Parts I-VI edited by Jebb, 1733: reprinted at Venice 1750. The parts often occur separately. I. _On the four causes of human ignorance_: authority, custom, popular opinion, and the pride of supposed knowledge. MS. Brit. Museum: Cott. Jul. F vii. fol. 186. II. _On the causes of perfect wisdom in Holy Scripture_, or, _On the dignity of philosophy_. III. _On the usefulness of grammar._ This part, Charles points out (p. 62), is not perfect in Jebb’s edition: see _Opus Tertium_, cap. XXVI, XXVII. IV. _On the usefulness of mathematics._ MSS. London:--British Museum: Cotton, Tib. C. V. (sec. xiv); Julius D. V. ‘De utilitate scientiarum’; Julius F vii. fol. 178 (sec. xv), ‘Declaratio effectus verae mathematicae.’ And fol. 180, ‘De moribus hominum secundum complexiones et constellationes.’ Royal 7 F vii, p. 1 (sec. xiii), ‘Pars quarta compendii studii theologiae’; pp. 82-125, ‘Descriptiones locorum’; pp. 133-140, ‘De utilitate astronomiae,’ or ‘Tractatus de corporibus coelestibus.’ Sloane 2629, f. 17, ‘De utilitate astronomiae.’ Also Lambeth Palace Library 200 (sec. xv), ‘De arte mathematica.’ Oxford:--Bodl. E Musaeo 155, p. 185 (sec. xv ineuntis), ‘Pars quarta in qua ostendit potestatem mathematicae in scientiis et rebus et occupationibus hujus mundi.’ Univ. Coll. 49 (sec. xvii). Paris:--Bibl. Nat. 7455 A (sec. xv), ‘De utilitatibus scientiae mathematicae verae.’ Cf. Bodl.: Digby 218, f. 98 (sec. xiii-xiv). Printed, except the last two chapters, by Combach, Frankfurt 1614, under the title: ‘Specula Mathematica in quibus de specierum multiplicatione ... agitur,’ &c. V. _Perspective and Optics._ MSS. London:--Brit. Mus.: Royal 7 F vii. p. 125 (sec. xiii), ‘De visu et speculis’; 7 F viii. f. 47 (sec. xiii), ‘Perspectiva quedam singularis,’ ‘Perspectiva R. Bacon, liber secundus.’ Sloane 2156, f. 1 (A. D. 1428), and 2542 (sec. xv): Addit. 8786, f. 84, ‘Incipit tractatus de modis videndi.’ Oxford:--Bodl. Digby 77 (sec. xiv) and 91 (sec. xvi). Paris:--Bibl. Nat. 2598, f. 57 (sec. xv). Venice:--St. Mark, Classis XI, Cod. 10 (sec. xiv). Rome:--Vatican (Cod. Lat.) 828, f. 49 (A. D. 1349). Printed by Combach, Frankfurt 1614, under the title, ‘Rogerii Baconis Angli ... Perspectiva.’ VI. _Experimental Science._ MSS. Brit. Mus.: Sloane 2629 (sec. xvi), extracts. Oxford:--Bodl.: Digby 235, p. 389; Canon. Misc. 334, fol. 53, ‘Alius tractatus ejusdem Fratris Rogeri extractus de sexta parte compendii studii theologiae.’ Univ. Coll. 49. VII. _Moral Philosophy._ _Inc._ ‘Manifestavi in precedentibus quod cognitio linguarum.’ MSS. Brit. Mus.: Royal 8 F ii. f. 167-179 (sec. xv), three parts out of six. Bodl.: Digby 235, p. 421[1347]. Omitted in Jebb’s edition: extracts printed by Charles, pp. 339-348. Printed at Dublin 1860 (?)[1348].