Roger Bacon : essays contributed by various writers on the occasion of the commemoration of the seventh centenary of his birth / collected and edited by A.G. Little.
- Date:
- 1914
Licence: In copyright
Credit: Roger Bacon : essays contributed by various writers on the occasion of the commemoration of the seventh centenary of his birth / collected and edited by A.G. Little. Source: Wellcome Collection.
422/442 page 410
![geometricarum apparet et quod ab eis accidit ex rebus naturalibus est fabricatio speculorum comburentium per conversionem radii solaris. Incesserunt (scii, philosophi) ergo inveniendo ea modis diversis.’ Expl. ‘super longi- tudinem quesitam. Sermo ergo iste comprehendit omnem operationem speculorum comburentium que sunt secundum hanc figuram et sunt fortioris combustionis omnibus speculis quoniam radii convertuntur ex tota superficie eorum ad punctum unum.’ MSS. Brit. Mus. : Vesp. A. ii, ff. 140-4, with many dia- grams on ff. 146, 147 (secc. xiii ex.-xiv in.), anon. Title (secc. xiv ex.-xv in.), ‘ De sectione Mukefi ; ’ inscribed in John Dee’s hand : ‘ Joannes Dee 1555. Antiquis- simus libellus de speculis comburentibus.’ ‘ Explicit de speculis quolibetmodo comburentibus.’—Tib. B. ix (see. xv in.), ff. 230v-2r, injured by fire ; beginning and end illegible : f. 23ir, ‘ In omni seccione parabola latus erectum duplum est,’ contains a few diagrams. Oxford : Corp. Chr. Coll. 260, p. 147 (sec. xvii in.), Twyne's copy of Vesp. A. ii. (Cf. Florence : Bibl. Naz. : Ashburnham 957 (sec. xv), ff. mr-22r (anon., no title, but following directly on the ‘ Spec. Almukefi sec. Roggerium Bacon ’) : ‘ Ut facilius fiant corpora quinque regularia de quibus tractat Euclides in ultimis suis libris ’ : expl. ‘ Sermo ergo iste ... ad punctum suum [cf. supra]. Explicit de speculis comburentibus feliciter ’ (this seems to contain matter not in Vesp. A. ii). Cf. Bodl. Can. Mise. 480, ff. 55r-6v : inc. ‘ Ut facilius fiant corpora ’ : expl. ‘ satis liquerunt ipsa proposita Deo gratias.’ Printed, the earlier part only, i. e. Vesp. A. ii, ff. 140-3 (to ‘ lateris erecti, et illud est quod demonstrare volumus ’), in a revised version by Gogava, ut supra, Louvain, 1548, under the title : Antiqui scriptoris libellus de speculo comburenti, concavitatis parabolae. Inc. ‘ Ex sublimioribus quae Geometrae ’ : expl. ‘ lateris erecti. Atque illud est quod in errandum sumpsimus.’ Cf. Nos. iya, lyb, above. 46. De mutabilibus pronosticorum elementorum. Inc. ‘ Scribo vobis qui vultis de mutabilibus pronosciorum elemen- torum que ab astris contingunt omni tempore seculi huius.’ ‘Explicit tractatus subtilissime considerationis fratris R. B. ordinis minorum qui experimentarius dicitur.’](https://iiif.wellcomecollection.org/image/b28993949_0422.jp2/full/800%2C/0/default.jpg)
