The Outline of Science, Vol. 1 (of 4)

J >> J. Arthur Thomson >> The Outline of Science, Vol. 1 (of 4)

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PELICAN'S BILL, ADAPTED FOR CATCHING AND STORING FISHES 191

SPOONBILL'S BILL, ADAPTED FOR SIFTING THE MUD AND CATCHING
THE SMALL ANIMALS, E.G. FISHES, CRUSTACEANS, INSECT
LARVAE, WHICH LIVE THERE 191

AVOCET'S BILL, ADAPTED FOR A CURIOUS SIDEWAYS SCOOPING IN
THE SHORE-POOLS AND CATCHING SMALL ANIMALS 191

HORNBILL'S BILL, ADAPTED FOR EXCAVATING A NEST IN A TREE,
AND ALSO FOR SEIZING AND BREAKING DIVERSE FORMS OF FOOD,
FROM MAMMALS TO TORTOISES, FROM ROOTS TO FRUITS 191

FALCON'S BILL, ADAPTED FOR SEIZING, KILLING, AND TEARING
SMALL MAMMALS AND BIRDS 191

PUFFIN'S BILL, ADAPTED FOR CATCHING SMALL FISHES NEAR THE
SURFACE OF THE SEA, AND FOR HOLDING THEM WHEN CAUGHT AND
CARRYING THEM TO THE NEST 191

LIFE-HISTORY OF A FROG 192

HIND-LEG OF WHIRLIGIG BEETLE WHICH HAS BECOME BEAUTIFULLY
MODIFIED FOR AQUATIC LOCOMOTION 192
Photo: J. J. Ward, F.E.S.

THE BIG ROBBER-CRAB (_Birgus Latro_), THAT CLIMBS THE
COCONUT PALM AND BREAKS OFF THE NUTS 193

EARLY LIFE-HISTORY OF THE SALMON 196

THE SALMON LEAPING AT THE FALL IS A MOST FASCINATING SPECTACLE 197

DIAGRAM OF THE LIFE-HISTORY OF THE COMMON EEL (_Anguilla
Vulgaris_) 200

CASSOWARY 201
Photo: Gambier Bolton.

THE KIWI, ANOTHER FLIGHTLESS BIRD, OF REMARKABLE
APPEARANCE, HABITS, AND STRUCTURE 201
Photo: Gambier Bolton.

THE AUSTRALIAN FRILLED LIZARD, WHICH IS AT PRESENT TRYING
TO BECOME A BIPED 202

A CARPET OF GOSSAMER 202

THE WATER SPIDER 203

JACKDAW BALANCING ON A GATEPOST 208
Photo: O. J. Wilkinson.

TWO OPOSSUMS FEIGNING DEATH 208
From Ingersoll's _The Wit of the Wild_.

MALE OF THREE-SPINED STICKLEBACK, MAKING A NEST OF
WATER-WEED, GLUED TOGETHER BY VISCID THREADS SECRETED
FROM THE KIDNEYS AT THE BREEDING SEASON 209

A FEMALE STICKLEBACK ENTERS THE NEST WHICH THE MALE HAS
MADE, LAYS THE EGGS INSIDE, AND THEN DEPARTS 209

HOMING PIGEON 212
Photo: Imperial War Museum.

CARRIER PIGEON 212
Photo: Imperial War Museum.

YELLOW-CROWNED PENGUIN 213
Photo: James's Press Agency.

PENGUINS ARE "A PECULIAR PEOPLE" 213
Photo: Cagcombe & Co.

HARPY-EAGLE 216
Photo: W. S. Berridge.

THE DINGO OR WILD DOG OF AUSTRALIA, PERHAPS AN INDIGENOUS
WILD SPECIES, PERHAPS A DOMESTICATED DOG THAT HAS GONE
WILD OR FERAL 216
Photo: W. S. Berridge, F.Z.S.

WOODPECKER HAMMERING AT A COTTON-REEL, ATTACHED TO A TREE 217

THE BEAVER 220

THE THRUSH AT ITS ANVIL 221
Photo: F. R. Hinkins & Son.

ALSATIAN WOLF-DOG 226
Photo: Lafayette.

THE POLAR BEAR OF THE FAR NORTH 227
Photo: W. S. Berridge.

AN ALLIGATOR "YAWNING" IN EXPECTATION OF FOOD 227
From the Smithsonian Report, 1914.

BABY ORANG 232
Photo: W. P. Dando.

ORANG-UTAN 232
Photo: Gambier Bolton.

CHIMPANZEE 233
Photo: James's Press Agency.

BABY ORANG-UTAN 233
Photo: James's Press Agency.

ORANG-UTAN 233
Photo: James's Press Agency.

BABY CHIMPANZEES 233
Photo: James's Press Agency.

CHIMPANZEE 238
Photo: W. P. Dando.

YOUNG CHEETAHS, OR HUNTING LEOPARDS 238
Photo: W. S. Berridge.

COMMON OTTER 239
Photo: C. Reid.

SIR ERNEST RUTHERFORD 246
Photo: Elliott & Fry.

J. CLERK-MAXWELL 246
Photo: Rischgitz Collection.

SIR WILLIAM CROOKES 247
Photo: Ernest H. Mills.

PROFESSOR SIR W. H. BRAGG 247
Photo: Photo Press.

COMPARATIVE SIZES OF MOLECULES 250

INCONCEIVABLE NUMBERS AND INCONCEIVABLY SMALL PARTICLES 250

WHAT IS A MILLION? 250

THE BROWNIAN MOVEMENT 251

A SOAP BUBBLE (_Coloured Illustration_) 252
Reproduced from _The Forces of Nature_ (Messrs. Macmillan).

DETECTING A SMALL QUANTITY OF MATTER 254
From _Scientific Ideas of To-day_.

THIS X-RAY PHOTOGRAPH IS THAT OF A HAND OF A SOLDIER
WOUNDED IN THE GREAT WAR 254
Reproduced by permission of X-Rays Ltd.

AN X-RAY PHOTOGRAPH OF A GOLF BALL, REVEALING AN IMPERFECT
CORE 254
Photo: National Physical Laboratory.

A WONDERFUL X-RAY PHOTOGRAPH 255
Reproduced by permission of X-Rays Ltd.

ELECTRIC DISCHARGE IN A VACUUM TUBE 258

THE RELATIVE SIZES OF ATOMS AND ELECTRONS 258

ELECTRONS STREAMING FROM THE SUN TO THE EARTH 259

PROFESSOR SIR J. J. THOMSON 262

ELECTRONS PRODUCED BY PASSAGE OF X-RAYS THROUGH AIR 262
From the Smithsonian Report, 1915.

MAGNETIC DEFLECTION OF RADIUM RAYS 263

PROFESSOR R. A. MILLIKAN'S APPARATUS FOR COUNTING ELECTRONS 263
Reproduced by permission of _Scientific American_.

MAKING THE INVISIBLE VISIBLE 266

THE THEORY OF ELECTRONS 267

ARRANGEMENTS OF ATOMS IN A DIAMOND 267

DISINTEGRATION OF ATOMS 270

SILK TASSEL ELECTRIFIED 270
Reproduced by permission from _The Interpretation of Radium_
(John Murray).

SILK TASSEL DISCHARGED BY THE RAYS FROM RADIUM 270

A HUGE ELECTRIC SPARK 271

ELECTRICAL ATTRACTION BETWEEN COMMON OBJECTS 271
From _Scientific Ideas of To-day_.

AN ELECTRIC SPARK 274
Photo: Leadbeater.

AN ETHER DISTURBANCE AROUND AN ELECTRON CURRENT 275
From _Scientific Ideas of To-day_.

LIGHTNING 278
Photo: H. J. Shepstone.

LIGHT WAVES 279

THE MAGNETIC CIRCUIT OF AN ELECTRIC CURRENT 279

THE MAGNET 279

ROTATING DISC OF SIR ISAAC NEWTON FOR MIXING COLOURS
(_Coloured Illustration_) 280

WAVE SHAPES 282

THE POWER OF A MAGNET 282

THE SPEED OF LIGHT 283
Photo: The Locomotive Publishing Co., Ltd.

ROTATING DISC OF SIR ISAAC NEWTON FOR MIXING COLOURS 283

NIAGARA FALLS 286

TRANSFORMATION OF ENERGY 287
Photo: Stephen Cribb.

"BOILING" A KETTLE ON ICE 287
Photo: Underwood & Underwood.

THE CAUSE OF TIDES 290

THE AEGIR ON THE TRENT 290
Photo: G. Brocklehurst.

A BIG SPRING TIDE, THE AEGIR ON THE TRENT 291
Photo: G. Brocklehurst.

The Outline of Science

INTRODUCTION

There is abundant evidence of a widened and deepened interest in modern
science. How could it be otherwise when we think of the magnitude and
the eventfulness of recent advances?

But the interest of the general public would be even greater than it is
if the makers of new knowledge were more willing to expound their
discoveries in ways that could be "understanded of the people." No one
objects very much to technicalities in a game or on board a yacht, and
they are clearly necessary for terse and precise scientific description.
It is certain, however, that they can be reduced to a minimum without
sacrificing accuracy, when the object in view is to explain "the gist of
the matter." So this OUTLINE OF SCIENCE is meant for the general reader,
who lacks both time and opportunity for special study, and yet would
take an intelligent interest in the progress of science which is making
the world always new.

The story of the triumphs of modern science is one of which Man may well
be proud. Science reads the secret of the distant star and anatomises
the atom; foretells the date of the comet's return and predicts the
kinds of chickens that will hatch from a dozen eggs; discovers the laws
of the wind that bloweth where it listeth and reduces to order the
disorder of disease. Science is always setting forth on Columbus
voyages, discovering new worlds and conquering them by understanding.
For Knowledge means Foresight and Foresight means Power.

The idea of Evolution has influenced all the sciences, forcing us to
think of _everything_ as with a history behind it, for we have travelled
far since Darwin's day. The solar system, the earth, the mountain
ranges, and the great deeps, the rocks and crystals, the plants and
animals, man himself and his social institutions--all must be seen as
the outcome of a long process of Becoming. There are some eighty-odd
chemical elements on the earth to-day, and it is now much more than a
suggestion that these are the outcome of an inorganic evolution, element
giving rise to element, going back and back to some primeval stuff, from
which they were all originally derived, infinitely long ago. No idea has
been so powerful a tool in the fashioning of New Knowledge as this
simple but profound idea of Evolution, that the present is the child of
the past and the parent of the future. And with the picture of a
continuity of evolution from nebula to social systems comes a promise of
an increasing control--a promise that Man will become not only a more
accurate student, but a more complete master of his world.

It is characteristic of modern science that the whole world is seen to
be more vital than before. Everywhere there has been a passage from the
static to the dynamic. Thus the new revelations of the constitution of
matter, which we owe to the discoveries of men like Professor Sir J. J.
Thomson, Professor Sir Ernest Rutherford, and Professor Frederick Soddy,
have shown the very dust to have a complexity and an activity heretofore
unimagined. Such phrases as "dead" matter and "inert" matter have gone
by the board.

The new theory of the atom amounts almost to a new conception of the
universe. It bids fair to reveal to us many of nature's hidden secrets.
The atom is no longer the indivisible particle of matter it was once
understood to be. We know now that there is an atom within the
atom--that what we thought was elementary can be dissociated and broken
up. The present-day theories of the atom and the constitution of matter
are the outcome of the comparatively recent discovery of such things as
radium, the X-rays, and the wonderful revelations of such instruments as
the spectroscope and other highly perfected scientific instruments.

The advent of the electron theory has thrown a flood of light on what
before was hidden or only dimly guessed at. It has given us a new
conception of the framework of the universe. We are beginning to know
and realise of what matter is made and what electric phenomena mean. We
can glimpse the vast stores of energy locked up in matter. The new
knowledge has much to tell us about the origin and phenomena, not only
of our own planet, but other planets, of the stars, and the sun. New
light is thrown on the source of the sun's heat; we can make more than
guesses as to its probable age. The great question to-day is: is there
_one_ primordial substance from which all the varying forms of matter
have been evolved?

But the discovery of electrons is only one of the revolutionary changes
which give modern science an entrancing interest.

As in chemistry and physics, so in the science of living creatures there
have been recent advances that have changed the whole prospect. A good
instance is afforded by the discovery of the "hormones," or chemical
messengers, which are produced by ductless glands, such as the thyroid,
the supra-renal, and the pituitary, and are distributed throughout the
body by the blood. The work of physiologists like Professor Starling and
Professor Bayliss has shown that these chemical messengers regulate what
may be called the "pace" of the body, and bring about that regulated
harmony and smoothness of working which we know as health. It is not too
much to say that the discovery of hormones has changed the whole of
physiology. Our knowledge of the human body far surpasses that of the
past generation.

The persistent patience of microscopists and technical improvements like
the "ultramicroscope" have greatly increased our knowledge of the
invisible world of life. To the bacteria of a past generation have been
added a multitude of microscopic _animal_ microbes, such as that which
causes Sleeping Sickness. The life-histories and the weird ways of many
important parasites have been unravelled; and here again knowledge means
mastery. To a degree which has almost surpassed expectations there has
been a revelation of the intricacy of the stones and mortar of the house
of life, and the microscopic study of germ-cells has wonderfully
supplemented the epoch-making experimental study of heredity which began
with Mendel. It goes without saying that no one can call himself
educated who does not understand the central and simple ideas of
Mendelism and other new departures in biology.

The procession of life through the ages and the factors in the sublime
movement; the peopling of the earth by plants and animals and the
linking of life to life in subtle inter-relations, such as those between
flowers and their insect-visitors; the life-histories of individual
types and the extraordinary results of the new inquiry called
"experimental embryology"--these also are among the subjects with which
this OUTLINE will deal.

The behaviour of animals is another fascinating study, leading to a
provisional picture of the dawn of mind. Indeed, no branch of science
surpasses in interest that which deals with the ways and habits--the
truly wonderful devices, adaptations, and instincts--of insects, birds,
and mammals. We no longer deny a degree of intelligence to some members
of the animal world--even the line between intelligence and reason is
sometimes difficult to find.

Fresh contacts between physiology and the study of man's mental life;
precise studies of the ways of children and wild peoples; and new
methods like those of the psycho-analyst must also receive the attention
they deserve, for they are giving us a "New Psychology" and the claims
of psychical research must also be recognised by the open-minded.

The general aim of the OUTLINE is to give the reader a clear and concise
view of the essentials of present-day science, so that he may follow
with intelligence the modern advance and share appreciatively in man's
continued conquest of his kingdom.

J. ARTHUR THOMSON.

I

THE ROMANCE OF THE HEAVENS

THE SCALE OF THE UNIVERSE--THE SOLAR SYSTEM

Sec. 1

The story of the triumphs of modern science naturally opens with
Astronomy. The picture of the Universe which the astronomer offers to us
is imperfect; the lines he traces are often faint and uncertain. There
are many problems which have been solved, there are just as many about
which there is doubt, and notwithstanding our great increase in
knowledge, there remain just as many which are entirely unsolved.

The problem of the structure and duration of the universe [said the
great astronomer Simon Newcomb] is the most far-reaching with which
the mind has to deal. Its solution may be regarded as the ultimate
object of stellar astronomy, the possibility of reaching which has
occupied the minds of thinkers since the beginning of civilisation.
Before our time the problem could be considered only from the
imaginative or the speculative point of view. Although we can to-day
attack it to a limited extent by scientific methods, it must be
admitted that we have scarcely taken more than the first step toward
the actual solution.... What is the duration of the universe in
time? Is it fitted to last for ever in its present form, or does it
contain within itself the seeds of dissolution? Must it, in the
course of time, in we know not how many millions of ages, be
transformed into something very different from what it now is? This
question is intimately associated with the question whether the
stars form a system. If they do, we may suppose that system to be
permanent in its general features; if not, we must look further for
our conclusions.

The Heavenly Bodies

The heavenly bodies fall into two very distinct classes so far as their
relation to our Earth is concerned; the one class, a very small one,
comprises a sort of colony of which the Earth is a member. These bodies
are called _planets_, or wanderers. There are eight of them, including
the Earth, and they all circle round the sun. Their names, in the order
of their distance from the sun, are Mercury, Venus, Earth, Mars,
Jupiter, Saturn, Uranus, Neptune, and of these Mercury, the nearest to
the sun, is rarely seen by the naked eye. Uranus is practically
invisible, and Neptune quite so. These eight planets, together with the
sun, constitute, as we have said, a sort of little colony; this colony
is called the Solar System.

The second class of heavenly bodies are those which lie _outside_ the
solar system. Every one of those glittering points we see on a starlit
night is at an immensely greater distance from us than is any member of
the Solar System. Yet the members of this little colony of ours, judged
by terrestrial standards, are at enormous distances from one another. If
a shell were shot in a straight line from one side of Neptune's orbit to
the other it would take five hundred years to complete its journey. Yet
this distance, the greatest in the Solar System as now known (excepting
the far swing of some of the comets), is insignificant compared to the
distances of the stars. One of the nearest stars to the earth that we
know of is Alpha Centauri, estimated to be some twenty-five million
millions of miles away. Sirius, the brightest star in the firmament, is
double this distance from the earth.

We must imagine the colony of planets to which we belong as a compact
little family swimming in an immense void. At distances which would take
our shell, not hundreds, but millions of years to traverse, we reach
the stars--or rather, a star, for the distances between stars are as
great as the distance between the nearest of them and our Sun. The
Earth, the planet on which we live, is a mighty globe bounded by a crust
of rock many miles in thickness; the great volumes of water which we
call our oceans lie in the deeper hollows of the crust. Above the
surface an ocean of invisible gas, the atmosphere, rises to a height of
about three hundred miles, getting thinner and thinner as it ascends.

[Illustration: LAPLACE

One of the greatest mathematical astronomers of all time and the
originator of the nebular theory.]

[Illustration: _Photo: Royal Astronomical Society._

PROFESSOR J. C. ADAMS

who, anticipating the great French mathematician, Le Verrier, discovered
the planet Neptune by calculations based on the irregularities of the
orbit of Uranus. One of the most dramatic discoveries in the history of
Science.]

[Illustration: _Photo: Elliott & Fry, Ltd._

PROFESSOR EDDINGTON

Professor of Astronomy at Cambridge. The most famous of the English
disciples of Einstein.]

[Illustration: FIG. 1.--DIAGRAMS OF THE SOLAR SYSTEM

THE COMPARATIVE DISTANCES OF THE PLANETS

(Drawn approximately to scale)

The isolation of the Solar System is very great. On the above scale the
_nearest_ star (at a distance of 25 trillions of miles) would be over
_one half mile_ away. The hours, days, and years are the measures of
time as we use them; that is: Jupiter's "Day" (one rotation of the
planet) is made in ten of _our hours_; Mercury's "Year" (one revolution
of the planet around the Sun) is eighty-eight of _our days_. Mercury's
"Day" and "Year" are the same. This planet turns always the same side to
the Sun.]

[Illustration: THE COMPARATIVE SIZES OF THE SUN AND THE PLANETS (Drawn
approximately to scale)

On this scale the Sun would be 17-1/2 inches in diameter; it is far
greater than all the planets put together. Jupiter, in turn, is greater
than all the other planets put together.]

Except when the winds rise to a high speed, we seem to live in a very
tranquil world. At night, when the glare of the sun passes out of our
atmosphere, the stars and planets seem to move across the heavens with a
stately and solemn slowness. It was one of the first discoveries of
modern astronomy that this movement is only apparent. The apparent
creeping of the stars across the heavens at night is accounted for by
the fact that the earth turns upon its axis once in every twenty-four
hours. When we remember the size of the earth we see that this implies a
prodigious speed.

In addition to this the earth revolves round the sun at a speed of more
than a thousand miles a minute. Its path round the sun, year in year
out, measures about 580,000,000 miles. The earth is held closely to this
path by the gravitational pull of the sun, which has a mass 333,432
times that of the earth. If at any moment the sun ceased to exert this
pull the earth would instantly fly off into space straight in the
direction in which it was moving at the time, that is to say, at a
tangent. This tendency to fly off at a tangent is continuous. It is the
balance between it and the sun's pull which keeps the earth to her
almost circular orbit. In the same way the seven other planets are held
to their orbits.

Circling round the earth, in the same way as the earth circles round the
sun, is our moon. Sometimes the moon passes directly between us and the
sun, and cuts off the light from us. We then have a total or partial
eclipse of the sun. At other times the earth passes directly between the
sun and the moon, and causes an eclipse of the moon. The great ball of
the earth naturally trails a mighty shadow across space, and the moon is
"eclipsed" when it passes into this.

The other seven planets, five of which have moons of their own, circle
round the sun as the earth does. The sun's mass is immensely larger than
that of all the planets put together, and all of them would be drawn
into it and perish if they did not travel rapidly round it in gigantic
orbits. So the eight planets, spinning round on their axes, follow their
fixed paths round the sun. The planets are secondary bodies, but they
are most important, because they are the only globes in which there can
be life, as we know life.

If we could be transported in some magical way to an immense distance in
space above the sun, we should see our Solar System as it is drawn in
the accompanying diagram (Fig. 1), except that the planets would be mere
specks, faintly visible in the light which they receive from the sun.
(This diagram is drawn approximately to scale.) If we moved still
farther away, trillions of miles away, the planets would fade entirely
out of view, and the sun would shrink into a point of fire, a star. And
here you begin to realize the nature of the universe. _The sun is a
star. The stars are suns._ Our sun looks big simply because of its
comparative nearness to us. The universe is a stupendous collection of
millions of stars or suns, many of which may have planetary families
like ours.

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