Chapter IV: Part 4

Then there is another point about these candles which will answer a question--that is, as to the way in which this fluid gets out of the cup, up to the wick, and into the place of combustion. You know that the flames on these burning wicks in candles made of beeswax, stearine, or spermaceti, do not run down to the wax or other matter, and melt it all away, but keep to their own right place. They are fenced off from the fluid below, and do not encroach on the cup at the sides.

I cannot imagine a more beautiful example than the condition of adjustment under which a candle makes one part subserve to the other to the very end of its action. A combustible thing like that, burning away gradually, never being intruded upon by the flame, is a very beautiful sight; especially when you come to learn what a vigorous thing flame is, what power it has of destroying the wax itself when it gets hold of it, and of disturbing its proper form if it come only too near.

But how does the flame get hold of the fuel? There is a beautiful point about that. It is by what is called capillary attraction that the fuel is conveyed to the part where combustion goes on, and is deposited there, not in a careless way, but very beautifully in the very midst of the centre of action which takes place around it.

_II.--The Brightness of the Candle_

Air is absolutely necessary for combustion; and, what is more, I must have you understand that _fresh_ air is necessary, or else we should be imperfect in our reasoning and our experiments. Here is a jar of air. I place it over a candle, and it burns very nicely in it at first, showing that what I have said about it is true; but there will soon be a change. See how the flame is drawing upwards, presently fading, and at last going out. And going out, why? Not because it wants air merely, for the jar is as full now as it was before, but it wants pure, fresh air. The jar is full of air, partly changed, partly not changed; but it does not contain sufficient of the fresh air for combustion.

Suppose I take a candle, and examine that part of it which appears brightest to our eyes. Why, there I get these black particles, which are just the smoke of the candle; and this brings to mind that old employment which Dean Swift recommended to servants for their amusement, namely, writing on the ceiling of a room with a candle. But what is that black substance? Why, it is the same carbon which exists in the candle. It evidently existed in the candle, or else we should not have had it here. You would hardly think that all those substances which fly about London in the form of soots and blacks are the very beauty and life of the flame. Here is a piece of wire gauze which will not let the flame go through it, and I think you will see, almost immediately, that, when I bring it low enough to touch that part of the flame which is otherwise so bright, it quells and quenches it at once, and allows a volume of smoke to rise up.

Whenever a substance burns without assuming the vaporous state--whether it becomes liquid or remains solid--it becomes exceedingly luminous. What I say is applicable to all substances--whether they burn or whether they do not burn--that they are exceedingly bright if they retain their solid state when heated, and that it is to this presence of solid particles in the candle-flame that it owes its brilliancy.

I have here a piece of carbon, or charcoal, which will burn and give us light exactly in the same manner as if it were burnt as part of a candle. The heat that is in the flame of a candle decomposes the vapour of the wax, and sets free the carbon particles--they rise up heated and glowing as this now glows, and then enter into the air. But the particles when burnt never pass off from a candle in the form of carbon. They go off into the air as a perfectly invisible substance, about which we shall know hereafter.

Is it not beautiful to think that such a process is going on, and that such a dirty thing as charcoal can become so incandescent? You see, it comes to this--that all bright flames contain these solid particles; all things that burn and produce solid particles, either during the time they are burning, as in the candle, or immediately after being burnt, as in the case of the gunpowder and iron-filings--all these things give us this glorious and beautiful light.

_III.--The Products of Combustion_

We observe that there are certain products as the result of the combustion of a candle, and that of these products one portion may be considered as charcoal, or soot; that charcoal, when afterwards burnt, produces some other product--carbonic acid, as we shall see; and it concerns us very much now to ascertain what yet a third product is.

Suppose I take a candle and place it under a jar. You see that the sides of the jar become cloudy, and the light begins to burn feebly. It is the products, you see, which make the light so dim, and this is the same thing which makes the sides of the jar so opaque. If you go home and take a spoon that has been in the cold air, and hold it over a candle--not so as to soot it--you will find that it becomes dim, just as that jar is dim. If you can get a silver dish, or something of that kind, you will make the experiment still better. It is _water_ which causes the dimness, and we can make it, without difficulty, assume the form of a liquid.

And so we can go on with almost all combustible substances, and we find that if they burn with a flame, as a candle, they produce water. You may make these experiments yourselves. The head of a poker is a very good thing to try with, and if it remains cold long enough over the candle, you may get water condensed in drops on it; or a spoon, or a ladle, or anything else may be used, provided it be clean, and can carry off the heat, and so condense the water.

And now--to go into the history of this wonderful production of water from combustibles, and by combustion--I must first of all tell you that this water may exist in different conditions; and although you may now be acquainted with all its forms, they still require us to give a little attention to them for the present, so that we may perceive how the water, whilst it goes through its protean changes, is entirely and absolutely the same thing, whether it is produced from a candle, by combustion, or from the rivers or ocean.

First of all, water, when at the coldest, is ice. Now, we speak of water as water; whether it be in its solid, or liquid, or gaseous state, we speak of it chemically as water.

We shall not in future be deceived, therefore, by any changes that are produced in water. Water is the same everywhere, whether produced from the ocean or from the flame of the candle. Where, then, is this water which we get from a candle? It evidently comes, as to part of it, from the candle; but is it within the candle beforehand? No! It is not in the candle; and it is not in the air round about the candle, which is necessary for its combustion. It is neither in one nor the other, but it comes from their conjoint action, a part from the candle, a part from the air. And this we have now to trace.

If we decompose water we can obtain from it a gas. This is hydrogen--a body classed amongst those things in chemistry which we call elements, because we can get nothing else out of them. A candle is not an elementary body, because we can get carbon out of it; we can get this hydrogen out of it, or at least out of the water which it supplies. And this gas has been so named hydrogen because it is that element which, in association with another, generates water.

Hydrogen gives rise to no substance that can become solid, either during combustion or afterwards, as a product of its combustion. But when it burns it produces water only; and if we take a cold glass and put it over the flame, it becomes damp, and you have water produced immediately in appreciable quantity, and nothing is produced by its combustion but the same water which you have seen the flame of a candle produce. This hydrogen is the only thing in Nature that furnishes water as the sole product of combustion.

Water can be decomposed by electricity, and then we find that its other constituent is the gas oxygen in which, as can easily be shown, a candle or a lamp burns much more brilliantly than it does in air, but produces the same products as when it burns in air. We thus find that oxygen is a constituent of the air, and by burning something in the air we can remove the oxygen therefrom, leaving behind for our study the nitrogen, which constitutes about four-fifths of the air, the oxygen accounting for nearly all the rest.

The other great product of the burning of a candle is carbonic acid--a gas formed by the union of the carbon of the candle and the oxygen of the air. Whenever carbon burns, whether in a candle or in a living creature, it produces carbonic acid.

_IV.--Combustion and Respiration_

Now I must take you to a very interesting part of our subject--to the relation between the combustion of a candle and that living kind of combustion which goes on within us. In every one of us there is a living process of combustion going on very similar to that of a candle. For it is not merely true in a poetical sense--the relation of the life of man to a taper. A candle will burn some four, five, six, or seven hours. What, then, must be the daily amount of carbon going up into the air in the way of carbonic acid? What a quantity of carbon must go from each of us in respiration! A man in twenty-four hours converts as much as seven ounces of carbon into carbonic acid; a milch cow will convert seventy ounces, and a horse seventy-nine ounces, solely by the act of respiration. That is, the horse in twenty-four hours burns seventy-nine ounces of charcoal, or carbon, in his organs of respiration to supply his natural warmth in that time.

All the warm-blooded animals get their warmth in this way, by the conversion of carbon; not in a free state, but in a state of combination. And what an extraordinary notion this gives us of the alterations going out in our atmosphere! As much as 5,000,000 pounds of carbonic acid is formed by respiration in London alone in twenty-four hours. And where does all this go? Up into the air. If the carbon had been like lead or iron, which, in burning, produces a solid substance, what would happen? Combustion would not go on. As charcoal burns, it becomes a vapour and passes off into the atmosphere, which is the great vehicle, the great carrier, for conveying it away to other places. Then, what becomes of it?

Wonderful is it to find that the change produced by respiration, which seems so injurious to us, for we cannot breathe air twice over, is the very life and support of plants and vegetables that grow upon the surface of the earth. It is the same also under the surface in the great bodies of water, for fishes and other animals respire upon the same principle, though not exactly by contact with the open air. They respire by the oxygen which is dissolved from the air by the water, and form carbonic acid; and they all move about to produce the one great work of making the animal and vegetable kingdoms subservient to each other.

All the plants growing upon the surface of the earth absorb carbon. These leaves are taking up their carbon from the atmosphere, to which we have given it in the form of carbonic acid, and they are prospering. Give them a pure air like ours, and they could not live in it; give them carbon with other matters, and they live and rejoice. So are we made dependent not merely upon our fellow-creatures, but upon our fellow-existers, all Nature being tied by the laws that make one part conduce to the good of the other.

AUGUSTE FOREL

The Senses of Insects

Auguste Forel, who in 1909 retired from the Chair of Morbid
Psychology in the University of Zürich, was born on September 1,
1848, and is one of the greatest students of the minds and senses
of the lower animals and mankind. Among his most famous works are
his "Hygiene of Nerves and Mind," his great treatise on the whole
problem of sex in human life, of which a cheap edition entitled
"Sexual Ethics" is published, his work on hypnotism, and his
numerous contributions to the psychology of insects. The chief
studies of this remarkable and illustrious student and thinker for
many decades past have been those of the senses and mental
faculties of insects. He has recorded the fact that his study of
the beehive led him to his present views as to the right
constitution of the state--views which may be described as
socialism with a difference. His work on insects has served the
study of human psychology, and is in itself the most important
contribution to insect psychology ever made by a single student.
Only within the last two years has the work of Forel, long famous
on the European Continent, begun to be known abroad.

_I.--Insect Activity and Instinct_

This subject is one of great interest, as much from the standpoint of biology as from that of comparative psychology. The very peculiar mechanism of instincts always has its starting-point in sensations. To comprehend this mechanism it is essential to understand thoroughly the organs of sense and their special functions.

It is further necessary to study the co-ordination which exists between the action of the different senses, and leads to their intimate connection with the functions of the nerve-centres, that is to say, with the specially instinctive intelligence of insects. The whole question is, therefore, a chapter of comparative psychology, a chapter in which it is necessary to take careful note of every factor, to place oneself, so to speak, on a level with the mind of an insect, and, above all, to avoid the anthropomorphic errors with which works upon the subject are filled.

At the same time the other extreme must equally be avoided--"anthropophobia," which at all costs desires to see in every living organism a "machine," forgetting that a "machine" which lives, that is to say, which grows, takes in nutriment, and strikes a balance between income and expenditure, which, in a word, continually reconstructs itself, is not a "machine," but something entirely different. In other words, it is necessary to steer clear of two dangers. We must avoid (1) identifying the mind of an insect with our own, but, above all, (2) imagining that we, with what knowledge we possess, can reconstruct the mind by our chemical and physical laws.

On the other hand, we have to recognise the fact that this mind, and the sensory functions which put it on its guard, are derived, just as with our human selves, from the primitive protoplasmic life. This life, so far as it is specialised in the nervous system by nerve irritability and its connections with the muscular system, is manifested under two aspects. These may be likened to two branches of one trunk.

(_a_) _Automatic_ or _instinctive_ activity. This, though perfected by repetition, is definitely inherited. It is uncontrollable and constant in effect, adapted to the circumstances of the special life of the race in question. It is this curious instinctive adaptation--which is so intelligent when it carries out its proper task, so stupid and incapable when diverted to some other purpose--that has deceived so many scientists and philosophers by its insidious analogy with humanly constructed machines.

But, automatic as it may appear, instinct is not invariable. In the first place, it presents a racial evolution which of itself alone already demonstrates a certain degree of plasticity from generation to generation. It presents, further, individual variations which are more distinct as it is less deeply fixed by heredity. Thus the divergent instincts of two varieties, _e.g._, of insects, present more individual variability and adaptability than do those instincts common to all species of a genus. In short, if we carefully study the behaviour of each individual of a species of insects with a developed brain (as has been done by P. Huber, Lubbock, Wasmann, and myself, among others, for bees, wasps, and ants), we are not long in finding noteworthy differences, especially when we put the instinct under abnormal conditions. We then force the nervous activity of these insects to present a second and plastic aspect, which to a large extent has been hidden from us under their enormously developed instinct.

(_b_) The _plastic_ or _adaptive_ activity is by no means, as has been so often suggested, a derivative of instinct. It is primitive. It is even the fundamental condition of the evolution of life. The living being is distinguished by its power of adaptation; even the amoeba is plastic. But in order that one individual may adapt itself to a host of conditions and possibilities, as is the case with the higher mammals and especially with man, the brain requires an enormous quantity of nerve elements. But this is not the case with the fixed and specialised adaptation of instinct.

In secondary automatism, or habit, which we observe in ourselves, it is easy to study how this activity, derived from plastic activity, and ever becoming more prompt, complex, and sure (technical habits), necessitates less and less expenditure of nerve effort. It is very difficult to understand how inherited instinct, hereditary automatism, could have originated from the plastic activities of our ancestors. It seems as if a very slow selection, among individuals best adapted in consequence of fortunate parentage, might perhaps account for it.

To sum up, every animal possesses two kinds of activity in varying degrees, sometimes one, sometimes the other predominating. In the lowest beings they are both rudimentary. In insects, special automatic activity reaches the summit of development and predominance; in man, on the contrary, with his great brain development, plastic activity is elevated to an extraordinary height, above all by language, and before all by written language, which substitutes graphic fixation for secondary automatism, and allows the accumulation outside the brain of the knowledge of past generations, thus serving his plastic activity, at once the adapter and combiner of what the past has bequeathed to it.

According to the families, _genera_, and species of insects, the development of different senses varies extremely. We meet with most striking contrasts, and contrasts which have not been sufficiently noticed. Certain insects, dragon-flies, for instance, live almost entirely by means of sight. Others are blind, or almost blind, and subsist exclusively by smell and taste (insects inhabiting caves, most working ants). Hearing is well developed in certain forms (crickets, locusts), but most insects appear not to hear, or to hear with difficulty. Despite their thick, chitinous skeleton, almost all insects have extremely sensitive touch, especially in the antennæ, but not confined thereto.

It is absolutely necessary to bear in mind the mental faculties of insects in order to judge with a fair degree of accuracy how they use their senses. We shall return to that point when summing up.

_II.--The Vision of Insects_

In vision we are dealing with a certain definite stimulus--light, with its two modifications, colour and motion. Insects have two sets of organs for vision, the faceted eye and the so-called simple eye, or ocellus. These have been historically derived from one and the same organ. In order to exercise the function of sight the facets need a greater pencil of light rays by night than by day. To obtain the same result we dilate the pupil. But nocturnal insects are dazzled by the light of day, and diurnal insects cannot see by night, for neither possess the faculty of accommodation. Insects are specially able to perceive motion, but there are only very few insects that can see distinctly.

For example, I watched one day a wasp chasing a fly on the wall of a veranda, as is the habit of this insect at the end of summer and in the autumn. She dashed violently in flight at the flies sitting on the wall, which mostly escaped. She continued her pursuit with remarkable pertinacity, and succeeded on several occasions in catching a fly, which she killed, mutilated, and bore away to her nest. Each time she quickly returned to continue the hunt.

In one spot of the wall was stuck a black nail, which was just the size of a fly, and I saw the wasp very frequently deceived by this nail, upon which she sprang, leaving it as soon as she perceived her error on touching it. Nevertheless, she made the same mistake with the nail shortly after. I have often made similar observations. We may certainly conclude that the wasp saw something of the size of a fly, but without distinguishing the details; therefore she saw it indistinctly. Evidently a wasp does not only perceive motion; she also distinguishes the size of objects. When I put dead flies on a table to be carried off by another wasp, she took them, one after another, as well as spiders and other insects of but little different size placed by their side. On the other hand, she took no notice of insects much larger or much smaller put among the flies.

Most entomologists have observed with what ingenuity and sureness dragon-flies distinguish, follow, and catch the smallest insects on the wing. Of all insects, they have the best sight. Their enormous convex eyes have the greatest number of facets. Their number has been estimated at 12,000, and even at 17,000. Their aerial chases resemble those of the swallows. By trying to catch them at the edge of a large pond, one can easily convince oneself that the dragon-flies amuse themselves by making sport of the hunter; they will always allow one to approach just near enough to miss catching them. It can be seen to what degree they are able to measure the distance and reach of their enemy.

It is an absolute fact that dragon-flies, unless it is cold or in the evening, always manage to fly at just that distance at which the student cannot touch them; and they see perfectly well whether one is armed with a net or has nothing but his hands; one might even say that they measure the length of the handle of the net, for the possession of a long handle is no advantage. They fly just out of reach of one's instrument, whatever trouble one may give oneself by hiding it from them and suddenly lunging as they fly off. Whoever watches butterflies and flies will soon see that these insects also can measure the distance of such objects as are not far from them. The males and females of bees and ants distinguish one another on the wing. It is rare for an individual to lose sight of the swarm or to miss what it pursues flying. It has been proved that the sense of smell has nothing to do with this matter. Thus insects, though without any power of accommodation for light or distance, are able to perceive objects at different distances.

It is known that many insects will blindly fly and dash against a lamp at night, until they burn themselves. It has often been wrongly thought that they are fascinated. We ought first to remember that natural lights, concentrated at one point like our artificial lights, are extremely rare in Nature. The light of day, which is the light of wild animals, is not concentrated at one point. Insects, when they are in darkness--underground, beneath bark or leaves--are accustomed to reach the open air, where the light is everywhere diffused, by directing themselves towards the luminous point. At night, when they fly towards a lamp, they are evidently deceived, and their small brains cannot comprehend the novelty of this light concentrated at one spot. Consequently, their fruitless efforts are again and again renewed against the flame, and the poor innocents end by burning themselves. Several domestic insects, which have become little by little adapted to artificial light in the course of generations, no longer allow themselves to be deceived thereby. This is the case with house-flies.

Bees distinguish all colours, and seldom confound any but blue and green; while wasps scarcely react to differences of colour, but note better the shape of an object, and note, for instance, where the place of honey is; so that a change of colour on the disc whereon the honey is placed hardly upsets them. Further, wasps have a better sense of smell than bees.

The chief discovery regarding the vision of insects made in the last thirty years is that of Lubbock, who proved that ants perceive the ultra-violet rays of the spectrum, which we are unable, or almost unable, to perceive.

It has lately been proved also that many insects appreciate light by the skin.

They do not see as clearly as we do; but when they possess well-developed compound eyes they appreciate size, and more or less distinctly the contours of objects.

Ants have a great faculty for recognition, which probably testifies to their vision and visual memory. Lubbock observed ants which actually recognised each other after more than a year of separation.

_III.--Smell, Taste, Hearing, Pain_

Smell is very important in insects. It is difficult for us to judge of, since man is of all the vertebrates except the whales, perhaps, the one in which this sense is most rudimentary. We can evidently, therefore, form only a feeble idea of the world of knowledge imparted by a smell to a dog, a mole, a hedgehog, or an insect. The instruments of smell are the antennæ. A poor ant without antennæ is as lost as a blind man who is also deaf and dumb. This appears from its complete social inactivity, its isolation, its incapacity to guide itself and to find its food. It can, therefore, be boldly supposed that the antennæ and their power of smell, as much on contact as at a distance, constitute the social sense of ants, the sense which allows them to recognise one another, to tend to their larvæ, and mutually help one another, and also the sense which awakens their greedy appetites, their violent hatred for every being foreign to the colony, the sense which principally guides them--a little helped by vision, especially in certain species--in the long and patient travels which they have to undertake, which makes them find their way back, find their plant-lice, and all their other means of subsistence.

As the philosopher Herbert Spencer has well pointed out, the visceral sensations of man, and those internal senses which, like smell, can only make an impression of one kind as regards space--two simultaneous odours can only be appreciated by us as a mixture--are precisely those by which we can gain little or no information relative to space. Our vision, on the contrary, which localises the rays from various distant points of space on various distinct points of our retina at the same time, is our most relational sense, that which gives us the most vast ideas of space.

But the antennæ of insects are an olfactory organ turned inside out, prominent in space, and, further, very mobile. This allows us to suppose that the sense of smell may be much more relational than ours, that the sensations thence derived give them ideas of space and of direction which may be qualitatively different from ours.

Taste exists in insects, and has been very widely written on, but somewhat inconclusively. The organs of taste probably are to be found in the jaws and at the base of the tongue. This sense can be observed in ants, bees, and wasps; and everyone has seen how caterpillars especially recognise by taste the plants which suit them.

Much has been written on the hearing of insects; but, in my judgment, only crickets and several other insects of that class appear to perceive sounds. Erroneous views have been due to confusing hearing with mechanical vibrations.

We must not forget that the specialisation of the organ of hearing has reached in man a delicacy of detail which is evidently not found again in lower vertebrates.

Pain is much less developed in insects than in warm-blooded vertebrates. Otherwise, one could not see either an ant, with its abdomen or antennæ cut off, gorge itself with honey; or a humble-bee, in which the antennæ and all the front of the head had been removed, go to find and pillage flowers; or a spider, the foot of which had been broken, feed immediately on this, its own foot, as I myself have seen; or, finally, a caterpillar, wounded at the "tail" end, devour itself, beginning behind, as I have observed more than once.

_IV.--Insect Reason and Passions_

Insects reason, and the most intelligent among them, the social hymenoptera, especially the wasps and ants, even reason much more than one is tempted to believe when one observes the regularly recurring mechanism of their instincts. To observe and understand these reasonings well, it is necessary to mislead their instinct. Further, one may remark little bursts of plastic judgment, of combinations--extremely limited, it is true--which, in forcing them an instant from the beaten track of their automatism, help them to overcome difficulties, and to decide between two dangers. From the point of view of instinct and intelligence, or rather of reason, there are not, therefore, absolute contrasts between the insect, the mammal, and the man.

Finally, insects have passions which are more or less bound up with their instincts. And these passions vary enormously, according to the species. I have noted the following passions or traits of character among ants: choler, hatred, devotion, activity, perseverance, and gluttony. I have added thereto the discouragement which is sometimes shown in a striking manner at the time of a defeat, and which can become real despair; the fear which is shown among ants when they are alone, while it disappears when they are numerous. I can add further the momentary temerity whereby certain ants, knowing the enemy to be weakened and discouraged, hurl themselves alone in the midst of the black masses of enemies larger than themselves, hustling them without taking the least further precaution.

When we study the manners of an insect, it is necessary for us to take account of its mental faculties as well as of its sense organs. Intelligent insects make better use of their senses, especially by combining them in various ways. It is possible to study such insects in their homes in a more varied and more complete manner, allowing greater accuracy of observations.

GALILEO

Dialogues on the System of the World

Galileo Galilei, famous as an astronomer and as an experimental
physicist, was born at Pisa, in Italy, Feb. 18, 1564. His talents
were most multifarious and remarkable; but his mathematical and
mechanical genius was dominant from the first. As a child he
constructed mechanical toys, and as a young man he made one of his
most important discoveries, which was that of the pendulum as an
agent in the measurement of time, and invented the hydrostatic
balance, by which the specific gravity of solid bodies might be
ascertained. At the age of 24 a learned treatise on the centre of
gravity of solids led to a lectureship at Pisa University. Driven
from Pisa by the enmity of Aristotelians, he went to Padua
University, where he invented a kind of thermometer, a proportional
compass, a microscope, and a telescope. The last invention bore
fruit in astronomical discoveries, and in 1610 he discovered four
of the moons of Jupiter. His promulgation of the Copernican
doctrine led to renewed attacks by the Aristotelians, and to
censure by the Inquisition. (See Religion, vol. xiii.)
Notwithstanding this censure, he published in 1632 his "Dialogues
on the System of the World." The interlocutors in the "Dialogues,"
with the exception of Salviatus, who expounds the views of the
author himself, represent two of Galileo's early friends. For the
"Dialogues" he was sentenced by the Inquisition to incarceration at
its pleasure, and enjoined to recite penitential psalms once a week
for three years. His life thereafter was full of sorrow, and in
1637 blindness added to his woes; but the fire of his genius still
burnt on till his death on January 8, 1642.

_Does the Earth Move_

SALVIATUS: Now, let Simplicius propound those doubts which dissuade him from believing that the earth may move, as the other planets, round a fixed centre.

SIMPLICIUS: The first and greatest difficulty is that it is impossible both to be in a centre and to be far from it. If the earth move in a circle it cannot remain in the centre of the zodiac; but Aristotle, Ptolemy and others have proved that it is in the centre of the zodiac.

SALVIATUS: There is no question that the earth cannot be in the centre of a circle round whose circumference it moves. But tell me what centre do you mean?

SIMPLICIUS: I mean the centre of the universe, of the whole world, of the starry sphere.

SALVIATUS: No one has ever proved that the universe is finite and figurative; but granting that it is finite and spherical, and has therefore a centre, we have still to give reasons why we should believe that the earth is at its centre.

SIMPLICIUS: Aristotle has proved in a hundred ways that the universe is finite and spherical.

SALVIATUS: Aristotle's proof that the universe was finite and spherical was derived essentially from the consideration that it moved; and seeing that centre and figure were inferred by Aristotle from its mobility, it will be reasonable if we endeavour to find from the circular motions of mundane bodies the centre's proper place. Aristotle himself came to the conclusion that all the celestial spheres revolve round the earth, which is placed at the centre of the universe. But tell me, Simplicius, supposing Aristotle found that one of the two propositions must be false, and that either the celestial spheres do not revolve or that the earth is not the centre round which they revolve, which proposition would he prefer to give up?

SIMPLICIUS: I believe that the Peripatetics----

SALVIATUS: I do not ask the Peripatetics, I ask Aristotle. As for the Peripatetics, they, as humble vassals of Aristotle, would deny all the experiments and all the observations in the world; nay, would also refuse to see them, and would say that the universe is as Aristotle writeth, and not as Nature will have it; for, deprived of the shield of his authority, with what do you think they would appear in the field? Tell me, therefore, what Aristotle himself would do.

SIMPLICIUS: To tell you the truth, I do not know how to decide which is the lesser inconvenience.

SALVIATUS: Seeing you do not know, let us examine which would be the more rational choice, and let us assume that Aristotle would have chosen so. Granting with Aristotle that the universe has a spherical figure and moveth circularly round a centre, it is reasonable to believe that the starry orbs move round the centre of the universe or round some separate centre?

SIMPLICIUS: I would say that it were much more reasonable to believe that they move with the universe round the centre of the universe.

SALVIATUS: But they move round the sun and not round the earth; therefore the sun and not the earth is the centre of the universe.

SIMPLICIUS: Whence, then, do you argue that it is the sun and not the earth that is the centre of the planetary revolutions?

SALVIATUS: I infer that the earth is not the centre of the planetary revolutions because the planets are at different times at very different distances from the earth. For instance, Venus, when it is farthest off, is six times more remote from us than when it is nearest, and Mars rises almost eight times as high at one time as at another.

SIMPLICIUS: And what are the signs that the planets revolve round the sun as centre?

SALVIATUS: We find that the three superior planets--Mars, Jupiter, and Saturn--are always nearest to the earth when they are in opposition to the sun, and always farthest off when they are in conjunction; and so great is this approximation and recession that Mars, when near, appears very nearly sixty times greater than when remote. Venus and Mercury also certainly revolve round the sun, since they never move far from it, and appear now above and now below it.

SAGREDUS: I expect that more wonderful things depend on the annual revolution than upon the diurnal rotation of the earth.

SALVIATUS: YOU do not err therein. The effect of the diurnal rotation of the earth is to make the universe seem to rotate in the opposite direction; but the annual motion complicates the particular motions of all the planets. But to return to my proposition. I affirm that the centre of the celestial convolutions of the five planets--Saturn, Jupiter, Mars, Venus, and Mercury, and likewise of the earth--is the sun.

As for the moon, it goes round the earth, and yet does not cease to go round the sun with the earth. It being true, then, that the five planets do move about the sun as a centre, rest seems with so much more reason to belong to the said sun than to the earth, inasmuch as in a movable sphere it is more reasonable that the centre stand still than any place remote from the centre.

To the earth, therefore, may a yearly revolution be assigned, leaving the sun at rest. And if that be so, it follows that the diurnal motion likewise belongs to the earth; for if the sun stood still and the earth did not rotate, the year would consist of six months of day and six months of night. You may consider, likewise, how, in conformity with this scheme, the precipitate motion of twenty-four hours is taken away from the universe; and how the fixed stars, which are so many suns, are made, like our sun, to enjoy perpetual rest.

SAGREDUS: The scheme is simple and satisfactory; but, tell me, how is it that Pythagoras and Copernicus, who first brought it forward, could make so few converts?

SALVIATUS: If you know what frivolous reasons serve to make the vulgar, contumacious and indisposed to hearken, you would not wonder at the paucity of converts. The number of thick skulls is infinite, and we need neither record their follies nor endeavour to interest them in subtle and sublime ideas. No demonstrations can enlighten stupid brains.

My wonder, Sagredus, is different from yours. You wonder that so few are believers in the Pythagorean hypothesis; I wonder that there are any to embrace it. Nor can I sufficiently admire the super-eminence of those men's wits that have received and held it to be true, and with the sprightliness of their judgments have offered such violence to their senses that they have been able to prefer that which their reason asserted to that which sensible experience manifested. I cannot find any bounds for my admiration how that reason was able, in Aristarchus and Copernicus, to commit such a rape upon their senses, as in despite thereof to make herself mistress of their credulity.

SAGREDUS: Will there still be strong opposition to the Copernican system?

SALVIATUS: Undoubtedly; for there are evident and sensible facts to oppose it, requiring a sense more sublime than the common and vulgar senses to assist reason.

SAGREDUS: Let us, then, join battle with those antagonistic facts.

SALVIATUS: I am ready. In the first place, Mars himself charges hotly against the truth of the Copernican system. According to the Copernican system, that planet should appear sixty times as large when at its nearest as when at its farthest; but this diversity of magnitude is not to be seen. The same difficulty is seen in the case of Venus. Further, if Venus be dark, and shine only with reflected light, like the moon, it should show lunar phases; but these do not appear.

Further, again, the moon prevents the whole order of the Copernican system by revolving round the earth instead of round the sun. And there are other serious and curious difficulties admitted by Copernicus himself. But even the three great difficulties I have named are not real. As a matter of fact, Mars and Venus do vary in magnitude as required by theory, and Venus does change its shape exactly like the moon.

SAGREDUS: But how came this to be concealed from Copernicus and revealed to you?

SIR FRANCIS GALTON

Essays in Eugenics

Sir Francis Galton, born at Birmingham, England, in 1822, was a
grandson of Dr. Erasmus Darwin. He graduated from Trinity College,
Cambridge, in 1844. Galton travelled in the north of Africa, on the
White Nile and in the western portion of South Africa between 1844
and 1850. Like his immortal cousin, Charles Darwin, Sir Francis
Galton is a striking instance of a man of great and splendid
inheritance, who, also inheriting wealth, devotes it and his powers
to the cause of humanity. He published several books on heredity,
the first of which was "Hereditary Genius." The next "Inquiries
into Human Faculty," which was followed by "Natural Inheritance."
The "Essays in Eugenics" include all the most recent work of Sir
Francis Galton since his return to the subject of eugenics in 1901.
This volume has just been published by the Eugenics Education
Society, of which Sir Francis Galton is the honorary president. As
epitomised for this work, the "Essays" have been made to include a
still later study by the author, which will be included in future
editions of the book. The epitome has been prepared by special
permission of the Eugenics Education Society, and those responsible
hope that it will serve in some measure to neutralise the
outrageous, gross, and often wilful misrepresentations of eugenics
of which many popular writers are guilty.

_I.--The Aims and Methods of Eugenics_

The following essays help to show something of the progress of eugenics during the last few years, and to explain my own views upon its aims and methods, which often have been, and still sometimes are, absurdly misrepresented. The practice of eugenics has already obtained a considerable hold on popular estimation, and is steadily acquiring the status of a practical question, and not that of a mere vision in Utopia.

The power by which eugenic reform must chiefly be effected is that of public opinion, which is amply strong enough for that purpose whenever it shall be roused. Public opinion has done as much as this on many past occasions and in various countries, of which much evidence is given in the essay on restrictions in marriage. It is now ordering our acts more intimately than we are apt to suspect, because the dictates of public opinion become so thoroughly assimilated that they seem to be the original and individual to those who are guided by them. By comparing the current ideas at widely different epochs and under widely different civilisations, we are able to ascertain what part of our convictions is really innate and permanent, and what part has been acquired and is transient.

It is, above all things, needful for the successful progress of eugenics that its advocates should move discreetly and claim no more efficacy on its behalf than the future will justify; otherwise a reaction will be justified. A great deal of investigation is still needed to show the limit of practical eugenics, yet enough has been already determined to justify large efforts being made to instruct the public in an authoritative way, with the results hitherto obtained by sound reasoning, applied to the undoubted facts of social experience.

The word "eugenics" was coined and used by me in my book "Human Faculty," published as long ago as 1883. In it I emphasised the essential brotherhood of mankind, heredity being to my mind a very real thing; also the belief that we are born to act, and not to wait for help like able-bodied idlers, whining for doles. Individuals appear to me as finite detachments from an infinite ocean of being, temporarily endowed with executive powers. This is the only answer I can give to myself in reply to the perpetually recurring questions of "why? whence? and whither?" The immediate "whither?" does not seem wholly dark, as some little information may be gleaned concerning the direction in which Nature, so far as we know of it, is now moving--namely, towards the evolution of mind, body, and character in increasing energy and co-adaptation.

The ideas have long held my fancy that we men may be the chief, and perhaps the only executives on earth; that we are detached on active service with, it may be only illusory, powers of free-will. Also that we are in some way accountable for our success or failure to further certain obscure ends, to be guessed as best we can; that though our instructions are obscure they are sufficiently clear to justify our interference with the pitiless course of Nature whenever it seems possible to attain the goal towards which it moves by gentler and kindlier ways.

There are many questions which must be studied if we are to be guided aright towards the possible improvement of mankind under the existing conditions of law and sentiment. We must study human variety, and the distribution of qualities in a nation. We must compare the classification of a population according to social status with the classification which we would make purely in terms of natural quality. We must study with the utmost care the descent of qualities in a population, and the consequences of that marked tendency to marriage within the class which distinguishes all classes. Something is to be learnt from the results of examinations in universities and colleges.

It is desirable to study the degree of correspondence that may exist between promise in youth, as shown in examinations, and subsequent performance. Let me add that I think the neglect of this inquiry by the vast army of highly educated persons who are connected with the present huge system of competitive examination to be gross and unpardonable. Until this problem is solved we cannot possibly estimate the value of the present elaborate system of examinations.

_II.--Restrictions in Marriage_

It is necessary to meet an objection that has been repeatedly urged against the possible adoption of any system of eugenics, namely, that human nature would never brook interference with the freedom of marriage. But the question is how far have marriage restrictions proved effective when sanctified by the religion of the time, by custom, and by law. I appeal from armchair criticism to historical facts. It will be found that, with scant exceptions, marriage customs are based on social expediency and not on natural instincts. This we learn when we study the fact of monogamy, and the severe prohibition of polygamy, in many times and places, due not to any natural instinct against the practice, but to consideration of the social well-being. We find the same when we study endogamy, exogamy, Australian marriages, and the control of marriage by taboo.

The institution of marriage, as now sanctified by religion and safeguarded by law in the more highly civilised nations, may not be ideally perfect, nor may it be universally accepted in future times, but it is the best that has hitherto been devised for the parties primarily concerned, for their children, for home life, and for society. The degree of kinship within which marriage is prohibited is, with one exception, quite in accordance with modern sentiment, the exception being the disallowal of marriage with the sister of a deceased wife, the propriety of which is greatly disputed and need not be discussed here. The marriage of a brother and sister would excite a feeling of loathing among us that seems implanted by nature, but which, further inquiry will show, has mainly arisen from tradition and custom.

The evidence proves that there is no instinctive repugnance felt universally by man to marriage within the prohibited degrees, but that its present strength is mainly due to what I may call immaterial considerations. It is quite conceivable that a non-eugenic marriage should hereafter excite no less loathing than that of a brother and sister would do now.

The dictates of religion in respect to the opposite duties of leading celibate lives, and of continuing families, have been contradictory. In many nations it is and has been considered a disgrace to bear no children, and in other nations celibacy has been raised to the rank of a virtue of the highest order. During the fifty or so generations that have elapsed since the establishment of Christianity, the nunneries and monasteries, and the celibate lives of Catholic priests, have had vast social effects, how far for good and how far for evil need not be discussed here. The point I wish to enforce is the potency, not only of the religious sense in aiding or deterring marriage, but more especially the influence and authority of ministers of religion in enforcing celibacy. They have notoriously used it when aid has been invoked by members of the family on grounds that are not religious at all, but merely of family expediency. Thus at some times and in some Christian nations, every girl who did not marry while still young was practically compelled to enter a nunnery, from which escape was afterwards impossible.

It is easy to let the imagination run wild on the supposition of a whole-hearted acceptance of eugenics as a national religion; that is, of the thorough conviction by a nation that no worthier object exists for man than the improvement of his own race, and when efforts as great as those by which nunneries and monasteries were endowed and maintained should be directed to fulfil an opposite purpose. I will not enter further into this. Suffice it to say, that the history of conventual life affords abundant evidence on a very large scale of the power of religious authority in directing and withstanding the tendencies of human nature towards freedom in marriage.

Seven different forms of marriage restriction may be cited to show what is possible. They are monogamy, endogamy, exogamy, Australian marriages, taboo, prohibited degrees, and celibacy. It can be shown under each of these heads how powerful are the various combinations of immaterial motives upon marriage selection, how they may all become hallowed by religion, accepted as custom, and enforced by law. Persons who are born under their various rules live under them without any objection. They are unconscious of their restrictions, as we are unaware of the tension of the atmosphere. The subservience of civilised races to their several religious superstitions, customs, authority, and the rest, is frequently as abject as that of barbarians.

The same classes of motives that direct other races direct ours; so a knowledge of their customs helps us to realise the wide range of what we may ourselves hereafter adopt, for reasons as satisfactory to us in those future times, as theirs are or were to them at the time when they prevailed.

_III.--Eugenic Qualities of Primary Importance_

The following is offered as a contribution to the art of justly appraising the eugenic values of different qualities. It may fairly be assumed that the presence of certain inborn traits is requisite before a claim to eugenic rank can be justified, because these qualities are needed to bring out the full values of such special faculties as broadly distinguish philosophers, artists, financiers, soldiers, and other representative classes. The method adopted for discovering the qualities in question is to consider groups of individuals, and to compare the qualities that distinguish such groups as flourish or prosper from others of the same kind that decline or decay. This method has the advantage of giving results more free from the possibility of bias than those derived from examples of individual cases.

In what follows I shall use the word "community" in its widest sense, as including any group of persons who are connected by a common interest--families, schools, clubs, sects, municipalities, nations, and all intermediate social units. Whatever qualities increase the prosperity of most or every one of these, will, as I hold, deserve a place in the first rank of eugenic importance.