claim more than a general acquaintance with the special branches of science.

It is less excusable, whether we put it down to lack of curiosity, to personal jealousy, or to want of sufficient appreciation of its importance, that Bacon makes no mention of Harvey's great discovery of the Circulation of the Blood. As Harvey began to teach this doctrine in 1619, and as he was court-physician to James I, it is difficult to suppose that Bacon had heard nothing of it 57.

Though the true theory of the Motion of Projectiles had not been distinctly stated till the publication of Galileo's Dialogues on Motion in 1638, still the speculations of Tartalea, Digges, &c., ought, if they had been known to Bacon, to have saved him from shewing suchcomplete ignorance, when treating of the subject, as he exhibits in Nov. Org. ii. 36 (6), ii. 48 ad fin., and other places 58. It is curious that one of the books (the Pantometria, published in 1591), in which Digges speaks of the compound motion of a projectile, was dedicated to Bacon's father.

Notwithstanding his frequent criticisms of the Peripatetic doctrine of Motion, it is plain that Bacon entertained no doubt of the 'latio gravium versus terram, et levium versus ambitum coeli 59,' or of the existence of bodies having positive levity. In fact, in Nov. Org. ii. 35, he repeats, in almost the precise words of Aristotle himself, the Aristotelian division of what is called 'motion of translation' (popá), and sums up his account with the words 'Atque ista pulchra dictu sunt.' And though, with respect to the circular and eternal motion of the heavenly bodies, he impugns Aristotle's theory in the Descriptio Globi Intellectualis 60, I am not aware of any passage in which it appears to occur to him that the received division of light and heavy, and the two kinds of motion founded thereon, may be without

Bacon. See some curious passages in his Works, vol. ii. pp. 515, 516; vol. iii. p. 621 (ed. of 1744). In the former passage, he seems to entertain no kind of doubt that he has produced silver out of gold, 'or at least a new kind of metal very different from gold.' Then, he concludes generally that there may be a real transmutation of one metal into another, even among the perfectest and noblest metals, and that effected by factitious agents in a short time, and, if I may so speak, after a mechanical manner.'

57 In the Historia Densi et Rari, and in the very part which was probably written during Bacon's last 'quinquennium,' he thinks it a sufficient account of pulsation in the heart and arteries of animals, to say that it is due to the endless and alternate dilatation and contraction of the spirits. See E. and S., vol. ii. p. 263.

58 See my notes on these two passages, especially the latter.

59 Nov. Org. ii. 46.

6 See my note on the passage on motion in Nov. Org. ii. 35.

foundation". At the same time, considering the obscurity of the views of motion which then prevailed, and the fact that the weight of the atmosphere had not yet been discovered, we are not here so much justified in complaining of ignorance, as of a want of that insight which in a man of Bacon's genius might possibly have been expected. Connected with these opinions, are the theory that air has no weight, being indifferent as regards gravity and levity, and that flame and 'living spirits' are positively light 62.

Passing to a very different subject, we find that, of the triad of Paracelsus, sulphur, mercury, and salt, Bacon adopts two principles, namely sulphur and mercury, as pervading the universe (quasi per universitatem rerum permeare), and being the very foundation of matter (naturas admodum primordiales, et penitissimos materiae schematismos; et inter Formas Primae Classis fere praecipuas) 63. The mode in which he traces these principles through all things in heaven and earth and under the earth appears to us peculiarly absurd. He omits Salt, as compounded of the two others, but, in doing so, can hardly be said to have improved on the theory of Valentinus and Paracelsus. In two notes on Nov. Org. ii. 50 (6) ad init., I have spoken at such length on the history of this dogma, and the manner in which Bacon presents it in various parts of his works, that it would be superfluous to say anything further on the subject in this place.

That in the Sylva Sylvarum (on which, however, see the apologetic remarks of Rawley in his preface to the work 64) Bacon affords his countenance to many of the most absurd fancies of his time, is a fact so well known and so universally confessed, that it hardly requires illustration.

61 He certainly criticises the explanations given (Nov. Org. ii. 35), but he does not call in question the supposed facts themselves. It should, perhaps, also be mentioned that he does not recognise in air and similar bodies 'tam fortis appetitus petendi superiora, quam putatur.' Historia Densi et Rari (E. and S., vol. ii. p. 255).

62 Animal spirits, as being compounded of air and flame, are intermediate, in point of levity, between the two. See Historia Densi et Rari (E. and S., vol. ii. Pp. 255, 256). 'At spiritus vivos aere ipso aliquanto rariores existimamus: tum quia inflammantur nonnihil; tum quia diligenter experti sumus, aerem ad minuendum aut sublevandum pondus nihil conferre. At corpus animale vivum

et mortuum gravitate manifesto differunt; licet haud tantum quantum putantur. Quare videtur aer pondus non minuere; spiritus autem vivus hoc facere.'

63 Cp. Nov. Org. ii. 50 (6) with Aditus ad Historiam Sulphuris, Mercurii, et Salis (E and S., vol. ii. p. 82).

In the section on the Opponents of Bacon, I have transcribed the more important part of Rawley's Apology.

67

I may give as instances, the conceit that the blood-stone is good for them that bleed at the nose, with the quaere, whether 'the stone taken out of the toad's head be not of the like virtue, for the toad loveth shade and coolness 65;' the 'report' of 'the writers of natural magic,' quoted apparently with approval, that the heart of an ape, worn near the heart, comforteth the heart, and increaseth audacity,' ' and that the same heart likewise of an ape, applied to the neck or head, helpeth the wit, and is good for the falling sickness 66;' the statement that 'there be divers sorts of bracelets fit to comfort the spirits, and they be of three intentions, refrigerant, corroborant, and aperient 7; the suggestion to try the force of imagination upon staying the working of beer when the barm is put in, or upon the coming of butter or cheese, after the churning, or the rennet be put in 68;' the sections on the influences of the moon 69; the notion that water is congealed into crystals 70. I might, of course, greatly extend this list, but there is no object in doing so. The reader, who is curious in such matters, may refer to the tenth century, which is full of absurdities of this kind. On Bacon's behalf, it may be pleaded that these were the fancies of his age, from which probably no man of that time was altogether free. We have only to look into books like Sir Thomas Browne's 'Vulgar and Common Errors' or the various works of Joseph Glanville, to see how persistent such notions were even in the generation after Bacon's death. Moreover, a large number of them may be grouped under the heads of 'sympathy and antipathy,' 'force of imagination,' &c., subjects on which peculiarly obscure ideas prevailed at this time. Lastly, Bacon's very hopefulness, and his sanguine expectations of what nature had in store for those who diligently studied her, may have rendered him peculiarly liable to be imposed on by these 'old wives' fables.'

But far the most important and, perhaps at first sight, the least excusable of Bacon's scientific errors was his persistent rejection of the Copernican theory". It seems strange that one who laid claim to be the great reformer of science should have steadily refused to

65 Exp. 967.

69 Exps. 890-897.

66 Exp. 978.

67 Exp. 961. 68 Exp 992. 70 Exp. 364. Cp. Nov. Org. ii. 48 (4). 71 M. Bouillet, in a note on Nov. Org. ii. 36, is so much startled with this fact that he is driven to the supposition that Bacon was deterred from embracing the Copernican theory by fear of the inconvenient consequences which might thereby be entailed on him, surtout sous un roi aussi dévot que Jacques Ier.' But this theory appears to me hardly worth discussion.

admit the greatest reform in scientific conceptions which had been proposed for many generations, and which had already been before the world for eighty years. To say nothing of Copernicans before Copernicus, the views of Kopernik himself were first published in a letter by Rheticus in 1540, though his great work 'De Revolutionibus orbium coelestium' did not see the light till the very day of his death, May 24, 154372. The precise thesis maintained, it must be recollected, was that if the sun be regarded as the immovable centre of the universe (we now, of course, know that it is not), and the earth be supposed to have both a diurnal and an orbital motion, the apparent phenomena of the heavens admit of a far more simple mathematical explanation than on the received or Ptolemaic system 79. Whether this hypothesis represents what really does take place, that is, whether the mathematical theory is also the true physical theory, was another question, which might be resolved differently, or left unresolved, by those who maintained the former. As Professor De Morgan says, 'the question whether Copernicus himself was a Copernican in the modern sense of the word is not easily settled. His phraseology is almost always that of a mathematical Copernican. In a very few places, and cautiously, he leans to the physical truth as probable, and to the diurnal motion as more probable than the orbital.' It was not till the discovery of the satellites of Jupiter by Galileo in 1609, that the Copernican system could be said to be

71 On which subject, see an excellent article, entitled 'Copernicus in Italy,' in No. 299 (July, 1877) of the Edinburgh Review. One of the works reviewed is I precursori del Copernico nell' Antichità. Ricerche Storiche. Di G. V. Schiaparelli. Milano, 1873.

72 The idea of his system, however, must have occurred to him before 1507. He informs Paul the Third in his Dedication that he had kept the book by him for four times the nine years recommended by Horace.

73 With reference to the merely hypothetical character ascribed to his reasoning, the reader will do well to consult the curious and interesting admonition Ad Lectorem de Hypothesibus hujus operis' prefixed to the work. This occurs in the first, as well as the subsequent editions, but it seems not to have been written by Copernicus himself. It is not necessary for the hypotheses to be true, or even probable, 'sed sufficit hoc unum, si calculum observationibus congruentem exhibeant.' The office of the astronomer is confined to observation and calculation, 'cum veras causas assequi nulla ratione possit.'

74 In addition to the ordinary books, Delambre, Whewell, &c, the student, who has time and inclination to pursue this subject, is recommended to consult two very interesting papers by the late Professor De Morgan, one entitled, 'Old Arguments against the Motion of the Earth,' which appeared in the Companion to the British Almanac for 1836, the other, which appeared in the same publication for 1855, entitled Notes on the Antegalilean Copernicans.'

recommended by any other important considerations than those of its simplicity. This important discovery, which was announced to the world in the Sydereus Nuncius in 1610, irresistibly suggested an analogy between the small system of Jupiter, now ocularly demonstrated, and the large system of the Sun, as depicted theoretically by the followers of Copernicus 75. From this point the controversy assumed a new phase, as is evidenced, amongst other things, by the increased warmth of the dispute. Even still, however, and notwithstanding the mathematical precision given to the theory by the investigations of Kepler (whose work De Motibus Stellae Martis was published in 1609), it cannot be said that, till the laws of formal astronomy were connected by Newton with the physical laws of matter and motion, the motions of the earth or its relation to the rest of the solar system could in any way be regarded as placed beyond the range of dispute. In Bacon's time, and especially during the earlier period of his life, men might be well excused who suspended their judgment, or who even preferred to adhere to the old assumption till their objections to the new theory were removed. The following sentences from Mr. De Morgan 76 are so apposite, and read a lesson so universally useful to us, in estimating the scientific judgments of men in past ages, that I am sure my readers will be grateful to me for transcribing them. By investing Copernicus with a system which requires Galileo, Kepler, and Newton to explain it, and their pupils to understand it, the modern astronomer refers the want of immediate acceptance of that system to ignorance, prejudice, and over adherence to antiquity. No doubt all these things can be traced; but the ignorance was of a kind which belonged equally to the partisans and to the opponents, and which fairly imposed on the propounder of the system the onus of meeting arguments, which, in the period we speak of, he did not and could not meet. It must be remembered that, in the sixteenth century, the wit of man could not imagine how, if the earth moved, a stone thrown directly upwards would tumble down upon the spot it was thrown from. Easy experiments verify the law of motion which now explains this; but to be proved by experiment, a law must be conceived and imagined. To be put under discussion, it must be proposed. Now the advocates

75 Even Bacon was sufficiently moved by this discovery to include among his affirmations in the Thema Coeli (E. and S., vol. iii. p. 780), 'solisequium ex natura inopiosa in ignibus infirmioribus Veneris et Mercurii; cum etiam inventae sint a Galilaeo stellulae errantes Jovis asseclae.'

76 Companion to the British Almanac for 1855, pp. 21, 22,