; rev. edn., 3 vols., London, 1900).

Decoration:

Chapter initials (3 lines; ff. 1r-8v) in blue, with pen-flourished decoration in red extending into the margin. Geometrical diagrams in the margins (ff. 2v, 4v-5r, 6r-7r, 8r) mostly in red. Occasional (ff. 1r-8v) paragraph marks in red and occasional sentence initials touched in red. Headings (ff. 1r-8v) in red. Running book numbers (ff. 1r-33r) added in dark brown ink in the upper margin of rectos by the later hand. Spaces (2 lines; ff. 8v-33r) left blank for chapter initials.