He began his studies on positive science before 1250[1322], and had by 1267 spent more than 2,000 librae[1323]

It is not necessary to assume that this sum was expended before he joined the Franciscan Order; he could, and undoubtedly did, obtain money by begging to carry on his experiments[1324]. Roger left Oxford for Paris some time before 1245; he states that he had seen Alexander of Hales with his own eyes[1325], and he heard William of Auvergne dispute on the Intellectus Agens before the whole University: William died in 1248[1326]. Roger was in France in 1250 when he saw the chief of the Pastoureaux, and remarked that

He is said by Rous to have been made D.D. of Paris and to have been incorporated as D.D. at Oxford[1328]. When he returned to Oxford is unknown; probably soon after 1250. He must have lectured at this time; he won some fame, as he says himself[1329], but without doubt made many enemies. About the year 1257 or 1258—when Adam Marsh could no longer protect his great pupil—Roger was exiled from England and kept under strict supervision in Paris for ten years[1330]. In 1263 he wrote an astronomical treatise called Computus Naturalium[1331]. Soon after this, a clerk named Raymund of Laon mentioned Bacon’s name to the Cardinal Bishop of Sabina and roused the latter’s interest in his discoveries[1332]. Bacon sent a letter in reply to the Cardinal’s communication: this has not been preserved. In 1265 the Cardinal became Pope Clement IV. On 22nd of June 1266, Clement wrote requesting Roger to send him a fair copy of the work which Raymond had mentioned, setting forth the remedies he proposed, ‘circa illa, quae nuper occasione tanti discriminis intimasti;’ the friar was to do this, in spite of any constitution of his Order to the contrary, secretly and without delay[1333]. The Pope’s supposition that the work was already written was erroneous;

However, although the book was not yet written, and notwithstanding endless difficulties, want of money, want of mathematical and other instruments and tables, the restrictions of the Rule, jealousy of his superiors and brethren who, he says,

the Opus Majus, the Opus Minus, and the Opus Tertium, were sent to the Pope within fifteen or eighteen months after the arrival of the papal mandate[1337]. ‘Such a feat’ says Brewer, ‘is unparalleled in the annals of literature.’ The Pope probably used his influence in behalf of Roger, as the latter seems to have returned to England about this time and to have been freed from annoyance[1338]. The works sent to Clement he regarded merely as handbooks; at the same time that he was writing them, he was engaged on a larger work which was to embrace the whole range of sciences as then understood[1339]. He was working at this in 1271[1340]. His attacks on all classes, including his own Order, became even more violent than hitherto. In 1277 and 1278 synods were held at Paris and Oxford to condemn erroneous doctrines. The repressive movement extended to the Franciscans; in 1278, Jerome of Ascoli, the Minister General, held a Chapter at Paris, and among other friars Roger Bacon was condemned ‘propter quasdam novitates[1341].’ He is believed to have remained in prison for fourteen years. Jerome of Ascoli, who became Pope Nicholas IV in 1288, died in 1292. Raymond Gaufredi, a man of liberal views, was elected General in 1289, and released many friars who had been imprisoned for their opinions by his predecessors. In 1292 he held a General Chapter at Paris, and it is probable that among the friars here set free was Roger Bacon[1342]. It is certain that the last work of Roger’s of which we have any notice was written in 1292[1343]. The date usually assigned for his death (1294) is a pure conjecture[1344]. John Rous says that he was buried among the Friars Minors at Oxford[1345].

Such then is the chronological outline of his life, as far as it can be ascertained. A list of his works will be more useful than a short account of his character or philosophy.

Roger Bacon’s Works were neglected and regarded with a pious horror in the Middle Ages[1346]. The result is that many of those which have survived at all have reached us in a fragmentary state. ‘It is easier,’ said Leland, ‘to collect the leaves of the Sibyl than the titles of the works written by Roger Bacon.’ The difficulty has to a considerable extent been removed by Mr. Brewer’s valuable preface to the Opera Inedita, and by the labours of M. Charles. The following account of Roger Bacon’s works is based chiefly on these two writers. Some additions have been made and some rearrangement attempted.

Miscellaneous works, lectures, &c., probably early:—

Computus naturalium, an astronomical treatise, is the earliest work of Bacon’s to which a date can be assigned; it was written A. D. 1263-4. Inc. ‘Omnia tempus habent.’

De termino Paschali, an earlier work, to which Bacon refers in the Computus naturalium; (Charles, p. 78).

Questions on Aristotle’s physics.

Quaestiones super librum physicorum a magistro dicto Bacon.

De vegetabilibus (gloss on this work then attributed to Aristotle).

In Aristotelis Metaphysica.

Tractatus ad declaranda quaedam obscure dicta in libro Secreti Secretorum Aristotelis. Inc. ‘Propter multa in hoc libro contenta qui liber dicitur Secretum Secretorum Aristotelis sive liber de regimine principum.’

Questiones naturales mathematice astronomice, &c. ‘Expliciunt reprobationes Rogeri Baconis.’

Bacon in Meteora. Inc. ‘Cum ad noticiam impressionum habendam.’

Processus fratris Rogeri Bacon ... de invencione cogitacionis (astrological fragment). Inc. ‘Notandum quod in omni judicio quatuor sunt inquirenda, scil. natura planetae.’

De somno et vigilia.

Logic:—

Summulae Dialectices, an elementary treatise on logic, characterised by Charles, who expresses a doubt as to its authenticity, as very dry, unimportant, and intended for lecturing purposes. Inc. ‘Introductio est brevis et apta demonstratio.’ ‘Expliciunt sumule magistri Roberti (sic) Baccun.’

Syncategoremata. Inc. ‘Partium orationis quaedam sunt declinabiles.’

Summa de sophismatibus et distinctionibus. Inc. ‘Potest queri de difficultatibus accidentibus.’

Tractatus de signis logicalibus. Inc. ‘Signum est in predicamento relationis.’

Opus Majus, written A. D. 1266-1267; 7 parts. Inc. ‘Sapientiae perfecta consideratio consistit in duobus.’

The parts often occur separately.

I. On the four causes of human ignorance: authority, custom, popular opinion, and the pride of supposed knowledge.

II. On the causes of perfect wisdom in Holy Scripture, or, On the dignity of philosophy.

III. On the usefulness of grammar.

IV. On the usefulness of mathematics.

V. Perspective and Optics.

VI. Experimental Science.

VII. Moral Philosophy. Inc. ‘Manifestavi in precedentibus quod cognitio linguarum.’

Opus Minus, written in 1266-7, was mainly an abstract of the Opus Majus with some additions on the state of scholasticism, on alchemy practical and speculative, and on astronomy. Charles gives the following description of it. It consisted of 6 parts:

i. Introduction or dedicatory letter; ii. Practical alchemy; iii. Explanation of the Opus Majus; the order of the sciences inverted, i.e. they were arranged according to their dignity, moral philosophy first; iv. Treatise on the seven sins of Theology; v. Speculative alchemy, or, De rerum generationibus (see below); vi. De Coelestibus.

Of this work only the fragment edited by Brewer (Opera Ined. 311-390) from MS. Bodl. Digby 218, has been discovered. This includes a few pages of Part ii., all of iii., most of iv., and part of v. Wood quotes a passage from the Opus Minus which does not occur in this fragment (Opera Ined. xciv. n. 1). From this it has been assumed that he had access to a MS. of the Opus Minus now lost; but the passage is quoted by Leland, and probably copied from him by Wood. It may perhaps occur in some other work of Bacon’s; thus the passage quoted in Op. Ined. pp. xcvii-xcviii, from which Brewer argues that ‘Wood must have seen some other copy of the Opus Minus not now discoverable,’ occurs in Brewer’s edition of the Opus Tert. pp. 272-3.

Part of the blank on p. 375 is to be filled up from the Opus Majus, Pars VI, Exemplum II, where the passage ‘Est autem—curabit et’ occurs, word for word. How much of the Opus Majus was here inserted is doubtful; probably to the end of Exemplum II. Thus MS. Bodl. Canonic. Miscell. 334, f. 53, begins with the words, ‘Corpora vero Adae et Evae,’ Opus Minus, p. 373, and leaves off with the words, ‘et alibi multis modis,’ which occur at the end of Opus Majus, Pars VI, Exemp. II.

The last part of the Opus Minus is wholly wanting in Brewer’s edition. The subject of this part may be gathered from Bacon’s words in Opus Tert., cap. xxvi (p. 96):

In Digby MS. 76, fol. 36 seq. (sec. xiii) is a treatise on this subject, forming part of the Physics in the great Compendium Philosophiae (see below). It is not improbable, that, before being incorporated in this larger work, it formed part of the Opus Minus sent to the Pope; on fol. 42 are the words:

Opus Tertium, written in 1267 (see Opera Ined. p. 277), 75 chapters.

Charles has been misled by a passage in the work called ‘Communia Naturalium’ into thinking that this latter formed part of the Opus Tertium; Charles, R. Bacon, pp. 65, 83-4; his description of Opus Tertium is consequently erroneous. The passage is from the Mazarine MS. of the Communia Naturalium (i.e. No. 3576), fol. 85:

These words refer to Bacon’s doctrine that the intellectus agens is not part of the soul, but God and angels. This is insisted on in the Opus Tertium, cap. xxiii, and it is not likely that Bacon would do more than refer to it again casually in the course of the same work. The relation of the Opus Tertium to the Commun. Nat. is probably as follows: the latter was written or begun first. Bacon repeatedly mentions that he was, while writing his three Opera for the Pope, engaged on a larger work, Scriptum Principale, which he did not send to Clement[1349]. Much of this larger work naturally found its way, probably in a summarised form, into the Opus Tertium as we know it, the treatise actually sent to the Pope.

Tractatus de multiplicatione specierum, or, De generatione specierum et multiplicatione et corruptione earum, is inserted by Jebb in the Opus Majus, pp. 358-445, between Part v and Part vi. The subject is however discussed in Part iv, which is often quoted or referred to in Part v. In the De multiplicatione, &c. (p. 368), are the words:

Again (p. 358):

There is nothing about this in the third part of the Opus Majus; but it is found in the Communia Naturalium. The treatise De multiplicatione specierum was therefore part of a work of which the Communia Naturalium formed the third part. This large work was according to Jebb, the Opus Minus; according to Charles, the Opus Tertium[1350]; according to Brewer, the encyclopaedic Compendium Philosophiae. Brewer is no doubt right; the De multiplicatione was intended as a sub-section of the great treatise on Physics.

How then did the treatise come to be regarded as part of the Opus Majus, and to be inserted in the MSS. of that work? There can be little doubt that it was, in its original form, the treatise on rays sent to the Pope with the Opus Majus, but as a separate work (Opera Ined. pp. 227, 230). The references to the Communia Naturalium are not inconsistent with this hypothesis: (1) the treatise on rays does not seem to have been written specially for the Pope, and consequently references to works which he could not know were not unnatural; (2) Bacon had already begun the encyclopaedic work, but found it impossible to get it finished or send it to the Pope (Opera Inedita, pp. 60, 315).

Inc. ‘Primum igitur capitulum circa influentiam agentis habet tres veritates.’

De speculis (on burning mirrors). Inc. ‘Ex concavis speculis ad solem positis ignis accenditur.’

Speculi Abnukefi compositio secundum Rogerium Bacon. Inc. ‘Quia universorum quos de speculis ad datam distanciam.’

Compendium Philosophiae, an encyclopaedic work, which if completed would have formed a kind of revised and enlarged edition of the Opus Majus, Opus Minus, and Opus Tertium. In the Communia Naturalium, cap. i. (MS. Bodl. Digby 70) Bacon gives a sketch of his plan. The work was to consist of four volumes, and to treat of six branches of knowledge, viz., vol. i. Grammar and Logic; vol. ii. Mathematics; vol. iii. Physics; vol. iv. Metaphysics and Morals. This Compendium seems to have been known also as Liber sex scientiarum. The latter title is found in the collection printed at Frankfurt in 1603[1351] in MSS. Bodl. Canonic. Misc. No. 334, fol. 49 b; ibid., No. 480, fol. 33; and E Musaeo 155, p. 689. In each of these MSS. the same passage is quoted, as follows:

Charles identifies the Liber sex scientiarum with the Opus Minus; but this passage does not occur in the extant portion of the Opus Minus which deals with the same subject and expresses the same ideas (Opera Ined., p. 370 seq.). It seems probable therefore that this passage is an extract from the section on Alchemy in vol. iii. of the Compendium Philosophiae.

Vol. I. Grammar and Logic. A portion of this has been edited by Brewer, Opera Ined., pp. 393-519, under the title Compendium Studii Philosophiae. It was written in 1271, and contains an introduction on the value of knowledge and the impediments to it, and the beginning of a treatise on grammar.

Two other treatises on grammar by Roger Bacon are extant, and probably formed part of the Comp. Phil.[1352]:

(1) Inc. ‘Primus hic liber voluminis grammatici circa linguas alias a Latino.... Manifestata laude et declarata utilitate cognitionis grammatice’ (chiefly on Greek grammar).

(2) Inc. ‘Oratio grammatica autem fit mediante verbo.’ ‘Explicit summa de grammatica magistri Rogeri Bacon.’

Vol. II. Mathematics; 6 books:

i. Communia mathematicae, ii-vi. Special branches of mathematics.

Liber i. Inc. ‘Hic incipit volumen verae mathematicae habens sex libros. Primus est de communibus mathematicae, et habet tres partes principales.’

Libri ii-vi. An extant fragment of a commentary on Euclid by Bacon may have belonged to this part; in De Coelestibus (Comp. Phil. vol. iii.) he often refers to his commentary on the Elements of Euclid (Charles, p. 85).

A treatise, De laudibus mathematicae, expressing the same ideas as Part iv. of the Opus Majus, may have been intended as an introduction to this volume.

Vol. III. Physics. First came general physics (1 book), then particular sciences (3 books).

Liber i. Communia Naturalium, divided into 4 parts.

Libri ii, iii, iv. The special natural sciences, according to the Royal MS. just quoted, were treated in three books. They were seven[1353] in number, as Bacon enumerates them in the second chapter of the first part of the Communia Naturalium.

Liber ii. (1) Optics or Perspective (a version of the De multiplicatione specierum). Inc. ‘Ostensum quippe in principio hujus Compendii Philosophiae.’

(2) Astronomy, or, De coelo et mundo.

(3) Gravity, Scientia ponderum de gravibus et levibus.

Liber iii. (4) Alchemy, or, De elementis[1354].

Liber iv. De vegetabilibus et generabilibus[1355].

(5) Agriculture.

(6) Medicine.

(7) Experimental Science.

Vol. IV. Metaphysics and Morals.

Inc. ‘Quoniam intencio principalis est innuere nobis vicia studii theologici que contracta sunt ex curiositate philosophie.’

It is, however, probable that these MS. fragments ought to be referred to Bacon’s last work, the Compendium Studii Theologiae, rather than to the Compendium Philosophiae.

Compendium studii theologiae, Bacon’s last work, bears the date 1292 (‘usque ad hunc annum Domini 1292’). Extracts from it are printed by Charles, pp. 410-416. This work consisted of six parts or more.

Part i. On the causes of error.

Part ii. Logic and grammar in reference to theology.

According to this MS. the work consisted of two parts:

Part v. is preserved in Royal MS. 7 F. viii. f. 2 (sec. xiii) (almost complete); it is a treatise on optics.

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.’

The three following treatises were printed at Frankfurt in 1603, under the title, Sanioris medicinae magistri D. Rogeri Baconis angli de arte chymiae scripta, &c., and elsewhere.

Summary of Avicenna’s De anima. Inc. ‘In illius nomine qui major est.’

Breve Breviarium, or, De naturis metallorum in ratione alkimica et artificiali transformatione, or, Coelestis alchymia, or, De naturis metallorum et ipsorum transmutatione.

Divided into two parts, speculative and practical alchemy; the work contains no doubt some of the ideas incorporated in the Opus Minus and the Comp. Philosophiae. The date is uncertain.

Inc. ‘Breve breviarium breviter abbreviatum.’

Tractatus trium verborum, or, Epistolae tres ad Johannem Parisiensem; namely:

i. ‘De separatione ignis ab oleo,’ or, ‘De modo projectionis’; ii. ‘De modo miscendi’; iii. ‘De ponderibus.’ Inc. ‘Cum ego Rogerus rogatus a pluribus.’

Fragment on alchemy, without title.

Libellus Rogerii Baconi ... de retardandis senectutis accidentibus et de sensibus conservandis (11 chapters). This work is assigned by Charles to the year 1276. Inc. prol. ‘Domine mundi ex nobilissima stirpe originem assumpsistis.’ Inc. cap. 1. (De causis senectutis). ‘Senescente mundo senescunt homines.’

Antidotarius, a second part of this work. Inc. ‘Post completum universalis sciencie medicacionis tractatum.’

Liber Bacon de sermone rei admirabilis, sive de retardatione senectutis. Inc. ‘Intendo componere sermonem rei admirabilis domino meo fratri E, cujus vitam deus prolonget.’

De universali regimine senum et seniorum. Inc. ‘Summa regiminis senum universalis est hoc ut dicit Avicenna.’