scarcely be expected of us to speak decisively on this head: yet has the author, in the other parts of his work, afforded such grounds of favourable presumption, that we are inclined to believe that the correctness of the tables is not wanting to the other excellencies of this valuable work *. Among the several causes to which Lord Bacon attributes the slow advancement of the sciences, is mentioned a disposition in the philosophers of his time to rest satisfied with the truths already established, and to devote their labour rather to the elucidation of existing systems than to the advancement of new discoveries; thus losing sight of the great and substantial ends of science. If we examine the history of the times in which this representation was given, the case will appear to be fairly stated: but Bacon,-who united the rare qualities of power of analysis, depth of judgment, and views the most comprehensive, with variety and universality of knowlege,—not only pointed out the cause of the disease under which philosophy laboured, but administered to its cure: so that, from his time, it seems to have assumed a new spirit and vigour, to have advanced rapidly in its march towards perfection, and to have proceeded always in the road that he pointed out. The interval between him and us is occupied by a splendid train of worthies, of whom we are tempted to speak in the language of * Although we are of opinion that the author is, in general, sufhciently copious, yet the subject of the 8th chapter [the system of the world] demanded a more particular detail of circumstances and a more comprehensive argumentation. The Copernican we believe to be the true system; yet the proof on which its truth rests is by no means competent to give the mind that complete satisfaction which a direct demonstration affords. Let it be recollected, too, what opponent this system had: Tycho Brahé, who occasioned a new epoch in the history of astronomy. To this great man might be applied what was formerly said of Cato, "Hac bona que videmus divina et egregia, ipsius scitote esse propria: quæ nonnunquam requirimus, ea sunt omnia non natura sed a magistro." We wish not idly to cavil, but reasonably to object. An expression of the author, in the beginning of the 8th chapter, appears to us faulty. He says, there are very few, if any enquiries of this kind (philosophical), where we can be led from the cause to the effect by a train of mathematical reasoning, so as to pronounce with certainty upon the cause.'-We would ask the Professor whether, after the labours of Newton, Euler, Clairaut, D'Alembert, de la Place, and de la Grange, (by which, assuming gravity as a principle, the phænomena of the universe have been calculated, and shewn to agree with actual observation,) he dares not pronounce gravity to be the principle, or cause of the effects that take place in the heavens ? exaggeration, exaggeration, as being of celestial birth and more than mortal intelligence: "Igneus est ollis vigor, et cœlestis origo." In the general progression of the sciences, it has been the lot of astronomy to have advanced the most rapidly; or it may be said to be a science which has increased not only by the accumulation of its own revenues, but by the tributary contribution of other sciences and arts. By the improvements in the mechanical arts, the instruments used in astronomy have been constructed with great exactness. In the science of dynamics, the means of affording more accurate measures of time have been ascertained, and new properties of the rays of light, and the laws by which they are governed, have been discovered; yet these discoveries, which otherwise might have afforded matter of curious speculation only, when applied to astronomy have turned to use and profit. Geometry has been enriched by a new branch of analysis, of most extensive application; yet its complex formule would have exercised ingenuity unprofitably, and the common question, of what use or substance are such abstract inquiries? would have involved a real objection, unless in astronomy had been found a field sufficiently spacious for its widest range and travel.-Formerly, astronomy depended on observation only: but, when gravity was discovered to be the cause of the heavenly motions, and a new path was opened to science, it could be calculated what was the form of the planets' orbits,-of what length were their periods,-by what law these were regulated,-and what derangements would ensue in consequence of the action of an extraneous force. To the determination of these questions, the most eminent geametricians have directed their attention; and they have enriched astronomy with so vast a number not only of distinct treatises, but of papers, memoirs, &c. that a person who views what has been done may possibly be discouraged from the study of the science; or, if emulous of establishing new truths, will look (as Dr. Johnson says) rather "upon the wastes of the intellectual world," than employ his labour in a province already so highly cultivated. The writings of learned men are scattered among the vo lumes of Transactions, Acts, &c. To understand them requires a profound knowlege of the subject; they are written by the learned to the learned; and as their object was not to put science in a better trim, but to endue her richly and substantially, we may with reason make a complaint directly opposite, in its terms and intention, to that of the learned Verulam: "Nam si quis in omnem illam librorum varietatem quâ K 3 artes artes et scientia exultant, diligentius introspiciat, ubique inveniet ejusdem rei repetitiones infinitas, tractandi modis diversas, inventione præoccupatas, ut omnia primo intuitu numerosa, facto examine pauca reperiantur.” Far different now is the state of things; we have abundance of important memoirs, but great deficiency of those treatises which should collect, reduce to order, and systematize what has been written. The work of M. de la Lande (excluding other objections) has not been translated; and those of Street, Mercator, Whiston, Keil, Long, Ferguson, Leadbetter, Dune thorne, Hodgson, Costard, &c. do not suit the present maturity of the science. Astronomy is now divided into two parts, plane and spheri cal: but in the time previous to that of Newton, the former only existed. The science ther depended on observation alone; aided, corrected, and informed, by the sciences of geometry, algeura, and trigonometry. Its distinguished cultivators were Hipparchus, Ptolemy, Copernicus, Tycho Brahé, and Kepler. This last great man may be considered as the first founder of physical astronomy, and the forerunner of the greater Newton, He suspected gravity to be a principle in the universe, yet touched on it but lightly, "extremis digitis." The discoveries of Kepler prepared the way for that memorable epoch of philosophy, when « Cœlum ascendit ratio, cœpitque profundis Naturam rerum causis, viditque quod usquam est." It was reserved for Newton to verify the suggestion of Kepler, and to prove how justly the antient philosophers had thought concerning the simplicity and unity of a principle which was to account for all phenomena; though they had constantly erred in assigning what that principle was. It is matter of curious speculation, to consider how strong the propensity has been, in all ages, and in all men, to establish a first cause or principle; to refer the infinite complication of effects, and the boundless variety of phænomena, to the varied operation of the same active cause, or to the different modifications of the same matter!--Thales of Miletus affirmed water to be the constituent principle of the universe; Anaxagoras thought that fire was the element by the activity of which Nature might be formed, was supported, and was animated; and at the distance of more than two thousand years, Democritus and Descartes agree in their system, and require only matter and motion to construct the universe. This idea of simplicity has probably been suggested by observing the constant effect of experiment and research; which has been to illustrate what at first appeared con confused, to find out effects which might properly be referred to the same class, to establish analogies, and to afford glimpses at least of a system dependent on certain general laws. Yet there is a precipitate propensity in man to form systems, a disposition to believe that an hypothesis which solves some few phænomena is competent to account for all, to leave too soon the severe inquisition of nature, and to follow the phantoms created by their own imagination *. A great philosopher has made an excellent remark which suits the present subject: "Hence (says he) it cometh that the mathematicians cannot satisfy themselves, except they reduce the motions of the celestial bodies to perfect circles, rejecting spiral lines, and labouring to be discharged of eccentrics.-Hence it cometh, that whereas there are many things in nature, as it were monodicą, sui juris ; yet the cogitations of man do feign unto themselves relatives, parallels, and conjugates, whereas no such thing is; as they have feigned an element of fire to keep square with earth, water, and air, and the like," &c. Advancement of Learning, 4to. p. 79, It is to be lamented that so much labour and ingenuity should have been thrown away by the antient philosophers ;that men, capable of adding to the substance and richness of science, should have been employed in spinning flimsy systems, the cobwebs of the mind,-of fine thread and workmanship, indeed, but of no use nor profit. It is to be lamented that they wanted a Bacon, whose sagacity was to point out the true route in which science was to be followed; and that they were unable to use, like Newton, the balance of an exalted geometry, by which, after having discovered the cause and principle of the universe, he could ascertain its law and intensity. Hence it was that they suspected only, but could not prove, the simplicity of God's workmanship, as he doth hang the greatest weights upon the smallest wires." " If it should be thought remarkable that there exists in human nature a strong propensity to believe that one or a few principles and elements are competent to the production of effects in appearance unconnected, and endless in their variety, it may seem not less so that, in laying down an hypothesis and constructing on it a system, so great an inattention should be manifested towards those facts which may be called negative facts; those which no possible subtility nor wile of reasoning can * M. Freret, speaking of the Greek philosophers who succeeded Aristotle, says; "On ne s'occupa plus de soin d'acquérir des connoissances nouvelles, mais de celui de ranger et de lier les unes aux autres, celles que Pon croyoit avoir, pour en former des systêmes." K 4 reduce reduce within the limits of that system, and subject to its power. The constant endeavour is to bring affirmations, facts which support an hypothesis; and to keep out of sight any that are contrary to it: yet is the power of these two classes of facts immensely different. A thousand facts of the former class may support an hypothesis, yet one single ascertained fact of the latter is competent to its destruction, and to reduce the system founded on it to the rank of those baseless unsubstantial theories, which are destined to please the imagination without satisfying reason. To speak particularly to the point: -Newton, in order to verify his hypothesis (for in his time it was only an hypothesis) that gravity observed the law of the inverse square of the distance, applied to the investigation of the most sensible phænomena; and the results of his calculations agreed well with observation. This law of gravity therefore seemed to prevail in many cases; yet its universality was by no means completely established. The geometricians of the continent adopted the hypothesis of Newton: but, in investigating the theory of the moon, it appeared (at first sight) that the quantity, representing the mean motion of the moon's apogee, was only half of the quantity determined by actual observation: here, then, the theory seemed eminently defective:but an oversight had been committed:-Clairaut, summing more terms of the series, found that the quantity determined by calculation agreed to great nearness with observation.-Yet had this single instance, which manifested the disagreement of theory and observation, been after mature consideration clearly established, the Newtonian law of gravity must have been abandoned; and indeed, before the discovery of his mistake, Clairaut had proposed to alter the law of gravity from the inverse square to a law compounded of the inverse square and biquadratic. This law would have solved a great number of the phænomena of the universe, although not all, as was proved by D'Alembert :-it was attacked (perhaps successfully) by the metaphysical arguments of Buffon.-To mention another instance-a single case solved by the doctrine of chances (such as is generally received) in the game of cross and pile, and of which the determination is plainly contradictory to our common conceptions, and most examined judgments, has subjected the whole doctrine to doubt; and the sagacious D'Alembert has sufficiently proved that its principles need revision and correction. If, indeed, we examine the history of science, we shall find abundant argument for admitting with caution any principles, however recommended by their simplicity. It was well answered by Pythagoras, to one who objected to his system as confused, |