According to this MS. the work consisted of two parts:
‘Incipit compendium studii theologiae et per consequens philosophiae ut potest et debet servire theologicae facultati, et habet duas partes principales; prima liberali communicatione sapientiae investigat omnes causas errorum, et modos errandi in hoc studio.... Secunda pars descendit ad veritates stabiliendas et ad errores cum diligentia exterminandos.’
Part v. is preserved in Royal MS. 7 F. viii. f. 2 (sec. xiii) (almost complete); it is a treatise on optics.
Incipit: ‘Acto prologo istius quintae partis hujus voluminis quam voco compendium studii theologiae, in quo quidem comprehendo in summa intentionem totius operis, extra partem ejus signans omnia impedimenta totius studii et remedia, nunc accedo ad tractatum exponens ea quae necessaria sunt theologiae de perspectiva et de visu.’
Part vi. is mentioned in Part v.: it is to be a treatise, ‘De multiplicatione Specierum.’
In Part iv. also the words ‘in partibus sequentibus’ occur.
Alchemy was treated in the Opus Minus and in the Compendium Philosophiae. Bacon divides it into (1) Speculative alchemy, ‘the science of the generation of things from elements’; (2) Practical alchemy, ‘which teaches us how to make noble metals and colours,’ &c., and the art of prolonging life (Opus Tertium, cap. xii). Wood mentions a treatise of Bacon’s De rerum generationibus, of which he had seen two copies varying much. These may have been the versions in the Opus Minus[1356] and the Compendium Philosophiae[1357]. A number of works on alchemy and medicine ascribed to Bacon have been preserved, some of them are undoubtedly genuine, others apocryphal.
Epistolae fratris Rogerii Baconis de secretis operibus artis et naturae et de nullitate magiae [or, De mirabili potestate artis et naturae].
The work consists of a letter or collection of letters in ten or eleven chapters, the last five of which Charles considers doubtful, addressed perhaps to William of Auvergne (who died in 1248), or to John of London, whom Charles identifies with John of Basingstoke (d. 1252).
Inc. cap. 1. ‘Vestrae petitioni respondeo diligenter. Nam licet.’