[Sidenote: Vision; the functions of the eye.] Meantime more correct ideas respecting vision were obtained. Alhazen's explanation of the use of the retina and lens was adopted. This had been the first truly scientific investigation in physiology. The action of the eye was reduced to that of the camera-obscura described by Da Vinci, and the old notion of rays issuing therefrom finally abandoned. It had held its ground through the deceptive ill.u.s.tration of the magic-lantern. Of this instrument the name indicates the popular opinion of its nature. In the stories of necromancers and magicians of the time are to be found traces of applications to which it was insidiously devoted--the raising of the dead, spectres skipping along the ground or dancing on the walls and chimneys, pendulous images, apparitions in volumes of smoke. [Sidenote: Optical instruments.] These early instruments were the forerunners of many beautiful inventions of later times--the kaleidoscope, producing its forms of marvellous symmetry: the stereoscope, aided by photography, offering the very embodiment of external scenery; the achromatic and reflecting telescope, to which physical astronomy is so greatly indebted; and the achromatic microscope, now working a revolution in anatomy and physiology.

[Sidenote: The undulatory theory.] In its theory optics has presented a striking contrast to acoustics. Almost from the very beginning it was recognized that sound is not a material substance emitted from the sounding body, but only undulations occurring in the air. For long, optics failed to reach an a.n.a.logous conclusion. The advancement of the former science has been from the general principle down to the details, that of the latter from the details up to the general principle.

That light consists of undulations in an elastic medium was first inferred in 1664. Soon after, reflexion, refraction, and double refraction were accounted for on that principle. The slow progress of this theory was doubtless owing to Newton's supremacy. He gave a demonstration in the second book of the "Principia" (Prop. 42) that wave motions must diverge into the unmoved s.p.a.ces, and carried popular comprehension with him by such ill.u.s.trations as that we hear sounds though a mountain interpose. It was thought that the undulatory theory was disposed of by the impossibility of seeing through a crooked pipe, though we can hear through it; or that we cannot look round a corner, though we can listen round one.

The present century finally established it through the discovery of interference, the destruction of the emission theory being inevitable when it was shown that light, interfering under certain circ.u.mstances with light, may produce darkness, as sound added to sound may produce silence--results arising from the action of undulating motion. The difficulties presented by polarization were not only removed, but that cla.s.s of phenomena was actually made a strong support of the theory. The discovery that two pencils of oppositely polarized light would not interfere, led at once to the theory of transverse vibrations. Great mathematical ability was now required for the treatment of the subject, and the special consideration of many optical problems from this new point of view, as, for example, determining the result of transverse vibrations coming into a medium of different density in different directions. As the theory of universal gravitation had formerly done, so now the undulatory theory began to display its power as a physical truth, enabling geometers to foresee results, and to precede the experimenter in conclusions. Among earlier results of the kind was the prediction that both the rays in the biaxial crystal topaz are extraordinary, and that circular polarization may be produced by reflexion in a rhomb of gla.s.s. The phenomena of depolarization offered no special difficulty; and many new facts, as those of elliptic polarization and conical refraction, have since ill.u.s.trated the power of the theory.

[Sidenote: The ether and its movements.] Light, then, is the result of ethereal undulations impinging on the eye. There exists throughout the universe and among the particles of all bodies an elastic medium, ether.

By reason of the repulsion of its own parts it is uniformly diffused in a vacuum. In the interior of refracting media it exists in a state of less elasticity compared with its density than in vacuo. Vibrations communicated to it in free s.p.a.ce are propagated through such media by the ether in their interior. The parts of shining bodies vibrate as those of sounding ones, communicating their movement to the ether, and giving rise to waves in it. They produce in us the sensation of light.

The slower the vibration, the longer the wave; the more frequent, the shorter. On wave-length colour depends. In all cases the vibrations are transverse. The undulatory movement pa.s.ses onward at the rate of 192,000 miles in a second. The mean length of a wave of light is 0.0000219 of an inch; an extreme red wave is about twice as long as an extreme violet one. The yellow is intermediate. The vibrations which thus occasion light are, at a mean, 555 in the billionth of a second. As with the air, which is motionless when a sound pa.s.ses through it, the ether is motionless, though traversed by waves of light. That which moves forward is no material substance, but only a form, as the waves seen running along a shaken cord, or the circles that rise and fall, and spread outwardly when a stone is thrown into water. The wave-like form pa.s.ses onward to the outlying s.p.a.ces, but the water does not rush forward. And as we may have on the surface of that liquid waves the height of which is insignificant, or those which, as sailors say, are mountains high in storms at sea, their amplitude thus differing, so in the midst of the ether difference of amplitude is manifested to us by difference in the intensity or brilliancy of light.

[Sidenote: The human eye; its capabilities.] The human eye, exquisitely constructed as it is, is nevertheless an imperfect mechanism, being limited in its action. It can only perceive waves of a definite length, as its fellow organ, the ear, can only distinguish a limited range of sounds. It can only take note of vibrations that are transverse, as the ear can only take note of those that are normal. In optics there are two distinct orders of facts; the actual relations of light itself, and the physiological relations of our organ of vision, with all its limitations and imperfections. Light is altogether the creation of the mind. The ether is one thing, light is another, just as the air is one thing and sound another. The ether is not composed of the colours of light any more than the atmospheric air consists of musical notes.

[Sidenote: Chemical influences of light.] To the chemical agency of light much attention has in recent times been devoted. Already in photography, it has furnished us an art which, though yet in its infancy, presents exquisite representations of scenery, past events, the countenances of our friends. In an almost magical way it evokes invisible impressions, and gives duration to fleeting shadows. Moreover, these chemical influences of light give birth to the whole vegetable world, with all its varied charms of colour, form, and property, and, as we have seen in the last chapter, on them animal life itself depends.

[Sidenote: Of heat; reflexion; refraction.] The conclusions arrived at in optics necessarily entered as fundamental ideas in thermotics, or the science of heat; for radiant heat moves also in straight lines, undergoes reflexion, refraction, double refraction, polarization, and hence the theory of transverse vibrations applies to it. Heat is invisible light, as light is visible heat. Correct notions of radiation originated with the Florentine academicians, who used concave mirrors; and, in the cold-ray experiment, ma.s.ses of ice of five hundred pounds weight. The refraction of invisible heat was ascertained in consequence of the invention of the thermoelectric pile. Its polarization and depolarization soon followed. Already had been demonstrated the influence of the physical state of radiant surfaces, and that the heat comes also from a little depth beneath them. [Sidenote: Exchanges of heat.] The felicitous doctrine of exchanges of heat imparted true ideas of the nature of calorific equilibrium and the heating and cooling of bodies, and offered an explanation of many phenomena, as, for instance, the formation of dew. [Sidenote: The dew, nature of.] This deposit of moisture occurs after sunset, the more copiously the clearer the sky; it never appears on a cloudy night; it neither ascends from the ground like an exhalation, nor descends like a rain. It shows preferences in its manner of settling, being found on some objects before it is on others.

All these singular peculiarities were satisfactorily explained, and another of the mysteries, the unaccountable wonders of the Middle Ages, brought into the att.i.tude of a simple physical fact.

[Sidenote: Incandescence. Physical instruments.] It is impossible, in a limited s.p.a.ce, to relate satisfactorily what has been done respecting ignition, the production of light by incandescence, the accurate measurement of the conductibility of bodies, the determination of the expansions of solids, liquids, gases, under increasing temperature, the variations of the same substance at different degrees, the heat of fluidity and elasticity, and specific heat, or to do justice to the great improvements made in all kinds of instruments--balances, thermometers, contrivances for linear and angular measures, telescopes, microscopes, spectroscopes, chronometers, aerostats, telegraphs, and machinery generally. [Sidenote: Effect of mechanical inventions.] The tendency in every direction has been to practical applications. More accurate knowledge implies increasing power, greater wealth, higher virtue. The morality of man is enhanced by the improvement of his intellect and by personal independence. Our age has become rational, industrial, progressive. In its great physical inventions Europe may securely trust. There is nothing more to fear from Arabian invasions or Tartar irruptions. The hordes of Asia could be swept away like chaff before the wind. Let him who would form a correct opinion of the position of man in the present and preceding phases of his progress reflect on the losses of Christendom in Asia and Africa, in spite of all the machinery of an Age of Faith, and the present security of Europe from every barbarian or foreign attack.

From almost any of the branches of industry facts might be presented ill.u.s.trating the benefits arising from the application of physical discoveries. As an example, I may refer to the cotton manufacture.

[Sidenote: Ill.u.s.tration from the cotton manufacture.] In a very short time after the mechanical arts were applied to the manufacture of textile fabrics, so great was the improvement that a man could do more work in a day than he had previously done in a year. That manufacture was moreover accompanied by such collateral events as actually overturned the social condition throughout Europe. Among these were the invention of the steam-engine, the ca.n.a.l system, the prodigious development of the iron manufacture, the locomotive, and railroads; results not due to the placemen and officers to whom that continent had resigned its annals, whose effigies enc.u.mber the streets of its cities, but to men in the lower walks of life. The a.s.sertion is true that James Watt, the instrument maker, conferred on his native country more solid benefits than all the treaties she ever made and all the battles she ever won. Arkwright was a barber, Harrison a carpenter, Brindley a millwright's apprentice.

[Sidenote: Development of the cotton manufacture in England.] By the labours of Paul or of Wyatt, who introduced the operation of spinning by rollers, a principle perfected by Arkwright; by the rotating carding-engine, first devised by Paul; by the jenny of Highs or Hargreaves; the water-frame; the mule, invented by Crompton, so greatly was the cotton manufacture developed as to demand an entire change in the life of operatives, and hence arose the factory system. [Sidenote: The steam-engine of Watt.] At a critical moment was introduced Watt's invention, the steam-engine. His first patent was taken out in 1769, the same year that Arkwright patented spinning by rollers. Watt's improvement chiefly consisted in the use of a separate condenser, and the replacement of atmospheric pressure by that of steam. Still, it was not until more than twenty years after that this engine was introduced into factories, and hence it was not, as is sometimes supposed, the cause of their wonderful increase. It came, however, at a fortunate time, nearly coincident with the invention of the dressing-machine by Radcliffe and the power-loom by Cartwright.

[Sidenote: Bleaching by chlorine.] If the production of textile fabrics received such advantages from mechanics, equally was it favoured by chemistry in the discovery of bleaching by chlorine. To bleach a piece of cotton by the action of the air and the sun required from six to eight months, and a large surface of land must be used as a bleach-field. The value of land in the vicinity of great towns presented an insuperable obstacle to such uses. By chlorine the operation could be completed in the course of a few hours, and in a comparatively small building, the fibre being beautifully and permanently whitened.

[Sidenote: Calico-printing by cylinders.] Nor were the chemical improvements restricted to this. Calico-printing, an art practised many thousand years ago among the Egyptians, was perfected by the operation of printing from cylinders.

It deserves to be remarked that the cotton manufacture was first introduced into Europe by the Arabs. Abderrahman III., A.D. 930, caused it to be commenced in Spain; he also had extensive manufactures of silk and leather, and interested himself much in the culture of the sugar cane, rice, the mulberry. One of the most valuable Spanish applications of cotton was in the invention of cotton paper. The Arabs were also the authors of the printing of calicoes by wooden blocks, a great improvement on the old Indian operation of painting by hand.

[Sidenote: Extent of the cotton manufacture.] We may excuse the enthusiastic literature of the cotton manufacture its boasting, for men had accomplished works that were nearly G.o.d-like. Mr. Baines, writing in 1833, states that the length of yarn spun in one year was nearly five thousand millions of miles, sufficient to pa.s.s round the earth's circ.u.mference more than two hundred thousand times--sufficient to reach fifty-one times from the earth to the sun. It would encircle the earth's...o...b..t eight and a half times. The wrought fabrics of cotton exported in one year would form a girdle for the globe pa.s.sing eleven times round the equator, more than sufficient to form a continuous sheet from the earth to the moon. And, if this was the case thirty years ago, by what ill.u.s.trations would it be possible to depict it now (1859), when the quant.i.ty of cotton imported by England alone is more than twelve hundred millions of pounds?

[Sidenote: Improvements in locomotion.] But such a vast development in that particular manufacture necessarily implied other improvements, especially in locomotion and the transmission of intelligence. The pedlar's pack, the pack-horse, and the cart became altogether inadequate, and, in succession, were replaced by the ca.n.a.l system of the last century, and by the steam-boats and railroads of this. [Sidenote: Brindley's ca.n.a.ls.] The engineering triumphs of Brindley, whose ca.n.a.ls were carried across valleys, over or through mountains, above rivers, excited unbounded admiration in his own times, and yet they were only the precursors of the railway engineering of ours. As it was, the ca.n.a.l system proved to be inadequate to the want, and oaken railways, which had long been used in quarries and coal-pits, with the locomotive invented by Murdoch in 1784, were destined to supplant them. [Sidenote: Stephenson's locomotives.] It does not fall within my present purpose to relate how the locomotion of the whole civilized world was revolutionized, not by the act of some mighty sovereign or soldier, but by George Stephenson, once a steam-engine stoker, who, by the invention of the tubular boiler and the ingenious device of blowing the chimney instead of the fire, converted the locomotive of the last century, which, at its utmost speed, could only travel seven miles an hour, into the locomotive of this, which can accomplish seventy. [Sidenote: The railway system.] I need not dwell on the collateral improvements, the introduction of iron for rails, metallic bridges, tubular bridges, viaducts, and all the prodigies of the existing system of railway engineering.

[Sidenote: Improvement in the construction of machinery.] It is not only on account of the gigantic nature of the work it has to execute that the machinery employed in the great manufactures, such as those of cotton and iron, is so worthy of our admiration; improvements as respects the correctness, and even the elegance of its own construction, attract our attention. It has been truly said of steam-engines that they were never properly made until they made themselves. In any machine, the excellence of its performance depends on the accuracy of its construction. Its parts must be made perfectly true, and, to work smoothly, must work without error. To accomplish such conditions taxed to its utmost the mechanical ingenuity of the last century; and, indeed, it was not possible to reach perfect success so long as the hand alone was resorted to. Work executed by the most skilful mechanic could be no more than approximately correct. Not until such machines as the sliding rest and planing engine were introduced could any approach to perfection be made.

Improvements of this nature reacted at once on the primary construction of machinery, making it more powerful, more accurate, more durable, and also led to the introduction of greater elegance in its planning or conception, as any one may see who will compare the clumsy half wooden, half metal machinery of the last century with the light and tasteful constructions of this.

[Sidenote: Social changes effected by machinery.] While thus the inventive cla.s.s of men were gratifying their mental activity, and following that pursuit which has ever engrossed the energetic in all ages of the world--the pursuit of riches; for it was quickly perceived that success in this direction was the high road to wealth, public consideration, and honour--the realization of riches greater than the wildest expectations of the alchemists; there were silently and in an un.o.bserved manner great social and national results arising. The operative was correct enough in his conclusion that machinery was throwing him out of work, and reflecting persons were right enough in their belief that this extensive introduction of machines was in some way accomplishing a disorganization of the social economy. Doubtless, for the time being, the distress and misery were very severe; men were compelled to starve or to turn to new avocations; families were deprived of their long-accustomed means of support; such must necessarily be the incidents of every great social change, even though it be a change of improvement. Nor was it until the new condition of things had pa.s.sed through a considerable advance that its political tendency began to be plainly discerned. It was relieving the labourer from the burden of his toil, supplanting manual by mechanical action. [Sidenote: Life in the mill.] In the cotton-mill, which may be looked upon as the embodiment of the new system and its tendencies, the steam-engine down below was doing the drudgery, turning the wheels and executing the labour, while the operatives above--men, women, and children--were engaged in those things which the engine could not accomplish--things requiring observation and intelligent action. Under such a state it was not possible but that a social change should ensue, for relief from corporeal labour is always followed by a disposition for mental activity; and it was not without a certain degree of plausibility that the philanthropist, whose attention was directed to this subject, a.s.serted that the lot of the labouring man was no better than it had been before: he had changed the tyrant, but had not got rid of the tyranny; for the demands of the insatiate, inexorable, untiring steam-engine must be without delay satisfied; the broken thread must be instantly pieced; the iron fingers must receive their new supply; the finished work must be forthwith taken away.

[Sidenote: Intellectual activity.] What was thus going on in the mill was a miniature picture of what was going on in the state. Labour was comparatively diminishing, mental activity increasing. Throughout the last century the intellectual advance is most significantly marked, and surprising is the contrast between the beginning and the close. Ideas that once had a living force altogether died away, the whole community offering an exemplification of the fact that the more opportunity men have for reflection the more they will think. Well, then, might those whose interests lay in the perpetuation of former ideas and the ancient order of things look with intolerable apprehension on what was taking place. They saw plainly that this intellectual activity would at last find a political expression, and that a power, daily increasing in intensity, would not fail to make itself felt in the end.

[Sidenote: Difference between past and present ages.] In such things are manifested the essential differences between the Age of Faith and the Age of Reason. In the former, if life was enjoyed in calmness it was enjoyed in stagnation, in unproductiveness, and in a worthless way. But how different in the latter! Every thing is in movement. So many are the changes we witness, even in the course of a very brief period, that no one, though of the largest intellect, or in the most favourable position, can predict the future of only a few years hence. We see that ideas which yesterday served us as a guide die to-day, and will be replaced by others, we know not what, to-morrow.

[Sidenote: Scientific contributions of various nations,] In this scientific advancement, among the triumphs of which we are living, all the nations of Europe have been engaged. Some, with a venial pride, claim for themselves the glory of having taken the lead. But perhaps each of them, if it might designate the country--alas! not yet a nation--that should occupy the succeeding post of honour, would inscribe Italy on its ballot. It was in Italy that Columbus was born; in Venice, destined one day to be restored to Italy, newspapers were first issued.

It was in Italy that the laws of the descent of bodies to the earth and of the equilibrium of fluids were first determined by Galileo. In the Cathedral of Pisa that ill.u.s.trious philosopher watched the swinging of the chandelier, and, observing that its vibrations, large and small, were made in equal times, left the house of G.o.d, his prayers unsaid, but the pendulum clock invented. To the Venetian senators he first showed the satellites of Jupiter, the crescent form of Venus, and, in the garden of Cardinal Bandini, the spots upon the sun. [Sidenote: especially of Italy.] It was in Italy that Sanctorio invented the thermometer; that Torricelli constructed the barometer and demonstrated the pressure of the air. It was there that Castelli laid the foundation of hydraulics and discovered the laws of the flowing of water. There, too, the first Christian astronomical observatory was established, and there Stancari counted the number of vibrations of a string emitting musical notes. There Grimaldi discovered the diffraction of light, and the Florentine academicians showed that dark heat may be reflected by mirrors across s.p.a.ce. In our own times Melloni furnished the means of proving that it may be polarized. The first philosophical societies were the Italian; the first botanical garden was established at Pisa; the first cla.s.sification of plants given by Caesalpinus. The first geological museum was founded at Verona; the first who cultivated the study of fossil remains were Leonardo da Vinci and Fracasta. The great chemical discoveries of this century were made by instruments which bear the names of Galvani and Volta. Why need I speak of science alone? Who will dispute with that ill.u.s.trious people the palm of music and painting, of statuary and architecture? The dark cloud which for a thousand years has hung over that beautiful peninsula is fringed with irradiations of light. There is not a department of human knowledge from which Italy has not extracted glory, no art that she has not adorned.

[Sidenote: Causes of her depression.] Notwithstanding the adverse circ.u.mstances in which she has been placed, Italy has thus taken no insignificant part in the advancement of science. I may at the close of a work of which so large a portion has been devoted to the relation of her influences, political and religious, on the rest of Europe, be perhaps excused the expression of a hope that the day is approaching in which she will, with Rome as her capital, take that place in the modern system to which she is ent.i.tled. The course of centuries has proved that her ecclesiastical relation with foreign countries is incompatible with her national life. It is that, and that alone, which has been the cause of all her ills. She has a.s.serted a jurisdiction in every other government; the price she has paid is her own unity. The first, the all-important step in her rest.i.tution is the reduction of the papacy to a purely religious element. Her great bishop must no longer be an earthly prince. Rome, in her outcry for the preservation of her temporal possessions, forgets that Christian Europe has made a far greater sacrifice. It has yielded Bethlehem, Gethsemane, Calvary, the Sepulchre, the Mount of the Ascension. That is a sacrifice to which the surrender of the fict.i.tious donations of barbarian kings is not to be compared.

The foregoing paragraphs were written in 1859. Since that time Italy has become a nation, Rome is its capital, Venice belongs to it. In 1870-71 I was an eye-witness of the presence of Italian troops in the Eternal City.

CHAPTER XII.

CONCLUSION.--THE FUTURE OF EUROPE.

_Summary of the Argument presented in this Book respecting the mental Progress of Europe._

_Intellectual Development is the Object of Individual Life.--It is also the Result of social Progress._

_Nations arriving at Maturity instinctively attempt their own intellectual Organization.--Example of the Manner in which this has been done in China.--Its Imperfection.--What it has accomplished._

_The Organization of public Intellect is the End to which European Civilization is tending._

A Philosophical principle becomes valuable if it can be used as a guide in the practical purposes of life.

[Sidenote: General summary of the work.] The object of this book is to impress upon its reader a conviction that civilization does not proceed in an arbitrary manner or by chance, but that it pa.s.ses through a determinate succession of stages, and is a development according to law.

[Sidenote: Individual and social life have been considered;] For this purpose we considered the relations between individual and social life, and showed that they are physiologically inseparable, and that the course of communities bears an unmistakable resemblance to the progress of an individual, and that man is the archetype or exemplar of society.

[Sidenote: in the intellectual history of Greece;] We then examined the intellectual history of Greece--a nation offering the best and most complete ill.u.s.tration of the life of humanity. From the beginnings of its mythology in old Indian legends and of its philosophy in Ionia, we saw that it pa.s.sed through phases like those of the individual to its decrepitude and death in Alexandria.

[Sidenote: and the history of Europe.] Then, addressing ourselves to the history of Europe, we found that, if suitably divided into groups of ages, these groups, compared with each other in chronological succession, present a striking resemblance to the successive phases of Greek life, and therefore to that which Greek life resembles--that is to say, individual life.

For the sake of convenience in these descriptions we have a.s.sumed arbitrary epochs, answering to the periods from infancy to maturity.

History justifies the a.s.sumption of such periods. [Sidenote: The contrasts its ages display.] There is a well-marked difference between the aspect of Europe during its savage and mythologic ages; its changing, and growing, and doubting condition during the Roman republic and the Caesars; its submissive contentment under the Byzantine and Italian control; the a.s.sertion of its manhood, and right of thought, and freedom of action which characterize its present state--a state adorned by great discoveries in science, great inventions in art, additions to the comforts of life, improvements in locomotion, and the communication of intelligence. Science, capital, and machinery conjoined are producing industrial miracles. Colossal projects are undertaken and executed, and the whole globe is literally made the theatre of action of every individual.

Nations, like individuals, are born, pa.s.s through a predestined growth, and die. One comes to its end at an early period and in an untimely way; another, not until it has gained maturity. One is cut off by feebleness in its infancy, another is destroyed by civil disease, another commits political suicide, another lingers in old age. But for every one there is an orderly way of progress to its final term, whatever that term may be.

[Sidenote: The object of development is intellect.] Now, when we look at the successive phases of individual life, what is it that we find to be their chief characteristic? Intellectual advancement. And we consider that maturity is reached when intellect is at its maximum. The earlier stages are preparatory; they are wholly subordinate to this.

[Sidenote: It is the same in individual life,] If the anatomist be asked how the human form advances to its highest perfection, he at once disregards all the inferior organs of which it is composed, and answers that it is through provisions in its nervous structure for intellectual improvement; that in succession it pa.s.ses through stages a.n.a.logous to those observed in other animals in the ascending scale, but in the end it leaves them far behind, reaching a point to which they never attain.

The rise in organic development measures intellectual dignity.

[Sidenote: and in the animal series,] In like manner, the physiologist considering the vast series of animals now inhabiting the earth with us, ranks them in the order of their intelligence. He shows that their nervous mechanism unfolds itself upon the same plan as that of man, and that, as its advancement in this uniform and predetermined direction is greater, so is the position attained to higher.

[Sidenote: and in the general life of the globe.] The geologist declares that these conclusions hold good in the history of the earth, and that there has been an orderly improvement in intellectual power of the beings that have inhabited it successively. It is manifested by their nervous systems. He affirms that the cycle of transformation through which every man must pa.s.s is a miniature representation of the progress of life on the planet. The intention in both cases is the same.

[Sidenote: Succession of automatism, instinct, and intelligence.]

The sciences, therefore, join with history in affirming that the great aim of nature is intellectual improvement. They proclaim that the successive stages of every individual, from its earliest rudiment to maturity--the numberless organic beings now living contemporaneously with us, and const.i.tuting the animal series--the orderly appearance of that grand succession which, in the slow lapse of time, has emerged--all these three great lines of the manifestation of life furnish not only evidences, but also proofs of the dominion of law. In all the general principle is to differentiate instinct from automatism, and then to differentiate intelligence from instinct. In man himself the three distinct modes of life occur in an epochal order through childhood to the most perfect state. And this holding good for the individual, since it is physiologically impossible to separate him from the race, what holds good for the one must also hold good for the other. Hence man is truly the archetype of society. His development is the model of social progress.

[Sidenote: The object of social development.] What, then, is the conclusion inculcated by these doctrines as regards the social progress of great communities? It is that all political inst.i.tutions--imperceptibly or visibly, spontaneously or purposely--should tend to the improvement and organization of national intellect.

The expectation of life in a community, as in an individual, increases in proportion as the artificial condition or laws under which it is living agree with the natural tendency. Existence may be maintained under very adverse circ.u.mstances for a season; but, for stability and duration, and prosperity, there must be a correspondence between the artificial conditions and the natural tendency.