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From the infusible, though evaporable, diamond to nitrogen itself, the metallic nature of which has been long suspected by chemists, though still under the mistaken notion of an oxyde, we trace a series of metals from the maximum of coherence to positive fluidity, in all ordinary temperatures, we mean. Though, in point of fact, cold itself is but a superinduction of the one pole, or, what amounts to the same thing, the subtraction of the other, under the modifications afore described; and therefore are the metals indecomposible, because they are themselves the decompositions of the metallic axis, in all its degrees of longitude and lat.i.tude. Thus the substance of the planet from which it _is_, is metallic; while that which is ever _becoming_, is in like manner produced through the perpetual modification of the first by the opposite forces of the second; that is, by the principle of contraction and difference at the eastern extreme-the element of fire, or the oxygen of the chemists; and by the elementary power of dilatation, or universality at its western extreme-the ?d?? ?? ?dat? of the ancients, and the hydrogen of the laboratory.
It has been before noticed that the progress of Nature is more truly represented by the ladder, than by the suspended chain, and that she expands as by concentric circles. This is, indeed, involved in the very conception of individuation, whether it be applied to the different species or to the individuals. In what manner the evident inters.p.a.ce is reconciled with the equally evident continuity of the life of Nature, is a problem that can be solved by those minds alone, which have intuitively learnt that the whole _actual_ life of Nature originates in the existence, and consists in the perpetual reconciliation, and as perpetual resurgency of the primary contradiction, of which universal polarity is the result and the exponent. From the first moment of the differential impulse-(the primaeval chemical epoch of the Wernerian school)-when Nature, by the tranquil deposition of crystals, prepared, as it were, the fulcrum of her after-efforts, from this, her first, and in part _irrevocable_, self-contraction, we find, in each ensuing production, more and more tendency to independent existence in the increasing mult.i.tude of strata, and in the relics of the lowest orders, first of vegetable and then of animal life. In the schistous formations, which we must here a.s.sume as in great measure the residua of vegetable creations, that have sunk back into the universal life, and in the later predominant calcareous ma.s.ses, which are the _caput mortuum_ of animalized existence, we ascend from the laws of attraction and repulsion, as united in gravity, to magnetism, electricity, and constructive power, till we arrive at the point representative of a new and far higher intensity. For from this point flow, as in opposite directions, the two streams of vegetation and animalization, the former characterised by the predominance of magnetism in its highest power, as reproduction, the other by electricity intensified-as irritability, in like manner. The vegetable and animal world are the thesis and ant.i.thesis, or the opposite poles of organic life. We are not, therefore, to seek in either for a.n.a.logies to the other, but for counterpoints. On the same account, the nearer the common source, the greater the likeness; the farther the remove, the greater the opposition. At the extreme limits of inorganic Nature, we may detect a dim and obscure prophecy of her ensuing process in the twigs and rude semblances that occur in crystallization of some of the copper ores, and in the well-known _arbor Dianae_, and _arbor Veneris_. These latter Ritter has already ably explained by considering the oblique branches and their acute angles as the result of magnetic repulsion, from the presentation of the same poles, &c. In the CORALS and CONCHYLIA, the whole act and purpose of their existence seems to be that of connecting the animal with the inorganic world by the perpetual formation of calcareous earth. For the corals are nothing but polypi, which are characterised by still pa.s.sing away and dissolving into the earth, which they had previously excreted, as if they were the first feeble effort of detachment. The power seems to step forward from out the inorganic world only to fall back again upon it, still, however, under a new form, and under the predominance of the more active pole of magnetism. The product must have the same connexion, therefore, with azote, which the first rudiments of vegetation have with carbon: the one and the other exist not for their own sakes, but in order to produce the conditions best fitted for the production of higher forms.
In the polypi, corallines, &c., individuality is in its first dawn; there is the same shape in them all, and a mult.i.tude of animals form, as it were, a common animal. And as the individuals run into each other, so do the different genera. They likewise pa.s.s into each other so indistinguishably, that the whole order forms a very network.
As the corals approach the conchylia, this interramification decreases.
The tubipora forms the transition to the serpula; for the characteristic of all zoophytes, namely, the star shape of their openings, here disappears, and the tubiporae are distinguished from the rest of the corals by this very circ.u.mstance, that the hollow calcareous pipes are placed side by side, without interbranching. In the serpula they have already become separate. How feeble this attempt is to individuate, is most clearly shown in their mode of generation. Notwithstanding the report of Professor Pallas, it still remains doubtful whether there exists any actual copulation among the polypi. The mere existence of a polypus suffices for its endless multiplication. They may be indefinitely propagated by cuttings, so languid is the power of individuation, so boundless that of reproduction. But the delicate jelly dissolves, as lightly as it was formed, into its own product, and it is probable that the Polynesia, as a future continent, will be the gigantic monument, not so much of their life, as of the life of Nature in them. Here we may observe the first instance of that general law, according to which Nature still a.s.similates her extreme points. In these, her first and feeblest attempts to animalize organization, it is latent, because undeveloped, and merely potential; while, in the human brain, the last and most consummate of her combined energies, it is again lost or disguised in the subtlety(15) and multiplicity of its evolution.
In the cla.s.s immediately above (Mollusca) we find the individuals separate, a more determinate form, and in the higher species, the rudiment of nerves, as the first scarce distinguishable impress and exponent of sensibility; still, however, the vegetative reproduction is the predominant form; and even the nerves "which float in the same cavity with the other viscera," are probably subservient to it, and extend their power in the increased intensity of the reproductive force. Still prevails the transitional state from the fluid to the solid; and the jelly, that rudiment in which all animals, even the n.o.blest, have their commencement; const.i.tutes the whole sphere of these rudimental animals.
In the snail and muscle, the residuum of the coral reappears, but refined and enn.o.bled into a part of the animal. The whole cla.s.s is characterised by the separation of the fluid from the solid. On the one side, a gelatinous semi-fluid; on the other side, an entirely inorganic, though often a most exquisitely mechanised, calcareous excretion.
Animalization in general is, we know, contra-distinguished from vegetables in general by the predominance of azote in the chemical composition, and of irritability in the organic process. But in this and the foregoing cla.s.ses, as being still near the common equator, or the punctum indifferentiae, the carbonic principle still a.s.serts its claims, and the force of reproduction struggles with that of irritability. In the unreconciled strife of these two forces consists the character of the _Vermes_, which appear to be the preparatory step for the next cla.s.s.
Hence the difficulties which have embarra.s.sed the naturalists, who adopt the Linnaean cla.s.sification, in their endeavours to discover determinate characters of distinction between the vermes and the insecta.
But no sooner have we pa.s.sed the borders, than endless variety of form and the bold display of instincts announce, that Nature has succeeded. She has created the intermediate link between the vegetable world, as the product of the reproductive or magnetic power, and the animal as the exponent of sensibility. Those that live and are nourished, on the bodies of other animals, are comparatively few, with little diversity of shape, and almost all of the same natural family. These we may pa.s.s by as exceptions. But the insect world, taken at large, appears as an intenser life, that has struggled itself loose and become emanc.i.p.ated from vegetation, _Florae liberti, et libertini!_ If for the sake of a moment's relaxation we might indulge a Darwinian flight, though at the risk of provoking a smile, (not, I hope, a frown) from sober judgment, we might imagine the life of insects an apotheosis of the petals, stamina, and nectaries, round which they flutter, or of the stems and pedicles, to which they adhere. Beyond and above this step, Nature seems to act with a sort of free agency, and to have formed the cla.s.ses from choice and bounty. Had she proceeded no further, yet the whole vegetable, together with the whole insect creation, would have formed within themselves an entire and independent system of Life. All plants have insects, most commonly each genus of vegetables its appropriate genera of insects; and so reciprocally interdependent and necessary to each other are they, that we can almost as little think of vegetation without insects, as of insects without vegetation. Though probably the mere likeness of _shape_, in the _papilio_, and the papilionaceous plants, suggested the idea of the former, as the latter in a state of detachment, to our late poetical and theoretical brother; yet a something, that approaches to a graver plausibility, is given to this fancy of a flying blossom; when we reflect how many plants depend upon insects for their fructification. Be it remembered, too, that with few and very obscure exceptions, the irritable power and an a.n.a.logon of voluntary motion first dawn on us in the vegetable world, in the stamina, and anthers, at the period of impregnation. Then, as if Nature had been encouraged by the success of the first experiment, both the one and the other appear as predominance and general character. THE INSECT WORLD IS THE EXPONENT OF IRRITABILITY, AS THE VEGETABLE IS OF REPRODUCTION.
With the ascent in power, the intensity of individuation keeps even pace; and from this we may explain all the characteristic distinctions between this cla.s.s and that of the vermes. The almost h.o.m.ogeneous jelly of the animalcula infusoria became, by a vital oxydation, granular in the polypi.
This granulation formed itself into distinct organs in the molluscae; while for the snails, which are the next step, the animalized lime, that seemed the sole final cause of the life of the polypi, a.s.sumes all the characters of an ulterior purpose. Refined into a horn-like substance, it becomes to the snails the subst.i.tute of an organ, and their outward skeleton. Yet how much more manifold and definite, the organization of an insect, than that of the preceding cla.s.s, the patient researches of Swammerdam and Lyonnet have evinced, to the delight and admiration of every reflecting mind.
In the insect, for the first time, we find the distinct commencement of a separation between the exponents of sensibility and those of irritability; _i.e._ between the _nervous_ and the _muscular_ system. The latter, however, a.s.serts its pre-eminence throughout. The prodigal provision of organs for the purposes of respiration, and the marvellous powers which numerous tribes of insects possess, of accommodating the most corrupted airs, for a longer or shorter period, to the support of their excitability, would of itself lead us to presume, that here the _vis irritabilis_ is the reigning dynasty. There is here no confluence of nerves into one reservoir, as evidence of the independent existence of sensibility _as_ sensibility;-and therefore no counterpoise of a vascular system, as a distinct exponent of the irritable pole. The whole muscularity of these animals, is the organ of irritability; and the nerves themselves are probably feeders of the motory power. The petty rills of sensibility flow into the full expanse of irritability, and there lose themselves. The nerves appertaining to the senses, on the other hand, are indistinct, and comparatively unimportant. The mult.i.tude of immovable eyes appear not so much conductors of light, as its ultimate recipient. We are almost tempted to believe that they const.i.tute, rather than subserve, their sensorium.
These eye-facets form the sense of light, rather than organs of seeing.
Their almost paradoxical number at least, and the singularity of their forms, render it probable that they impel the animal by some modification of its irritability, herein likewise containing a striking a.n.a.logy to the known influence of light on plants, than as excitements of sensibility.
The sense that is nearest akin to irritability, and which alone resides in the muscular system, is that of touch, or feeling. This, therefore, is the first sense that emerges. Being confined to absolute contact, it occupies the lowest rank; but for that very reason it is the ground of all the other senses, which act, according to the ratio of their ascent, at still increasing distances, and become more and more ideal, from the tentacles of the polypus, to the human eye; which latter might be defined the outward organ of the ident.i.ty, or at least of the indifference, of the real and ideal. But as the calcareous residuum of the lowest cla.s.s approaches to the nature of horn in the snail, so the c.u.mbrous sh.e.l.l of the snail has been transformed into polished and moveable plates of defensive armour in the insect. Thus, too, the same power of progressive individuation articulates the tentacula of the polypus and holothuria into antennae; thereby manifesting the full emersion and eminency of irritability as a power which acts in, and gives its own character to, that of reproduction. The least observant must have noticed the lightning-like rapidity with which the insect tribes devour and eliminate their food, as by an instinctive necessity, and in the least degree for the purposes of the animal's own growth or enlargement. The same predominance of irritability, and at the same time a new start in individuation, is shown in the reproductive power as generation. There is now a regular projection, _ab intra ad extra_, for which neither sprouts nor cuttings can any longer be the subst.i.tutes. We have not s.p.a.ce for further detail; but there is one point too strikingly ill.u.s.trative and even confirmative of the proposed system, to be omitted altogether. We mean the curious fact, that the same characteristic tendency, _ad extra_, which in the males and females of certain insect tribes is realized in the functions of generation, conception, and parturiency, manifests and expands itself in the _s.e.xless_ individuals (which are always in this case the great majority of the species), as instincts of art, and in the construction of works completely detached and inorganic; while the geometric regularity of these works, which bears an a.n.a.logy to crystallization, is demonstrably no more than the necessary result of uniform action in a compressed mult.i.tude.
Again, as the insect world, averaging the whole, comes nearest to plants, (whose very essence is reproduction,) in the mult.i.tude of their germs; so does it resemble plants in the sufficiency of a single impregnation for the evolution of myriads of detached lives. Even so, the metamorphoses of insects, from the egg to the maggot and caterpillar, and from these, through the nympha and aurelia into the perfect insect, are but a more individuated and intenser form of a similar transformation of the plant from the seed-leaflets, or cotyledons, through the stalk, the leaves, and the calyx, into the perfect flower, the various colours of which seem made for the reflection of light, as the antecedent grade to the burnished scales, and scale-like eyes of the insect. Nevertheless, with all this seeming prodigality of organic power, the whole tendency is _ad extra_, and the life of insects, as electricity in the quadrate, acts chiefly on the superficies of their bodies, to which we may add the negative proof arising from the absence of sensibility. It is well known, that the two halves of a divided insect have continued to perform, or attempt, each their separate functions, the trunkless head feeding with its accustomed voracity, while the headless trunk has exhibited its appropriate excitability to the s.e.xual influence.
The intropulsive force, that sends the ossification inward as to the centre, is reserved for a yet higher step, and this we find embodied in the cla.s.s of _fishes_. Even here, however, the process still seems imperfect, and (as it were) initiatory. The skeleton has left the surface, indeed, but the bones approach to the nature of gristle. To feel the truth of this, we need only compare the most perfect bone of a fish with the thigh-bones of the mammalia, and the distinctness with which the latter manifest the co-presence of the _magnetic_ power in its solid parietes, of the _electrical_ in its branching arteries, and of the third greatest power, viz., the _qualitative_ and interior, in its marrow. The senses of fish are more distinct than those of insects. Thus, the intensity of its sense of smell has been placed beyond doubt, and rises in the extent of its sphere far beyond the irritable sense, or the feeling, in insects. I say the _feeling_, not the touch; for the touch seems, as it were, a supervention to the feeling, a perfection _given_ to it by the reaction of the higher powers. As the feeling of the insect, in subtlety and virtual distance, rises above the solitary sense of taste(16) in the mollusca, so does the smell of the fish rise above the feeling of the insect. In the fish, likewise, the eyes are single and moveable, while it is remarkable that the only insect that possesses this latter privilege, is an inhabitant of the waters. Finally, here first, unequivocally, and on a _large_ scale, (for I pretend not to control the freedom, in which the necessity of Nature is rooted, by the precise limits of a system,)-here first, Nature exhibits, in the power of sensibility, the consummation of those vital forms (the _nisus formativi_) the adequate and the sole measure of which is to be sought for in their several organic products.
But as if a weakness of exhaustion had attended this advance in the same moment it was made, Nature seems necessitated to fall back, and re-exert herself on the lower ground which she had before occupied, that of the vital magnetism, or the power of reproduction. The intensity of this latter power in the fishes, is shown both in their voracity and in the number of their eggs, which we are obliged to calculate by _weight_, not by _tale_. There is an equal intensity both of the _immanent_ and the _projective_ reproduction, in which, if we take in the comparative number of individuals in each species, and likewise the different intervals between the acts, the fish (it is probable) would be found to stand in a similar relation to the insect, as the insect, in the latter point, stands to the system of vegetation. Meantime, the fish sinks a step below the insect, in the mode and circ.u.mstances of impregnation. To this we will venture to add, the predominance of _length_, as the _form_ of growth in so large a proportion of the known orders of fishes, and not less of their rectilineal path of motion. In all other respects, the correspondence combined with the progress in individuation, is striking in the whole detail. Thus the eye, in addition to its moveability, has besides acquired a saline moisture in its higher development, as accordant with the life of its element. Add to these the glittering covering in both, the splendour of the scales in the one answering to the brilliant plates in the other,-the luminous reservoirs of the fire-flies,-the phosph.o.r.escence and electricity of many fishes,-the same a.n.a.logs of moral qualities, in their rapacity, boldness, modes of seizing their prey by surprise,-their gills, as presenting the intermediate state between the spiracula of the grade next below, and the lungs of the step next above, both extremes of which seem combined in the structure of birds and of their quill-feathers; but above all, the convexity of the crystalline lens, so much greater than in birds, quadrupeds, and man, and seeming to collect, in one powerful organ, the hundred-fold microscopic facettes of the insect's _light_ organs; and it will not be easy to resist the conviction, that the same power is at work in both, and reappears under higher auspices. The intention of Nature is repeated; but, as was to have been expected, with two main differences.
First, that in the lower grade the reproductions themselves seem merged in those of irritability, from the very circ.u.mstance that the latter const.i.tutes no pole, either to the former, or to sensibility. The force of irritability acts, therefore, in the insect world, in full predominance; while the emergence of sensibility in the fish calls forth the opposite pole of reproduction, as a _distinct_ power, and causes therefore the irritability to flow, in part, into the power of reproduction. The second result of this ascent is the direction of the organizing power, _ad intra_, with the consequent greater simplicity of the exterior form, and the subst.i.tution of condensed and flexible force, with comparative unity of implements, for that variety of tools, almost as numerous as the several objects to which they are to be applied, which arises from, and characterises, the superficial life of the insect creation. This grade of ascension, however, like the former, is accompanied by an apparent retrograde movement. For from this very accession of vital intensity we must account for the absence in the fishes of all the formative, or rather (if our language will permit it) _fabricative_ instincts. How could it be otherwise? These instincts are the surplus and projection of the organizing power in the direction _ad extra_, and could not, therefore, have been expected in the cla.s.s of animals that represent the first intuitive effort of organization, and are themselves the product of its first movement in the direction _ad intra_. But Nature never loses what she has once learnt, though in the acquirement of each new power she intermits, or performs less energetically, the act immediately preceding.
She often drops a faculty, but never fails to pick it up again. She may seem forgetful and absent, but it is only to recollect herself with _additional_, as well as _recruited_ vigour, in some after and higher state; as if the sleep of powers, as well as of bodies, were the season and condition of their growth. Accordingly, we find these instincts again, and with them a wonderful synthesis of fish and insect, as a higher third, in the feathered inhabitants of the air. Nay, she seems to have gone yet further back, and having given B + C = D in the birds, so to have sported with one solitary instance of B + D = A in that curious animal the dragon, the anatomy of which has been recently given to the public by Tiedemann; from whose work it appears, that this creature presents itself to us with the wings of the insect, and with the nervous system, the brain, and the cranium of the bird, in their several rudiments.
The synthesis of fish and insect in the birds, might be ill.u.s.trated equally in detail with the former; but it will be sufficient for our purpose, that as in both the former cases, the insect and the fish, so here in that of the birds, the powers are under the predominance of irritability; the sensibility being dormant in the first, awakening in the second, and awake, but still subordinate, in the third. Of this my limits confine me to a single presumptive proof, viz., the superiority in strength and courage of the female in the birds of prey. For herein, indeed, does the difference of the s.e.xes universally consist, wherever both the forces are developed, that the female is characterised by quicker irritability, and the male by deeper sensibility. How large a stride has been now made by Nature in the progress of individuation, what ornithologist does not know? From a mult.i.tude of instances we select the most impressive, the power of sound, with the first rudiments of modulation! That all languages designate the melody of birds as singing (though according to Blumenbach man only sings, while birds do but whistle), demonstrates that it has been felt as, what indeed it is, a tentative and prophetic prelude of something yet to come. With this conjoin the power and the tendency to acquire articulation, and to imitate speech; conjoin the building instinct and the migratory, the monogamy of several species, and the pairing of almost all; and we shall have collected new instances of the usage (I dare not say law) according to which Nature lets fall, in order to resume, and steps backward the furthest, when she means to leap forwards with the greatest concentration of energy.
For lo! in the next step of ascent the power of sensibility has a.s.sumed her due place and rank: her minority is at an end, and the complete and universal presence of a nervous system unites absolutely, by instanteity of time what, with the due allowances for the transitional process, had before been either lost in sameness, or perplexed by multiplicity, or compacted by a finer mechanism. But with this, all the a.n.a.logies with which Nature had delighted us in the preceding step seem lost, and, with the single exception of that more than valuable, that estimable philanthropist, the dog, and, perhaps, of the horse and elephant, the a.n.a.logies to ourselves, which we can discover in the quadrupeds or quadrumani, are of our vices, our follies, and our imperfections. The facts in confirmation of both the propositions are so numerous and so obvious, the advance of Nature, under the predominance of the third synthetic power, both in the intensity of life and in the intenseness and extension of individuality, is so undeniable, that we may leap forward at once to the highest realization and reconciliation of both her tendencies, that of the most perfect detachment with the greatest possible union, to that last work, in which Nature did not a.s.sist as handmaid under the eye of her sovereign Master, who made Man in his own image, by superadding self-consciousness with self-government, and breathed into him a living soul.
The cla.s.s of _Vermes_ deposit a calcareous stuff, as if it had torn loose from the earth a piece of the gross ma.s.s which it must still drag about with it. In the insect cla.s.s this residuum has refined itself. In the fishes and amphibia it is driven back or inward, the organic power begins to be intuitive, and sensibility appears. In the birds the bones have become hollow; while, with apparent proportional recess, but, in truth, by the excitement of the opposite pole, their exterior presents an actual vegetation. The bones of the mammalia are filled up, and their coverings have become more simple. Man possesses the most perfect osseous structure, the least and most insignificant covering. The whole force of organic power has attained an inward and centripetal direction. He has the whole world in counterpoint to him, but he contains an entire world within himself. Now, for the first time at the apex of the living pyramid, it is Man and Nature, but Man himself is a syllepsis, a compendium of Nature-the Microcosm! Naked and helpless cometh man into the world. Such has been the complaint from eldest time; but we complain of our chief privilege, our ornament, and the connate mark of our sovereignty. _Porphyrigeniti sumus_!
In Man the centripetal and individualizing tendency of all Nature is itself concentred and individualized-he is a revelation of Nature!
Henceforward, he is referred to himself, delivered up to his own charge; and he who stands the most on himself, and stands the firmest, is the truest, because the most individual, Man. In social and political life this acme is inter-dependence; in moral life it is independence; in intellectual life it is genius. Nor does the form of polarity, which has accompanied the law of individuation up its whole ascent, desert it here.
As the height, so the depth. The intensities must be at once opposite and equal. As the liberty, so must be the reverence for law. As the independence, so must be the service and the submission to the Supreme Will! As the ideal genius and the originality, in the same proportion must be the resignation to the real world, the sympathy and the inter-communion with Nature. In the conciliating mid-point, or equator, does the Man live, and only by its equal presence in both its poles can that life be manifested!
If it had been possible, within the prescribed limits of this essay, to have deduced the philosophy of Life synthetically, the evidence would have been carried over from section to section, and the _quod erat demonstrandum_ at the conclusion of one section would reappear as the principle of the succeeding-the goal of the one would be the starting-post of the other. Positions arranged in my own mind, as intermediate and organic links of administration, must be presented to the reader in the first instance, at least, as a mere hypothesis. Instead of demanding his a.s.sent as a right, I must solicit a suspension of his judgment as a courtesy; and, after all, however firmly the hypothesis may support the phenomena piled upon it, we can deduce no more than a practical rule, grounded on a strong presumption. The license of arithmetic, however, furnishes instances that a rule may be usefully applied in practice, and for the particular purpose may be sufficiently authenticated by the result, before it has itself been duly demonstrated. It is enough, if only it hath been rendered fully intelligible.
In a system where every position proceeds from a scientific preconstruction, a power acting exclusively in length, would be magnetism by virtue of our own definition of the term. In like manner, a surface power would be electricity, as far as that system was concerned, whether it accorded or not with the facts ordinarily so called. But it is inc.u.mbent on us, who must treat the subject _a.n.a.lytically_, to show by experiment that magnetism does in fact act longitudinally, and electricity superficially; and that, consequently, the former is distinguished from, and yet contained in, the latter, as a straight line is distinguished from, yet contained in, a superficies.
First, that magnetism, in its conductors, seeks and follows length only, and by the length is itself conducted, has been proved by Brugmans, in his philosophical Essay on the Matter of Magnetism, where he relates that a magnet capable of supporting a body four times heavier than itself, and which acted as a magnetic needle at the distance of twenty inches, was so weakened by the interposition of three cast-iron plates of considerable thickness, as scarcely to move the magnetic needle from its place at a distance of only three inches. A similar experiment had been made by Descartes. I concluded, therefore, said Brugmans, that if the iron plates were interposed between the magnet and the needle lengthways, instead of breadthways or right across, the action of the magnet on the magnetic needle would, in consequence of this great increase of resistance, become still weaker, or perhaps evanescent. But not less to my surprise than my admiration, I found that the power of the magnet was so far from being _diminished_ by this change in the relative position of the iron-plates; that, on the contrary, it now extended to a far greater distance than when no iron at all was interposed. Some time after the same philosopher, out of several iron bars, the sides of which were an inch broad each, composed a single bar of the length of more than ten feet, and observed the magnetism make its way through the whole ma.s.s. But, in order to try whether the action could be propagated to any length indefinitely, after several experiments with bars of intermediate lengths, in all of which he had succeeded, he tried a four-cornered iron rod, more than twenty feet long, and it was at this length that the magnetic power first began to be diminished. So far Brugmans.
But the shortest way for any one to convince himself of this relation of the magnetic power would be, in one and the same experiment, to interpose the same piece of iron between the magnet and the compa.s.s needle first _breadthways_; and in this case it will be found that the needle, which had been previously deflected by the magnet from its natural position at one of its poles, will instantly resume the same, either wholly or very nearly so-then to interpose the same piece of iron _lengthways_; in which case the position of the compa.s.s needle will be scarcely or not at all affected.
The a.s.sertion of Bernoulli and others, that the absolute force of the artificial magnet increases in the ratio of its superficies, stands corrected in the far more accurate experiments of Coulomb (published in his Treatise on Magnetism), which proves that the increase takes place (in a far greater degree) in the ratio of its length. The same naturalist even found means to determine that the directing powers of the needle, which he had measured by help of his _balance de tortion_, stand to the length of the needle in such a ratio as that, provided only the length of the needle is from forty to fifty times its diameter, the momenta of these directing powers will increase in the very same direct proportion as the length is increased. Nor is this all that may be deduced from the experiment last mentioned. If only the magnet be strong enough, it will show likewise that magnetism _seeks_ the length. The proof is contained in the remarkable fact, that the iron interposed between the magnet and the magnetic needle _breadthways_ constantly acquires its two opposite poles at both ends _lengthways_. Though the preceding experiments are abundantly sufficient to prove the position, yet the following deserves mention for the beautiful clearness of its evidence. If the magnetic power is determined exclusively by length, it is to be expected that it will manifest no force, where the piece of iron is of such a shape that no one dimension predominates. Bring a _cube_ of iron near the magnetic needle and it will not exert the slightest degree of power beyond what belongs to it as mere iron. By the perfect equality of the dimensions, the magnetism of the earth appears, as it were, perplexed and doubtful. Now, then attach a second cube of iron to the first, and the instantaneous act of the iron on the magnetic needle will make it manifest that with the length thus given, the magnetic influence is given at the same moment.
That electricity, on the other hand, does not act in length merely, is clear, from the fact that every electric body is electric over its whole surface. But that electricity acts both in length and breadth, and _only_ in length and breadth, and not in depth; in short, that the (so-called) electrical fluid in an electrified body spreads over the whole surface of that body without penetrating it, or tending _ad intra_, may be proved by direct experiment. Take a cylinder of wood, and bore an indefinite number of holes in it, each of them four lines in depth and four in diameter.
Electrify this cylinder, and present to its superficies a small square of gold-leaf, held to it by an insulating needle of gum lac, and bring this square to an electrometer of great sensibility. The electrometer will instantly show an electricity in the gold-leaf, similar to that of the cylinder which had been brought into contact with it. The square of gold-leaf having thus been discharged of its electricity, put it carefully into one of the holes of the cylinder, _so_, namely, that it shall touch only the bottom of the hole, and present it again to the electrometer. It will be then found that the electrometer will exhibit no signs of electricity whatsoever. From this it follows, that the electricity which had been communicated to the cylinder had confined itself to the _surface_.
If the time and the limit prescribed would admit, we could multiply experiments, all tending to prove the same law; but we must be content with the barely sufficient. But that the _chemical process_ acts in _depth_, and first, therefore, _realizes_ and integrates the fluxional power of magnetism and electricity, is involved in the _term_ composition; and this will become still more convincing when we have learnt to regard _decomposition_ as a mere co-relative, _i.e._ as decomposition relatively to the body decomposed, but composition _actually_ and in respect of the substances, _into_ which it was decomposed. The alteration in the specific gravity of metals in their chemical amalgams, interesting as the fact is in all points, is _decisive_ in the present; for gravity is the sole _inward_ of inorganic bodies-it _const.i.tutes_ their depth.
I can now, for the first time, give to my opinions that degree of intelligibility, which is requisite for their introduction as hypotheses; the experiments above related, understood as in the common mode of thinking, prove that the magnetic influence flows in length, the electric fluid by suffusion, and that chemical agency (whatever the main agent may be) is qualitative and _in intimis_. Now my hypothesis demands the converse of all this. I affirm that a power, acting exclusively in length, is (wherever it be found) _magnetism_; that a power which acts _both_ in length and in breadth, and _only_ in length and breadth, is (wherever it be found) _electricity_; and finally, that a power which, together with length and breadth, includes depth likewise, is (wherever it be found) _constructive agency_. That is but _one_ phenomenon of magnetism, to which we have appropriated and confined the term magnetism; because of all the natural bodies at present known, iron, and one or two of its nearest relatives in the family of hard yet coherent metals, are the only ones, in which all the conditions are collected, under which alone the magnetic agency can appear in and during the act itself. When, therefore, I affirm the power of reproduction in organized bodies to be magnetism, I must be understood to mean that this power, as it exists in the magnet, and which we there (to use a strong phrase) catch in the very act, is to the same kind of power, working as reproductive, what the root is to the cube of that root. We no more confound the force in the compa.s.s needle with that of reproduction, than a man can be said to confound his liver with a lichen, because he affirms that both of them grow.
The same precautions are to be repeated in the identification of electricity with irritability; and the power of depth, for which we have yet no appropriated term, with sensibility. How great the distance is in all, and that the lowest degrees are adopted as the exponent terms, not for their own sakes, but merely because they may be used with less hazard of diverting the attention from the _kind_ by peculiar properties arising out of the degree, is evident from the third instance, unless the theorist can be supposed insane enough to apply sensation in good earnest to the effervescence of an acid or an alkali, or to sympathise with the distresses of a vat of new beer when it is working. In whatever way the subject could be treated, it must have remained unintelligible to men who, if they think of s.p.a.ce at all, abstract their notion of it from the contents of an exhausted receiver. With this, and with an ether, such men may work wonders; as what, indeed, cannot be done with a plenum and a vacuum, when a theorist has privileged himself to a.s.sume the one, or the other, _ad libitum_?-in all innocence of heart, and undisturbed by the reflection that the two things cannot both be true. That both time and s.p.a.ce are mere abstractions I am well aware; but I know with equal certainty that what is _expressed_ by them as the _ident.i.ty_ of both is the highest reality, and the root of all power, the power to suffer, as well as the power to act. However mere an _ens logic.u.m_ s.p.a.ce may be, the _dimensions_ of s.p.a.ce are real, and the works of Galileo, in more than one elegant pa.s.sage, prove with what awe and amazement they fill the mind that worthily contemplates them. Dismissing, therefore, all facts of degrees, as introduced merely for the purposes of ill.u.s.tration, I would make as little reference as possible to the magnet, the charged phial, or the processes of the laboratory, and designate the three powers in the process of our animal life, each by two co-relative terms, the one expressing the _form_, and the other the _object_ and _product_ of the power. My hypothesis will, therefore, be thus expressed, that the const.i.tuent forces of life in the human living body are-first, the power of length, or REPRODUCTION; second, the power of surface (that is, length and breadth), or IRRITABILITY; third, the power of depth, or SENSIBILITY. With this observation I may conclude these remarks, only reminding the reader that Life itself is neither of these separately, but the copula of all three-that Life, _as_ Life, supposes a positive or universal principle in Nature, with a negative principle in every particular animal, the latter, or limitative power, constantly acting to individualize, and, as it were, _figure_ the former. _Thus_, then, Life itself is not a _thing_-a self-subsistent _hypostasis_-but an _act_ and _process_; which, pitiable as the prejudice will appear to the _forts esprits_, is a great deal more than either my reason would authorise or my conscience allow me to a.s.sert-concerning the Soul, as the principle both of Reason and Conscience.
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