vier and the naturalists, and notwithstanding | by one huge planet on another; nor to go the presence of such questioners as Maedler and seek another hemisphere, or make experiand Owen, chemistry is the science of the ments with electron at the North Pole; nor century; and that, not by any means for to dig extinguished worlds of animation from what has yet been done or conceived in it, nor the laminated hide of the old Earth; nor yet yet for the unprecedented conquests which to sprinkle the ground with urine and the farthe chemists are making ready to attempt fetched dung of monstrous birds. It was with success, but because there are sciences never in the divining, the excavation, and the at work, which cannot advance a step farther intellectual manipulation of the concrete facts (we do not say in mere breadth, but) in depth, of nature that they came before, excelled, or until this eminently terrestrial (yet cosmical even equalled the men of renovated Christenand ideal) science be carried nearer its per- dom. In the art of experiment, and in tryfection. ing to find his way with untripped step among details, the Greek was as feeble as a child: whereas in the sphere of ideas and vast general conceptions, as well as in the fine art of embodying such universals and generalities in beautiful and appropriate symbols, it is not a paradox to say that he was sometimes stronger than a man. Could old Leucippus, or De Of such sort, then, is the circumstantially determined succession of the sciences;-mechanics, astronomy, chemistry. It is not our cue to trace this part of scientific history more curiously, as, for instance, to show the circumstantial relation of optics to mechanics and astronomy; nor to follow it any farther up, as by exhibiting the dependence of phy-metrius of Abelæa, or, better still, that vagasiology on chemistry, of psychology on physiology, and so forth, until the full development of the natural, and partly natural sciences (at least in method) shall render it possible for philosophy to evolve a many-sided doctrine of man. These illustrations will suffice for the indication of this second and more superficial, but equally unfailing law, of the history of science. It is a third and still more interesting historic law, connected with the origin and growth of many of our modern ideas in science, that the Atomic Theory brings into view. It is certainly the most provocative and wonderful thing in the history of positive knowledge, that many of the best results of modern science were anticipated, some four or five centuries before Christ, by the physiological and other schools of Greek or EgyptoGrecian philosophy. They did not, indeed, propose to draw forth some precious and unheard-of combustible airs from the olive-oils of their country-groves, and send them all through Athens in a system of arterial tubes, to illuminate the city of Minerva when Dian should be resting from the labors of the chase; nor to cross the Hellespont, or tempt the broad Ægean in fantastic barges rowed by fire and water; nor to whisper words of amity to their allies, defiance to their enemies, swifter far than the flight of a dove to her mate, through the invisible hollows of a copper-wire; nor to dash strange metals out of marble and natron by means of subterranean levin-brands, filched from the carriers of Vulcan on their way to the heaven of Jupiter Tonans; nor to make a hundred complex calculations of the disturbing forces exerted bond philosophical quidnunc, Apollonius the Tyanean, be resuscitated now, carried from Vienna to Paris, from Paris to metrocosmical London, and shown all the contents and ongoings and aims of their myriad museums, laboratories, observatories, studies, libraries, and officinums, the antique scholar might well be as much bewildered and overawed as any African convert, or steadfast Indian chief, fresh from the wilds-but let some alleloquent Coleridge, or logical Hamilton, or, better still again, some all-conceiving and ideal Goethe, take the venerable Ghost to his quiet chamber, and there expound the fundamental ideas and largest conceptions of all those arts and sciences, perhaps beginning at the Atomic Theory, or the Law of Polarity, the Ancient might (just as well) break in on the discourse, profess he knew it all before, and vanish contented to his early haunt. Not that all the broad and general conceptions of positive science were foreknown (and therein predicted) by pre-Christian thinkers and seers, but so many of the capital points of modern theory did actually constitute principal elements of the Greek idea of nature, as to arrest and astonish the historical inquirer at almost every turn; and it is really not wonderful that our fonder Hellenists, living with reverted eye upon the men of that most fascinating past, and refusing to be comforted because they are not, swear like insulted lovers at the present unoffending age, and claim all our discoveries, forsooth, for the silent gods of their idolatry! The peculiar circumstance attending our rediscovery of their old truths, is the fact of our having reached the summits in question by a long course of ob servation and strict induction, climbing every step of the ascent slowly and surely, while they sprang to the tops of thought at one bound, namely, from the standing-ground of the most obvious facts at the very foot of the mountain-range set before them and us. Happily, the immense labors of our modern method are accompanied at every step, richly compensated, and even glorified, by the most marvellous discoveries of every kind, else its noble toils might have been too great for mortal man to undergo. It takes fourteen years to make out a new fact that is worth while, said a living chemist of the true Baconian genius, on an occasion in point some years ago; and every discoverer in the world, whose wealth of experience is not of yesterday, would assuredly indorse the note;-but what a strange contrast does the thing present to the swift improvisations of those patriarchal grandsires of the present race of inquirers! The maximum of concrete labor and working talent, with as much genius as can be is the formula of the latter: the maximum of genius and daring, with as little experience as possible-was that of the for For example, Democritus and Empedocles foresaw those things at once, but it was "as in a glass darkly," which Dalton and Faraday, or rather large companies of craftsmen represented by these great names, have slowly and painfully brought out to the surface, flooding their every secret part with the blessed common light of day and now they are as minute and true as a daguerreotype, without losing a single line of their old grandeur of aspect. The reference is made, in this instance, to the four elemental forms of material manifestation-solid, liquid, aerial, and imponderable or dynamidal and to the Atomic Theory of the three sensible forms of such manifestation: nor could a better illustration of the species of historical nexus now under discussion, (namely, that which subsists between the divinations of the Egypto-Grecian foreworld and the generalizations of the Christian afterworld of human science) be anywhere found than the history of this Atomic Theory in its two movements, before the Coming of Christ, and since that Beginning of Days. After a quick glance into the idea of that Theory as it made its appearance on those fertile shores where Apollo, being a god and the son of a god, condescended to men of lowly spirit, and kept the sheep of Admetus, making music as he went, we may consider it to more advantage in its outward developments, now that it has sprouted anew, grown up as wondrously as the parabolic mustard-seed of the evangelist, and spread far and wide over the cultivated fields of Christendom. It would appear that some sort of doctrine, conceiving of sensible matter as being produced or constituted by the concourse of substantial or underlying atoms, not touching (but moving more or less freely about) one another, was very early promulgated among the ancient Hindoos; and that in logical opposition to the extreme Idealism which has always predominated in the East. If the opinion of some critics be correct, that the monads of Pythagoras were endowed with corporeity or bodily presence, it is probable that a similar tenet was discussed by the initiates of the old Egyptian mysteries also ;— and that (it is almost certain) in the same antithesis, namely, in contest with that inborn Idealism, which has never been able to die out of the world of speculative thought, notwithstanding its doing such violence to the common notions of us Christianized, western, and world-subduing Teutonic Tribes, as to take all the phenomena of nature for nothing but the co-instantaneous shapings of the spirit. That aspect of the Atomic Theory, however, which is under view at present, originated in the skeptical and penetrating soul of Democritus, the successor of Empedocles in the physiological or second movement of Greek Philosophy,-if the reader will permit the whole effort of that national intellect, from Thales down to its dual consummation in Aristotle and Plato, to be dignified by courtesy (like the family of a prince) with that aristocratic and all-exclusive style and title. It was the teeming head of Democritus that first conceived of the proposition, for instance, that a pebble from the brook is not a blank extended substance or dead stone (as it seems to the bodily eye, and as it always remains to the judgment of common sense, like the Yellow Primrose of Peter Bell), but a palpable thing resulting from the congregation of multitudes of atoms, or particles incapable of being broken to pieces, as the stone is broken when dashed against a rock, or worn to powder by friction with its neighbors. It was the secondary, but co-essential half of this definition, that these co-aggregated and constituent atoms of the stone are not in contact with one another, albeit that human eyesight is not fine enough to see the spaces between them. This marvellous view (for marvellous it was and still is, although now as trite as the dust under foot) was pro bably the lineal offspring of his earlier thought, to wit, that the Milky Way (hitherto sacred to the white feet of down-coming gods and the heaven-scaling heroes) is no blank extensive show of far-spread light, but the unique resultant of multitudinous heaps of stars, so distant and so crowded in their single plane of vision (though as free of one another as kings, in reality) as to render the interspaces undistinguishable by the sight of man or lynx. The astronomical illustration of Professor Nichol applies to the crystalstone as well as to the firmament:-Across some vast American lake, the forest-farmer is accustomed to see the mass of forest over against his log-hut as if it were some vast and silent and solid shadow on the shore, "some boundless contiguity of shade;" but he knows, with the same certainty as he knows his homestead, that it is in reality a vast, clamorous, and unresting assembly of trees, standing respectfully apart. Democritus had possibly also observed how the common stars of night are brought out, into visibility, even on the mid-day sky, when looked at from the depths of a pit; and one might venture to suppose this to have been the origin of that famous proverb of his, in which truth was represented as lying in wait at the bottom of a well. Such, at all events, and so truly sublime as well as true, were two of the great conceptions in which the disciple of Leucippus showed the lucidity with which he had seized the perceptions of his master, that the truth of appearance in Nature is not the truth of reality, and also that the latter has to be eliminated from the former by the afterthought of science. It is to be understood, then, in the meantime, that the Atomic Theory of Democritus,-elaborated by Epicurus into a system of natural-legal atheism (not without a sublime aspect of its own), and so set to monotonous, but eloquent music by Lucretius towards the nightfall of that long day; repeated and consolidated by Anaxagoras, in his holding that every particular kind of sensible matter has its particular shape and size of constituent particles, or its own homoömeric parts; somewhat heedlessly retained by Plato, who treats with complacency of the atoms of the elements as so many different shapes cut off, or assumed by, the one First Matter or primordial stuff of nature; and, finally, contended against by the thoroughgoing geometers ;-for the most part stood in opposition, not to any form of idealism, but to the counter-tenet that the sensible matter of common experience is always to be considered as being infinitely divisible, and that by the very nature of those mathematical ideas or archetypes which stand embodied in creation. It was in conflict with the notion of the endless divisibility of material substances, also, that the buried and forgotten Atomic Theory was revived by the Cartesians; and, likewise, that Dalton suffered it to be placed by more than one of his earlier opponents, to say nothing now of his applauding judges and disciples, even of the lasest dates. The gist of the argument urged by the mathematicians against the Atomic Theory, as thus put in antagonism to the theory of the infinite divisibility, was just this:-Whatsoever possesses length, breadth, thickness (whatsoever has dimensions, in short), is essentially and mathematically divisible, that is to say, can be supposed to be halved, the halves halved again, and so forth forever :a thing most true, if that had only been the right method of considering the point under inquisition, which it certainly was not. The reiterated argument of the Atomicians, from Democritus down to Newton, was something like the following plea :—If the invisible but extant particles, composing the framework of sensible matter, were not adamantine and perdurable, but divisible, they should wax old and crumbling, perhaps yet cracked, and the nature of the bodily shapes depending on their agglutination be thereby changed, whereas, air, earth, and water are as full and fair as ever. "Water and earth," said Newton himself, "composed of old worn particles would not be of the same nature and texture now with water and earth composed of entire particles at the beginning. And, therefore, that nature may be lasting, the changes of corporeal things are to be placed only in the various separations and new associations and motions of these permanent particles, sensible bodies being apt to break, not in the midst of solid particles, but where those particles are laid together, and touch in a few points." It is the old argument, enlarged by the chemical and astronomical notions of "new associations and motions;" and nothing but an argument it was, any more than the geometrical flourish just recorded for the thousand and first time. The first thing that strikes the modern critic, no thanks to him, but all to his position (won for him by those contending predecessors) is the now patent fact that the disputants did not argue in answer to one another at all. The mathematicians came down, and that with a vengeance, from the idea of space to the fact of nature: the physicists struck right up from the fact of nature to the idea of space: and therefore they crossed swords without touching one another. A hit was impossible betwixt them. Although they stood opposed to one another, they stood aside, and each tought his own shadow:-an easy foeman, because dealing no blows, and yet a troublesome combatant, being always ready to stand up to another play of arms. The sophistication of the mathematical heads is admirably put by Henry More, our own Platonizing divine, in his book against Atheism. "If a body be divisible into infinite parts, it has infinite extended parts: and, if it have an infinite number of extended parts, it cannot but be a hard mystery to the imagination of man that infinite extended parts should not amount to one whole infinite extension: and thus a grain of mustard-seed would be as well infinitely extended, as the whole matter of the universe; and a thousandth part of that grain as well as the grain itself. Which things," slyly adds the quaint and puzzling Dominus, "are more inconceivable than anything in the nature of a spirit." cal instrumentation as is capable of dividing a piece of marble, made up as it is of multitudes that cannot be numbered of marbleatoms. But present an atom of potassa to one of marble, and it is divided at once ;— yet not into two bits, only into its ingredient simpler atoms, namely, carbonic acid, which cleaves to the intruding potassa, and quicklime, which is set free. It is precisely as if some stronger planet were brought near enough to draw the moon off from the earth; in which case the compound stellar unit, called the terrestrial system, composed of the earth and the moon, would be decomposed : only, a poor little planetary artisan like man cannot mix up celestial systems, and heat the mixture in a furnace, or set fire to it in some supersolar atmosphere. Again: the particles of neither carbonic acid nor quicklime are simple atomic bodies. Potassa cannot divide an atom of lime indeed, but bring potassium (the metal of which potassa is the rust) into the atomic neighborhood of quicklime, and its particle falls with ease into two simpler atoms, one of oxygen which unites with the potassium, and one of calcium (the metal of which lime is only the rust On the other hand, the mere special plead- or oxyde) which is set free. Were it but ing of the physiologists (as they were de- known, beyond the reach of doubt, that the nominated, without specific reference to what particles of the so-called elements (oxygen, are now called physiological studies) is put brimstone, gold, and the rest of them) are an end to, as at once unnecessary and not to really elementary or simple, it might be the point, by the more elaborated definitions worth while to confine the name of Atoms to of modern chemistry. An atom, if the un- them, and to call all compound homoömeric fortunate word be taken in its literal accepta- parts by the name of Particles, and perhaps tion, is a thing incapable of being cut into, all groups of particles by that of Molecules: bruised, broken, frayed, or otherwise in- but it is not known, nay, it is grievously fringed upon; an absolutely solid little nu- doubted by many, and even plainly called cleus, an incalculably hard kernel of infini- in question by more than one good man and tesimally (but not infinitely) small dimen- true; so that Atoms and Particles (if not sions, an indivisible quodlibet: and that by Molecules too) must just be jumbled together the sovereign will of the maker of it, or by in the current phraseology a little longer, at the eternal necessity and fitness of things, least until the dawn of a new day on the sciaccording as you side with Parson Adams or ence. In the meantime, the proper definition Philosopher Square. Such is now under- of atoms is something like this:-they are stood to be by no means the legitimate defi- invisibly small pieces of matter, constituting nition of a particle. Retaining the old and by their co-aggregation under the force of ever-venerable term, an atom is a vastly lit cohesion the sensible forms of nature, contle portion of matter never divided in the stituting by their combination under the mechanical and chemical operations of na- force of affinity the compound particles of ture, any more than a sun or a planet is ever chemistry, and indivisible (in the sense of divided in the astronomical processes over- never being divided) by the forces which dihead; but by no means essentially or mathe-vide their aggregates and combinations. No matically indivisible. Then there are com- sort of atoms or particles, how compound pound atoms (or atomic systems) as there soever they may be, are ever divided in the are compound stars or stellar systems,-the mechanical operations of nature; and no terrestrial, the Jovian, the Uranian, the solar simple atoms are ever divided by the powers systems, and so forth. An atom or particle of chemistry: whence the attribute of Indiof marble is indivisible by any such mechani-visibility, as it is asked for them hypotheti cally and a priori, is lent to them on the | by Davy, Gay-Lussac, and Berzelius, and by credit of experience. Atoms are not essen- the whole phalanx of the chemists of the tially indivisible, but they are never divided: present century, quickly carried the fact of both the old parties were wrong, and both chemical proportionals (as associated with of them were right. They were severally the idea of the homoömeric constitution of right in what they affirmed, and wrong in matter) towards its consummation through a what they denied:-an immensely frequent, million of new and interesting particulars, and if not an unfailing, double circumstance in not a few important general deductions: and the controversies of mankind. Lavoisier now the ancient theory stands embodied in affirmed that the dephlogisticated air of the entire fabric of an absolutely Post-ChrisPriestley is the acidifying principle, denying tian and most practical science. Dalton bethe property to other principles; but Davy gan to promulgate his views towards the soon found his negation wrong, the affirma- close of the first decade of the century: they tive part of the proposition remaining intact: were probably conceived and crescent by the oxygen is only an Acidifier, and that was all beginning of it: the New System was pubIt lished in 1808-10. Some twenty long years after that historical publication, Daubeny, the Oxford professor, rendered its fontal thought familiar to the English student. Turner explained it in a shorter and more popular essay. Berzelius' large Treatise, and all the minor text-books, up to the latest manual of Organic Chemistry, are so many elaborate illustrations of the fact of chemical proportionals, and of the Atomic Theory of Democritus, Newton, and our Dalton,-the Manchester Dominie, and the greatest discoverer of the times in which he lived. that Nature had affirmed to Lavoisier! therefore behoves the true and completed man of science to lay down no exclusive propositions. On the other hand, he may withhold belief from the affirmations of another: but he will do well to trample nothing affirmative under foot, to reject nothing with an empty No. It is unnecessary to recur to the atomic views of the Cartesians, because they were dialectical and discursive, not experimental and productive. Nor need we do more than merely remember that it was Newton who first put the conception of atoms into clear hypothetical connection with the phenomena of chemistry. It was John Dalton that imparted enlargement, vitality, and fertility to the pertinent and memorable thought of the astronomer-royal of the world. That arithmetician descried a principle of proportion lurking among the incondite mass of recorded chemical analyses, which had been accumulating ever since the introduction of the balance as an organ of chemical discovery by Lavoisier (the historical successor of Stahl as Stabl was the historical successor of Roger Bacon, and the consolidator of Positive Chemistry), and it led him right to the revival of the Newtonian application of the idea of Democritus. He discovered the fact of definite proportions in chemical combination and decomposition. Two brothers of the name of Wenzel had well nigh anticipated the discovery by 1777, but only within a very small range of inquiry. In 1792, Richter had pursued their conception a little farther, and published tables of the combining ratios of certain acids and bases. But Dalton generalized the indication in all its breadth, and rose to its dependence on the Atomic Theory of sensible forms. Wollaston and the late erudite and independent Thomson of Glasgow College were his earliest converts of established reputation. These ingenuous men, followed Now that it has been worked out by its originator and his exact and scrupulous disciples, (to a wonderful degree, that is to say, but not merely to its completion), the Atomic Theory of the nineteenth hundred years of Christianity is characterized and distinguished, from that which preceded our era, by three notable things; but first and foremost by one glorious peculiarity and the glory is of a right Christian kind, being no other than the grace of humility. It does not overween; it does not dictate itself; it is not oracular. It comes forward, knowing that it is a hypothesis. It offers itself as a sufficing explanation of all known phenomena at all related to its idea. It claims no divine rights as a revelation of genius, nor professes to be demonstrable after the manner of a geomeametrical or logical truth. It simply advances as an amazingly probable proposition, willing to rest its reception as such on the amazing number (and the significant kind) of things it renders coherent and intelligible. Like the theory of celestial gravitation, it is its simple and self-possessed plea, that it explains everything. Its more arduous advocates, indeed, are not slow to avow their conviction that the mass of such presumptive evidence in its favor is so mountainous and transcending as to constitute an analogon of demonstration, so compulsive that only the unreasonable and |