hypotheses points to another want in the Baconian doctrine. If that power form part of the true method, then the mind is not wholly passive or recipient; it anticipates nature, and moulds the experience received by it in accordance with its own constructive ideas or conceptions; and yet further, the minds of various investigators can never be reduced to the same dead mechanical level.1 There will still be room for the scientific use of the imagination, and for the creative flashes of genius.2 to fall; the authority not only of school doctrines but of the church had been discarded; while here and there a few devoted experimenters were turning with fresh zeal to the unwithered face of nature. The fruitful thoughts which lay under and gave rise to these scattered efforts of the human mind, were gathered up into unity, and reduced to system in the new philosophy of Bacon.3 It is assuredly little matter for wonder that this philosophy should contain much that is now inapplicable, and that in many If, then, Bacon himself made no contributions to science, respects it should be vitiated by radical errors. The details if no discovery can be shown to be due to the use of his of the logical method on which its author laid the greatest rules, if his method be logically defective, and the prob- stress have not been found of practical service; yet the lem to which it was applied one from its nature in- fundamental ideas on which the theory rested, the need for capable of adequate solution, it may not unreasonably be rejecting rash generalisation, and the necessity for a critical asked, How has he come to be looked upon as the great analysis of experience, are as true and valuable now as leader in the reformation of modern science? How is it they were then. Progress in scientific discovery is made that he shares with Descartes the honour of inaugurating mainly, if not solely, by the employment of hypothesis, modern philosophy? To this the true answer seems to be, and for that no code of rules can be laid down such as that Bacon owes his position not only to the general spirit | Bacon had devised. Yet the framing of hypothesis is no of his philosophy, but to the manner in which he worked mere random guess work; it is not left to the imagination into a connected system the new mode of thinking, and to alone, but to the scientific imagination. There is required the incomparable power and eloquence with which he ex- in the process not merely a preliminary critical induction, pounded and enforced it. Like all epoch-making works, but a subsequent experimental comparison, verification, or the Novum Organum gave expression to ideas which were proof, the canons of which can be laid down with precision. already beginning to be in the air. The time was ripe for To formulate and show grounds for these laws is to construct a great change; scholasticism, long decaying, had begun a philosophy of induction, and it must not be forgotten that the first step towards the accomplishment of the task was made by Bacon, when he introduced and gave due prominence to the powerful logical instrument of exclusion or elimination. 1 Whewell, Phil. of Ind. Sc., ii. 399, 402-3; Ellis, Int. to Bacon's Works, i. 39, 61; Brewster, Newton, ii. 404; Jevons, Princ. of Science, ii. 220. A severe judgment on Bacon's method is given in Dühring's able but one-sided Kritische Gesch. d. Phil., in which the merits of Roger Bacon are brought prominently forward. 2 Although it must be admitted that the Baconian method is fairly open to the above-mentioned objections, it is curious and significant that Bacon was not thoroughly ignorant of them, but with deliberate consciousness preferred his own method. We do not think, indeed, that the notiones of which he speaks in any way correspond to what Whewell and Ellis would call "conceptions or ideas furnished by the mind of the thinker;" nor do we imagine that Bacon would have admitted these as necessary elements in the inductive process. But he was certainly not ignorant of what may be called a deductive method, and of a kind of hypothesis. This is clear from the use he makes of the Vindemiatio, from certain hints as to the testing of axioms, from his admission of the syllogism into physical reasoning, and from what he calls Experientia Literata. The function of the Vindemiatio has been already pointed out; with regard to axioms, he says (N.O., i. 106), "In establishing axioms by this kind of induction, we must also examine and try whether the axiom so established be framed to the measure of these particulars from which it is derived, or whether it be larger or wider. And if it be larger and wider, we must observe whether, by indicating to us new particulars, it confirm that wideness and largeness as by a collateral security, that we may not either stick fast in things already known, or loosely grasp at shadows and abstract forms, not at things solid and realised in matter." (Cf. also the passage from Valerius Terminus, quoted in Ellis's note on the above aphorism.) Of the syllogism he says, "I do not propose to give up the syllogism altogether. S. is incompetent for the principal things rather than useless for the generality. In the mathematics there is no reason why it should not be employed. It is the flux of matter and the inconstancy of the physical body which requires induction, that thereby it may be fixed as it were, and allow the formation of notions well defined. In physics you wisely note, and therein I agree with you, that after the notions of the first class and the axioms concerning them have been by induction well made out and defined, syllogism may be applied safely; only it must be restrained from leaping at once to the most general notions, and progress must be made through a fit succession of steps."-("Letter to Baranzano," Letters and Life, vii. 377.) And with this may be compared what he says of mathematics (Nov. Org., ii. 8; Parasceve, vii.) In his account of Experientia Literata (De. Aug., v. 2) he comes very near to the modern mode of experimental research. It is, he says, the procedure from one experiment to another, and is not a science, but an art or learned sagacity (resembling in this Aristotle's ayxívola), which may, however, be enlightened by the precepts of the Interpretatio. Eight varieties of such experiments are enumerated, and a comparison is drawn between this and the inductive method; "though the rational method of inquiry by the Organon promises far greater things in the end, yet this sagacity, proceeding by learned experience, will in the meantime present mankind with a number of inventions which lie near at hand." (Cf. N. O., i. 103.) . Of the general characteristics of Bacon's philosophy, and of the consequent place he holds in the history of modern speculative thought, this is not the place to speak. It is curious and significant that in the domain of the moral and metaphysical sciences his influence has been perhaps more powerful, and his authority has been more frequently appealed to, than in that of the physical. This is due, not 5 so much to his expressed opinion that the inductive method was applicable to all the sciences, as to the generally practical, or, one may say, positive spirit of his system. Theological questions, which had tortured the minds of generations, are by him relegated from the province of reason to that of faith. Even reason must be restrained from striving after ultimate truth; it is one of the errors of the human intellect that it will not rest in general principles, but must push its investigations deeper. Experience and observation are the only remedies against prejudice and error. Into questions of metaphysics as commonly understood Bacon can hardly be said to have entered, but a long line of thinkers have drawn inspiration from him, and it is not without justice that he has been looked upon as the originator and guiding spirit of that empirical school which numbers among its adherents such names as Hobbes, Locke, Hume, Hartley, Mill, Condillac, the Encyclopædists, and many others of smaller note. In concluding this article, the writer desires to express his obligations to Mr James Spedding for various observations and suggestions made upon it before it went to press, and for the use of certain MS. notes relating to disputable passages in Bacon's life. Biography.-Spedding, Letters and Life of Lord Bacon, 7 vols. 1862-74; Macaulay, Essays; Campbell, Lives of Chancellors; Montagu, Works, vols. xvi. and xvii., 1834; Hepworth Dixon, Personal History of Lord Bacon, 1861, and Story of Lord Bacon's Life, 1862. Works. The classical edition is that by Messrs R. L. Ellis, J. Spedding, and D. D. Heath, 2d ed., 7 vols., 1870 (i.-iii. contains Philosophical Works; iv. v., Translations; vi. vii., Literary and Professional Works). Montagu's edition (17 vols., 1825-34) is full, but badly arranged and edited. Of numerous editions of individual works, or portions of the whole, the following are good:Euvres Philosophiques de Bacon, par Bouillet, 3 vols., 1834; Essays, by Whately, 5th ed., 1866, and by W. A. Wright, 1862; Novum Organum, by Kitchin (1855); Translation by the same (1855); Advancement of Learning, by W. A. Wright. Philosophy. Besides the Introductions in Ellis and Spedding's edition, the following may be noticed :-Kuno Fischer, Franz Bacon und seine Nachfolger, 2d ed., 1875 (1st ed., 1856, trans. into English by Oxenford, 1857); Rémusat, Bacon, sa vie, &c., 1857 (2d ed., 1858); Craik, Bacon, his Writings and his Philosophy, 3 vols. 1846-7 (new ed., 1860); A. Dorner, De Baconis Philosophia, Berlin, 1867; Liebig, Ueber Francis Bacon von Verulam und die Methode der Naturforschung, 1863; Lasson, Ueber Baco von Verulam's wissenschaftliche Principien, 1860; Böhmer, Ueber F. Bacon von Verulam, 1864. (R. AD.) John. BACON, JOHN, who may be considered the founder of | the British school of sculpture, was born Nov. 24, 1740. He was the son of Thomas Bacon, cloth-worker in Southwark, whose forefathers possessed a considerable estate in Somersetshire. At the age of fourteen he was bound apprentice in Mr Crispe's manufactory of porcelain at Lambeth, where he was at first employed in painting the small ornamental pieces of china, but by his great skill in moulding he soon attained the distinction of being modeller to the work. The produce of his labour he devoted to the support of his parents, then in somewhat straitened circumstances. While engaged in the porcelain works he had an opportunity of seeing the models executed by different sculptors of eminence, which were sent to be burned at an adjoining pottery. An observation of these productions appears to have immediately determined the direction of his genius; he devoted himself to the imitation of them with so much success, that in 1758 a small figure sent by him to the Society for the Encouragement of Arts received a prize, and the highest premiums given by that society were adjudged to him nine times between the years 1763 and 1776. During his apprenticeship he also improved the method of working statues in artificial stone, an art which he afterwards carried to perfection. Bacon first attempted working in marble about the year 1763, and, during the course of his early efforts in this art, was led to improve the method of transferring the form of the model to the marble (technically called getting out the points), by the invention of a more perfect instrument for the purpose, which has since been adopted by many sculptors both in this and other countries. This instrument possesses many advantages above those formerly employed; it is more exact, takes a correct measurement in every direction, is contained in a small compass, and can be used upon either the model or the marble. In the year 1769 he was adjudged the first gold medal given by the Royal Academy, and in 1770 was made an associate of that body. He shortly afterwards exhibited a figure of Mars, which gained him considerable reputation, and he was then engaged to execute a bust of George III., intended for Christ Church College. He secured the king's favour, and retained it throughout life. His great cele brity now procured him numerous commissions, and it is said, that of sixteen different competitions in which he was engaged with other artists, he was unsuccessful in one case only. Considerable jealousy was entertained against him by other sculptors, and he was commonly charged with ignorance of classic style. This charge he repelled by the execution of a noble head of Jupiter Tonans, and many of his emblematical figures are in perfect classical taste. On the 4th of August 1799, he was suddenly attacked with inflammation, which occasioned his death in little more than two days, in the 59th year of his age. He left a widow, his second wife, and a family of six sons and three daughters. Of his merit as a sculptor, the universal reputation of his works affords decisive proof, and his various productions which adorn St Paul's Cathedral, London, Christ Church and Pembroke Colleges, Oxford, the Abbey Church, Bath, and Bristol Cathedral, give ample testimony to his powers. Perhaps his best works are to be found among the monuments in Westminster Abbey. (See Memoir of the late John Bacon, R.A., by the Rev. Richard Cecil: London, 1811.) BACON, SIR NICHOLAS, lord keeper of the great seal in Nichola the reign of Queen Elizabeth, was born at Chislehurst in Kent in 1510, and educated at the university of Cambridge, after which he travelled in France, and made some stay at Paris. On his return he settled in Gray's Inn, and applied himself with such assiduity to the study of the law, that he quickly distinguished himself; and, on the dissolution of the monastery of St Edmund's Bury in Suffolk, he obtained a grant of several manors from King Henry VIII., then in the thirty-sixth year of his reign. Two years later he was promoted to the office of attorney in the court of wards, which was a place of both honour and profit. In this office he was continued by King Edward VI.; and in 1552 he was elected treasurer of Gray's Inn. His great moderation and prudence preserved him through the dangerous reign of Queen Mary. Very early in the reign of Elizabeth he was knighted; and in 1558 he succeeded Nicholas Heath, archbishop of York, as keeper of the great seal of England; he was at the same time made one of the queen's privy council. As a statesman, he was remarkable for the clearness of his views and the wisdom of his counsels, and he had a considerable share in the settling of ecclesiastical questions. That he was not unduly elated by his preferments, appears from the answer he gave to Queen Elizabeth when she told him his house at Redgrave was too little for him, "Not so, madam," returned he, "but your majesty has made me too great for my house." On only one occasion did he partially lose the queen's favour. He was suspected of having assisted Hales, the clerk of the hanaper, in his book on the succession, written at the time of Lady Catherine Grey's unjust imprisonment. Bacon was deprived of his seat at the council, and it was even contemplated to deprive him of the seal also. seems, however, to have quickly regained his position, and to have stood as high in the royal favour as before. He died on the 26th of February 1579, having held the great seal more than twenty years, and was buried in St Paul's, London, where a monument, destroyed by the great fire of London in 1666, was erected to his memory. Granger observes that he was the first lord keeper who ranked as lord chancellor; and that he had much of that penetrating genius, solidity, judgment, persuasive eloquence, and comprehensive knowledge of law and equity, which afterwards shone forth with such splendour in his illustrious son. He BACON, ROGER. The 13th century, an age peculiarly Roger. rich in great men, produced few, if any, who can take higher rank than Roger Bacon. He is in every way worthy to be placed beside such thinkers as Albertus Magnus, Bonaventura, and Thomas Aquinas. These had an infinitely wider renown in their day, while he was ignored by his contemporaries and neglected by his successors; but modern criticism has restored the balance in his favour, and is even in danger of going equally far in the opposite direction. Bacon, it is now said, was not appreciated by his age because he was so completely in advance of it he is a 16th or 17th century philosopher, whose lot has been by some accident cast in the 13th century; he experimental researches. Among all the instructors with Coger. is no schoolman, but a modern thinker, whose conceptions | scholastic routine, and devoted himself to languages and of science are more just and clear than are even those of his more celebrated namesake.1 In this view there is certainly a considerable share of truth, but it is much exaggerated. As a general rule, no man can be completely dissevered from his national antecedents and surroundings, and Bacon is not an exception. Those who take up such an extreme position regarding his merits have known too little of the state of contemporary science, and have limited their comparison to the works of the scholastic theologians. We never find in Bacon himself any consciousness of originality; he has no fresh creative thought or method to introduce whereby the face of science may be changed; he is rather a keen and systematic thinker, who is working in a well-beaten track, from which his contemporaries were being drawn by the superior attractions of theology and metaphysics. Roger Bacon was born in 1214, near Ilchester, in Somersetshire. His family appears to have been in good circumstances, for he speaks of his brother as wealthy, and he himself expended considerable sums on books and instruments; but in the stormy reign of Henry III. they suffered severely, their property was despoiled, and several members of the family were driven into exile. Roger completed his studies at Oxford, though not, as current traditions assert, at Merton or at Brazenose, neither of those colleges having then been founded. His great abilities were speedily recognised by his contemporaries, and he came to be on terms of close intimacy with some of the most independent thinkers of the time. Of these the most prominent were Adam de Marisco and Robert Grosseteste (Capito), afterwards bishop of Lincoln, a man of liberal mind and wide attainments, who had especially devoted himself to mathematics and experimental science. Very little is known of Bacon's life at Oxford; it is said he took orders in 1233, and this is not improbable. In the following year, or perhaps later, he crossed over to France, and studied for a considerable length of time at the university of Paris, then the centre of intellectual life in Europe. The years Bacon spent there were unusually stirring. The two great orders, the Franciscans and Dominicans, were in the vigour of youth, and had already begun to take the lead in theological discussion. Alexander of Hales, the author of the great Summa, was the oracle of the Franciscans, while the rival order rejoiced in Albertus Magnus, and in the rising genius of the angelic doctor, Thomas Aquinas. The scientific training which Bacon had received, partly by instruction, but more from the study of the Arab writers, made patent to his eyes the manifold defects in the imposing systems reared by these doctors. It disgusted him to hear from all around him that philosophy was now at length complete, that it had been reduced into compact order, and was being set forth by a certain professor at Paris. Even the great authority on which they reposed, Aristotle, was known but in part, and that part was rendered well-nigh unintelligible through the vileness of the translations; yet not one of those professors would learn Greek so that they might arrive at a real knowledge of their philosopher. The Scriptures, if read at all in the schools, were read in the erroneous versions; but even these were being deserted for the Sentences of Peter Lombard. Physical science, if there was anything deserving that name, was cultivated, not by experiment in the true Aristotelian way, but by discussion and by arguments deduced from premises resting on authority or custom. Everywhere there was a show of knowledge covering and con cealing fundamental ignorance. Bacon, accordingly, who knew what true science was, and who had glimpses of a scientific organon or method, withdrew from the usual 1 See Dühring, ritiscretes. 1. Phil., 192, 249 51. It is probable that Bacon, during his stay in Paris, acquired considerable renown. He took the degree of doctor of theology, and seems to have received from his contemporaries the complimentary title of doctor mirabilis. In 1250 he was again at Oxford, and probably about this time, though the exact date cannot be fixed, he entered the Franciscan order. His fame spread very rapidly at Oxford, though it was mingled with suspicions of his dealings in magic and the black arts, and with some doubts of his orthodoxy. About 1257, Bonaventura, general of the order, interdicted his lectures at Oxford, and commanded him to leave that town and place himself under the superintendence of the body at Paris. Here for ten years he remained under constant supervision, suffering great privations, and strictly prohibited from writing anything which might be published. But during the time he had been at Oxford his fame had reached the ears of the Papal legate in England, Guy de Foulques, a man of culture and scientific tastes, who in 1265 was raised to the papal chair as Clement IV. In the following year he wrote to Bacon, who had been already in communication with him, ordering him, notwithstanding 2 It is difficult to identify this unknown professor. Brewer thinks the reference is to Richard of Cornwall; but the little we know of Richard is not in harmony with what is said here, nor with the terms Erdmann conjectures in which he is elsewhere spoken of by Bacon. Thomas Aquinas, which is extremely improbable, as Thomas was unquestionably not the first of his order to study philosophy. Cousin and Charles think that Albertus Magnus is aimed at, and certainly much of what is said applies with peculiar force to him. But some things do not at all cohere with what is otherwise known of Albert. The unknown is said to have received no regular philosophic training; we know that Albert did. The unknown entered the order when very young; unless the received date of Albert's birth be false, he did not enter till nearly twenty-eight years of age. Albert, too, could not be said with justice to be utterly ignorant of alchemy, and his mechanical inventions are well known. It is worth pointing out that Brewer, in transcribing the passage bearing on this (Op. Ined. p. 327), has the words Fratrum puerulus, which in his marginal note he interprets as applying to the Franciscan order. In this case, of course, Albert could not be the person referred to, as he was a Dominican. But Charles, in his transcription, entirely omits the important word Fratrum. There are other instances in which Brewer and Charles do not agree, e. g., according to Brewer, Bacon speaks of Thomas and Albert as pueri duorum ordinum; according to Charles, he says, primi duorum ordinum; a discrepancy not unimportant. Retardandis Senectutis Accidentibus, 1590-translated as the "Cure of Old Age," 1683; (4.) Sanioris Medicina Magistri D. Rogeri Baconis Anglici de Arte Chymia Scripta, 1603-a collection of small tracts containing Excerpta de Libro Avicennae de Anima, Breve Breviarium, Verbum Abbreviatum,2 Secretum Secretorum, Tractatus Trium Verborum, and Speculum Secretorum; (5.) Perspectiva, 1614, which is the fifth part of the Opus Majus; (6.) Specula Mathematica, which is the fourth part of the same; (7.) Opus Majus ad Clementem IV., edited by Jebb, 1733; (8.) Opera hactenus Inedita, by J. S. Brewer, 1859, containing the Opus Tertium, Opus Minus, Compendium Studii Philosophiae, and the De Secretis Operibus Naturæ. any injunctions from his superiors, to write out and send | Naturæ, 1542-English translation, 1659; (3.) Libellus de Roger. to him a treatise on the sciences which he had already asked of him when papal legate. Bacon, who in despair of being ever able to communicate his results to the world, had neglected to compose anything, and whose previous writings had been mostly scattered tracts, capitula quædam, took fresh courage from this command of the Pope. Relying on his powerful protection, he set at naught the many obstacles thrown in his way by the jealousy of his superiors and brother friars, and despite the want of funds, instruments, materials for copying, and skilled copyists, completed in about eighteen months three large treatises, the Opus Majus, Opus Minus, and Opus Tertium, which, with some other tracts, were despatched to the Pope by the hands of one Joannes, a young man trained and educated with great care by Bacon himself. The composition of such extensive works in so short a time is a marvellous feat. We do not know what opinion Clement formed of them, but before his death he seems to have bestirred himself on Bacon's behalf, for in 1268 the latter was released and permitted to return to Oxford. Here he continued his labours in experimental science, and also in the composition of complete treatises. The works sent to Clement he regarded as mere preliminaries, laying down principles which were afterwards to be applied to the several sciences. The first part of an encyclopaedic work probably remains to us in the Compendium Studii Philosophiae, belonging to the year 1271. In this work Bacon makes a vehement attack upon the ignorance and vices of the clergy and monks, and generally upon the insufficiency of the existing studies. In 1278 he underwent the punishment which seems to have then been the natural consequence of outspoken opinions. His books were condemned by Jerome de Ascoli, general of the Franciscans, a gloomy bigot, who afterwards became Pope, and the unfortunate philosopher was thrown into prison, where he remained for fourteen years. During this time, it is said, he wrote the small tract De Retardandis Senectutis Accidentibus, but this is merely a tradition. In 1292, as appears from what is probably his latest composition, the Compendium Studii Theologiæ, he was again at liberty. The exact time of his death cannot le determined; 1294 is probably as accurate a date as can be fixed upon. Bacon's Works.-Leland has said that it is easier to collect the leaves of the Sibyl than the titles of the works written by Roger Bacon; and though the labour has been somewhat lightened by the publications of Brewer and Charles, referred to below, it is no easy matter even now to form an accurate idea of his actual productions. His writings, so far as known to us, may be divided into two classes, those yet in manuscript and those printed. An enormous number of MSS. are known to exist in British and French libraries, and probably all have not yet been discovered. Many are transcripts of works or portions of works already published, and therefore require no notice. Of the others, several are of first-rate value for the comprehension of Bacon's philosophy, and, though extracts from them have been given by Charles, it is clear that till they have found an editor, no representation of his philosophy can be complete.1 The works hitherto printed (neglecting reprints) are the following:-(1.) Speculum Alchimia, 1541-translated into English, 1597; (2.) De Mirabili Potestate Artis et 1 The more important MSS. are:-(1.) The extensive work on the fundamental notions of physics, called Communia Naturalium, which is found in the Mazarin Library at Paris, in the British Museum, and in the Bodleian and University College Libraries at Oxford; (2.) On the fundamental notions of mathematics, De Communibus Mathematica, part of which is in the Sloane collection, part in the Bodleian; (3.) Baconis Physica, contained among the additional MSS. in the British Museum; (4.) The fragment called Quinta Pars Compendii Theologia, How these works stand related to one another can only be determined by internal evidence, and this is a somewhat hazardous method. The smaller works, which are chiefly on alchemy, are unimportant, and the dates of their composition cannot be ascertained. It is known that before the Opus Majus Bacon had already written some tracts, among which an unpublished work, Computus Naturalium, on chronology, belongs probably to the year 1263; while, if the dedication of the De Secretis Operibus be authentic, that short treatise must have been composed before 1249. It is, however, with the Opus Majus that Bacon's real activity begins. That great work, which has been called by Whewell at once the Encyclopædia and the Organum of the 13th century, requires a much fuller notice than can here be given. As published by Jebb it consists of six parts; there should, however, be a seventh, De Morali Philosophia, frequently referred to in the Opus Tertium. Part I. (pp. 1-22), which is sometimes designated De Utilitate Scientiarum, treats of the four offendicula, or causes of error. These are, authority, custom, the opinion of the unskilled many, and the concealment of real ignorance with show or pretence of knowledge. The last error is the most dangerous, and is, in a sense, the cause of all the others. The offendicula have sometimes been looked upon as an anticipation of the more celebrated doctrine of Idola; the two classifications, however, have little in common. In the summary of this part, contained in the Opus Tertium, Bacon shows very clearly his perception of the unity of science, and the necessity of an encyclopædical treatment. "Nam omnes scientiæ sunt annexæ, et mutuis se fovent auxiliis, sicut partes ejusdem totius, quarum quælibet opus suum peragit, non solum propter se, sed pro aliis."-(Op. Ined., p. 18.) Part II. (pp. 23-43) treats of the relation between philosophy and theology. All true wisdom is contained in the Scriptures, at least implicitly; and the true end of philosophy is to rise from the imperfect knowledge of created things to a knowledge of the Creator. Ancient philosophers, who had not the Scriptures, received direct illumination from God, and only thus can the brilliant results attained by them be accounted for. Part III. (pp. 44-57) treats of the utility of grammar, and the necessity of a true linguistic science for the adequate comprehension either of the Scriptures or of books on philosophy. The necessity of accurate acquaintance with any foreign language, and of obtaining good texts, is a subject Bacon is never weary of descanting upon. He lays down very clearly the requisites of a good translator; he should know thoroughly the language he is translating r. from, the language into which he is translating, and the subject of which the book treats. Part IV. (57-255) contains an elaborate treatise on mathematics," the alphabet of philosophy," and on its importance in science and theology. Bacon shows at great length that all the sciences rest ultimately on mathematics, and progress only when their facts can be subsumed under mathematical principles. This singularly fruitful thought he exemplifies and illustrates by showing how geometry is applied to the action of natural bodies, and demonstrating by geometrical figures certain laws of physical forces. He also shows how his method may be used to determine some curious and long-discussed problems, such as the light of the stars, the ebb and flow of the tide, the motion of the balance. He then proceeds to adduce elaborate and sometimes slightly grotesque reasons tending to prove that mathematical knowledge is essential in theology, and closes this section of his work with two comprehensive sketches of geography and astronomy. That on geography is particularly good, and is interesting as having been read by Columbus, who lighted on it in Petrus de Alliaco's Imago Mundi, and was strongly influenced by its reasoning. Part V. (pp. 256-357) treats of perspective. This was the part of his work on which Bacon most prided himself, and in it, we may add, he seems to owe most to the Arab writers Alkindi and Alhazen. The treatise opens with an able sketch of psychology, founded upon, but in some important respects varying from, Aristotle's De Anima. The anatomy of the eye is next described; this is done well and evidently at first hand, though the functions of the parts are not given with complete accuracy. Many other points of physiological optics are touched on, in general erroneously. Bacon then discusses very fully vision in a right line, the laws of reflection and refraction, and the construction of mirrors and lenses. In this part of the work, as in the preceding, his reasoning depends essentially upon his peculiar view of natural agents and their activities. His fundamental physical maxims are matter and force; the latter he calls virtus, species, imago agentis, and by numberless other names. Change, or any natural phenomenon, is produced by the impression of a virtus or species on matter the result being the thing known. Physical action is, therefore, impression, or transmission of force in lines, and must accordingly be explained geometrically. This view of nature Bacon considered fundamental, and it lies, indeed, at the root of his whole philosophy. To the short notices of it given in the 4th and 5th parts of the Opus Majus, he subjoined two, or perhaps three, extended accounts of it. We possess at least one of these in the tract De Multiplicatione Specierum, printed as part of the Opus Majus by Jebb (pp. 358-444). We cannot do more than refer to Charles for discussions as to how this theory of nature is connected with the metaphysical problems of force and matter, with the logical doctrine of universals, and in general with Bacon's theory of knowledge. Part VI. (pp. 445-477) treats of experimental science, "domina omnium scientiarum." There are two methods of knowledge: the one by argument, the other by experience. Mere argument is never sufficient; it may decide a question, but gives no satisfaction or certainty to the mind, which can only be convinced by immediate inspection or intuition. Now this is what experience gives. But experience is of two sorts, external and internal; the first is that usually called experiment, but it can give no complete knowledge even of corporeal things, much less of spiritual. On the other hand, in inner experience the mind is illuminated by the divine truth, and of this supernatural enlightenment there are seven grades. Experimental science, which in the Opus Tertium (p. 46) is distinguished from the speculative sciences and the | operative arts in a way that forcibly reminds us of Francis Bacon, is said to have three great prerogatives over all other sciences :-(1.) It verifies their conclusions by direct experiment; (2.) It discovers truths which they could never reach; (3.) It investigates the secrets of nature, and opens to us a knowledge of past and future. As an instance of his method, Bacon gives an investigation into the nature and cause of the rainbow, which is really a very fine specimen of inductive research. The seventh part of the Opus Majus, not given in Jebb's edition, is noticed at considerable length in the Opus Tertium (cap. xiv.) Extracts from it are given by Charles, (pp. 339-348). As has been seen, Bacon had no sooner finished this elaborate work than he began to prepare a summary to be sent along with it. Of this summary, or Opus Minus, part has come down and is published in Brewer's Op. Ined. (313-389), from what appears to be the only MS. The work was intended to contain an abstract of the Opus Majus, an account of the principal vices of theology, and treatises on speculative and practical alchemy. At the same time, or immediately after, Bacon began a third work as a preamble to the other two, giving their general scope and aim, but supplementing them in many points. The part of this work, generally called Opus Tertium, is printed by Brewer (pp. 1-310), who considers it to be a complete treatise. Charles, however, has given good grounds for supposing that it is merely a preface, and that the work went on to discuss grammar, logic (which Bacon thought of little service, as reasoning was innate), mathematics, general physics, metaphysics, and moral philosophy. He founds his argument mainly on passages in the Communia Naturalium, which indeed prove distinctly that it was sent to Clement, and cannot, therefore, form part of the Compendium, as Brewer seems to think. It must be confessed, however, that nothing can well be more confusing than the references in Bacon's works, and it seems well-nigh hopeless to attempt a complete arrangement of them until the texts have been collated and carefully printed. All these large works Bacon appears to have looked on as preliminaries, introductions, leading to a great work which should embrace the principles of all the sciences. This great work, which is perhaps the frequently referred to Liber Sex Scientiarum, he began, and a few fragments still indicate its outline. First appears to have come the treatise now called Compendium Studii Philosophia (Brewer, pp. 393-519), containing an account of the causes of error, and then entering at length upon grammar. After that, apparently, logic was to be treated; then, possibly, mathematics and physics; then speculative alchemy and experimental science. It is, however, very difficult, in the present state of our knowledge of the MSS., to hazard even conjectures as to the contents and nature of this last and most comprehensive work. Bacon's fame in popular estimation has always rested on his mechanical discoveries. Careful research has shown that very little in this department can with accuracy be ascribed to him. He certainly describes a method of constructing a telescope, but not so as to lead one to conclude that he was in possession of that instrument. Gunpowder, the invention of which has been claimed for him on the ground of a passage in his works, which fairly interpreted at once disposes of any such claim, was already known to the Arabs. Burning-glasses were in common use, and spectacles it does not appear he made, although he was probably acquainted with the principle of their construction. His wonderful predictions (in the De Secretis) must be taken cum grano salis; and it is not to be forgotten that he believed in astrology, in the doctrine of signatures, and in the philosopher's stone, and knew that the circle had been squared. |