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THE HEAVENS AND THEIR STORY

THE HEAVENS

AND THEIR STORY

ANNIE S. D. MAUNDER

HONORARY FELLOW OF THE ROYAL ASTRONOMICAL SOCIETY OF CANADA

AND

E. WALTER MAUNDER

SUPERINTENDENT OF THE SOLAS DEPARTMENT, ROYAL OBSERVATORY, GREENWICH

FELLOW OF THE ROYAL ASTRONOMICAL SOCIETY

FOREIGN ASSOCIATE OF THE SOCIETA DEGLI SPETTROSCOPISTI ITALIANI

HONORARY FELLOW OF THE ROYAL ASTRONOMICAL SOCIETY OF CANADA

AUTHOR OP

' THE ROYAL OBSERVATORY, GREENWICH, ITS HISTORY AND WORK '

' ASTRONOMY WITHOUT A TELESCOPE,'

•THE ASTRONOMY OF THE BIBLE'

WITfi EIGHT COLOURED PLATES

AND THIRTY-EIGHT ASTRONOMICAL PHOTOGRAPHS

AND FIFTY-ONE OTHER ILLUSTRATIONS

'§on'bon

ROBERT CULLEY

25-35 CITY ROAD AND 26 PATERNOSTER ROW, E.C.

PRINTED BY

WILLIAM CLOWES AND SONS, LIMITED,

LONDON AND BECCLES.

PREFACE

The present book, which stands in the joint names of
my wife and myself, is almost wholly the work of my
wife, cis circumstances prevented my taking any further
part in it soon after it was commenced.

It is not intended as a text-book to teach astronomy ;
it has rather been written with the hope that the reader
may be drawn by it to study astronomy for himself.
The old story tells us that King Alfred was first stirred
up to a desire to learn to read by his rpother showing
him the pictures in a beautifully illuminated book. And
so it has been our desire to point our readers to some
of the pictures presented to us by the heavens, in the
hope that they may desire to spell out their meaning for
themselves.

For ' the heavens are telling ' stories of interest,
stories of wonder, if we but have the eyes to see and
the ears to hear. It is not necessary to be a rich man,
and to build a great observatory, in order to become

8 PREFACE

an astronomer. There were great astronomers before
ever the telescope was invented ; there have been
astronomers even in our own days, there are some still
Hving, whose work needs no other instrument than their
eyes.

In the first book we have dealt with some of the
lessons — only with some of them — which the open
heavens can teach us, if we watch them with attention
and thought. With no telescope, with no apparatus,
there is still much that we can learn. It is true that the
particular lessons treated of in this book were all learned
by our forefathers long ago. But it will be a real benefit
to ourselves if we work them out afresh, and to any one
who has a soul capable of appreciating the wonder and
beauty of Nature in her sublimest aspect, it cannot fail
to be the source of real pleasure.

In the second book, a few — only a very few — of
the lessons which we have learned concerning the sun,
by means of the telescope, the spectroscope, and photo-
graphy, are touched upon ; particularly with regard to
the question so often asked nowadays whether sun-
spots have any influence on the earth. The third book
is devoted to a few particulars respecting the planets
and other members of the solar system ; the design
being to point out wherein they differ from the world

PREFACE 9

whereon we live. The concluding book touches lightly
on the structure of the stellar universe, and is intended
to suggest, rather than to describe, the vastness and
mystery of that great starry system of which our sun
and his family occupy a small and insignificant corner.
We start, therefore, with a little plot of ground upon this
earth of ours, and watching from thence the sun, moon,
and stars circling round it, we learn that our earth is a
vast globe floating unsupported in space. Next, we
study the sun — that other vaster globe that lights and
warms us. Then we look round on our companion
worlds, also like ourselves dependent on the sun for
light and heat, and find that there is not one that is
probably the home of intelligent life. So far, we learn
of the greatness of the earth and of its importance ;
last of all we go into the depths of space to learn how
small it is, how insignificant.

Our grateful acknowledgements are due to the many
friends who have helped us in the matter of the illustra-
tions : to the Astronomer-Royal, Sir W. H. M. Christie,
K.C.B., for Plates XL, XVII., XIX., XXV., XXVI.,
XXXVI., LI., LVL, LVIIL, LXL, LXIL, and LXIIL ;
to the Royal Astronomical Society, for permission to use
Plate XLIV., the reproduction of four of the late Mr.
N. E. Green's drawings of Mars, also Plates XXIV.

lo PREFACE

and LX.; to M. E. M. Antoniadi, for Plates XL I. and
XLIII. ; to Miss Gertrude Bacon, for Plate XLII. ; to
Professor E. E. Barnard, for Plates LXVI. to LXXI.
inclusive ; to Mr. Franklin Adams, for Plate LIV, ; to
Lord Hampton and the Hon. Miss Edith Pakington,
for Plate XX VH.; to Mr. F. W. Longbottom, for the
photograph of the Plough stars in Plate LV. ; to
Miss L. Martin- Leake, for Plate XXVHL; to Professor
£:. C. Pickering, for Plates XIL and XXIX. ; to the
Rev. T. E. R. Phillips, for Plates XXXVHL, XXXIX.,
and XL., ; to M. Puiseux, for Plates XLVL, XLVII.,
XLVIII., and XLIX.; to Professor Ritchey, for Plates
L., LIX., and LXXI I. ; and to Professor Max Wolf,
for Plates LVII. and LXIV.

E. WALTER MAUNDER.

St. John's,

London, S.E.,

September, igo8.

CONTENTS

STORIES TOLD BY THE HEAVENLY
MOVEMENTS

JHAPTER PACE

I. The Story told by the Sun 19

II. The Story told by the Moon .... 42

III. The Story told by the Stars .... 58

IV. The Story told by the Planets .... 74

STORIES TOLD BY THE SUN

V. The Story told by the Sun's Surface . . .103

VI. The Story told by the Sun and Planets together 119

VII, The Story told by Sun-spots . . . .131

VIII. The Story told by the Sun and Moon together 144

IX. The Story told by the Sun's Broken Light . 164

X. The Story told by the Sun and Earth together 178

STORIES TOLD BY THE SUN'S FAMILY

XI. The Story told by the Planet Jupiter . . 197
XII. The Story told by the Planet Saturn . .212

12 CONTENTS

CHAPTER PAGE

XIII. The Story of Vknus and Mars .... 225

XIV. The Story told by the Moon .... 246
XV. The Story told by Comets 263

STORIES TOLD BY THE STARS
AND NEBULAE

XVI. The Story told by the Star in the Centaur . 277

XVII. The Story told by the Stars in the Plough . 292

XVIII. The Story told by the Nebulae .... 305

XIX. The Story told by the Milky Way . . .327

Index .353

LIST OF ILLUSTRATIONS

COLOURED PLATES

PLATE PAGE

XXXIV. Solar and Stellar spectra Frontispiece

XXVII. Total solar eclipse in Lapland, August 9, 1896 .... 148

XXVIII. Telescopic view of Corona, May 28, igoo 151

XXIX. Eruptive and quiescent prominences 156

XXXIX. Jupiter, February 2, 190S, by the Rev. T. E. R. Phillips . . 205

XL. Jupiter, February 10, 1908, by the Rev. T, E. R. Phillips . . 209

XLIII. Mars, by M. E. M. Antoniadi 232

XLIV. Mars. Four drawings by the late Mr. N. E. Green . . .238

CHAPTER I.

An open-air Observatory 25

The divisions of the clock-face, the compass, and the circle .... 26

Rising points of the Sun on the Eastern horizon 31

Varying lengths of the shadow at noon 31

Apparent daily paths of the Sun at different seasons of the year ... 32

Proof that the Earth is round 39

CHAPTER II.

The bow of the crescent Moon points to the Sun 40

Photograph of the Full Moon 47

Progress of the Moon during the month 48

CHAPTER III.

The Constellation of Cassiopeia 63

The Constellation of Taurus 64

Photograph of Trails of Stars near the North Pole 69

Photograph of the Constellation of the Southern Cross 70

14 LIST OF ILLUSTRATIONS

CHAPTER IV.

PAGE

Path of Mars amongst the stars in 1907 83

Path of Jupiter amongst the stars in 1907 . , 83

Elongations and conjunctions of an inner planet ...... 84

Oppositions and quadratures of an outer planet ...... 84

Which ran : The man or the tree ? • 97

The Sun's atmosphere is deeper at its rim than at its centre .... 98

The forward motion of an outer planet ....... 98

The stationary points of an outer planet ....... 98

The retrogression of an outer planet ........ 98

The annual parallax of a star . 98

CHAPTER V.

Flamsteed's method of observing the sun ....... 109

Dallmeyer photo-heliograph of Greenwich Observatory 109

Passage of a Sun-spot across the Sun's disc . . . . . . . I lo

Photograph of the Sun, July 14, 1905 113

Granulation of the Sun's surface 114

Granulation of the Sun's surface, showing blurring . . . . .121

CHAPTER VI.

Sun setting behind St. Paul's .122

Binocular vision ........... 122

Determining the distance of the Moon . 122

The relative distances of Mars and the Earth from the Sun . . . .122

The diurnal parallax of Mars 122

The diurnal parallax of Eros . 122

Plan of the Solar S3rstem 133

CHAPTER VII.

Distribution of Sun-spots in solar latitude 13^

Photographof a group of Sun-spots, July 31, 1906 130

Photograph of a group of Sun-spots, August 3, 1906 140

CHAPTER VIII.

The Corona of May 18, 1901 (southern region) leo

The Corona of May 18, 1901 (eastern region) 160

LIST OF ILLUSTRATIONS 15

CHAPTER IX.

PAGE

Path of rays throngh a prism . 169

Simple spectroscope ........... 169

Flan of simple spectroscope 169

Coincidence of D lines with sodium lines 170

Reversal of D lines in spectram of limelight 170

CHAPTER X.

Carves of Snn-spot Areas and Annual Rainfall 181

Corves of Sun-spot Areas and Magnetic Daily Ranges 181

Fhotc^raphic trace of magnetic storm, February 13, 1892 . . . .182

Corona of January 22, 1898, showing long rays 199

CHAPTER XI.

Jupiter and his satellites 200

CHAPTER XII.

Saturn 223

CHAPTER XIII.

Photograph of Douglas, Isle of Man, from balloon 224

Photograph of the Medway, Kent, from balloon 224

Drawings of Venus in 1871 247

CHAPTER XIV.

Photograph of the Moon, April 5, 1900 24S

Photograph of the Moon, September 12, 1903 253

Phob^raph of the Sea of Clouds 254

Photc^raphof the Moon's chief mountain ranges 257

Photograph of the lunar crater Copernicus 258

CHAPTER XV.

Photograph of Daniel's comet, August 10, 1907 267

Donati's comet, October S, 1858 268

Forms of cometary orbits .......••• 285

Halley's comet, from the Bayeuz tapestry 285

LIST OF ILLUSTRATIONS

CHAPTER XVI.

Photograph of the Milky Way around Alpha Centauri

PASS
286

CHAPTER XVII,

Photograph of the stars of the Plough 301

Drift of the stars of the Plough 301

CHAPTER XVIII.

Photograph of the great nebula in Orion ....... 302

Photographs of the nebulosities in Orion . 309

Photograph of the great nebula in Andromeda . . . . . .310

Photograph of the nebula about Nova Persei, September 20, 1901 . . . 315
Photograph of the nebula about Nova Persei, November 13, igoi . . . 315

Photograph of the comet of 1882 .316

Astrographic telescope of Greenwich Observatory ..... 321

Photograph of the stars of the Pleiades . . . . . . .322

Photograph of the nebulosities of the Pleiades ...... 325

Photograph of the exterior nebulosities of the Pleiades ..... 326

CHAPTER XIX.

Photograph of the Milky Way in Cygnus
Photograph of the region of Rho Ophiuchi .
Photograph of the region of Theta Ophiuchi
Photograph of the great rift near Theta Ophiuchi
Photograph of the great star cloud in Sagittarius .
Photograph of the small star cloud in Sagittarius .
Photograph of the region of cluster. Messier 1 1
Photograph of the Veil nebula in Cygnus

333
334
337
338
341
342
347
348

BOOK I

STORIES TOLD BY THE
HEAVENLY MOVEMENTS

CHAPTER I
THE STORY TOLD BY THE SUN

' T^HE sweet singer of Israel' long ago proclaimed
-■■ that the heavens had a message for us, some-
thing to say :

The heavens declare the glory of God ;
And the firmament showeth His handywork.
Day unto day uttereth speech,
Night unto night showeth knowledge.

Yet David was well aware that though the heavens had
this testimony to offer, it was not expressed in sounds,
He was not dreaming of any fancied 'music of the
spheres,' such as Shakespeare makes Lorenzo refer to in
The Merchant of Venice :

Look, how the floor of heaven.
Is thick inlaid with patines of bright gold ;
There 's not the smallest orb, which thou behold'st,
But in his motion like an angel sings.
Still quiring to the young-eyed cherubins :
Such harmony is in immortal souls ;
But, whilst this muddy vesture of decay
Doth grossly close it in, we cannot hear it.

David, on the contrary, knew

There is no speech nor language ;
Their voice cannot be heard.

19 B 2

20 STORIES BY HEAVENLY MOVEMENTS

And yet, in a very real sense, they were speaking to
those who cared to listen :

Their line is gone out through all the earth,
And their words to the end of the world.

This message of the glory of God, this testimony to
' His everlasting power and divinity,' is the first, the
most important, word which the heavenly bodies have to
make known to us. But they have also many other
' words,' much other ' knowledge,' to declare ; equally
without speech or language, or voice that can be heard,
and yet not hard to be understood if we listen for them
in the right way.

And men began so to listen from the very begin-
ning ; and astronomy, the study of the heavenly bodies,
began when there was first a reasoning human being to
look upon them. For there are two great lights in the
sky which it is impossible to overlook : the sun and the
moon. The first discoverer of the sun and of the moon
must have been none other than the first man, the first
living creature possessing intelligence, the first being
' made in the image of God.'

And he must have made this discovery in the begin-
ning of time. For the first use which man made of his
discovery of the sun and moon was to measure time.
Until he had noticed the sun, and that he seemed to
move, and was sometimes present and sometimes absent,
it was not possible to measure the lapse of time at all.

THE STORY TOLD BY THE SUN 21

So far as men were concerned, there was no time before
that. Astronomy therefore began with the first man,
and at the beginning of time ; for without the sun and
moon there is no means of dating, of reckoning time.
Our time is given us by the two great lights. It was for
this purpose that they had been originally made, for the
command had gone forth :

' Let there be lights in the firmament of the heaven
to divide the day from the night; and let them be for
signs, and for seasons, and for days, and years.'

But how is the sun ' for signs and for seasons' ? It
is quite clear how he is ' for days ' ; for when he is
present it is light, it is day ; and when he is absent, it is
darkness and night.

At first sight it is not easy to see what the sun can
tell us more than this, the difference between day and
night. The sun himself does not change in appearance.
He looks to-day exactly as he did yesterday, and one
part of the sky across which he seems to move looks
exactly like another. Since no voice is heard in his
story, it must be spelled out as from a writing. But
how can we spell out a story where all the letters from
A to Z are alike in shape ; where all the letters, words,
and sentences are joined together in a chapter con-
sisting of one unbroken, unswerving line ; where one
chapter is very like another ?

This was the difficulty which the first beginners in

2 2 STORIES BY HEAVENLY MOVEMENTS

astronomy had to encounter when they tried to spell
out the story that the sun had to tell. But little by
little they were able to do it, and we may, if we will,
put ourselves in their place, and watching the sun, as
with their eyes, read for ourselves what it was that the
sun had to tell them.

The book in which the story told by the sun is
written is the open sky, and the writing is simply the
apparent place in the sky where we see the sun at this
time or at that. The writing, therefore, is not all over
the page, the margins are broader than the text, and the
chapters are not all exactly alike. The sky, too, seems
to rest on the earth at its lower edge, and to rise from it
like a dome. The lower edge of the sky, therefore, is
marked out by objects on the earth ; and though one
part of the sky overhead looks, during the daytime, just
like another, the earth itself distinguishes one part of
the skyline from another.

Our first forefathers, then, when they tried to spell
out the story which the sun had to tell them, must have
taken their stand in the open, where they could see the
sky from horizon to horizon, and their first measuring
instrument must have been the apparent circle of the
earth. Let us do the same, and see what the sun can
tell us under such conditions.

For myself, a dweller in the smoke-laden air of
London, shut in by houses, the nearest spot from whence

THE STORY TOLD BY THE SUN 23

I can watch the whole open page upon which the story
told by the sun is written, is afforded by the ' Hilly
Fields,' a pleasant little park close at hand, on the top of
a rounded hill, that rises, like a miniature Ararat, above
the flood of bricks and mortar which has submerged all
the region round. Let us take our stand there, and see
what it is that the sun has to tell ; what the story that
he writes for us on the face of the sky. (See Pirate I.)

Towards the east the Hilly Fields look down rather
sharply on the valley of the Ravensbourne, the little
river that separates Surrey from Kent, flowing due
north to enter the Thames at Deptford Creek. The
tower of the town hall at Catford — the ford so shallow
that a cat would not object to cross it — rises almost due
south of us. We can trace the course of the stream by
the green spaces of the Recreation Ground, through
which it winds, until its course is broken by a tiny fall,
just at the foot of the venerable tower of St. Mary's
Church, Lewisham, nearly south-east of our position.
Further north, the course of the stream is hidden, but the
hills on the opposite side of the little valley are clearly
seen, and many good landmarks present themselves.

Starting from the north, there is, first of all, almost
due north, the spire of St. John's Church, in the Lewis-
ham High Road. Passing round to the east, Trinity
Church, Blackheath Hill, is 29° from the north point;
the spire of the Roman Catholic Church in Croom's

24 STORIES BY HEAVENLY MOVEMENTS

Hill lies 4° nearer the east. A little north of Trinity
Church rise the four tall chimneys of the generating
station which the London County Council so thought-
fully erected exactly on the meridian of Greenwich
Observatory. From 37° to 40° stretch the roofs of
Lansdowne Place. The trees of Greenwich Park hold
the horizon line next, and no special landmark can be
discerned until we come to the spire of St. John's
Church, St. John's Park, at 58°. All Saints' Church,
Blackheath, comes next at 66°; and St. James's, Kid-
brook, at 70°. The great line of Shooter's Hill forms a
background to these spires, and carries the tall chimney
of the Brook fever hospital on its western slope at
74°. St. Michael's, Blackheath Park, stands at 77°,
and the delicate spire of St. Margaret's, Lee, at 78°;
the Wesleyan Church, Albion Road, at 82°; Christ
Church, Lee, stands at 86°; Trinity Church, Lee, at
91°. Farther south, the Congregational Church in the
Lewisham High Street is at 111°, whilst St. Mary's,
Lewisham, is at 130°, and St. Mildred's, Burnt Ash Hill,
lies almost midway between the two at 123°; the
Catford Town Hall stands at 174°, and the Board
School at Rushey Green is precisely due south.

These spires and towers and houses stand up
against the eastern sky as marks to which we can refer
the sun when he comes up from the underworld at the
break of day. Each day, then, is a separate chapter in

I'LATI-: I.

('0

J,^-i.^..>.^../,^.aa?. ^,.",J, .i/&t...,^W. ,.t.

(I')

AN OPEN-AIR OliSERVATORY

The 'Hilly Fields' Park, London, S.E. Looking towards {<!) the north-east, and
(b) the south-east.

PLAFK II.

iVesr

Relation of ihe Divisions of the Clock-face, the Compass, and the Circle

THE STORY TOLD BY THE SUN 27

the sun's story, each rising point is the heading and
opening of the chapter, and there are 365 chapters
in all.

We may begin to read our book where we will, and,
for the greater convenience in the reading, we will begin
in spring-time. It is March 21, and the sun rises at six
o'clock. We see it first appear over the high ground to
the east, midway between Trinity Church, Lee, and St.
Mark's ; in a word, almost due east of us. He does not
climb up straight into the sky, but obliquely, with an
ascent of 4 in 5, or at an angle of 38^°, equal to the
angle between the figure XII on a clock and a point
nearly 6^ minutes from it. {See Plate II.)

When the sun rises the next morning, his rising point
is not quite the same, but is shifted slightly towards the
north. Morning by morning his rising point shifts, and
in less than a week the sun rises over Christ Church,
Lee. A fortnight later, and St. Margaret's, Lee, marks
his point of first appearance, and two mornings later still,
St. Michael's, Blackheath, Every succeeding morning
shows a slight movement northward of the rising point,
until, a month after the first observation, the spire of St.
James's, Kidbrook, gives the signal for the sun's first
appearance, and we see that the paths followed by the
sun, in his daily travel from east to west, are not the
same on succeeding days, but lie close to each other,
much as cotton is wound upon a reel.

28 STORIES BY HEAVENLY MOVEMENTS

But, as the summer draws on, this northerly move-
ment becomes less marked. The movement amounted
to nearly 20° in the first month of observation ; it is
only a little over 14° in the second month, and after that
it becomes very slow. The Colfe Grammar School is
reached in the middle of June, when the sun rises 40°
north of due east, only 5° short of the north-east point.
And now we seem to have come to the end of the reel,
and one turn of the cotton is piled on the top of the
preceding one, so as to start another layer, for in ten
days in June there is less movement than was observed
from one morning to the next in March, and in the last
ten days of June this movement, small as it is, is not
northward, but back again towards the south. But
though the sun rises now so far from the point of the
horizon where he rose in March, his daily path, as he
moves upward in the sky, still slants as it did then, at an
incline of 4 in 5, that is, at an angle of 38^° to the
horizon. {See Plate III., fig. i.)

Day by day, during these three months, March 21
to June 21, the sun has risen earlier. It rose at six
o'clock on March 21, it rose before five on April 21, and
at four o'clock on May 21. After this there was little
change in the time of its rising, and it was a quarter to
four when it rose on June 21.

Day by day, during these three months, the setting
points of the sun have moved northward along the

THE STORY TOLD BY THE SUN 29

western horizon, to correspond with the movement of
the rising points along the eastern, and the sun has
set later each day. On March 2^1 he set soon after
six o'clock, and very nearly due west. On April 2 1 he
did not set until after seven, and he went down 19°
north of the west point. On May 2 1 it was nearly eight
o'clock before he set, at 33^° north of west. On June 21
he did not go down until eighteen minutes past eight,
and his setting point was 40° north of west. Thus the
days were longer as the time went by, lengthening out
from twelve hours in March to fourteen in April, to
almost sixteen in May, and to sixteen and a half hours
on June 21.

But, throughout, the inclination to the horizon of the
sun's path was the same at rising, the same at setting :
an inclination of 4 in 5, or of 38^°.

At midday, when the sun was highest in the sky,
and the shadows cast were shortest, he was always due
south, straight over the Board School at Rushey Green.
And on March 21, when he rose almost due east
and set almost due west, he reached just this same
elevation of 38^° from the horizon when he was due
south ; an upright stick four feet long would cast a
shadow five feet in length ; the sun's elevation was four
in five.

But his noon-tide elevation on April 21 was very
different. Then it was necessary to look up much

30 STORIES BY HEAVENLY MOVEMENTS

higher in order to see him, and the shadow cast by a
stick four feet in length, instead of being five feet long,
was only three feet four inches. By May 21, the sun's
elevation at noon was greater still, and the shadows
were shorter : two feet five inches instead of five feet.
On June 21 he was higher still, and the four-foot staff
would throw a shadow only very little more than two
feet long. {See Plate III., fig. 2.)

After June 21 the sun begins to turn back over his
old course ; a second layer of cotton is being wound over
the first. Each morning his rising place is a little farther
to the south ; each midday his height is a little less, and
the shadows are a little longer ; each evening his setting
place is a little farther south. His path on July 23 is
the same as it was on May 21 ; on August 22 as on
April 21 ; on September 23 as on March 21. He then
again rises about due east, attains a height of 38^° at
midday, and sets again about due west after a twelve-
hour day.

But as autumn fades into winter he still continues
his southerly course. He rises above the Congregational
Church in the Lewisham High Street on October 28 ;
the day is only ten hours long, and his setting point
is 21° south of west. So, day by day, his rising point
moves southward, his daily path is shorter, his midday
height less, his setting point closer to the south-west;
until, by December 22, he has reached his limit, and

PLATE III.

-3

c
s
en

PLATE IV.

^of>r^

THE STORY TOLD BY THE SUN 33

rises over St. Mary's Church, Lewisham, at six minutes
past eight; he is' only 15° high at noon, a four-foot
staff casting a shadow close on fifteen feet in length,
and he sets, after a day of seven hours and three-
quarters, 40° south of the west point. Then again he
turns back, winding his coil northwards, until the
book of his year is finished in March, and a new year
is begun.

Shakespeare refers to this change in the sun's place
of rising when' he describes the meeting of the con-
spirators in the orchard of Brutus, before the dawning
of that fatal day whereon great Caesar fell. The time
is supposed to be not yet three o'clock in the morning,
and the date is the Ides of March, when the sun should
not begin to rise until about three hours later; but
Decius says :

Here lies the east : doth not the day break here ?

Casca says, ' No,' and Cinna replies :

O, pardon, sir, it doth ; and yon grey lines
That fret the clouds are messengers of day.

Casca rejoins :

You shall confess that you are both deceived :
Here, as I point my sword, the sun arises ;
Which is a great way growing on the south.
Weighing the youthful season of the year.
Some two months hence up higher towards the north
He first presents his fire ; and the high east
Stands, as the Capitol, directly here.

34 STORIES BY HEAVENLY MOVEMENTS

But long before the day of either Shakespeare or
Caesar, men were wont, both in this land and in others,
to ' weigh the season of the year ' by the place of the
sun's rising behind the landmarks of the horizon. What
we have been doing on the Hilly Fields, and using
the church spires of St. Margaret and St. Mary, the
chimneys of the London County Council, or the water
tower at Catford, in the doing, so men did long ago
on Salisbury Plain, though we do not know whether the
men were the Britons whom Caesar fought, or another
and unknown race. For this they reared up the great
circle of stones called Stonehenge. Just as they used
the horizon as their measuring instrument, and the
great stones as a graduation on it, so we use the
horizon, with the spires and chimneys and towers out-
lined on it, as our measuring instrument. And the sun
repeats to us the story that he told long ago to them.

This, then, is the first story which the sun tells to
men ; namely, that he has his appointed paths in the
sky. He does not cross it at haphazard, rising any-
where, setting anywhere ; but for each day in the year
he has a definite rising point, a definite setting point, a
definite path between the two. For each day in the year
there are definite points of the compass at which the sun
rises and sets, and these points are the same for that day
year after year. There is a defined region on the
eastern horizon along which the sun's rising shifts in

THE STORY TOLD BY THE SUN 35

regular order, and beyond which it never strays. In the
words of Job, ' the dayspring is made to know its
place.' The path of the sun up the sky, or down it,
slants each day to the horizon in exactly the same way.
The daily paths of the sun through the sky in the year
form an unshifting, unchanging band of even width,
the same band from year to year ; and the width of this
band is 47°, or like the arc between two clock-hands
pointing nearly eight minutes apart. {See Plate IV.)

If we leave the Hilly Fields and go northward
towards the pole, or southwards towards the equator,
we find that each * dayspring' throughout the year has its
appointed 'place,' just as it had at the Hilly Fields. The
slant of the sun's path has altered, sloping still more
as we go north, and becoming more erect as we go
south. The sun's band is unaltered ; the difference
between the heights of the sun at noon in midwinter
and midsummer is always the same : 47°, or nearly
eight minutes between the hands on our clock. • The
band of the sun's daily paths is unchanged in breadth ;
it is merely swerving down or up in the sky.

These daily paths of the sun tell our directions on
the earth. For he rises in the east, — on March 2 1 and
September 21 due east. When he has reached his
greatest height for the day, no matter what the season
of the year, he is due south. He sets in the west, — on
March 21 and September 21 due west.

36 STORIES BY HEAVENLY MOVEMENTS

The sun also marks out for us two great circles in
the sky, the equator and ecliptic. The first is the
central line of the sun's band, which, passing through
the east and west points, is to the celestial vault
what the terrestrial equator is on the earth. The one
is, indeed, a projection of the other, and their poles
point in the same direction. The ecliptic is another
circle intersecting the celestial equator and so inclined
to it that the angle between the two circles is half
the width of the sun's band ; that is to say, the
angle between them is 23^°, or the angle that there
is between two clock-hands pointing nearly four minutes
apart.

And the sun tells us what is the shape of the earth.
If the earth were flat, then the sun's path, as he rose
in the east, would be inclined to the horizon line at
the same angle wherever we were. It would also be
inclined at a constant angle to the vertical, the direction
given by a plumb-line, which is, of course, at right
angles to the horizon line. But we find that as we
move northward or southward the inclination of this
path varies. As we go north, the sun mounts the sky
more gradually ; as we go south, the slant of his path
becomes steeper.

But as it is the same sun that we see, whether
we watch him from Cape Wrath, or from Land's End,
or from Gibraltar, and the path that he follows is the

THE STORY TOLD BY THE SUN 37

same in each case, it must be the plumb-line, and by
similar reasoning the horizon also, that changes its
inclination. The earth, therefore, is not a level plane,
but its surface at one place is inclined at an angle to
its surface at another. And this is true of the surface
of the water as well as of the land, for the sun's path
shows this change of inclination to different parts of
the sea just as clearly. The surface both of land and
sea is thus gently bent into a great and regular curve,
showing the earth to be a globe, just as the vault of
heaven above us appears to be a hollow sphere. {See
Plate V., figs, i and 2.)

The sun also tells us our latitude on the earth. For
just so far as the path that the sun traces out in the sky
on March 21 or September 21 lies above the horizon,
just so high as is the sun at noon on one of these days,
just so many degrees of latitude lie between our stand-
point and the north pole of the earth. In much the
same way the sun tells us the size of the earth. The
problem was actually worked out more than two
thousand years ago by Eratosthenes, who noticed that
the sun was exactly overhead at noonday at midsummer
at Syene, now Assuan, where the first cataract of the
Nile occurs. At the same time the sun was 7 degrees
and one-fifth of a degree from the zenith, i.e. the overhead
point, at Alexandria, due north of Syene. The distance
between the two places in a north and south line had

38 STORIES BY HEAVENLY MOVEMENTS

been measured as 5,000 stadia. Since 7^° is the fiftieth
part of 360° the entire circumference of the earth must
be 250,000 stadia. Our present measures give this
circumference as nearly 25,000 miles ; whence 10 stadia
should equal one mile. The sun therefore told men not
only the shape of the earth, but also its size,

A question that men very early asked was, ' Where
does the sun go to when he sets ? whence does he come
when he rises ? ' The answer is soon given : he comes
from the ' under world ' ; he passes below the earth. His
path during the twenty-four hours is a complete circle, of
which we see only the part that he traverses during the
day. In winter time, when he is up for less than eight
hours, two-thirds of that circle is below the earth ; in
summer time, when the day is sixteen hours long, only
one-third of that circle is below. ' His going forth is
from the end of the heaven, and his circuit unto the ends
of it.'

The sun therefore tells us that there is a clear way
under the earth. Does that clear way extend every-
where, right from the north to the south ? That
question the sun cannot answer for us. Watching him
from the Hilly Fields, it would be possible to imagine
that, far to the north, the earth rested on some great
pillar, or support, and far to the south upon another.
This was the very idea which the Babylonians held of
old: they thought the earth stood upon two great

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PLATE VI.

THE STORY TOLD BY THE SUN 41

mountains, and that the sun passed every night through
a vast tunnel or valley that lay between them. Two
great scorpion men — so they imagined to themselves —
stood on either side of this tunnel, or valley, at the gate
of the west, and guarded the entrance to the under
world, the abode of the dead.

So the sun has a full story to tell, a story told merely
by the path which he follows day after day across the
unmarked heavens. He tellS men that the ea,rth on
which they dwell is a round globe, some 25,000 piiles in
circuit; he tells them that, for the most part at least,
the earth is unsupported in space ; there is a clear way
under it. The sun, too, is not free to wander anywhere
in the sky ; he has a rigidly appointed path, a path
which differs indeed from one day to the next, but is
definitely fixed for each day throughout the year. For
these changes of path run through a definite cycle which
is completed in a year ; after which they recur again in
their former order. The movements of the sun are all
in obedience to an unswerving law. He is set 'f6r
signs and for seasons, and for days and for years.'

CHAPTER II
THE STORY TOLD BY THE MOON

How like a queen comes forth the lovely moon,
Walking in beauty to her midnight throne !

Croly.

WE do not need the help of the telescope to demon-
strate to us the difference in appearance between
the sun and the moon. They are the ' two great lights '
set in the heavens ; but whilst the ' greater light ' is
overpoweringly bright, we can look without flinching at
the gentler radiance of the ' lesser.' From the earliest
time that there have been men upon the earth, they have
recognized two things about the moon. Her face was
marked with spots or stains, showing like a map — marks
that never changed. But whilst these marks or spots
did not change, the moon herself changed. Sometimes
she presented a broad, shining face, as round as the
sun himself. Sometimes she showed only a narrow arch
of light, the thin outline of a semi-circle.

These changes, or ' phases,' of the moon are obvious,
and it is impossible to overlook them ; they were as

THE STORY TOLD BY THE MOON 43

manifest to our forefathers before the Flood as to our-
selves to-day. They are the letters by which the moon
spells out her story to us ; and the reading of that story,
the intelligent watching of the phases of the nioon, is
astronomy — a small department of astronomy indeed,
but quite a real one. The unintelligent watching of the
phases of the moon produces myth and fable — very
beautiful myths and fables, it may be, but unreal and
unfruitful.

One of the most beautiful of these lunar myths was
told by the Babylonians in the song of the Descent of
Istar. Istar is described as the daughter of the Moon
god, and among the Phoenician nations was called
Ashtoreth, sometimes even Ashtoreth Karnaim, or
' Ashtoreth of the Horns.' The legend runs that Istar
fixed her mind to go down

To the House of Eternity,
To the House men enter — but cannot depart from ;
To the Road men go — ^but cannot return.
The abode of darkness and famine,
Where earth is their food : their nourishment clay,
Light is not seen: in darkness they dwell.
Ghosts like birds flutter their wings there,
On the door and gateposts the dust lies undisturbed.

Bright Istar descended through seven portals, but as
she passed through each the porter made her shed, bit
by bit, her jewels and her shining raiment, until when
she reached the abode of darkness, she was bereft of

44 STORIES BY HEAVENLY MOVEMENTS

everything. Then in the full assembly of the gods,
the Sun came along with the Moon, his father, and
weeping, spoke unto Hea, the king of the under world,
and he bade that I star should be allowed to come forth
again. Again she passed back through the seven
portals, and as she passed, the porters readorned her,
bit by bit, with her jewels and her shining raiment,
until at last she stood forth again, ' walking in beauty
to her midnight throne,' in all her brightness and
glory.

The story is beautiful, but it is the story of fancy,
not of knowledge ; it is not the story that the moon is
writing for us to read. What she really tells us is that
her changes of brightness depend absolutely upon the
changes in her seeming distance from the sun. He it is
who is responsible for her growth in breadth and bright-
ness, from the thin arch of light which she shows at one
time, to the full round shield we see a fortnight later ;
and then to her decrease again from that full circle to
the thin curve in the fortnight which follows.

We shall see this plainly if we watch the moon night
after night. It may be that some evening, soon after
the sun has set, we see the moon as a narrow crescent
in the western sky. If we think of the bright arch as a
bow stretched for the shooting, then the point of the
unseen arrow would be directed towards the place
where the sun, now below the horizon, must be. The

THE STORY TOLD BY THE MOON 45

middle of the arch of the bow looks towards the sun.
{See Plate VI.)

The next evening, when the moon is first seen, she
is higher above the western horizon than she was on the
first evening, and she sets later. At the same time, her
arch of light is not quite so narrow. The third evening
she sets later still, and her bow is broader. Now she is
still above the horizon when the stars begin to appear,
and we can see her position with respect to them.

The same change continues to progress on the
following evenings : each succeeding night we see that
the moon has moved towards the east quite a long way
amongst the stars — fully twenty times her own diameter.
Each succeeding night we see that she is higher in
the sky at the time of sunset, she sets later, and
fuller and rounder does her disc become. At length the
time comes when she is the entire breadth of the sky
away from the sun ; she rises as he sets, and does not
set until he is about to rise on the following morning.
She rides the sky the whole night through, and her circle
is complete; she is 'full.' Then is she truly the queen
of night. Sometimes the sun and the full moon are
seen together, the one resting on the western horizon
and the other on the eastern.

After this the moon rises later night after night, and
does not set until after the sun has risen on the next
morning. She still moves eastward amongst the stars,

46 STORIES BY HEAVENLY MOVEMENTS

but she begins to shrink in her seeming size. When
seen earlier in the month it was her western edge that
was rounded, and the eastern dark; now it is the
western edge that begins to shrink, whilst the eastern
keeps its full curve.

Most people looking at the full moon think that it
looks like a rather sad face. Two large, dark eyes are
seen above a large and somewhat distorted mouth,
twisted with a rather pained expression, towards the
right of the face. Over the left eye, and quite near the
side of the face, is seen a small, round, dark spot. This
small spot was observed when the moon was only a
few days old, but it is not seen long after the moon
has become full. As the light passes from the more
westerly edge, it withdraws from this spot, which is
not seen again until the early days of another month.
{See Plate VII.)

During the mornings of the later part of the month
the moon rises later and later, appearing to come
closer and closer towards the sun, and at the same
time the narrower becomes the arch of light which she
displays, until she is seen, just before daybreak, a mere
thin, semi-circular line of light, slanted towards the
eastern horizon, where the sun is about to appear. The
next three or four nights no moon is seen at all ; morning
and evening the sun rides the sky alone. Then comes
an evening when once again a narrow crescent is seen in

PLATK \-II.

SOUTH
Photograph of Full Moon (erect as seen in the sky)

PLATE VIII.

o 5

NEW MOON

MEW CPESCENT /
MOON I

FIRST QUARTER

GIBBOUS MOON
BETORE FULL

S to T

I a

FULL MOON

, THIRD OR LAST (
\ QUARTER '

OLD DE.-CRE5CENT /
MOON \

iSt

NEW MOON

THE STORY TOLD BY THE MOON 49

the sky, with its bow bent towards the western horizon
where the sun has just gone down. It is by the associa-
tion together of these several things that the moon tells
us her story — tells us that she shines by no light of her
own, but by reflecting to us the light of the sun.

We know these things by seeing that in every month
there is a continual change in the position of the moon
in the sky relative to the sun and to the stars, and in
the shape of the illuminated figure which she shows us.
In the first part of the month she is seen in the sky
when the sun sets, or before, and day by day she sets
later, thus getting farther and farther away from the
sun. Day by day she also gets fuller and fuller. Then
comes the time when she is exactly opposite the sun,
rising as he sets and setting as he rises ; and at this
time of the month she is full, because she is turning the
same face to the sun as she turns to the earth. After
this she rises later and later every evening, and appears
to come closer and closer to the sun on the other side,
and at the same time her illuminated face begins to
diminish. There is no way of accounting for this
invariable association between the apparent place, relative
to the sun, of the moon in the sky, and the change in
her light, except by supposing that she is herself dark,
and reflects his light. {See Plate VIII.)

The moon also tells us that she is a round globe, not
a mere flat disc, like a plate. For the change in her

5° STORIES BY HEAVENLY MOVEMENTS

seeming shape is exactly the change which takes place
when a dark globe is placed in different positions with
respect to a strong light ; the curves shown by the
moon's defective edge are the curves which would be
shown by the illuminated part of such a globe as seen
from different directions.

Yet again, the moon tells us that she moves round
the earth ; not merely as the sun and the stars seem to
do — once every day; but she moves past the sun and
the stars, her seeming motion in the sky day by day
being slower than that of either star or sun. And as the
moon moves round the earth she always turns the same
face towards us ; the markings on her surface do not
change their shape or, perceptibly, their position ; more
or less may be visible of them as the moon is more or
less fully lighted up, but the markings themselves do
not change.

This is a wonderful thing to have learned from the
moon : that she is, of herself, a dark body, and not a
' light ' at all. If we could imagine that the sun had
become cold and dark we should never know of the
existence of the moon, unless we guessed it by noting,
after very careful watching, that the stars here and there
were blotted out for a few minutes at a time. We could
not talk with Croly of the lovely moon walking as a queen
in beauty to her midnight throne; we should rather
think that the starry heavens were haunted by a lurking

THE STORY TOLD BY THE MOON 51

thief who was continually pocketing the diamonds of the
celestial treasure-house, and then dropping them again
through the holes of his ragged pouch.

In the legend of the Descent of Istar, seven times
did she go through the portals of the east, each time
shedding a portion of her glory ; seven times was she
seen at the portals of the west in ever-increasing splen-
dour. So the Babylonians conceived that the moon
ruled as queen of the night, from her midnight throne in
the upper world, during the fortnight from half-moon,
through full, to half-moon again. Then for seven days,
gradually discarding her glory from day to day, she
descended towards the abode of darkness, where she
remained unseen and lost until summoned forth by the
sun. For seven days more, day by day, her glory was
gradually restored to her, until, half-full again, she lit
up the darkest hours of the night.

For it is the full moon that rules the night : when
she fully reflects the light of the sun, she gives that light
to the earth from sun setting to sun rising. In the city
of the New Jerusalem we are told that 'the city had no
need of the sun, neither of the moon, to shine in it.* In
our cities to-day we certainly need the light of the sun,
but we seem not to need the light of the moon ; in the
houses and in the streets there are artificial lights
enough to make us indifferent as to whether the moon
is shining or not, to make us even unaware of its

52 STORIES BY HEAVENLY MOVEMENTS

presence. But in the country it is not so : men cannot
work on the nights when sun and moon have gone down
together ; men will stumble when they even walk abroad.
A writer, telling recently of his travels in Russia,
mentions what seemed to him to be a crowning hardship
of the poverty-stricken peasants. For, being too poor
to afford even a rushlight on the long, dark, winter,
moonless nights, there was nothing possible for them
to do but to stay in bed from the early setting of the
sun until the late break of day, even though the hours
of daylight were too short for all that needed to be done
in them.

The full moon is opposite to the sun : she sets as he
rises, she rises as he sets ; at midnight we may, then.

Behold the wandering moon
Riding near her highest noon.

Through the heaven's wide pathless way.

When the moon is full she not only gives most light, but
she gives it for the greatest length of time ; and in the
night time, when there is no sunlight. Moreover, she is
up the longest and rides nearest her highest noon in the
winter time. For then the sun dips lowest below the
horizon at midnight, and the full moon, being opposite
to him, climbs to her highest, most nearly to the zenith.
Within the Arctic Circle, during the long night which
lasts through the whole winter, though the days are

THE STORY TOLD BY THE MOON 53

unmarked, the months are divided into two fortnights —
the one when it is always Hght, and the other when it is
always dark. In the one : —

Mark, what radiant state she spreads.
In circle round her shining throne,
Shooting her beams like silver threads ;
This, this is she alone,
Sitting like a goddess bright.
In the centre of her light.

She is then Istar, queen of Heaven, reigning in the
upper world, continuously clad in her shining robes of
state. In the other, she is Istar of the Descent, shorn
of her beams, abiding in darkness, and leaving the world
in darkness.

Speaking precisely, the moon is ' new ' when she is
in conjunction, that is, when she is between the sun
and the earth, and — turning her dark side towards us —
is invisible. But, generally, the young moon that is first
visible after conjunction with the sun is termed the
' new moon,' and such will be the meaning that we will
ascribe to it.

The ' new moon ' is, then, a very slender crescent
of light, so slender that it cannot be seen in sunlight.
It lies to the east of the sun, and, therefore, is seen over
the western horizon, a little above the point where the
sun has very lately gone down. If the conjunction of
sun and moon occurred eighteen hours before sunset,
it might be possible to perceive for a few minutes

54 STORIES BY HEAVENLY MOVEMENTS

before it sets the thin crescent of the moon, in the
twilight of the same evening ; but if the time between
conjunction and sunset were less than eighteen hours,
then the moon's bow could not be seen until the follow-
ing evening. Thus the interval of time between one
new moon and another is uncertain by a day.

Many of the ancient nations — the Jews, Babylonians,
and Assyrians — used true lunar months ; not months of
arbitrary lengths, as we do to-day. To these ancient
nations the month began in the evening : it began with
the observation of the first thin crescent of the young
moon. The month contained a number of complete
days ; but this number was sometimes twenty-nine days
and sometimes thirty, and they could not tell for long
beforehand which months would have the one number
of days, and which the other.

Our rule for telling the number of days in our
months runs thus —

Thirty days hath September,
April, June, and November,
All the rest have thirty-one,
February has twenty-eight alone ;
But Leap Year coming once in four —
February's days are one day more.

No such simple and general rule was possible for the
Babylonian months, but yet these had several advan-
tages of their own. There was then no need, with

THE STORY TOLD BY THE MOON 55

Bottom, in A Midsummer Night's Dream, to cry
out —

A calendar, a calendar ! look in the almanac,
Find out moonshine, find out moonshine !

For the calendar was based on moonshine, and the day
was dated according to the amount of moonshine, and by
the time when the moon rose or set. When the moon
was growing, and set before the middle of the night,
those were the early days of the month. When the
moon was full, and set as the sun rose, or rose as the
sun set, that was the fourteenth or fifteenth day of
the month, and then only could an eclipse of the moon
take place. When the waning moon rode in the
morning hours of the night, this was a sign that the
month was drawing to a close, and when it had wholly
vanished, on the twenty-eighth or twenty-ninth days of
the month, then only could an eclipse of the sun occur.
Moreover, from observing on the fourteenth or fifteenth
days of the month whether the moon set or not before
the sun rose, it could be judged whether or no that
month would contain thirty days. We have a report to
this effect from Balasi, an ancient Assyrian astronomer,
which runs : ' When the moon is not seen with the sun
on the fourteenth day of Adar, the day will complete
Nisan.' And this is interpreted to mean that that
month of Adar would contain thirty days.

56 STORIES BY HEAVENLY MOVEMENTS

If we frequently measure the time from one obser-
vation of the new moon until the next, we find that the
number of days is either twenty-nine or thirty, so we
cannot from this find out the true length of the month, or
learn whether the months are all equally long, since there
is an uncertainty of a full day in the observation itself.
But if we try to measure the time of the other phases ;
if, for instance, we take the time from the waxing moon
being exactly half full, until the waning moon is exactly
half full again, we shall find that this ' fortnight ' is not the
same length in every month. In other words, the moon
moves more quickly round the earth at some points of her
path than at others, and she passes through her phases
at a varying pace ; and being at some times nearer to
the earth than at others, she sometimes looks larger.

We do not know if the romantic writers of old
Assyria treated the moon, upon whom all true lovers
call, as erratically as do some novelists of the present
day. Probably not, for they could not have failed to
know that the young crescent moon is never seen to rise,
or the thin arch of the old moon to set, and neither
are ever seen high in the sky. If, in the morning dawn,
before daybreak, we glimpse in the east a pale arc of
light, we are sure that it is not the crescent, the young
moon, but the decrescent, the old moon, soon to be lost in
the rays of the pursuing sun. And since the moon is
always the same solid globe, whether it is wholly lighted

THE STORY TOLD BY THE MOON 57

up, or only just touched with a thread of sunlight, it is
impossible that we should ever see a star through its
bulk, as the Ancient Mariner declared he had done,
when he described

The hornM moon, with one bright star
Within the nether tip.

The story told by the moon, therefore, is that the
heavens contain dark bodies, as well as bright, and that
she is one of the former, shining not by her own light,
but by the light shed upon her by the sun. So, lighted
by him, she travels through space unceasingly, a great
round ball, unsupported by any pillars ; travels round
the earth, but always turns the same face towards it,
though she does not turn the same face always to
the sun.

CHAPTER III
THE STORY TOLD BY THE STARS

THE day sky is the page on which the sun writes his
story. His writing does not cover all the page,
but is kept within an even band of closely inscribed
text. The margins of his page are very broad and fair
and clean.

But if we turn to the night sky, we find that this
page is written over also, but the handwritings here are
by other writers than the sun, and the page has no
margins. We have learnt to understand a little the
language of the sun's book ; with this knowledge we
can also begin

To read the page
Where every letter is a glittering world.

The sun has just gone down behind the western bar,
but his light is left behind. North, east, south, and
overhead the sky is a deep blue, but in the west there
is a rosy glow. Nothing else is to be seen. The blue
deepens and the rosy glow fades ; and, first here, then

THE STORY TOLD BY THE STARS 59

there, perhaps in the darkest east, or the clear zenith, or
even in the light from the sun long set, there seems to
be set a pin-point spark of light, fighting for its light to
shine out even in the overpowering light left by the sun.
And, as the straggling sunbeams are summoned below
the western steep, hundreds of other stars spring out, as
if from ambush, to harass and hustle away the rearguard
of a retreating force.

Where do the stars of twilight spring from ? Have
they been there in ambush all the time, whilst the sun
was marching across the day sky ? or are they merely his
camp-followers, keeping to his rear, but straggling over
the whole region in the midst of which his road lies ?
We are under no doubt as to whether or not the sun
is present. He ascends in pomp above the eastern
bar ; he marches in solitary state across the sky ; none
but the moon is ever seen to make any approach to him.
But what about the stars ? Can we tell if they are there,
in hiding, in the sunlight? Can we tell if these are
forming an invisible escort to the sun ? If they, too,
like the sun, write a history of their daily travel, how
can we tell the different histories, and the different stars,
from each other ?

As the daylight fades, the stars are seen not near the
low east only, but overhead, or in the north, or south, or
even in the west. They have not, then, rushed up from
the under world as the sun goes down, but they are there

6o STORIES BY HEAVENLY MOVEMENTS

already. They have been there, but hidden in the
sunlight. As we watch them, and the daylight fades,
we see that they are moving ; whether they are overhead
or in the east, or south, or west, they are all moving
towards the western skyline. Above the eastern skyline
we see new stars climb ; below the western horizon we
see the stars, that we have been watching, descend.
Not so in the north. Here all the stars indeed move ;
but some are moving west, some north, some south,
and some east.

We began to read the story of the sun by watching
his rising in the east. Let us begin to read the stories
of the stars in the same way. And the first thing that
we note is a difference between the two. The day-dawn
is the messenger of the sun : he sends his beams to
herald his approach. So great is his pomp and
splendour that, silent as it is, there seems appropriate-
ness in the expression of one writer that —

The dawn comes up like thunder.

But with the stars there is none of this. Just above the
eastern skyline, one moment there is no star ; the next,
there is a star. It was not, and it is. And as we watch
the east, from the extremest south, even to the farthest
north, we see them thus rising at its every point, a
single scoiit there, a company here, all coming from
below and mounting into the sky.

THE STORY TOLD BY THE STARS 6i

If we keep our watch on the east through all the
long hours of the night, we see the silent ascent of
the stars go on, until the horizon begins to pale, and
the glitter of the stars seems swallowed up in the
brightness of the dawn. One or two of the most
brilliant we can hold steadily until they, too, are lost
in the rays of the rising sun.

Are they all different, these stars that we have been
watching rise through the long night ? Have many of
them, have any of them, risen for us a second time as
we watched? How are we to tell one star from another?
How are we to recognize a star when we see it ? The
sun needs no label, but how are we to name the stars ?
We can see no difference between one star and another,
except in brightness. Can we tell whether the stars,
like the moon, wax and wane ?

Then follow one up from the east. Like the sun,
it climbs the ascent of heaven obliquely; its path is
slanted to the horizon at the same angle of 38^°, at
the same inclination of 4 in 5, if we are watching from
the Hilly Fields, or anywhere in the latitude of London.
It mounts the sky until it hangs due south, then it
descends and drops slantingly below the western horizon
at the same angle that it mounted. If we follow the
course of another star, it rises, perhaps, from a very
different point of the eastern skyline, but it slants
upwards at the same angle as did the sun or the other

62 STORIES BY HEAVENLY MOVEMENTS

star ; it reaches the highest point of its path when due
south, and it sinks down below the west by the same
inclined path. The stars may be of very different
brightness, they may rise and set at different points of
the skyline, they may mount to different heights; but
they all mount and fall at the same steady, even pace,
by the same slant of path.

Here, then, are the means by which we may
distinguish the stars. They do not jostle or hurry
each other, they keep an even pace, at unchanging
distance from each other. In the north are many stars
that do not rise or set, but move round in an unending
circle ; yet the stars that rise and set never alter their
distances from these, whilst we see them above the
skyline.

The stars never alter their distances from each other,
and the stars differ in brightness. We can, then, fancy
patterns or pictures nailed by the stars to the sky, and
recognize the pattern again by the way the nails are
driven in. Look, for instance, at the stars in the north.
There are seven very brilliant stars swinging round in
the sky every night ; four of them are in a rough oblong
like a country cart, three others curve like the shaft of
the cart. These never change in brightness ; we can
recognize the seven again and again, and call them by
the name of the Plough, or the Wain, or the Ladle, or
the Dipper, as the fancy takes us. {See Plate LV.)

PLATE IX.

PLATE X.

THE STORY TOLD BY THE STARS 65

In the same circle swings another set of five stars, not
so bright, in the shape of a sprawling W. This we may
fancy marks the Chair of a Lady enthroned in it. {See
Plate IX.) Farther to the south, amongst the stars
that rise and set, we see a very little V-shaped group,
of which none of the stars, except a yellow one at the
end of one of the prongs, is very bright ; following it is
another little cluster of six stars, so close together that,
as Tennyson sings of them, they seem

Like a swarm of fireflies tangled in a silver braid.

We may imagine that we have a bull's head, outlined by
the V-shaped group, and that its brightest/ star is the
eye of the bull. The little cluster of brilliants we may
fancy as a cluster of doves, or of maidens, or of grapes,
sheltering on the shoulder of the bull. A bull's head
is not really pictured here, any more than a man
whose name is Smith is therefore an artificer in
metals, but that is the name that has been given to the
constellation, or grouping, of the stars. The reason
why this name was given has a history of its own. {See
Plate X.)

So the stars scattered oyer the sky are constellated
or divided out into groups ; and names, fanciful names
they seem, are given to the different groups. The
individual stars are recognized by their positions in or
near the groups.

66 STORIES BY HEAVENLY MOVEMENTS

As the stars rise in the east we can recognize them
by their places in the star groupings, and we can
definitely tell that they do not rise oftener than once in
the twenty-four hours. Night after night, as we watch
them, we see that though, like the sun, they always rise
with the same slant to the skyline, yet, unlike the sun,
they do not shift their points of rising. At whatever
point of the compass a star rises on one night, on every
other night, and through the whole year round, it rises
at that same. It makes the same slant in its path as
does the sun, and makes its round in nearly the same
time. Nearly, but not quite ; for, as we watch the stars,
dawn by dawn, that are last seen in the morning twilight
near the sun, we notice at each break of day they are
seen for a longer time, until they lose their pre-eminence,
and other stars, nearer the rising sun, are seen. And
evening by evening, the stars near the west, where the
sun has set, are ever becoming less clearly seen, ever
drawing into the sunlight, until they are glimpsed no
longer. As the seasons pass, new stars occupy these
positions, until as the year comes round we recognize
again the stars we first saw. Each season, each time of
the year, is marked by the setting and rising together of
the sun and certain stars. For the stars gain on the
sun, just as the sun gained on the moon ; as the moon
made one round of the sky in each month fewer than the
sun did, so the sun makes one round of the sky in each

THE STORY TOLD BY THE STARS 67

year fewer than the stars do. The sun moves amongst
the stars.

The stars last seen in morning twilight, those rising
just before sunrise, are said to be rising heliacally. The
stars just seen in the evening twilight, setting where the
sun has set, are said to be setting heliacally. The stars
that rise as the sun sets, and set as he rises, are said to
rise and set acronychally.

By means of the stars that rise and set heliacally, we
can trace those amongst which the sun's path seems to
be laid, and the belt of constellations through which his
path, which is called the ecliptic, seems to lie is known
as the Zodiac. These constellations are twelve in
number, and form a complete band round the sky.
Their names are preserved in the old rhyme —

The Ram, the Bull, the Heavenly Twins,
And next the Crab, the Lion, shines,

The Virgin and the Scales ; '

The Scorpion, Archer, and Sea-goat,
The Man that pours the water out,

And Fish with gUttering tails.

If we watch a star rising at the point on the horizon
which is due east, and take its height when it souths,
we find, at the Hilly Fields, that it is 38^° the same
height as the sun had at noon when he moved in the
equator on March 21 or September 21. This star, then,
marks out the equator in the night sky, as the sun
marked it in the day sky. We have thus the two great

68 STORIES BY HEAVENLY MOVEMENTS

circles of the ecliptic and the equator marked out both
for daylight and for night ; and, as we have seen, they
are inclined to each other at an angle such as is made
by the hands of a clock pointing four minutes apart.

If we draw a line from the south point through the
sky to the north point, through the zenith, it will pass
near a bright star, to which the front stars of the
Plough, swinging round the northern sky, also point.
This bright star wheels in a smaller circle than any
other in the sky, and is nearly 90° from the equator, i.e.
is close to its pole, just as the north pole of the earth is
90° of latitude from the earth's equator. It is near to
this star that the axis of the earth is pointing, and if
we measure its average height above the north point of
the horizon at the Hilly Fields, we find that it is 51^°,
the 'complement' of the angle of 38 J° given by the
slant of the paths of the sun and the stars ; that is, the
angle required to make it up to 90°. Round this star,
known as ' the Pole Star,' all the others seem to circle.

If we tilt a photographic camera so as to point to
this region of the sky, and keeping it rigidly fixed,
expose the plate to the starlight, we shall find on
development that the stars have tracied out parts of
circles, more or less nearly complete, according to the
length of time that the plate has been exposed. The
diameters of these circles depend on the distances from
the pole of the stars that drew them ; the distinctness

PLATE XI.

Photograph of Trails of Stars near the North Pole, taken at the Royal Observatory,

Greenwich.

PLATE XII.

•#

Photograph of the Constellation of the Southern Cross. From the Annals of the Harvard
College Observatory, Vol. xxvi. Part 2.

THE STORY TOLD BY THE STARS 71

and breadth of the curving lines so drawn depend on
the brightness of the stars. {See Plate XI.)

If we leave the Hilly Fields and go northward, the
Pole Star rises higher in the sky, and more and more
stars wheel clear of the horizon, and are never lost to
view. If we go southward, the Pole Star sinks lower,
and fewer stars never set. But if we now look at the
stars in the extreme south, we see that some have risen
there that we never saw when standing on the Hilly
Fields. Stars, then, there are, that never rise ; there
are constellations which on the Hilly Fields we can
never see.

One of the most famous of the constellations that
we, in England, never see, is the star group of the
Southern Cross. {See Plate XII.) It is not until we
get near the tropics, — ^go down the Red Sea, or travel
up the Nile — that it climbs over the southern horizon.
And then it is only seen at seasons of the year when
the sun is in the region of the zodiac that is remote
from it.

Therefore, it would be impossible for Colonel Trench
to say — as Mr. Mason represents him saying in The
Four Feathers, on the night of his release from the
Stone House in Omdurman — that for three years he
had watched it every night.

If we go northward we find that the stars — and the
sun likewise — rise in paths less inclined to the horizon.

72 STORIES BY HEAVENLY MOVEMENTS

at a smaller slant. If we go southward we find they
rise at a greater slant. And, as with the sun, this tells
us that the earth is a round globe. If it were a level
flat plain, the inclination of the axis of the sky to that
plain would be everywhere the same, and so also would
be the inclination of the apparent paths of the Istars, for
the whole of the starry heavens move as in one piece.
So, like the sun, the stars enable us to measure the
earth. If we measure the height of the Pole Star, — or
rather of the Pole itself, which is the centre of the
little circle round which that star appears to revolve, —
and then travel southward until the Pole has sunken
one degree lower, we shall find that we have travelled
nearly seventy miles, or more nearly, sixty-nine miles,
and that therefore the entire 360°, the whole circum-
ference of the earth, must be about twenty-five thousand
miles.

He that is dizzy thinks the world goes round.

Do all these myriad stars move round the earth, or
does the earth turn round upon herself ? The appear-
ances, so far as we have described them, would be the
same vvhichever happened, but surely it is simpler to
suppose that it is the earth that turns.

The daily course of the sun told us that there is
a clear way under the earth, but we could not learn
from it — at least, not in England — that the earth was

THE STORY TOLD BY THE STARS 73

everywhere unsupported, that everywhere the way is
clear. This the stars can tell. At every point of the
western horizon, at all times, stars go down, and pass
round through the under world to the eastern horizon,
from every point of which they arise. At no point,
even in the farthest north or most extreme south, is
there a blank space in the sky where no stars wheel ;
nowhere in the under world can there be a support
through which a star cannot pass. The Babylonians
held that the earth is supported on two great mountains.
The Hebrews had better read the story of the stars,
for they wrote : ' He ' (God) ' stretcheth out the north '
(i.e. the northern circumpolar constellations) ' over empty
space, and hangeth the earth upon nothing.'

CHAPTER IV
THE STORY TOLD BY THE PLANETS

Like as a star.
Without haste, without rest.

THIS is the characteristic of a star. It keeps its
own appointed path unswervingly, moving at an
unchanging pace. Its path is a circle, complete for
those stars that wheel in the north, broken by the sky-
line for the others. But no star retraces backwards its
way, no star overtakes or lags behind its neighbour;
there are no stragglers in the ranks of this great army.

Are we sure of this ? The stars are very many ; we
cannot keep a continual watch on each one to see if ever
it should err and stray aside. For the stars in the
north, that wheel round the pole unceasingly, we can
look upon them night after night, the whole year
through ; we can be certain that the Seven Stars keep
the form of the Plough ; that the W which forms the
Lady's Chair never ceases to sprawl. But the more
southern stars, those that for some part of every year
are swallowed up in sunlight, can we be very sure that

THE STORY TOLD BY THE PLANETS 75

these always keep the same pattern ; especially when we
see but a little of the pattern ?

During the short nights of May and June, a bright
constellation is seen very low down in the southern sky.
Its principal features are a curved line of bright stars,
upright to our horizon, followed by a longer curve of
yet brighter stars that lie along the horizon. In
particular, three bright stars are seen close together, of
which the middle is much the brightest, and is of an
orange-red colour. There are very few stars in the sky
that are of so pronounced a colour to the naked eye as
this one is.

The ancients considered these stars as forming a
g^ant scorpion, with his tail curled up to sting the foot
of a man who was trampling upon him, and the bright
reddish star iS known as the Scorpion's Heart.

The star of the Scorpion's Heart rises year after year
about three o'clock in the morning in the middle of
February. But if we had been looking at Scorpio about
the middle of February, 1907, we should have seen the
pattern of the constellation quite altered. For north of
the Scorpion's Heart was another star, very like it in
brightness and in colour. And as the constellation
reached the meridian, a little before the dawn blotted
out the stars, these two stood out, the one above the
other, like a couple of danger signals.

This star above the Scorpion's Heart had certainly

1(> STORIES BY HEAVENLY MOVEMENTS

not been always there. If we had looked out a little
before daybreak on the first morning of the year, and
watched the Scorpion's Heart rise in the south-east, we
should not have seen its red companion near it then.
But if we had looked farther to the south, we should
have seen a reddish star, not nearly so bright as the
Scorpioa's Heart, already fairly high up in the sky, in
a constellation known as 'the Virgin,' just about the
place where her left foot is supposed to be resting
upon one of the Scales, which the constellation between
the Virgin and the Scorpion is considered to represent,
and not far from its brightest star.

If, morning by morning, we had watched the Scor-
pion through the last fortnight in February, we could
not help noticing that the new red star was moving
relatively to the stars of the Scorpion. On February 14
it rose before the Scorpion's Heart ; by the end of the
month the two stars rose together ; by the end of March,
Antares, as the Scorpion's Heart is called, rose at
midnight, but the stranger star not until an hour and
twenty minutes later. It had now passed clear out of
the Scorpion and was in the constellation of the Archer ;
it was passing amongst the stars in the same direction as
the moon does ; and it moved in the course of a single
night over a space equal to the apparent diameter of the
full moon. All through April, all through May, this
movement of the stranger went on. By the end of

THE STORY TOLD BY THE PLANETS n

April, it had reached the middle of the constellation of
the Archer, and was close to his brightest star, the
one that marks his right shoulder.

And now the stranger star was one that it was not
possible to overlook. Rising about midnight, and pass-
ing the meridian a little before dawn, it shone brightly
low down in the southern sky ; brightly, for it was now
quite four or five times as bright as when it was close
to Antares. No other star in all that region of the
sky could rival it in brightness ; none could compare
with it in vividness of colour.

And so the red star went its way, across the con-
stellation of the Archer ; but as the month of May drew
to a close, it became clear that it was moving much
more slowly. It then took four or five days to move
a distance equal to the moon's diameter, a distance for
which a single day had been equal before. Night after
night its rate of motion declined, until, early in June,
it seemed to change the direction of its course, and
instead of moving eastward among the stars, it began
to turn southward ; and before June had come to its
close, it was hurrying westward, as if to overtake the
stars that it had recently passed. By July 15 it
had got back as far as the bright star in the shoulder
of the Archer, a star which it had first passed on the
north side on April 28 ; now it passed it well to the
south, travelling almost with its original pace. Its'

78 STORIES BY HEAVENLY MOVEMENTS

speed toward the west soon slackened, and, as August
began, the red star for several days remained almost
motionless in the sky. But what a splendid object it
was throughout July ! — rising before sunset, on the
meridian at midnight, setting at sunrise ; visible, there-
fore, all the short night through, it shone with a lustre
ten times as great as when it was noticed in February.
No star in the whole sky, not even Sirius, the brightest
of them all, could compare with it. It caught the notice
of many, even of the dull, unobservant dwellers in cities,
who asked with a tepid curiosity what that big red star
might be. It was noticed, it could not fail to be noticed,
by peasants and desert wanderers and savages the world
over ; and, no doubt, to many of them it seemed to
shine with a baleful ill-omened light, and to threaten
some undefined evil.

It is possible that there were some who formed a
vague idea from the rapid motion of the star, and its
increase in brightness, that it was some fiery enemy
approaching the earth and destined to overwhelm it.
If so, its movements during August and September
would have reassured the timid watcher, though they
added an element of fresh mystery. For, at the end
of the first week in August, the red star came to a
dead stop, and then, after a few evenings, recommenced
again its progress towards the east. On September 2,
it passed the star in the Archer's shoulder for the third

THE STORY TOLD BY THE PLANETS 79

time, still to the south of it, but much nearer than it
had been before. As September went on, the pace of
the red star quickened, until by the end of the month
the original pace of about a moon's diameter in twenty-
four hours had been fully regained ; and early in October
it had passed from the constellation of the Archer, in
which it had followed so erratic a course, into that of
the Seagoat. And thenceforward throughout the year,
there was no break in the steadiness of its eastward
progress. Evening by evening it set earlier, until by
the end of the year it had gone down an hour before
midnight. But during all this time its brightness had
been fading, at first slowly, later more quickly, until as
the old year expired, it was no brighter than it had been
when it stood just above the Scorpion's Heart. It had
come far enough since then, having passed through the
whole of the constellations of the Scorpion, the Archer,
the Seagoat, and the Waterpourer, or very nearly a third
of the entire sky. {See Plate XI IL, fig. i.)

Here was a star that obeyed a law quite different
from that of the general starry host.

Is this the only one, or are there others ? There are
certainly others. For if we had been watching atten-
tively the part of the heavens which the red star had
reached in its wanderings as the year 1907 came to a
close, we should have seen that there was another
stranger star here. This is rather a dull region of the

8o STORIES BY HEAVENLY MOVEMENTS

heavens : the neighbourhood of the more westerly of the
two Fishes, where the constellations of the Fishes, the
Waterpourer, and the Sea-monster meet. This region
comes into view at about five o'clock in the morning at
the end of March. It is up all night in September, and
it is lost again in the sunset about the beginning of
March. When the stars of the Western Fish begin to
draw away from the sun, in the early mornings of April,
1907, a star much brighter than any of those which
make up this constellation was seen in a void region of
the sky somewhat to the south of them. Through April
and through May it followed a steady course eastward,
taking five or six days to travel over a space equal to
the diameter of the full moon. Towards the middle of
July, however, it came to a full stop, and then through
August, September, and October, drifted westward until
very nearly the end of November, when again it stopped
in order to resume, in December, its eastward drift. The
entire range of its wanderings, during these eight
months, was only over a small part of a constellation,
perhaps one-fiftieth part of the circle of the sky ; but the
movement amongst the stars, though much slighter than
that of the red stranger, was quite evident. It moved
more slowly, and it changed little in brightness. There
was a dull leaden quality about its light, though it shone
steadily ; it was much brighter than all the stars near to
it, but neither sparkled nor twinkled.

THE STORY TOLD BY THE PLANETS 8i

The midnight sky is in its greatest glory in winter.
If we look out at eleven o'clock in the evening on
the first of January, we see, due south before us, the
beautiful constellation of Orion, the brightest in the sky.
Lower down to the south-east, the great Dog, with
flashing Sirius as its chief jewel, is shining ; above Orion
and Sirius, the rich stream of the Milky Way flows down
from north-west to south-east ; on the further border
is the bright constellation of the Twins, Castor and
Pollux ; whilst Procyon, the lesser Dog, attends at their
feet. Nearly overhead is Capella, one of the three
brightest stars of the northern hemisphere, and the chief
brilliant of the constellation, Auriga, Holder of the Reins ;
a little further west along the Milky Way is the long
stream of stars that mark out Perseus ; and below the
feet of both, bending his head to repel the attack of
Orion, is the Bull, with the bright star of .Aldebaran
shining as his eye. Nowhere else in our northern lati-
tudes do we see such a glorious collection of stars.

But on the first day of 1907, this glorious collection
of stars was rendered yet more brilliant by the presence
in its midst of a star that far outshone them all. It
shone with a serene and steady silver light, very unlike
the quick twinkling of the chief stars around it. It lay
nearly midway between the five bright stars, Capella,
Aldebaran, Betelgeuse, Procyon, and Pollux ; and was
thus just within the constellation of the Twins, near the

82 STORIES BY HEAVENLY MOVEMENTS

feet of Castor, the northern Twin. It was an object not
possible to overlook. {See Plate XIII., %. 2,)

This serene star was no more stationary in the sky
than the red one. It was moving throughout the whole
of January, westward amongst the stars, but it never
quite succeeded in escaping from the constellation of the
Twins. It reached the border line between the Twins
and the Bull about the end of February, and then it
turned back and pursued an eastward course through
March, April, and May, crossing the space equal to the
moon's diameter in about three days. It was lost in the
sunlight early in June, at which time it was drawing near
to the Twin stars. Castor and Pollux. It was seen again
at the beginning of August, early in the morning, when
the Twin stars emerged again from neighbourhood to
the sun. Then, for the rest of the year, it moved steadily
eastward till the beginning of December, when it stood
still for a second time, and then again retraced its steps.
The whole of the last month of 1907, and the first three
months of 1908, it was travelling westward, and it came
to a s.top for a third time at the end of March, 1908, in
the middle of the constellation of the Crab, just as it had
come to a stop the first time at the end of February,
1907, near the feet of the Twins. It had thus measured
off in a year the whole of a constellation ; and for
a third of a year it had been travelling backwards
amongst the stars over a third of a constellation, a

PLATE XIII.

• ''.

Ser-IK

•

»^«rp

•

"•

•

• 1

~r~-

•

, 1

Capricornus
the 1

5(M Goat '

SagiUarms

tht

Archer

,..^

•

.'-

•

Scorpio

trie

•

OCorcon

Fig. I. — Apparent Path of Mars amongst the Stars during the year 1907.

Lyn«

Auriga
Ural IfKHciiv

Bull

_• Twins

Cancer

the
Crab

Monoceroa

trie

Unicorn

Fig. 2.— Apparent Path of Jupiter amongst the Stars during the year 1907.

PLATE XIV.

Fig. I. — Elongations and Conjunctions of an Inner Planet.

ouADRA rum
wesr

QUADRATURE
EAST

conjufiCTion

Fig. 2. — Quadratures, Opposition, and Conjunction of an Outer Planets

THE STORY TOLD BY THE PLANETS 85

thirty-sixth part of the circumference of the sky, or 10°
of arc.

These three stars, the red star, the leaden star, and
the serene star, are evidently quite unlike the rank and
file of the heavenly host We know them to-day, as the
ancients knew them of old, as planets, that is to say,
wanderers ; and it was a very slow and tedious process
by which men reached an understanding of their
movements.

The names by which we know them to-day are
those of three of the gods of ancient Rome. The red
star is Mars; the serene, Jupiter; and the leaden
star, Saturn. Their movements are like the movements
of the moon, with one remarkable difference. The
moon moves always eastward amongst the stars —
moves rapidly eastward, more than twenty times its
own diameter in a single day. Jupiter, Saturn, and
Mars move eastward too, but each of them has a
time when their eastward motion becomes very slow,
then ceases, and is converted into a westward motion.
This lasts for a considerable time, and then, in its turn,
diminishes, comes to a stop, and is reversed. The
great difference, then, between the movements of these
three planets and that of the moon, is that the former
pass through stationary points and a period of retro-
gression ; that is, of westward, of backward motion.

This period of retrogression takes place at the

86 STORIES BY HEAVENLY MOVEMENTS

time when the planet is opposite the sun, and is
therefore visible all night. For Mars, it begins about
six weeks before the planet is exactly opposite the
sun, and lasts for about six weeks after. For Jupiter,
it begins about two months before opposition, and lasts
about the same time after. For Saturn, the half-period
of retrogression is ten weeks. Then the rate of motion
across the sky of the three planets is very different
from that of the moon ; for, while she traverses more
than twenty times her own diameter in a day, Mars,
at his quickest motion, takes an entire day to traverse
a space equal to a single diameter of the moon ;
Jupiter takes three days, and Saturn five.

When we watch the ' morning stars ' escaping from
the rays of the rising sun, or the ' evening stars ' being
enmeshed in the rays of the setting sun, do we find
that all of the former escape from the rising sun and
all the latter are imprisoned by the setting sun ; or
is it sometimes the other way about ? It is worth
while to devote our mornings and our evenings for
a time to making certain.

Let us suppose that we are beginning our watch in
the February of 1906. It is more than a month before
the spring equinox, and as we look, evening by evening,
first the stars in the stream that the man pours from
his watering-pot, then the stars in the Fishes, fade into
the setting sun ; morning by morning, the stars in the

THE STORY TOLD BY THE PLANETS 87

Archer — half man, half horse — then the stars in the Sea-
goat and the Waterpourer are earlier and earlier seen.
Everything is as we expected : the stars keep on their
steady march westward, there are no stragglers in
their ranks, and the sun shifts steadily in the one
direction past them. We have watched for a month
and seen nothing out of rule; is there any need to
watch longer ?

It still wants a week until the equinox, and the sun
has set nearly half an hour. The stars of the twin
Fishes are lost in the twilight, but surely there is a
star just over the west point of the horizon that has
no place in the constellation of the Fishes. It shines
with a silvery light, but more steadily than the other
stars of the sky. And a little farther from the sun,
a little farther to the north of the silvery star, there
is another. It is fainter than the silvery star, but it
twinkles like a real star. Then both set. Are these
two stars new creations ? How else should we not
have seen them before when the other ' evening stars '
were clearly seen ? They are both set amongst the
stars of the Fishes, but they are both much brighter
than any of these.

But on the next evening, when they should have
disappeared, both stars are yet more clearly seen. The
•evening stars* have shifted westward as regards the
setting sun ; the silver star and the twinkler have moved

88 STORIES BY HEAVENLY MOVEMENTS

eastward, a little more into the dark and the open —
they have moved eastward amongst the westering army
of stars. For a day or two the twinkling star is seen,
and then drifts back into the sunset glow, but the silver
star takes a steady eastward path backwards through
the stars, away from the sun.

During the summer months it travels backwards
through the Twins, the Crab, the Lion, and the Virgin,
its easterly motion just sufficient to keep it out of the
sunset glow, but it has been growing brighter as it
recedes ; until, by September 20, it can be seen in the
sky even as the sun is setting, and the distance between
the two is as the distance between two hands of a
clock pointing eight minutes apart.

But no farther does the silver star recede from the
sun. After September 20, the sunlight begins to draw
it back again ; yet still it brightens, until, by October 26,
there is no star in all the heavens can compare with it.
Still it moves more slowly eastward, and yet more
slowly, until, by November 9, it has ceased its easterly
motion and is a brilliant star, fixed amongst the other
stars, far outshining its neighbour, Antares, the jewel
of the Scorpion. Then it begins its westerly movement,
rushing more quickly than the other stars to be im-
prisoned in the rays of the setting sun, lost to sight
before the third week of November is out.

But not for long. The first week of December is

THE STORY TOLD BY THE PLANETS 89

not over before a new star has arisen as herald of the
sun.

Hesperus, that leads
The starry host, rides brightest.

But Hesperus, the silver evening star, is seen no more,
and a silver morning star, Phosphorus, has risen. Phos-
phorus is moving westward, as Hesperus was moving
when last we saw it. But Phosphorus ceases to move
west by December 19; remains fixed, and again begins
its eastward movement. By January 4, 1907, it has
attained to all the brightness that Hesperus held on
October 25, shining now in the head of the Scorpion,
but giving it a jewel far surpassing all the other living
sapphires of the sky. To the eastward it continues its
road, gaining on the rising sun, and straying further
from him. Phosphorus can be seen high in the morn-
ing sky even when the sun is lifting above the eastern
horizon, and if we measure its distance from the sun
on some morning near the end of the first week of
February, we find it is very nearly that between the
two hands of a clock pointing eight minutes apart.
This would tell us that the western 'elongation' of
Phosphorus was 48° very nearly, the same as the
eastern 'elongation' of Hesperus. It is also its
greatest elongation, for, after February 9, Phosphorus
begins to sink back into the rays of the rising stin,
unlike the stars of the Archer's bow amongst which

90 STORIES BY HEAVENLY MOVEMENTS

it is shining low down in the eastern sky, much lower
than was Hesperus when it shone amongst the stars of
the Virgin in the west.

Phosphorus sinks back very slowly into the sun's
rising during the long summer months of 1907. We see
it threading its way through the stars of the Archer, the
Sea Goat, the Waterpourer, the Fishes, the Ram, the
Bull, and the Twins, until, at the end of July, we find it
lying below the great Twin stars, Castor and Pollux. But
the Twin stars are escaping from the sun's rising light,
whilst Phosphorus is sinking into it, to be seen no more
in the morning; though Hesperus reappears in the stars
of the Scales when the long nights of November have
come in.

In our watch, morning by morning, and evening by
evening, we have come on no other stars than these
that do not obey the Law of the Stars. We have
discovered Saturn the leaden star, Jupiter the serene
star, and Mars the red star. Also, we have discovered
Phosphorus and Hesperus, and the twinkling star.
Phosphorus and Hesperus, we are almost sure, are one
and the same star ; for the story of Phosphorus, of its
movements in one direction or another, its stationary
points amongst the stars, and its changes of brightness,
is but the story of Hesperus as seen in a looking-glass.
The star, Hesperus or Phosphorus, we call Venus.

The twinkling star is far harder to watch, and,

THE STORY TOLD BY THE PLANETS 91

indeed, here in England, it can only be seen occasionally.
But if watched for, year after year, on every possible
opportunity, its movements are seen to be just of the
same character as those of Venus, The ancients had
discovered this thousands of years ago, and we inherit
from them the name Mercury, which we give to it.

These five wandering stars, or planets, do not obey
wholly, though they seem to obey in part, the Law of
the Sun. Like the sun, they shift their rising and their
setting places, within limits, on the eastern and western
skylines. But their change of rising and setting bears
no relation to the seasons, and their pace across the sky
is not steady and unswerving. They do not obey
wholly, though they seem to obey in part, or at times,
the Law of the Stars, for the latter have their places
of rising and setting unalterable, and wheel continually
without haste and without rest. They do not obey
wholly, though they seem to obey in part, the Law of
the Moon, for this never retraces its path nor stands still.
They do not all even seem to obey the same law. The
law that governs Saturn, Jupiter, and Mars seems
different from the law of Venus and Mercury.

Let us take Jupiter and Venus, the two greatest and
brightest stars in all the sky, and contrast them. In
brilliancy and silver light they are rivals. But there is
one great difference between them. Jupiter, like the
moon, after emerging from the sun's setting rays, recedes

92 STORIES BY HEAVENLY MOVEMENTS

farther and farther from him in the sky, until, when he
is brightest, he rises, as does the full moon, in the east
at sunset, rides his highest in the south at midnight,
and sets in the west at sunrise, thus being opposite to
the sun the whole night long. It was for this reason
that the ancient Babylonians called Jupiter by the name
' Nibur ' — ' he who crosses over ' — because he crossed the
midnight meridian. And they also called him by the
name of their chief god, Merodach, who represented the
sun in his strength. For just as the sun passes through
one of the twelve signs in a month, Jupiter passes
through one of them in a year.

But Venus, so like Jupiter in lustre and brightness,
is never opposite to the sun. The moon's movements
would resemble hers, if we could suppose the moon to
be stayed in the evening sky, when four days old, and
sent back on her path ; or, to use the Babylonian . myth,
if I star had been stopped at the fourth portal and
been sent back through the gates into the under world.
So, therefore, as the Babylonians gave the name
Merodach to Jupiter, they gave the name Istar to
Venus, as well as to the moon. For she, like the moon,
was an attendant on the sun — his handmaid and his
bride.

It is worth while to step out under the open sky,
and to watch the coming and going of these five planets,
so seemingly capricious in their movements, so different

THE STORY TOLD BY THE PLANETS 93

from the unswerving, ordered march of the stars. It is
also worth while to remember that long before men had
telescopes, or any means for delicate measurement, they
had not only detected these five wanderers, but they
had mastered part of the secret of their movements,
and had learned to predict long beforehand when they
would appear, when they would seem to stand still in
the sky, and when reverse their paths.

It is quite clear that the moon travels round the
earth ; is it not possible that Mercury and Venus travel
round the sun ? The interval between the time when
Mercury is farthest from the sun as an evening star,
to the east of him, and again to the time when he is
farthest as a morning star to the west, is a little over
six weeks. The interval from his greatest distance as a
morning star to his next greatest distance as an even-
ing star is a little over ten weeks. In all, the interval
from one elongation to the same elongation again is
about 1 1 6 days, or i6^ weeks. If, therefore, we suppose
that Mercury is travelling round the sun in a period of
this length of time, as viewed from our earth, his
apparent movements amongst the stars might be ex-
plained ; and it is quite clear that we should have to
suppose that Mercury was between us and the sun,
midway in his passage from evening star to morning
star ; and beyond the sun, midway in his passage from
morning star to evening star. (See Plate XIV., fig. i.)

94 STORIES BY HEAVENLY MOVEMENTS

Venus moves in a similar fashion to Mercury, but she
swings through a wider arc and moves more slowly.
She takes 143 days to fulfil her entire passage from her
greatest distance in the east as evening star, to her
greatest in the west as morning star ; whilst she
requires 441 days to pass behind the sun in her reverse
course. Her entire period, as judged from the earth, is
584 days.

It is evident that Venus never recedes from the sun
so far as the earth is. But suppose the sun had another
attendant, that could move further from him than the
earth. Clearly, instead of coming between the earth
and the sun, it would pass behind the earth, and thus be
seen opposite to the sun, just as the full moon is seen.
Necessarily, it would then make its nearest approach to
the earth, and would look large and bright. The sun
appears to go round the earth once in a year. If this
attendant on the sun took considerably more than a year
to go round him, then we should have just exactly what
we notice in the case of Mars, which takes seven weeks
more than two full years between one * opposition ' and
the next. If the attendant took several years to go
round the sun, then it would be brought by the sun, at
the end of a year, nearly to * opposition,' but there would
be a small distance still to be made up, because of the
planet's own movement round the sun. Now, Jupiter
travels from one opposition to the next in a year and

THE STORY TOLD BY THE PLANETS 95

thirty-four days, Saturn in a year and thirteen days.
Hence, they take nearly twelve years, and nearly thirty
years respectively, to travel round the sun, since thirty-
four days is nearly the twelfth part of this apparent
period of Jupiter, and thirteen days nearly the thirtieth
part of this apparent period of Saturn. {See Plate
XIV., fig. 2.)

But does the sun travel round the earth, carrying all

these planets with him, or is it the earth that travels

round the sun, just as the other planets do ? It would

make no difference in the appearance of things, so far as

observations made by the naked eye are concerned,

which was the fact. But surely it is better to take the

simpler explanation, and just as, when the stars had told

us that the earth was a globe unsupported in space, it

was easier to account for the apparent circuit of the stars

round the earth by supposing that it was the earth that

turned, so it is simpler to suppose that the earth travels

round the sun, just as we see that the planets do, rather

than that he travels round the earth, carrying all the

planets, with their various motions round him. We know

how difficult it is if we are sitting in a train in a railway

station, side by side with another train, and we are

watching the latter, to say which is moving, this train or

that. The probability is that if the other train moves,

we think it is ours ; if it is our train, we think it is the

other one, if our motion be smooth enough. But there

96 STORIES BY HEAVENLY MOVEMENTS

is no motion so smooth and so swift as that of the
heavenly bodies ; they move without haste and without
rest, and they jar over no stones in the road that they
travel. So, as when we are in an express train, horses
and hedges and trees seem to fly past us, whereas it is
we that are flying past them, the sun seems to be
circling round us in the course of a year whilst we are
really circling round him. So in the pair of little
sketches {see Plate XV.), it is the tree that seems to
have moved, not the man.

This gives us the clue to the meaning of those
strange backward movements of Mars, Jupiter, and
Saturn. The earth is nearer to the sun than they are,
and moves round him in a shorter time. Hence there is
one part of our path in which we pass them, and whilst
we are passing them, since we are not conscious of
our own movement, they seem to be going back-
wards in the sky. There is a further point. We
have seen that Mercury and Venus appear only to
wander from the sun to a restricted degree: Mercury
is never more than about 30° from the sun, nor Venus
much more than 45°. That means to say that 30° is
the apparent size of half the orbit of Mercury as seen
from the earth, and 46° of the orbit of Venus. This
does not tell us how big those orbits actually are in
miles, but it gives us the relative size of the two orbits,
so that if we knew the scale of the one we should know

PLATE XV.

t
O

^
k

PLATE XVI.

Fig. I. — The light from the edge of the
Sun's disc has passed through a much
greater depth of his atmosphere than
that from the centre.

Fig. 2. — Illustrating the apparent forward
motion (eastward) of an outer Planet.

Fig. 3.— Illustrating the ' .stationary points '
of an outer Planet.

Fig. 4. — Illustrating the ' retrogression '
(westward motion) of an outer Planet.

Fig. 5. — Illustrating the determination of Stellar Parallax.

THE STORY TOLD BY THE PLANETS 99

the scale of the other, and also the scale of the
earth's orbit. {See Plate XVI., figs. 2, 3, and 4.)

Just in the same way the apparent swing backwards
of Mars, Jupiter, or Saturn, whilst they are going back-
ward in the sky between their two stationary points, is
an indication of the apparent size of the orbit of the
earth as seen from these three planets, and consequently
of their relative distances. We could therefore draw a
map of the Solar system to scale, but we could not tell
the value of the scale, whether an inch represented
hundreds, or thousands, or millions of miles.

This, then, is the story that the planets have to tell,
namely, that they are moving round the sun at very
different distances from him, and at very different speeds,
and that the earth is one of their number.

So much the movements of the heavenly bodies —
Sun, Moon, Stars, and Planets — have been able to tell
us without the need for our using telescope or observa-
tory. So much, and much more, men had read from
those movements two thousand years ago. Is there
any good, then, in our learning again what has been
known so long ?

There is every good. Those who wish to learn
something of other sciences than astronomy, such as
botany and geology, are never content merely to read
about them in books. They go to the fields and rocks
to see with their own eyes that which the masters in

loo STORIES BY HEAVENLY MOVEMENTS

these sciences have known and taught long before.
And they do rightly. It is by our own observation
that we learn to know ; it is by this that our perceptions
become keener, and our interpretations more certain.

If we would begin our study of astronomy aright, let
us go out, under the open sky ; and what beauty, sub-
limity, and wonder greet us as we turn our eyes to the
heavens! The movements of the machinery of men
are with noise, dirt, and shaking ; but this machine,
infinitely greater than any man has ever produced,
moves as easily as a thought. For the movements that
we watch are those of the machine of God's own
making, and how swift, smooth, silent, and inscrutable
those movements are !

BOOK II

STORIES TOLD BY THE SUN

CHAPTER V

THE STORY TOLD BY THE SUN'S
SURFACE

T N February, 1 866, as I ^ was returning home from
-*■ school one evening, I saw the sun, low down in the
west, shining red through the mist. The sun was dim
and red enough for me to look at him without blink-
ing, and I saw plainly on him a round black spot, just
as if a nail had been driven into him up to the head.
It was the first time that I had ever seen anything on
the surface of the sun.

If we are to see anything on the sun's face, we must
be able to look at him. If the day is very clear, we
are too dazzled by his light to see him. The im-
pression that we get is that he has a round, glowing
golden disc, all so overpoweringly brilliant that we
cannot say that one part of it is any brighter than
another part. For aught we could tell, it is a perfectly
flat disc, as flat as a golden sovereign, or as our fore-
fathers thought the earth to be.

We now know that the earth is not flat, but rounded

' E. Walter Maunder.
103

I04 STORIES TOLD BY THE SUN

as a sphere or globe ; the stories of the sun and stars
told us that. But the atmosphere surrounds the earth
and fits it like a skin, like a skin that, for the size of the
earth, is not so thick as the skin of an apple is for the
fruit. We know that the earth's skin of air is not
thick, for the sky is much clearer overhead than
towards the horizon, and if we could ascend high
above the ground we should see that, of the circle of
the earth beneath our feet, the region in the centre is
the clearest, and the land lying near the borders in
all directions is blurred and dim.

We cannot gaze at the sun when he is in the clear
sky overhead ; we can look steadily only at the low
sun when his brightness is diminished by the thicker
air of the horizon. Then we see that the golden
disc is not equally bright, equally golden, all over. The
centre is brightest and still of a golden yellow, but
everywhere towards the border of the circle the bright-
ness dims and the gold deepens into orange or red.
It is not our atmosphere that causes this diversity,
else the gold and orange would be in layers above
our skyline ; the difference must be in the sun himself :
his dim border must be at a greater distance from us
than his bright centre, and he must have an atmosphere
of his own, lying thicker over his border than his
middle, as we found our air lying thick on our hori-
zon. The sun, then, is not a flat disc like a golden

STORY TOLD BY THE SUN'S SURFACE 105

sovereign, but a globe, a sphere, rounded as the earth
is round. {See Plate XVI., fig. i.)

The next time that I saw the sun lying low and red
in the west, I saw the black spot like the head of a nail
again, but it had changed its place, and was now much
further from the centre of the sun. Two or three days
later it had gone.

I have seen similar spots with the naked eye on
many occasions since. On November 18, 1882, Queen
Victoria was holding a review in Hyde Park. The
morning was somewhat foggy, and the sun shone dull
and red through the thick air, so that it was easy to
look at him. On this occasion there was a great spot
on the sun; so big that it caught the attention of the
soldiers who were marching across Blackheath, to go
to the review, and they pointed it out to each other.
Eleven years later, in August, 1893, I was on a voyage
and watched the smoke from the steamer pass across
the sun ; every time that it did so, and I was able for
the moment to look at the sun, I saw two great spots
upon him. And so on other occasions. On one day in
February, 1907, no fewer than four spots could be seen
separately on the sun at the same time.

So the face of the sun changes, even to the naked
eye. There are sometimes blemishes on it, and some-
times there are not. It is not possible to go much
further than this in the study of the sun's surface without

io6 STORIES TOLD BY THE SUN

the aid of a telescope — we can see that the sun is a
globe, that he has an atmosphere, and that spots come
and go upon his face. We cannot tell whether it is
always the same, or a different, face that he turns to us.

Every now and then we can see spots on the
sun with the naked eye, and several such were seen
in the centuries before the telescope was invented, yet
the people who saw them did not recognize that the
black blemishes were really spots on the sun's face.
In the days of Charlemagne, one was recorded as
lasting for eight days, but those in the Middle Ages,
who read the record, thought that it was Mercury that
was seen, passing straight between the earth and the
sun. But Mercury it could not have been, for two
reasons. The little planet takes only six weeks to pass
from its east elongation to its west, over a space in the
sky nearly two-thirds of a right-angle ; it could not,
when it seemed to be moving at its quickest pace, loiter
for eight days of that time, over barely the one hundred
and seventieth part of that space. Besides, the planet
is so little that we can only see it with the naked eye
when it is a bright point of light, not when it is but a
black dot on the bright sun.

To study the features of the sun's face we must have
a telescope, and we can use it in one of three ways.
We can look at the sun directly through it — though in
this case we must use a very dark glass to dim the glare

STORY TOLD BY THE SUN'S SURFACE 107

of his light, which would blind us utterly. Or we can
let the magnified image of the sun made by the lenses
of the telescope fall upon a white card, and study the
features that we see there. Or we can place, instead
of the card, a photographic plate, and let the sun imprint
his own image. In this last case, since the sun is very
bright, the very brightest object we know, we must give
very short exposures, perhaps but the one thousandth
part of a second. Plate XVII., fig. i, shows the second
of these methods as used at the Royal Observatory,
Greenwich, by Flamsteed, the first Astronomer- Royal ;
and Plate XVIL, fig. 2, shows one of the 'photo-
heliographs,' or photographic telescopes for solar work,
now in use at the same observatory.

The spot that was seen in the days of Charlemagne
lasted for eight days. It lay on the sun's face, when
first it was seen, nearly a quarter of the sun's breadth
away from the left-hand edge. But day by day it
shifted its place, creeping right across its middle, until,
on the last day that it was seen, it lay about a quarter
of the sun's breadth from the right-hand edge. Either,
then, the spot was moving on the sun, or the spot was
fixed in its place and the sun was turning with it round
in the same direction that we ourselves seem to move.

It is only rarely that we notice naked-eye spots,
but very soon after the invention of the telescope
Galileo turned his new instrument upon the sun, and

io8 STORIES TOLD BY THE SUN

in April, 1611, announced that he had discovered dark
spots on the body of the sun. For in the telescope
spots are frequently to be seen, and these may remain
visible not for eight days only, but perhaps for thirteen
or fourteen, appearing first at the very eastern edge
of the sun, and crossing his face to disappear at his
western edge. And these show that the sun himself
is carrying the spots. They are not merely transit-
ing over his face, as Venus or Mercury transit, passing
between the earth and the sun. For when the spots
appear at the sun's eastern edge they are like a thin
line along it; they seem but stains on him, much
foreshortened as they lie on a part of his globe that
is turned much away from us. As day by day passes,
the spot group comes more clearly into view, until it
is fully presented in the centre of the sun's disc. Then,
day by day, as it creeps on towards the west, it fore-
shortens again, showing clearly that the sun is a globe,
and that he is turning round upon his axis. From these
same spots we can tell how fast he is turning. For, since
the sun is a globe, we can only see half of it at any time,
the hemisphere that is turned to us. But it seems to us
to take the sun thirteen or fourteen days to carry a spot
from one boundary of that hemisphere to its other, and
it takes, therefore, just so long to carry it again across
the hemisphere that we do not see round into sight
again at the eastern edge. Thus the sun appears to

PLATE XVII.

a.
2 c

-r!

P-i

•"■

ti*

109

PLATE XVIII.

Diagram showing the Track of a Sun-spot across the Sun's Disc.

{From a drawing made in September and October, 1850, by the late Father Sestini at the
Georgetown College Observatory.)

STORY TOLD BY THE SUN'S SURFACE m

us to turn round in about twenty-seven days. In reality
he turns round in less time by a couple of days, for,
as the earth is travelling round the sun in the same
direction as the spots do, we keep the spots longer in
view than if we remained still ; just as we might follow
down the platform a train that is moving out of the
station, to keep a departing friend a few seconds longer
in sight. {See Plate XVIII.)

The spots go at the sun's western edge into the
hemisphere that we do not see. Shall we ever see
these spots again ? How shall we recognize them if
they are the same spots ? How can we tell one spot
from another ? Do they always come up at the same
point of the sun's eastern rim as the stars do on the
earth's horizon, or do they shift their rising places like
the moon and the planets ? Do they wax and wane like
the moon ; do they wander to the east or to the west
like the planets ; or, like the stars, do they move without
haste and without rest ? or do none of these laws have
anything to do with sun-spots ?

A spot, when seen with the naked eye, is round and
black, like a nail's head ; and one nail is very like
another. But that is because the naked eye is not
powerful enough to see its details. Magnified by the
telescope, and projected on the white card, or imprinted
on the photographic plate, a spot is seen to have defined
form and characteristics enough for it to be recognized

112 STORIES TOLD BY THE SUN

again. But so has a cloud in the sky characteristics
and a defined form, and just as clouds change so do
sun-spots. The sun-spot of one day may have altered
or lost every peculiarity by which we thought to
remember it, ere the next has passed. A single spot
may have broken up and become scattered into many ;
a group of spots may have coalesced into one.

Spots differ much in their shape and size, and in the
length of time that they last. The most stable spots,
those that change least and last the longest, are very
nearly round. They appear black in the centre, which
is not quite half as broad as the entire spot. In this
black region, the nucleus, or umbra, of the spot, as it is
called, there are sometimes points of intenser blackness,
as if pits were sunk in the floor of a great cavity.
Round the umbra is a lighter region, which surrounds
it as the iris surrounds the pupil of an eye. This is
called \}ae. penumbra, and is marked throughout by wavy
lines flowing inwards, making the penumbra look as if it
were built up of thatch straws. Where the penumbra
borders on the umbra, it is ravelled out into a narrow
fringe. Round the spot, outside the penumbra, the
surface of the sun is brighter than usual, and seems to
be heaped up ; and every now and then, some of this
intensely bright white stuff will, as it were, boil over,
and either flow right across the spot, forming what is
known as ' a bridge,' or else flow into it.

Photograph ok the Sun taken at the Royal Observatory, Greenwich,

on July 14, 1905.

(Two streams of sun-spots of different types are seen.)

113

PLATE XX.

TiiK Solar Surface, showing tpee Granulations. Diameter of Solar image = 3 feet.

(From a pIiotoi;raph taken Scpteinbcr, 1883, ad. 8/i. ^or/i. 20s. Paris Rlcan Tivn; at the McnJon
Observatory, by the late Professor Jansseti.)

114

STORY TOLD BY THE SUN'S SURFACE 115

But spots are not generally seen singly ; they are
seen in groups. A very ordinary occurrence is for two
very small spots to appear near each other. Then they
grow very quickly and move apart as they grow. This
movement is usually one of astonishing rapidity, since
they travel away from each other at the rate of about
8,000 miles a day, five or six times as fast as an express
train. The spot that leads is usually nearly round, and is
dark and well defined. The spot that follows is often the
larger of the two, but is not so dark, and not so regular
in shape. Between the two a number of smaller spots
generally appear, but these are not seen for long, as the
bright surface of the sun seems to swell up in this
region and to flow over these smaller spots, hiding them
from view. The irregular spot in the rear dis-
appears next, and the round leader remains alone and
may sometimes last for several weeks, or even months,
after the rest of the group has gone. {See Plate
XIX.)

Spots, therefore, change their form ; they increase
and diminish, they are born and die. Some never
become more than a faint, tiny smirch, which may last
only a few minutes and then melt again into the general
brightness of the sun's surface. Others grow and
spread and darken, and may last for days, weeks, or
even months, crossing the sun's disc again and again.
Some may develop slowly, and decay in the same

ii6 STORIES TOLD BY THE SUN

fashion. Others may break out almost full grown,
or may die down whilst apparently in full vigour.

But the spots are not the only markings upon the
sun. As already noted, round the spots, and in the
middle of their groups, we often see masses of material
much more brilliant even than the general surface ; as
if the substance of the sun were here boiling over and
eddying round and across the gaps made by the spots.
Masses of similar shining matter are also seen by
themselves near the rim of the sun, more generally
near the east or west ; in form they look like branches
of gleaming coral. They are in the centre of the sun's
disc also, but there their lustre is lost in the general
brightness. They rise high into the sun's atmosphere
like mountains, and its greater depth near the rim of
the disc shades down the brilliancy of his surface, so
that these bright masses— /acwlae they are called — shine
out by contrast. These great groups of faculae, like
the spots, come round into our sight over the eastern
rim of the sun ; we lose them in the brightness of the
centre, and we see them again near the western rim
befpre they disappear into the hidden hemisphere.

We have seen sun-spots and faculae on the surface
of the sun ; but what is that surface itself like ? Its
texture is not even ; it has its pattern, a wonderful and
ever-changing pattern. On what seems to be a dark,
or at least less brilliant, background, there float minute

STORY TOLD BY THE SUN'S SURFACE 117

grains of intense brightness, and of irregular form.
If we do not magnify it much, the general effect is
like the roughness of drawing-paper, or like the curdling
of milk that is turning sour. But, greatly magnified,
it seems to be formed of tiny granules which run
together here and there into grains, which rriay be
round in shape, or drawn out into pointed filaments,
and these grains aggregate, and separate out to form
the changing pattern on the sun's face. One observer
describes them as being like snowflakes sparsely
scattered over a greyish cloth, another likens them to
' willow-leaves,' figuring the sun over like basket-work ;
another sees them as simple rice grains in shape. Over
the edges of the umbra of spots, they form the fringe
of the penumbra, hanging over the blackness like
thatch straw.

On some very beautiful photographs that Professor
Janssen took of the sun, this pattern came up, at one
time coarsely, at another time finely textured. At places
the texture, whether coarse or fine, seems smeared and
ill-defined, as if the pattern had been outKned in lumin-
ous ink, and ere it dried, a careless sleeve had brushed
across it. What causes this smearing, or how long it
lasts, we do not yet know. It might be supposed that
it was due to small but very rapid currents in our own
atmosphere which make the parts of the sun seen
through them ill-defined, as landscape shimmers in

ii8 STORIES TOLD BY THE SUN

extreme heat. But it seems clear that it arises from
some cause in the sun itself, from some motion or
whirling of the grains themselves, or of the sun's
atmosphere above them, so rapid that the small fraction
of a second for which the photograph was exposed was
all too long for them to seem at rest. {See Plates
XX. and XXI.)

The story told by the sun's surface, as we see it or
photograph it by means of a telescope, is one that we
should not have been likely to guess from anything that
we can see of it with the naked eye. The whole of
that surface is in commotion and change. Bright as it
is on the whole, there are parts which are much brighter
than the rest ; there are parts, too, which, though really
bright, appear to be dark, appear even to be absolutely
black, as compared with the general radiance. Yet
even the blackest part of the darkest sun-spot is probably,
surface for surface, thousands of times as bright as the
full moon.

And these spots change, change rapidly, in a way
that hints at the action of mighty forces below the
surface.

Finally, the sun is a globe, turning upon his axis
once in twenty-five days, and so presenting in turn
every face towards us.

CHAPTER VI

THE STORY TOLD BY THE SUN AND
THE PLANETS TOGETHER

SOME years ago my study window faced north-west
and looked over London. One evening in August
it was very clear as I * watched the sun go down, and I
hoped to see him set behind the houses, and not lose
him in the smoke of the chimneys before he reached
them. He was very close to the skyline, when I saw in
his lower right-hand edge a black piece bitten out : a
bite which grew larger and larger, just as the moon, in
a solar eclipse, seems to eat the sun. Yet I knew that
there was no eclipse of the sun possible on that evening.
Farther and farther did the round black body encroach,
until, when the sun was nearly hidden, an upright tower,
surmounted by a cross, was outlined on the reddened
disc. It was St. Paul's that was eclipsing the sun ;
dome and tower together exactly fitting into the sun's
round shield. {See Plate XXI L, fig. i.)

We can cover up the sun's whole face more easily
than by getting him to set behind St. Paul's to us at

' E. Walter Maunder.
119

I20 STORIES TOLD BY THE SUN

Blackheath. If a halfpenny is held at a distance of nine
feet from one of our eyes, exactly between the eye and
the sun, no whit of the sun will be seen ; or if a three-
penny-bit is held about five feet away, again the sun
will be exactly hidden. So a threepenny-bit at five feet
distance, a halfpenny at nine feet, the dome and cross of
St. Paul's as seen from Blackheath, and the sun, if all in
a straight line from the eye, will all appear exactly the
same size. Now we can measure the distance to the
threepenny-bit, and its size ; to the halfpenny, and its
size ; to the dome and cross of St. Paul's, and their size ;
but how are we to measure the distance to the sun to get
his size ? We cannot pace the distance, or measure it
with a chain.

Suppose that we are looking at a candle with both
our eyes, and that the candle is not far off. If, whilst
we are looking at it, we shut our right eye, the candle
seems as if it had shifted a little to the right ; if we
shut the left eye instead, it seems to. shift a little to the
left. Yet the candle has not moved at all ; it is simply
that our eyes are two and a half inches apart, and we
look first with one, and then with the other. The
direction from the right eye to the candle is not quite the
direction of the left eye to the candle. The whole shift
that it appears to us to make is the width between the
pupils of our two eyes, as this would appear to a person
in the place of the candle. Now the width between our

PLATE XXI.

%
■Si*

EAST

The Solar Surface, showing the Blurring of the Granulations.

Diameter of the Solar image = 3 feet.

(From a photograph taken July 10, 1887, 7/;. 35'«. 55^'., Paris Mean Time, at tlie Meudon
Obsen'atory, by the late Professor Jatissen.)

121

PLATE XXII.

OJ
3

(1)

STORY BY THE SUN AND PLANETS 123

eyes to that person will seem greater or less according
as he is near or far from us ; the farther he goes away
the closer together will our eyes appear to him. If
we measure the distance between our eyes, and measure
the shift that the candle seems to make, we can tell the
distance that it is from us, even though we do not
measure the distance to it. {See Plate XXII. , fig. 2.)

It is in exactly the same way that we can measure
the distance to the moon, and so tell her real size. We
do not do it by shutting first one eye and then the other,
and measuring the shift of the moon in the sky, because
the moon is so very far away, that her shift — the distance
between our eyes as seen from the moon — is too small
for us to perceive it. The moon is so far away that we
must look at her direction from two points that are
thousands of miles apart, instead of a few inches, in
order to get a sufficient change in the place she seems
to have.

.But here are two difficulties. When we measured
the distance of the candle by observing its apparent
change of place as seen with the one eye and the other,
we watched it shift with respect to something much
more distant. But what is more distant than the moon ?
The stars, and to them we can refer the moon's place.

Instead of our two eyes we can take two very distant
observatories. The Royal Observatory, Greenwich,
was built largely in order to observe the moon ; and

124 STORIES TOLD BY THE SUN

in order to co-operate with it — to be, as it were, the
second eye — the Royal Observatory at the Cape of Good
Hope was built. Now these two observatories are 6,000
miles apart, and the moon, as seen from Greenwich,
does not seem to be in precisely the same part of the
sky as it is when seen from the Cape ; indeed, the
apparent change' of place is two and a half times
the apparent diameter of the moon, or nearly so. Now
this is the apparent distance apart of two objects which
are really a foot apart if viewed from a distance of forty
feet, or a yard apart if viewed from forty yards. In
other words, the moon is forty times the distance between
the two observatories at Greenwich and the Cape, that
is, nearly 240,000 miles ; more exactly (for we have only
dealt in round figures hitherto), 238,400 miles. (See
PlateXXII., fig. 3.)-

But we have a far more difficult problem when we
try to measure the distance of the sun. First of all, we
cannot measure his position with reference to the stars,
as they are not visible by daylight. Next, the sun is
not an easy body to observe. He is large, with his
rim ill-defined, and is so bright and hot that we cannot
get his centre with precision. We should need to get
his centre exact to the one eighth-thousandth part of a
hair that we are holding about a foot distant, where we
can see it best. Yet we could not tell where is the real
rim of the sun by the breadth of many hairs.

STORY BY THE SUN AND PLANETS 125

The third difficulty is, as before, to get a ' base-line ' ;
that is, to get two places sufficiently far apart from whence
to make our measurements.

The first two difficulties we can get over together by
measuring the distance — that is, getting its shift with
respect to the stars — of one of the sun's planets instead
of the sun himself. We can always draw a map of the
solar system, accurate to any degree we like to name, at
any given moment, but we do not know the scale on
which that map is .drawn ; we cannot say how many
millions of miles should go to the inch.

Let us select the planet Mars, Let S be the sun,
MiMa be the orbit of Mars, E1E2 be the orbit of the
earth. Then Mars makes one complete revolution in his
orbit in 687 days, and the earth in hers in 365^. We
know both of these times by observing when Mars
and the sun return to the same place amongst the stars.
Note the date when Mars is in opposition ; that is to
say, when he lies in the same straight line from the
earth to the sun. After a certain number of days, say
four months, when the earth has reached Eg, note his
elongation or apparent distance from the sun. This is the
angle MgEgS. We know the length of time that it takes
Mars to travel right round his orbit, and therefore we
can tell how much of it he describes in 1 20 days ; we
can tell the angle MjSMj. Therefore we know the pro-
portion that the distance SMj bears to the distance E^S,

126 STORIES TOLD BY THE SUN

though we do not know the actual measure of either.
If we can measure the distance to Mars, therefore, we
can tell the distance to the sun. {See Plate XXII.,

fig. 4-)

We can get over the difficulty about the length of
the base line, from whose ends we should measure,
without leaving the spot on which we are standing.
The earth is a great spinning globe, and we who stand
on its surface are some 8,000 miles away in the morning
from where we were in space twelve hours before,
even if the earth were not moving in her orbit round
the sun. Suppose, now, that Mars is at opposition, and
that we fix both Mars and the earth for a while in their
places, preventing them from moving round the sun,
but not preventing the earth from spinning on her axis,
Mars, being on the other side from the sun, seems to
rise as the sun sets, and sets as he rises. But the
direction of Mars should seem to us to shift, as the
earth turns round, from EM^ as we saw him when
rising, to WMzy as we saw him when setting. We
know the distance ECW, for it is the diameter of the
earth, and we have just measured the angle EMW, so
we can tell the distance EM. This is the principle of
the method, but, of course, as neither Mars nor the
earth have remained fixed in their places during the
twelve hours or so that have elapsed between two
observations, corrections have to be made for the

STORY BY THE SUN AND PLANETS 127

distances that they have travelled. (See Plate XXII.,

fig. 5-)

Mars is the best of all the major planets, as it is

outside the earth's orbit, and it is the nearest of those
outside, but some of the minor planets are better than
Mars for this purpose. One in particular, Eros, some-
times comes nearer to the earth than any other heavenly
body except the moon, and it is also such a small point
of light that there is no difficulty in deciding its centre.
Figure 6 in Plate XXII. will indicate how the shift
is measured. Suppose that Si, S2, and S3 are stars, and
Ee is the position of Eros in the evening shortly after
rising ; Ew the position in the morning shortly before
setting. The distances of Re and Ew from these stars
are measured, and the differences between the measures
when corrected for the motion of the little planet and of
the earth, gives the shift in the interval of time between
the two observations. {See Plate XXII., fig. 6.)

By this method, or by some method like it, it has been
found that the average distance of the earth from the
sun is 92,892,000 miles, but this value may perhaps be
too great or too small by about 1 20,000 miles. This is
the average distance, for as the earth does not move
round the sun in a circle, they are nearer to each other
at one time of the year than at another ; in winter they
come as close as ninety-one millions of miles ; in summer
they are as far away as ninety-four millions.

128 STORIES TOLD BY THE SUN

It is hard to picture such a distance to one's self, or
even to conceive of it. There are about ninety-four
millions of seconds in three years, so that if we travelled
a mile in a second and went straight from the earth to
the sun, we should not reach him in less than three years.

And if the sun is so far away, how big must he be .-*
As nine feet is to the size of the halfpenny, so is ninety-
three millions of miles to the size of the sun. This sum
in proportion works out at 866,400 miles for the diameter
of the sun ; the diameter of the earth being only 7,920
miles, not the one-hundredth part. The sun's great
globe would contain 1,300,000 of the quantity of matter
in the earth.

Sir John Herschel long ago gave directions for
making a model of the solar system to scale which will
give an idea of how vast are the distances which separate
its members. On a wide level common, place a globe
two feet in diameter to represent the sun. At a distance
of 82 feet from it put a mustard seed to represent
Mercury ; a pea at 142 feet would stand for Venus, and
another pea at 215 feet for the earth; whilst Mars
would be indicated by a peppercorn at 327 feet. A
fair-sized orange nearly a quarter of a mile from the
central globe would stand for Jupiter, whilst the minor
planets would be represented by minute grains of sand,
mostly from 500 to 600 yards from the centre, though
some would be as near as Mars, others as far as Jupiter.

STORY BY THE SUN AND PLANETS 129

Saturn would be a small orange at two-fifths of a mile,
Uranus a large cherry at three-quarters of a mile, and
Neptune a plum at a mile and a quarter.

If these little models of the planets were set in
motion, then, in a day, the mustard seed for Mercury
would have to travel a yard ; the peas representing
Venus and the earth 24 inches and 22 inches respec-
tively. Mars would move 18 inches, Jupiter 10 J,
Saturn 7^, Uranus 5, and Neptune 4 inches. The
further off from the sun a planet is, the more slowly it
moves in its orbit. The moon, on the same scale,
would be a smaller seed than Mercury, moving with
the earth, but at a distance of about 6f inches from it.
Its daily motion round the earth would only amount to '
about two-thirds of an inch. (See Plate XXIII.)

When we looked at the sun and saw a spot on it
with the naked eye, it looked no bigger than the head
of a small nail driven into it. But what must have
been the size of that spot to be seen at all ? If we
placed a globe the size of the earth on the face of the
sun, it would look no larger than a halfpenny at three
hundred yards ; but a halfpenny at three hundred yards'
distance from us we could not see at all. A naked-
eye spot cannot be smaller than 25,000 miles across,
more than three times the diameter of the earth.

And many of the spots cover an area of a thousand
million square miles or more. Cavities, they seem to

I30 STORIES TOLD BY THE SUN

yawn, so vast that they might swallow up Earths as
peas might be poured into a saucer. If then the grains
and granules on the sun are the flecks of foam, the
faculae are the billows, and the spots are the eddies on
this sea of flame, what vast powers and forces do we see
here in action !

CHAPTER VII
THE STORY TOLD BY SUN-SPOTS

SIN BAD the Sailor relates in one of his adventures
that he and his companions once encamped on what
they took to be a desert island. Just as they were
settling down to their evening meal, the supposed island
began to sink, for it was a whale that had been wakened
out of sleep by the inconvenience of having a fire lit on
his back. There are certain points of resemblance that
we may note between islands and whales, and certain
points of difference. Both are situated in the oceans of
our globe ; both partake, of the earth's daily rotation on
its axis. But islands are fixed in their places; we define
their position by their longitude and latitude on the
earth; if we go, and return to them, we are sure of
finding them in the same place as we left them. Not so
with whales. They migrate, and where we have seen
one once, we cannot expect to see it again. But, though
whales do not obey the laws of islands, they are not
wholly lawless. They may not remain fixed in the
same spot, but they are constant to certain haunts.

131

132 STORIES TOLD BY THE SUN

Whalers must sail to their peculiar localities, must seek
them in their own seas to find them.

With sun-spots it is as with whales rather than with
islands. They are not to be found everywhere on the
sun's great sea of flame ; they have their own peculiar
haunts, beyond which they rarely stray ; nor are they
always to be seen upon the surface even in these.

Unlike islands they are not fixed, but they migrate,
wandering to and fro. Our earth turns on her axis as a
whole, and one part does not pass or lag behind another.
Not so with sun-spots. If we were watching the spots
on the sun's equator in order to determine the rate at
which he turned, we should decide that he took about
twenty- four and a half days to complete a rotation. If
we watched the spots of latitude 35°, he would seem to
take nearly twenty-seven days. This would be very
much as if islands on the equator of our earth, like
Sumatra and Borneo, had a day of twenty-three hours ;
whilst islands in the position of Japan would have a day
of twenty-five hours. It is quite clear in such a case
as this, that Japan would lag behind Sumatra and
Borneo, which would gain about 2,000 miles upon it in
every rotation of the earth. Such a state of things
of course could not take place on any solid globe,
and we know, therefore, that we are watching on the
sun no solid structure, but rather the upper surface
of a shell of glowing clouds — clouds that move far

PLATE XXIII.

Per,o

VJranHi

Plan or the Solar System

133

PLATE XXIV.

134

THE STORY TOLD BY SUN-SPOTS 135

more freely, far more quickly, than any clouds in our
atmosphere.

Next, as to the peculiar haunts of sun-spots on the
sun, we have seen in the Story told by the Sun's
Surface that he turns on his axis in about twenty-
five days, as the earth turns on h^rs in twenty-four
hours ; so that he, too, like the earth, has his poles and
an equator. It is very rarely that any spots are found
outside the parallels of the sun's latitude that are 35°
north or south of the equator. A very few have been
found in a latitude so far from the equator as 40° ; one
spot has been seen in 50° ; but all of these were very
small, and lasted for no longer than two or three days.
The seas in which we find the solar whales are ' tropical '
or 'sub-tropical.' Should we compare the spot -zones
with those of our geography, we should include the whole
of the inhabited region of the southern hemisphere ;
but we should exclude, in the northern hemisphere, all
Europe, Canada, and all the northern confederacy of
the United States, and all Siberia.

Nor do the solar spots migrate freely between these
limits of 40° north and south of the solar equator.
Rather there seem to be narrower zones within which
the spots that arise there may move, but beyond which
they may not transgress. This seems the first law laid
upon them.

The next law seems to be that in any particular

136

STORIES TOLD BY THE SUN

zone on the sun's surface spots do not arise at all times,
but only at particular times do spots seem to be formed.
There are long intervals when the zone breeds no spots
at all. (5^^ Plate XXIV.)

The third law seems to be that though spots do
not stray from one zone to another, there is a bond of
connexion between the different spot-breeding zones,
for there is an order observed in the times of breaking
out of spots in neighbouring zones.

Let us take an example from the southern' hemi-
sphere, and divide it into zones 5° wide.

Southern Hemisphere.

5° zone in

Period when

Southern

spots were

no spots

spots were

no spots

Hemisphere.

visible.

were visible.

visible.

were visible.

3o°-35°

1880 July U

1881 Apr./^ ^^■

9 yrs.

1890 MayUi vrs
1893 Nov.P^ yrs-

-9 years.

25-30

i88oFeb.\, „,^
i884Mar.hy'^^-

sf „

1889 Dec.l 1
1^95 Max.P^ "

7 „

1880 July \
1885 Aug./5 »

1889 Aug.1,
1896 Aug./' "

4 ,,

20-25

4 ))

15-20

i879Dec.\a
1887 Nov./** "

If »

1889 Aug.Uo
1898 Apx.n "

3* »

10-15

i88oDec.\o
1888 Dec./" "

2i „

1891 Junelgs
1900 Apr. / »

2i „

5-10

1881 May\„i
i89oAug./9* "

2 ,,

1892 July ^ 2
1902 Feb./'^ "

i| .,

o-s

1882 Mar.\ 1
1889 Aug./'* »

3i „

1893 Decj J
1903 June/^^ >'

2} ,,

There are several interesting points to note about
this table. In the first place there is quite a long
interval of time between two outbreaks of spots in any

THE STORY TOLD BY SUN-SPOTS 137

of the zones ; always a year or two, perhaps many
years ; so that there is no doubt as to when an epidemic
of spots begins and ends in any particular zone. Next,
the time during which the outbreaks last is shorter, and
the interval between the outbreaks is longer, for the zones
which are farther from the equator, than for those nearer
to it. It is as if our solar whales belonged to different
species in the different zones, and sought the solar
depths for periods of time that varied with their distance
from the solar equator ; and then brought the young
schools to the surface to sport for lengths of time that
again varied with their distance from the solar equator.
Third, the whole time from the beginning or end of one
outbreak of spots until the beginning or end of the next
does not greatly differ for the different zones. If a
school of solar whales stay long upon the surface, it
must stay the shorter time below ; and the two times
together make up about eleven years. Fourth, the
outbreak of spots in the zones far from the solar equator
begins earlier, and therefore ends much earlier, than those
outbreaks that are near the equator. This is so marked,
that we have a new outbreak starting in the highest
latitudes before the old outbreak in the lowest latitudes
has subsided. During a period, then, of about eleven
years we seem to have an outbreak of spots on the sun
beginning in the regions farthest from his equator, and
spreading to the lower zones, increasing for a while as it

138 STORIES TOLD BY THE SUN

spreads. Finally it dies out at the equator, when a new
outbreak of spots has already started in high latitudes.
This period of change is called the sun-spot cycle.

The first spots of a cycle are few and small. During
the next three, four, and five years they increase rapidly
in number, and many of them in size, and they occur
most frequently in latitudes that lie between io° and 25°
from the sun's equator. Their number, and the spots
of large size, are fewer and fewer during the next six
years or so, and the spots that appear are frequently in
the lower latitudes. The last spots of a cycle, again
are few and small.

What do we mean by small spots or large spots?
We measure whitings by inches, whales by feet, and
islands by miles. What is the measure that we should
apply to sun-spots ? We measure them in terms of the
space on the sun's disc that they occupy : in millionths
of the sun's visible surface. The smallest spot that we
measure would occupy about the one millionth of the sun's
disc, and the biggest might occupy as much as three
thousand millionths. To know how big any sun-spot
is, we must therefore know how big the sun is. This
we found in the last chapter has a diameter of nearly a
million miles, so that the surface of its hemisphere
visible to us is more than a million million of square
miles; therefore, the smallest spot we can measure
covers an extent of ground of at least a million square

PLATK XXV,

•-0 A
O z

— o
O 2

l1 ^

e;ast
139

PLATE XXVI.

O 5

» ^SP* •**"

o Z °

O JJ

EAST
140

THE STORY TOLD BY SUN-SPOTS 141

miles, the bigger spots hundreds or thousands of times
this area. The smallest spot we measure would be
about half the size of Russia, Poland, and Finland
together; into the larger spots there might be poured
worlds like ours as peas are poured into a saucer. (See
Plate XXV.)

As a general rule, the bigger a sun-spot the longer
it lives ; but the life of any sun-spot, huge though it is,
is but short, as we reckon time. Very many spots do
not last through the twenty-four hours of our day ;
the area that an average spot of this longevity would
occupy is about twelve millions of square miles. The
average area of a group of spots lasting for eight days
is about twenty-two millions. The longest time that any
group of spots has lasted, during the last quarter of a
century, has not been as much as seven months. The
disturbances of the sun's surface are stupendous and on
a vast scale, but they do not last for long.

The sun-spots do not stray from their peculiar zones,
but in the zones they move with considerable freedom.
The Law of the Stars is that they neither haste nor rest,
they do not jostle each other nor lag behind. Not so
with sun-spots. They move more quickly or more
slowly, they may jostle each other or move apart ; the
same spot does not move always at the same pace.
The very zones seem to move at different rates, the
low latitude spots moving as a rule more rapidly than

142 STORIES TOLD BY THE SUN

the high latitude. The rate at which the sun, as a
whole, appears to turn round may not be the rate at
which any spot travels ; it is but the average rate of all
the spots, taken at all times.

What causes the spots we do not yet know. We
may never know, for their cause seems to lie deep down
in the sun itself, and we can but see the sun's surface ;
we do not know how to probe beneath it. We cannot
tell if it is the same cause that gives rise to the outbreak
of spots in each zone, eleven years after eleven years.
If the spots are the same, cycle after cycle, we have no
means of recognizing them. We can recognize again a
star by its place in the pattern of stars ; we can do the
same with a planet by its colour and its movements ; we
can know again an island on the earth, for it does not
change its place ; we can even know again a whale if it
has had a harpoon driven into it ; but how are we to
know a sun-spot when it emerges again from the solar
depths ?

We do not know what makes the sun-spots, or what
brings about their changes. We have learnt, neverthe-
less, some of the laws that seem to govern their changes,
some of the fixed rules that they obey. Of the laws of
faculae we know less than of sun-spots ; we cannot see
them except near the sun's edge. (See Plate XXVI.)
We know that they too lie in zones of latitude, and these
zones extend farther from the sun's equator than do the

THE STORY TOLD BY SUN.SPOTS 143

sun-spot zones ; that they diminish and increase in a
cycle of years as do the sun-spots ; that they move at
a different rate from the sun-spots. We know that
they change, but their forms are not defined as are the
spots, and we do not know their manner of change, or
their lengths of life. Of the grains and granules that
cover the sun's whole face we know still less. We can
see that they change continually and rapidly, but how
they change, or if their changes run through a cycle,
we do not know.

CHAPTER VIII

THE STORY TOLD BY THE SUN AND
MOON TOGETHER

WE cannot see the stars in the daytime. This is not
because the stars are not there, or have lost any
of their brightness, but because the sun is himself so
bright that he lights up the atmosphere, and we cannot
distinguish the brightness of the stars from the bright-
ness of the sky. We have to wait until the sun is
gone down below the earth, and no longer lights up the
night sky, to see the shining of the stars. We do not
see the sun's bright faculae in the middle of his disc.
That is not because there are no faculae in the middle
of the sun's round disc, nor because the faculae there
have lost their brightness. It is because the middle of
the sun is as bright as the faculae that we cannot see
the one for the other. We can only see the brightness
of the faculae near the sun's edge where the sun's atmo-
sphere has dimmed its brightness. We do not see the
light of a candle if we hold it up between us and

the sun. It is not that the candle flame has lost its

144

THE SUN AND MOON TOGETHER 145

light, but it is because the flame is not brighter than the
sun. To see the shining of the lighted candle we must
hold it away from the sunlight, or else we must put
something, a book or some screen, between the flame
and the sun.

How can we tell, then, that we see everything that
there is on the sun, or near the sun ? The sun has an
atmosphere, we know, for it dims the sun's light near
his edge. Can we see this atmosphere extending
beyond the sun ? Can we tell if there is anything but
atmosphere surrounding the sun ? Heliography is so
different from geography that we cannot be certain
unless we know; sun-spots, for instance, behave more
like whales than like continents or islands.

It is no use to hold a screen up to shut off the sun's
direct light. The sun still lights up the air in the sky
so greatly that we could not distinguish any other light.
We would need to hold the screen right outside the
atmosphere, far away in the airless space that lies
between us and the sun, where it would prevent the
sunlight falling on the earth's air. We have no pole
long and steady enough to hold up such a screen.

There is one object that might act as such a screen.
The moon appears to us to be of very nearly the same
size as the sun, and we know that she is in herself a
dark globe. If, then, the moon were exactly in a line
with the sun and earth, she would blot out a part or the

146 STORIES TOLD BY THE SUN

whole of the sun. Here, then, is the screen that may
allow us to see the sun's surroundings by covering up
the sun itself. But to do so, the moon must cover the
whole of the sun ; if she only partially covers him, his
uneclipsed part is brilliant enough, be it never so small
an arc of sunshine, to drown the sky and all near him
in a sea of light. When the moon completely covers
up the sun's disc, she does so only for a short time ; it
may be for a few seconds, or at the very longest, eight
minutes. She does so rarely ; on an average there may
be once in two or three years a total eclipse of the sun
where it is possible to observe it. The whole amount
of time available in half a century of eclipses may not
exceed an hour.

One of the most impressive sights that the heavens
afford us is an eclipse of the sun. When the sky is
clear and the sun unclouded, then there is little time to
spare for anything terrestrial. One observer, at Algiers,
of the eclipse of 1900, describes it thus : * The sky was
deep purple, while over the sea was a strange light on
the horizon ; a compromise between a thunderstorm
and a sunset. The colour faded from the sea and trees,
a shouting and wailing arose from the square below, the
light was fading; suddenly the moon slipped over the
sun and the eclipse was total. A deep purple sky, a
black globe, surrounded by a crimson glow, and above
and below it a milk-like flame, stretching its long

rT,A1'E XXVII.

148

THE SUN AND MOON TOGETHER 149

streamers away into the purple.' But when clouds hide
the eclipsed sun, then the weird effects, upon landscape
and seascape, of the sun darkened whilst it is yet day,
are the only observations that can be made. An
astronomer writes of the cloudy eclipse in Lapland of
1896: 'I observed that the clouds, which had been
lightish grey, had suddenly assumed a very deep
blackish-purple colour, while the whitish spaces between
the clouds were glowing with a vivid amber-yellow tint.
It seemed that the whole scene was illuminated by this
amber light ; the colours of objects around were quite
perceptible, but much subdued. The distant hills were
dark indigo, and the sea very dark, except where
it reflected the streaks of amber light. The whole
effect was lurid and impressive in a high degree.' And
yet another observer of the same eclipse likened the
cloud-covered sky to a purple pall with a golden fringe,
canopied over the earth. Lord Hampton, also an
observer of this same eclipse, painted the scene, and his
painting is here reproduced by the kind permission of
his son and daughter. {See Plate XX VH.)

There is not much time then for us to study the
sun's surroundings. And when the moon has completely
covered the sun, we see that there is so much in his
surroundings that is novel and unlooked-for, that we
have a good deal to study.

The moon has completely covered up the sun's disc ;

ISO STORIES TOLD BY THE SUN

and as the sun and moon appear to be just about the
same size, the moon can only just cover the sun, with
but little, if any, to spare. Instead of the brilliant orange-
coloured sun, we see blackness, for the moon gets no
light now except from the sunlit earth. But round this
blackness, fringing it, is a bright, red, ragged rim. This
does certainly not belong to the moon — whether we see
her waxing, or full, or waning, we see her outline hard
and sharp, either sharp moonshine or sharp blackness.
This red, ragged rim belongs, then, to the sun — it looks
as if he were covered with a fiery red Turkey carpet,
whose burning pile was pulled and torn. Everywhere
round the moon's edge is seen this red rim; everywhere,
then, on the sun does it lie. {See Plate XXVIII.)

But this red rim is not all. Here and there are
tongues of flame. Not the peaceful, steady flame of a
bat's-wing gas burner, but twisting, turning serpents'
tongues. They are not always most like flaming tongues ;
sometimes they are tree-like : trees spreading as do
the cedars in Turner's pictures, or burning, bent and
bowing under a strong wind, and shedding their fiery
leaves in the blast like a flaming shower. There are
tongues of silver flame sometimes, as well as tongues or
trees of red fire. And enveloping both in a wonderful,
pure, cold radiance, stretching out far beyond them,
is a silver glory : not a halo only, but a crown, a
glory like nothing else that we see on earth or in

PLATE XXVIII.

'SI '~~

o 0)

151

THE SUN AND MOON TOGETHER 153

the heavens. We must compare it to many things, for
no one comparison can convey what it is like. It is like
a silver mist, it is like ivory gauze, it is like the wings
of an angel, it is like the petals of the lilies of heaven.
Its form takes on here and there the shape of a flower-
leaf, and when I saw the sun's eclipse in 1898 it seemed
to me as if a child had been playing the game of ' Loves
me, loves me not,' until but three or four of the sun-
flower's petals had been left on the red-rimmed, black-
hearted stalk. {See Plate XXXVII.)

Red rim, fiery flames, and silver radiance — * chro-
mosphere,' ' prominences,' and ' corona ' — are there
whether or not we can see them, whether or not the sun
is eclipsed. In every eclipse we see them at the edge
of the sun. But though we can only see them at the
edge of the sun when it is undergoing eclipse, since the
sun turns round, all must be everywhere on the sun's
surface, no matter in what direction it is presented. On
the sun's disc turned towards us there must be, not only
the granules, spots, and faculae that we can see, but also
the chromosphere, prominences, and corona that we do
not see or recognize.

All these belong to the sun. What connexion have
they with each other ? What effect have they on each
other }

These questions we can only answer in part as
yet, for they are some of the problems that we are

154 STORIES TOLD BY THE SUN

still trying to solve, and for the answer we go to the
ends of the earth to see an eclipse of the sun. The
corona we can, as yet, only see during a total solar
eclipse. The spots, faculae, and granules we cannot see
during an eclipse, for then they are covered by the
moon. Prominences and chromosphere we see during
an eclipse ; but, by means of the spectroscope {see
Chapter IX.), we can see the chromosphere and some
of the prominences when the sun is not in eclipse ; some
of the prominences only — the scarlet ones, but not the
white. Here, then, is a connecting-link, by which we
may perhaps learn if sun-spots have aught to, do with
the corona.

As we have said, red rim, fiery flames, and silver
corona are there whether we can see them or not ; but
they are not always the same. They are different in
form and shape and place from one eclipse to another. Is
this because they turn with the sun, and we see a different
edge in each eclipse ? or do all change continually, and
in cycles of years, as do the spots, the faculae, and the
granules on the sun's surface ?

The prominences rotate with the sun. Whether
the sun is eclipsed or not, whether we observe them
without the spectroscope or with it, we see their form
and their changes when they are on the edge of the sun.
But we see them coming out of the visible hemisphere
upon the eastern edge, and we can see them disappear

PLATE XXIX.

Eruptive and Quiescent Prominences.

The upper group of prominences was observed on April 29, 1873,, at iqIi 5"^ a.m. It changed its form

very rapidly. Its extreme height at the time of observation was 90,000 miles. The lower group was

observed on April 15, 1872, at 10'' o^ a.m. Extreme height, 70,000 miles. Observer, L. Trouvelot.

F7-oin '■Astronomical Engravings' published by the Harvard College Ohseri'atory.

156

THE SUN AND MOON TOGETHER 157

at the western into the sun's hemisphere that is turned
away from us. In this way they behave just as do the
sun-spots. Therefore, the differences in the prominences
that we note at different times is due in part to different
regions of the sun being presented edgewise to us.
But only in part, for even as we watch the prominences
stretching beyond the sun's edge, we note that they are
changing, continually changing, as do sun-spots, and even
more rapidly. We may watch a prominence spring
actually into existence, flame up to a height of thousands
of miles, and die out again ; and all this within the space
of time of two or three minutes. Or the prominence
that we have watched on the eastern edge may last so
long, as still to exist when it has traversed the sun's
breadth and reached the western edge. Sun-spots
change, and so do prominences. (See Plate XXIX.)

Both change in cycles. Sun-spots and faculae
increase, multiply, diminish, and increase again, in cycles
of about eleven years. So do prominences ; though
the three may not coincide, even within a year or two,
in their epoch of greatest or least display. Sun-spots
have their zones of latitude beyond which they are not
found ; so have faculae, but their zones extend further
from the equator. So, too, prominences have their
favourite zones, and their zones extend farther still,
almost up to the sun's poles.

There are points of closer connexion still between

158 STORIES TOLD BY THE SUN

sun-spots and prominences. There must be prominences
where there are no spots, for we find those near the
poles where these never break out. But if we observe
with a spectroscope the place on the sun's edge where a
great and changing spot is just coming or passing away,
there we are sure, or almost sure, to find great and
rapidly changing prominences. Sun-spots seem to
spout forth prominences.

The corona seen during one eclipse is not the corona
seen during another. Is this because the corona rotates
with the sun, or because it changes in itself?

^ We cannot say that the cc zona rotates as do
the prominences, spots, and faculae ; we cannot say
that it rotates as one with the sun, or not as one
with the sun. We have failed to make any successful
observations of the rotation of the corona on the sun
itself.

But we do know that it changes its form, and we
know that it does so in some sort of sympathy with the
changing prominences arid sun-spots. When there are
many sun-spots, and they are scattered widely over the
zones in which they may appear, then the silver petals
of the great sunflower are many, and surround the
whole of the stalk. The child has not begun to play
the game of * Loves me, loves me not,' has not plucked
out any of the silver petals, but has only ruffled them,
broken them, cramping one behind another in a bunch

PLATE XXX.

Southern Region of the Corona of JIay iS, igpi, showing the polar 'phimes.'
(From a photograph by Mrs. ll^iltcr Maunder, taken in Mauritius.)

159

PLATE XXXI

Eastekn Region of the Corona of May iS, 1901.
(From a fhotogrttpli by Mrs. Walter Maunder, taken in Mauritius.]

160

THE SUN AND MOON TOGETHER i6i

here, or spreading them out thin there. But he plays
his game as the spots diminish and creep downward to
the sun's equator ; the petals are ruthlessly pulled out,
and if we look upon the eclipsed sun at such a time, we
see but the short protecting leaves, and here or there a
long petal remaining, looking longer by its solitariness ;
and when the cycle has reached its time of minimum
activity, and the sun-spots lie only in two narrow zones
to the north and to the south of the sun's equator, then
the resemblance to the silver sunflower has departed^
and the sun's corona has become like four great wings :
angels' wings, folded wings ; one pair stretched along to
the east of the sun, the other pair to the west. Whilst
round the north and south poles of the sun a beautiful
row of fine plume-like rays is seen, each plume bending
more or less away from the pole. The corona, like the
prominences, the spots, and the faculae, has its cycle of
changes, which it runs through in about eleven years.
{See Plate XXX.)

Bufthere is a closer connexion still between the
changes of spots, prominences, and the petals of the
corona. Spots give forth or spout prominences, and the
base of the corona petal seems to envelop or stand upon
the spot group, though stretching out far beyond it on
all sides. Directly above the prominence the material
of the petal seems forced up to form a dome, or rather, a
series of domes or groined arches. The prominence

1 62 STORIES TOLD BY THE SUN

looks as if it were sheltered beneath a number of glass
cases. {See Plate XXXI.)

As the prominences and spots change, so they seem
to change the form of the corona lying round and just
above them. Nowadays, astronomers strive to observe
an eclipse at places very far apart, because it takes time
for the shadow of the moon to travel along its path on
the earth. So the observers who watched the eclipse
of 1 90 1 in Mauritius watched it an hour and a half
earlier than the observers who saw it in Sumatra. And
it was thus found that, in such an interval of time, the
shape of the corona near the chief spot and prominence
underwent a distinct alteration.

What is the shape of the silver petals of the great
sunflower ? At the broad base of it we often find a
spot or prominence, or both. Spots and prominences
rise, live their life, which may be but a very short one,
and die. And there rise again — in the same zone, it
may be from the very same region — other spots. From
these zones, from these very regions, perhaps, the great
silver petals spring. If the active regions are in the high
latitudes and in many zones, then many petals arise ; if
the sun is quiet and the few spots that break out lie
near his equator, then the petals are few and lie folded
along the equator.

But the petals do not have a round or pointed tip ;
the outermost groined arch that covers the place where

THE SUN AND MOON TOGETHER 163

the prominence is, or has been, is not complete, but
seems to taper out indefinitely into a long, rod-like ray.
How long the rod-like ray extends we cannot see. One
that was photographed in the eclipse of 1898 was seen
to stretch out from the sun for at least eleven millions
of miles. In the Story told by the Sun and Earth
together (Chapter X.), we shall see that such a length
is probably but a small fraction, but a tithe, of its extent.

CHAPTER IX

THE STORY TOLD BY THE SUN'S BROKEN

LIGHT

THE earliest astronomy was learned by the exercise
of the unaided sight. Men watched where the sun
appeared to rise and set, they noticed the changing
phases of the moon, and how different constellations of
stars were seen on different nights of the year, and from
these, and many other such observations, they formed
their first ideas of the relation of the earth to the rest of
the universe. Three hundred years ago the telescope
was invented, and ' astronomy ' took on a much wider
meaning. Men were able to read far more in sun, moon,
planets, and stars than they had ever dreamed of before.
But just as the astronomy of the telescope had advanced
far beyond what was possible to the astronomy of the
unassisted sight, so, fifty years ago, a new instrument
extended men's powers of research far beyond anything
which the telescope could have done, and gave birth to
a yet newer and more searching astronomy still.

This newer astronomy might well be called the

164

THE SUN'S BROKEN LIGHT 165

'Story told by the Rainbow,* for the many-coloured
arch of light ' seen in the cloud in the day of rain ' is
at once the type and an example of the principle of
the new science.

We know that if sunlight is allowed to fall upon a
triangTilar piece of glass, a rainbow-coloured strip of
light emerges from it. At one time it was much the
custom to have chandeliers and gasaliers of glass hung
with a number of long, triangular glass pendants. The
light falling on such a chandelier would pass through it
to form a great number of beautifully coloured images
on the wall behind. The light fell upon these prisms, as
the triangular pieces of glass are called, as white light ;
it came forth as coloured light.

The explanation of this is simple. Light is made
up of an infinite number of very small vibrations, or
waves, and these waves are of different lengths, the
longest giving us the impression which we call red ;
the shortest the impression which we call violet. Now,
light moves forward in straight lines, but when it
passes from one medium, like air, to another medium
of a different density, like glass, it is bent out of its
course and travels in a different straight line through the
second medium. Passing out of that second medium
again into the first, the course is again changed, and
the amount by which it is changed on each occasion
depends partly on the relative density of the two

1 66 STORIES TOLD BY THE SUN

media, and partly on the angle at which it meets the
new surface.

Here it is that the principle of the prism, of the
triangle, comes in. A ray of light passing through a
sheet of glass with parallel sides would be turned
out of its course indeed, but its final course would be
parallel to its original course, because its change of
direction on leaving the glass would be just the reverse
of that on entering it. But if the two sides of the piece
of glass are greatly inclined to one another, in other
words, if the glass is a prism, then the direction of the
light after leaving the prism is quite different from that
which it had before entering it.

This is what is called the refraction of light, but
there is another effect. The very short waves of light
are turned more out of their course than the very long.
Consequently, the many different waves which entered
the glass all in company leave it separately. If we had
a company of men advancing at the double over smooth
ground they would keep together, but if they came on a
piece of difficult ground, irregular broken ground, with
long grass or brushwood, wedged into the smooth plain,
the stronger, bigger men would work their way through
most quickly, and with least change of their direction ;
the smaller, weaker men would be most hindered, and
the company would emerge no longer together, but
straggling.

THE SUN'S BROKEN LIGHT 167

In like manner, light falling upon a prism enters it
as a full company, compact and close, of all the different
coloured rays, and when all the rays thus reach our eyes
together, they produce upon us that sensation which we
call white. But such white light leaving the prism,
leaves it straggling, each colour following a different
path, each colour therefore seen more or less separately, so
that, instead of white light, we get a rainbow-tinted band.

Now let us make this experiment more carefully.
We will take a western room on which the sun is shin-
ing as it nears its setting ; we will close the shutters, but
in one of the shutters we will bore a small round hole
(A), so that the sunlight falls on the opposite wall and
makes a round bright spot (?'), there. If we place a
triangular piece of glass (P), just inside the hole, we find
that the spot of light has greatly changed its position on
the wall and instead of being round it is about five times
as long as it is broad — red at one end and violet at the
other (V to R), and with the other colours of the rain-
bow somewhat less clearly seen in the middle. {See
Plate XXXII., fig. i.)

Now, it is clear if there are only seven colours, and
therefore seven different little coloured spots of sun-
light, that these must overlap, since the whole image is
only five times as long as it is broad. None of the
colours therefore are quite pure, and in the centre of the
band they are still a good deal mixed.

1 68 STORIES TOLD BY THE SUN

Can we get over this ? The simplest way to do so
would be to have a very narrow slit instead of a round
hole in the shutter. In that case, we should find that
the colours were far purer than they were before, and we
should find also, as did Professor WoUaston, the great
chemist of more than a century ago, that the rainbow-
tinted band was not complete ; there were certain narrow
dark spaces in it. In other words, the sun sends us
a great number of different colours, but not every colour
possible. This we can test by substituting a very bright
artificial light, like the limelight, for the light of the sun ;
no matter how narrow and sharp we make the slit, we
get no dark lines amongst the colours coming from the
limelight.

It is not always convenient to set apart an entire
room for the purpose of such an experiment, and a little
instrument was devised for the study of the sun's
spectrum, as the strip of rainbow light was called, which
was at once much more convenient and more powerful.
This instrument was called a spectroscope. A metal
slit (S) was provided, the breadth of which could be
regulated by a screw, and this admitted the light into
a tube (A), carrying a lens, called a collimator, at the
other end. The tube was of such a length that the
slit was exactly in the focus of the lens, so that the rays
of light diverging from the slit were rendered parallel by
it ; then came a box containing a prism (P), and the

PLATE XXXII.

Fig. I. — Path of Kays through a Prism.

Fig, 2. — Simple .Spectroscope.

A COLLIMATOR

Fig. 3, — Plan of Simple Spectroscope.
169

PLATE XXXIII.

^^^E A ''^^?^^%i^'i^^^l
^^B,^^^^'^'^^^-^ ^^H

'":'''Jr-i^i'^

:: V -I.

3 :^ C :

■uinjiogdi^ J^'|C'S i" l-'^J

■LU[i4]D3dg mnipoc; jo S3ui';[ ii.|Siig

170

THE SUN'S BROKEN LIGHT 171

rays, after they had passed through the prism, were
examined by a small telescope (B).

Such is the form of a simple spectroscope. Spectro-
scopes of great size and very complex form are now
common, but such a simple spectroscope as that just
described exemplifies the fundamental principle of all.
{See Plate XXXII., figs. 2 and 3.)

Turning such a spectroscope upon the sun, it was
seen that its 'spectrum,' that is to say, the long coloured
band into which the sun's light was spread out, was not a
perfectly continuous one, but was interrupted by dark
lines to the number of many hundreds, or, indeed, if a
very powerful spectroscope be used, of many thousands ;
and that these lines were distributed irregularly through-
out all the colours, making up a definite pattern which
was the same from day to day. {See Plate XXXIV.)

These lines of the spectrum are the characters in
which ' the sun's broken light ' tells its story, and at
first they proved very hard to read. Some of the lines
were evidently due to the influence of the earth's atmos-
phere, for they were seen when the spectroscope was
turned upon the sun near his rising or setting, that is to
say, when he was looked at through a great thickness of
our atmosphere ; but they got thinner, fewer, and fainter
as the sun rose higher in the sky. Many more, obviously,
belonged to the sun himself, since certain of the stars
showed different sets of lines. The spectrum of Arcturus

172 STORIES TOLD BY THE SUN

is very like that of the sun, but the spectra of Sirius and
Vega, though very like each other, are quite different
from that of the sun, or of Arcturus. The spectrum of
Antares, again, is different from both. In short, many
varieties were found amongst the spectra of stars ; one
star differed from another, not merely in its glory — in the
amount of the light it gave — but in the quality of its
light, and five principal types of star spectra were
recognized. The white stars gave one type, like that
of Sirius, some of the slightly greenish stars in the
constellation of Orion giving a modified form of the same
type ; the yellowish stars quite another type, like that of
Arcturus, or Alpha Centauri, or of the sun ; the deeper
coloured stars like Antares, the chief of the Scorpion,
gave a third ; and the red stars, of which there is no
bright specimen, gave a fourth. {See Frontispiece, Plate
XXXIV.)

These dark lines in sun or star therefore are due to
something in sun or star itself, sun and stars each
sending us a message in their broken light.

It was a very common substance that gave the key
to the interpretation of these strange gaps in the
spectrum. If a candle or spirit-lamp be fed with a
little common salt or carbonate of soda, a yellow tinge
is given to the flame. When a spectroscope is turned
upon such a flame a spectrum is seen which has a very
bright line in the yellow, and, if the slit is made very

THE SUN'S BROKEN LIGHT 173

narrow, it is seen that this bright line is really a
very close pair of bright lines. These two lines are
simply images of the slit, through which the light from
the spirit lamp comes into the spectroscope ; and we
learn from it that the yellow light of the spirit lamp is
due to two kinds of yellow light that differ very slightly
the one from the other. In like manner the dark lines
in the spectrum of the sun are negative images of the
slit ; the sun sends us light of many shades, but not of
all, and the gaps or dark lines in the spectrum are in
the places corresponding to the missing shades.

Now, if we look at the sun's spectrum we see, in the
yellow, a close pair of very dark lines, corresponding in
position to those given us by the carbonate of soda in
the spirit lamp. They correspond so closely that if we
allow sunlight to come through part of the slit of a
spectroscope, and light from a sodium flame to come
through another part of the same slit, we shall find that
the bright lines from the flame are an exact prolongation
of the dark lines in the sun. {See Plate XXXIII., fig. i.)

We can go a step further. The limelight, as we
have seen, gives us a complete spectrum — all the colours
of the rainbow. A sodium flame gives us the two close
bright lines. If, then, we look at a limelight through
the spectroscope, and place a flame plentifully supplied
with sodium between the spectroscope and the lime-
light, what shall we see .-* A bright spectrum of all the

174 STORIES TOLD BY THE SUN

colours with two lines specially bright in the yellow ?
No. We see a spectrum with the full succession of
colours, except in the yellow, where there are two dark
lines. Remove the sodium flame and the spectrum is
complete. Remove the limelight, and have the sodium
flame alone, and we have the two bright lines. View
the limelight through the sodium flame, and in the place
of two bright lines we have two dark ones. To the
extent of these two dark lines we have built up an
artificial solar spectrum. The sodium flame, which had
the power of sending out light of these two particular
shades, has also the power of stopping light of these
two shades ; and the lines which it gives look dark
because they are so much fainter than the corresponding
portion of the bright limelight spectrum. {See Plate
XXXIII., fig. 2.)

This is the reading of one set of characters written
for us by the sun in his broken light. His bright
surface sends out light of every shade — white light —
but round him, enveloping him, are highly heated,
glowing gases, themselves giving forth light of certain
particular shades or colours, and therefore opaque to
those same colours. These gases, if we could see them
by themselves, would give us spectra of bright lines;
but when we look at the body of the sun through them,
they stop out the light corresponding to those lines and
give us dark lines. In this way we have been able to

THE SUN'S BROKEN LIGHT 175

recognize the presence round the sun of a number of
elements with which we are familiar here, but in a
different state. Hydrogen, here one of the two con-
stituents of water, is there a free gas. Iron, nickel,
cobalt, magnesium, and many other metals here always
solids, are there always gases, glowing with intensity of
heat. The same elements have been recognized also in
the stars, but in apparently different proportions in
different stars ; at least, the evidence for their presence
is given in different manner.

There are times and seasons when we can see these
gases by themselves, apart from the sun's light. Some
of them, as, for instance, hydrogen and calcium, surround
the sun to such a depth that we can put the slit of
the spectroscope pointing some distance away from the
edge of the sun, and yet have some of these gases
within its field of view. In this way we are able to
recognize the presence round the sun of a shell three
thousand miles deep, largely composed of hydrogen
gas, from which great flames — prominences or protu-
berances, as they have been called — shoot up from
time to time to a distance, in some cases, of more
than 100,000 miles.

Of these prominences or red flames we first learnt
during, total eclipses of the sun, when the dark body of
the moon had cut off the direct light of the sun from
us, and a great number of the elements more closely

176 STORIES TOLD BY THE SUN

surrounding the sun show their bright lines to us, for
a couple of seconds, at the beginning and end of such a
total eclipse.

The stories which have been told by the broken
light of sun and stars would require an entire volume as
large as this to summarize even in the briefest fashion.
But there is one further fact told by them that must
be mentioned here. They have not only told us that
the sun is made up of elements known to us on the
earth, and that those elements are there in an extremely
highly heated condition, but they have been able to tell
us of movements of those elements, or of sun and stars
themselves. It sometimes happens that a vast quantity
of glowing hydrogen gas is shot forth from the part of
the sun that appears to us as its edge, and we then see
it travelling away from the sun, for it is moving across
our field of view ; it seems to be moving on the vault of
the sky. But it may happen that such a stream of
hydrogen may rise from the very centre of the sun's disc
and come straight towards us. Or it may be that we
are watching a star, and that from some cause or
another, the star is moving with great rapidity in a
straight line either towards or away from the earth.
These motions are what we call ' motion in the line of
sight,' or ' radial motion,' because it is motion along a
radius having the earth for its centre. Now, if the star
or the hydrogen gas is coming towards us, then the fact

THE SUN'S BROKEN LIGHT 177

of it so approaching us will make the waves of light
appear little shorter than they really are ; we shall meet
more of them in a second of time than we should other-
wise have done. Any particular line, whether bright or
dark, in the spectrum of the body thus approaching us,
would therefore seem to be shifted just a little towards
the violet end of the spectrum, the end of the short
waves. If the body were moving away from us, the
shift would seem to be towards the red, the end of
the longer waves. In this way we have been told
of movements towards us or away from us, whether of
gas streams in the sun, or of stars far in the depths of
space — movements which formerly it seemed hopeless
that we should ever detect.

CHAPTER X

THE STORY TOLD BY THE SUN AND
EARTH TOGETHER

WE have already seen how great are some of the
spots that form upon the sun. Thus on February
13, 1892, there was a great group on the sun, the
principal member of which was 92,000 English miles in
extreme length, and 62,000 in extreme breadth. Smaller
spots accompanying the chief disturbance were seen
round it on every side, so that the entire group was
162,000 miles in extreme length, and 75,000 in extreme
breadth. . The area covered by the chief spot was close
upon 3,000 millions of square miles, or, including the
smaller spots that clustered so thickly round the central
one, the area covered by the whole group was upwards
of 3,500 millions of square miles. Such an area is more
than seventeen times that of the entire surface of the
terrestrial globe ; or, to put the matter in another way,
some seventy worlds as large as our own could have
lain side by side in that immense hollow.

Even larger spots than this have occasionally been

178

THE SUN AND EARTH TOGETHER 179

seen. In February, 1905, another great outbreak
attained an area of very nearly 4,000 millions of square
miles, and groups of half that size are not very infrequent
objects.

Now, at first sight, it would seem as if a spot of such
dimensions could not fail to produce a great effect upon
the earth. If there was an object as bright as the sun,
surface for surface, and of the same apparent size as the
great spot of 1892, shining in the;nidnight sky, it would
give us more light than 3,500 full moons, and 130,000
times as much as all the stars in the heavens put
together. Now as the spot appears to us to be dark, it
might seem that whilst it was marring the sun we were
losing this enormous amount of sunlight. Indeed, when
we compare the position of the earth with that of the
other planets dependent on the sun for their light, it
seems manifest that the spots represent a most im-
portant loss ; for the entire sun does not look nearly
as large from Uranus as this great spot appeared to us.
Even Saturn, bright and readily seen as that planet is,
does not receive much more than twice the light from
the sun that we receive from a part of the sun equal in
area to the sun-spot.

These figures have led many people to expect an
immediate and striking change upon the earth in answer
to the formation of a great spot upon the sun. The
spot is so really vast, so much greater in size than the

i8o STORIES TOLD BY THE SUN

little world on which we live, that it seems quite natural
at first sight to ascribe a great influence to it.

So, from time to time, we hear it said, if we have a
hot season, that it is due to there being many spots
upon the sun, or else to the sun being free from spots.
And in just the same way we find the same said if we
have cold seasons, or rainy seasons, or dry seasons.
Any weather that is at all irregular is at once ascribed
to the presence of spots on the sun, or to their absence.
Now, the amount of rain that we get in England varies
from one year to another. Let us take the rainfall as
registered at Greenwich, and compare it with the area of
the spots observed on the sun. It is only necessary to
look at the two curves to see that they have no connexion
with each other. There is a sort of regular swing about
the changes in the sun-spot area in eleven years or so ;
there is no such regular swing in the changes of the
rainfall. Sometimes a very dry year, sometimes a very
wet year, falls when there are most spots on the sun ;
and exactly the same thing happens when the spots are
very few. {See Plate XXXV., fig. i.)

But England may not be a fair example, and a much
more hopeful and important inquiry has been set on foot
as to whether the famines in India may not in some
way correspond to the variations on the sun. So far, no
connexion has been definitely established ; the nearest
approach to such a connexion being a possible greater

PLATE XXXV.

Fig. I. — Curves of Son-spot Areas and Annual Rainfall.

The dotted line shows the numbers of Sun-spots, year by year ; the continuous line the Annual Rainfall
at Greenwich (expressed in inches) for the same years.

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PLATE XXXVI.

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Photographic Trace of Magnetic Storm of February 13, 1892.
{From the photographic registers taken at the Royal Observatory, Greenwich, from noon
February 12 to noon February 14.)

The upper register shows the abrupt beginning of the storm and the contrast between the normal and

the disturbed traces.

THE SUN AND EARTH TOGETHER 183

frequency of famines or scarcities iif one province of
India — the Madras Presidency — when spots are rela-
tively few.

And if we think over it, there is no reason for
surprise that we should find it very difficult to make
out any connexion of the kind. A spot like that of
February, 1892, is enormous of itself, but it is a very
small object compared with the sun ; and spots of such
size do not occur frequently, and last but a very short
time. We have no right to expect, therefore, that a time
of many sun-spots should mean any appreciable falling off
in the light and heat we have from the sun. Indeed,
since the surface round the spots is generally bright
beyond the ordinary, it may very well be that a time of
many spots means no falling off, but rather the reverse.

Is there no connexion, then, between these great
changes on the sun and any kind of change on this
earth of ours? The sun has upon him spots, faculae,
prominences, and corona, that change and move, wax
and wane, in sympathy, and according to some law.
The sun turns round upon his axis and carries with him
the spots, faculae, and prominences. Has that motion of
his any effect upon us ? Would it matter to us if he could
not turn ? Would it make any difference to us here
if he were blank and unchanging, as, for the most part,
he seems to be to the naked eye ? Are any of the laws
of the sun laid upon the earth ? The corona is always

1 84 STORIES TOLD BY THE SUN

surrounding the sun ; the prominences may be there,
though we cannot see them. Can they affect us here on
the earth whether we should ever see them or not?
Could they affect us here on the earth even if we hid
ourselves in her depths, shut off by many feet of cold
ground from the sight of the sun, from the knowledge
of day and night, of summer heat or winter cold ?

In a deep, windowless cellar, guarded from all light
or heat or knowledge of the sun, there hangs a long
steel bar, poised level by a silken thread fastened to its
middle. It is balanced true, so that it moves neither up
nor down, but the silk thread that suspends it allows it
to move, as it will, to right or left. The room is not
quite dark, for there is a lamp, and a ray of light from
this falls on a little mirror on the steel bar, and is by it
reflected to a sheet of photographic paper. The paper
is wrapped round a drum which revolves, so that, if
the steel bar remains steady, the ray of light reflected
from the mirror upon it leaves a straight black trace
on the moving paper. But if the bar swings to
left or right, quickly or slowly, then the ray reflected
from the mirror fastened to it dances to and fro upon
the paper on the drum, and leaves behind it a wavy or
a jagged line.

But why should the steel bar swing or quiver ? It
is hanging deep down in an underground cellar, where
no breath of wind can ever come to stir it, where no

THE SUN AND EARTH TOGETHER 185

overhead traffic can shake the earth and send it quiver-
ing. It is in the still depths, far from the madding
crowd's ignoble strife. What disturbing message can
make it quiver ?

But the sun has other messengers than his rays of
light and heat : messengers that do not heed bolts and
thick doors or walls ; that care not for darkness and cold.
To such messages as these bring the steel bar responds
day by day, year by year, cycle by cycle ; answering
back not only to the movement of the sun as he runs his
daily and his yearly course in our sky, but quivering
in sympathy with the very state of the sun himself,
whether he is suffering from a great outbreak of spots,
prominences, and faculae, or whether he seems to have
sunk back into quiescence.

The steel bar — a magnetic needle it is called — is
balanced so that it will point nearly due north and south
if undisturbed. But it does not remain undisturbed for
long. From about nine in the morning till about two in
the afternoon there is a feeble swing of the magnet to
the west, and during the remaining hours it creeps back.

Day by day the magnetic needle swings to and fro,
but the extent of the swing is not always the same. If
we plot down the extreme distance of its pulse for each
day, month by month, and year by year, we see that the
swing is greater in the summer months, when the sun is
long visible and high above the horizon, than in the winter

i86 STORIES TOLD BY THE SUN

months. But the average swing in the summer months
for one year is not the same as for another, nor yet do
the winter months give always the same swing. If we
take the average of all the swings, year by year, we still
find a steady progression. There is a pulse, too, in the
years — a cycle — and the extent of the cycle is about
eleven years, the same as the cycle of the sun-spots, the
faculae, the prominences, and the corona.

Is this a coincidence merely, or is there any con-
nexion between the sun's surroundings and the mag-
netized bar, swinging in the cold and dark ? It cannot be
a mere coincidence, for not only are the lengths of the
cycles the same, but one can superpose them. The
greater the number of spots and faculae, the greater the
swing of the magnetic needle ; when the sun sinks into
a quiet state the swing of the needle is short and feeble.
Thus in Plate XXXV., fig. 2, in which the areas of
sun-spots and faculae are exhibited diagrammatically
year by year in comparison with the daily variation
shown by the magnetic needles, it will be seen at once
that the maxima of the solar curves correspond always
with the maxima of the magnetic curves, and the minima
with the minima. There is, then, a connexion between
the state of the sun and the swing of the needle. But
how close is it ?

Every now and then — we cannot foretell when — a
monster spot breaks out upon the sun. It passes across

THE SUN AND EARTH TOGETHER 187

the sun's disc into his unseen hemisphere, and may come
again round his eastern rim a second, even a third, fourth,
and fifth time. We know it to be the same spot by its
place upon the sun — its solar longitude and latitude.

Every now and then, without warning, the magnetic
needle, swinging gently to and fro in the stillness,
becomes violently agitated. It quivers and starts as
if it were transmitting a panic-stricken messag'e, uttered
so hastily that light is not a writer quick enough
to transcribe it. The quivering and the agitation may
last for hours or days ; then it ceases, and weeks may
pass before the quiet swing is disturbed again. Who
sent this message ? Where does he stay ? What does
it mean ?

In the November of 1882, a monster sun-spot,
easily visible to the naked eye, crossed the sun, and
when it was about halfway across, on November 1 7, a
very violent magnetic storm, as these agitations of the
magnetic needle are called, occurred. It began very
sharply at ten o'clock in the evening. Ten years later,
in February, 1892, a still greater spot, the one already
referred to, appeared upon the sun, and when it had
passed a little to the west of the sun's centre, on February
13, at five o'clock in the evening, a still, more violent
magnetic storm occurred than in 1882. It also began
very suddenly. This great spot passed off the sun, and
returning to the eastern edge, again crossed the sun's disc.

1 88 STORIES TOLD BY THE SUN

When it arrived at the same distance from the centre
of the sun, there suddenly broke out again upon the
earth a great magnetic storm. This was at ten-thirty
on the morning of, March 12, 1892. Eleven years later,
in October, 1903, yet another giant sun-spot appeared,
and when it had got a little more than halfway across
the sun, there was a magnetic storm, but not a violent
one. But a fortnight later, when an important, but
smaller, spot had got into a central position on the sun's
disc, a magnetic storm burst suddenly, at six o'clock in
the afternoon of October 31, the most violent that has
been experienced in the memory of man ; so violent that
it disturbed the submarine cables all over the world, and
stopped the sending of any telegraphic messages. {See
Plate XXXVI.)

Had the spots and the storms anything to do with
each other ? They happened together, but though some
monstrous spots came at the same time as monstrous
storms, yet the biggest spot we have ever known of
came with quite a feeble storm ; and a spot of moderate
size accompanied the most violent of all storms. Yet
further, there are many spots and many storms, but we
cannot link them all. Many great spots are accompanied
by no storms at all ; many storms occur when we cannot
see a spot on the sun at all. Why does the law which
connects them only seem to work sometimes ? What is
the association between them .■*

THE SUN AND EARTH TOGETHER 189

It is the great spot of 1892 that supplies the clue to
the mystery. The time between the return of the spot
to the same place is the apparent time that it takes the
sun to turn on his axis, and that is the time that occurs
over and over again as the interval between successive
magnetic storms. On a particular region of the sun
some commotion occurs : sun-spots, faculae, prominences,
are formed ; above the disturbed area a great petal-like
streamer of corona arises, its apex drawn out into a rod-
like ray, which extends from the sun to distances which
may be expressed in scores or hundreds of millions
of miles. Indeed, in the eclipse of 1898 such rays were
photographed, and they have been photographed in
other eclipses, though not to quite the same great
extent. {See Plate XXXVII.) In these rays the par-
ticles, whatever their nature, are not now connected with
the sun, though they once were ; each still keeps the
direction and motion which it had when it left the sun.
If, then, we could look down on the sun, we should
see him spouting forth, from one region or another,
as smoke issues from the funnel of a steamer, long rays,
which remain as spirals behind him as he turns con-
tinually on his axis. The sun may go on spouting a
coronal stream from the same region for months at a
time, and in this region spots may break out and die,
and again break out ; for sun-spots are but one symptom
of the sun's activity, and, perhaps, not even the most

I90 STORIES TOLD BY THE SUN

important symptom. As the earth moves round the
sun, which is himself turning on his axis, the same long
stream may strike and pass it, may strike and pass
again, month after month, for many months at a time ;
or perhaps it may sometimes strike and sometimes miss.
There is no reason for surprise, then, that sometimes
a great sun-spot is not answered by a magnetic storm
on earth, for the ray from it may have missed our little
world. So, too, we may have a storm when there is no
spot visible, for the coronal ray may have been shot
forth before the spot has formed or may be still in
action after the spot has been covered over or filled up.

The law that governs the changes of the sun, his
waxing and waning cycles in spots and faculae and
prominences, has its answer in the earth. It is under
the influence of this law that the magnetic needle writes
in the darkness and stillness of the cellar ; it writes of
great changes, great commotions, that are going on in
the sun ; and of the sending forth of these stupendous
coronal rays, which we can only see at rare intervals,
and by the accident, as it would seem, of the moon's
dark body shutting off the sun's light, and allowing us
to look upon the lesser brilliance of his surroundings.

It does not seem strange that such stupendous com-
motions on the sun should have an effect upon the
earth. The spots are but a minor symptom in the great
solar outbreak, and these spots, very many of them,

THE SUN AND EARTH TOGETHER 191

could engulf the earth entirely. The wheel can certainly
affect the fly upon it.

But can the fly affect the wheel ? Can the earth
exert any influence on the sun, or on the monstrous
commotions upon it ? The question seems to stand
self-condemned as an utterly foolish one. But — does
the earth influence the sun or the sun-spots ?

The sun's equator and his poles are definite regions
on him ; they are fundamental positions on his surface,
due to his turning on his axis. But the eastern rim,
the western rim, and the central line of the sun, as we
see them, are not definite and unaltering regions on him ;
each region of the sun takes up all these positions in
turn. East on the sun is east and west is west only to
us on the earth ; they would not hold these same positions
to another planet; an observer on the sun could not
recognize them at all. The sun's visible hemisphere
only differs from the sun's invisible hemisphere in the fact
of the earth's relation to the two. If, then, the eastern
half of the sun differs systematically from the western
half, or the visible hemisphere in any way from the
invisible hemisphere, those differences must be due to
the earth.

We do not see the sun's invisible hemisphere, and
therefore we cannot measure the spots that are there,
or count them. But the sun is continually turning
round, and we can count the spots that come into view

192 STORIES TOLD BY THE SUN

round the eastern rim, and we can count the spots that
disappear round the western rim. If the earth had no
influence on sun-spots, the numbers that came on should
be, in the long run, just about equal to the numbers that
go off. If more spots in the long run come round than
go off, then the earth's influence must tend to kill the
spots. If more go off than come on, then the earth's
influence must tend to develop them. We find that the
earth tends to kill the spots, and that to a degree which
is out of proportion to its size. In a period of eleven
years, though 947 spots came round the east, only ']']^
went round the west. The earth put out 1 70 spots in
eleven years.

If we measure the areas of all the spots when they
were seen in the eastern half of the sun, and also in the
western half, we find, similarly, that, in the long run, the
eastern areas are greater than the western, for the earth
tends to diminish the spots and to quiet down the
commotions on the sun.

And if the earth tends to subdue the sun's agitation,
so probably do the other planets — Mercury, Venus,
Mars, Jupiter, and the rest — though their influences we
can only suspect ; we cannot yet measure.

We have seen how the sun influences the earth — by
his heat, his light, and the changes in himself which pro-
duces magnetic storms on the earth. In how many
other ways he dominates the earth we have yet to learn

THE SUN AND EARTH TOGETHER 193

— whether his changes cause our blizzards and our heat-
waves, our hurricanes or earthquakes. We may know
some time, definitely, that with his changes these things
do come or do not come ; but we do not yet know.

Nor do we know by what means the earth influences
the sun. We have seen that it tends to quiet some of
his disturbances, but how we do not know. Nor do
we know if sometimes, or by some means, it or any
of the other members of his family may tend to rouse
him to greater activity.

BOOK III

STORIES TOLD BY THE SUN'S
FAMILY

CHAPTER XI

THE STORY TOLD BY THE PLANET
JUPITER

TUTE may think of a nation as a collection of families
^ bound together by common laws. The head of
a family is its representative in the nation ; and in each
family, laws special to it also hold good, though these
laws must not run counter to the laws of the nation, else
both nation and family will suffer.

We may think of the universe of stars as a collection
of solar systems. We classify these suns by their re-
semblances to our sun, or by their differences from him.
We may well believe that all, or many, of these suns
have systems dependent on their control, but of only
one such system have we any knowledge — that belong-
ing to our sun. And, just as we may study the cha:-
racters of the members of a family, so may we study
the characteristics of the members of the solar system.
Their individualities are distinct; they differ much
amongst themselves and from the sun; yet some of
them have traits that are distinctly sun-like.

197

198 STORIES BY THE SUN'S FAMILY

The one planet that is more eminently sun-like than
any of the others is the planet Jupiter. He is more
than equal in size to all the other planets put together ;
he controls a numerous minor system of his own ; like
the sun, he has a spotty globe ; he is a semi-sun.

But the sun has a diameter of 866,400 miles ; the
diameter of Jupiter is but a tithe of this. The sun is
distant only some ninety-two millions of miles ; Jupiter
is more than four times as far even when at his nearest
to us. We cannot see that Jupiter is not a mere point
of light with the naked eye ; we should have to magnify
him at least fifty times to make him seem as big as the
sun looks without the aid of a telescope.

If we look at Jupiter through a telescope which
magnifies his actual size fifty times or even two hundred
times, he seems to have a very different appearance from
that of drawings of him in astronomical books. The
picture of Jupiter in the book is perhaps drawn to a
scale of two or three inches to the planet's diameter, and
so if we held it at the distance from our eyes that we
usually hold a book, it would cover up a space in the
sky twenty or thirty times the breadth of the sun.
When we are looking at the sun low down in the sky
we are looking at him over trees, or houses, or hills.
We know that these last are really larger than they
may appear to us to be ; we unconsciously compare the
sun with them, knowing that the great light is vastly

PLATE XXXVII.

"-•-.

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tJO

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PLATE XXXVIII.

Jupiter and his Satellites.
As seen in a 12-inch reflector with a magnifying power of about 300.

THE PLANET JUPITER 201

more distant ; so we unconsciously magnify his apparent
size ; we seem to see him covering a greater space than
he really does.

But when we look at Jupiter in a telescope that
magnifies him fifty times, we see him alone, cut off by
the telescope tube from any houses, or trees, or hills with
which to compare him ; there is nothing to make us
unconsciously magnify his appearance ; he looks as he
really is, a very small object ; no bigger than a sixpence
looks seven feet away. The drawing by the Rev. T. E. R.
Phillips in Plate XXXVIII. gives a good idea of the
actual appearance of Jupiter and his moons in the field
of a telescope when a magnifying power of about 306
is employed.

To the naked eye, the sun looks but a glowing disc
of light. It is only rarely that the unassisted sight can
see speck or flaw on his bright surface ; and when the
eye can see a spot, it looks like a round black nail's head
driven into the sun. But Jupiter, when he is magnified
to the same apparent size as the sun, does not look like
this. His is no flawless disc of light, but one barred by
parallel bands, bright and dark. Nor are the bands,
whether bright or dark, quite uniform : the brightness
seems coagulated here, the darkness knotted there.

If we enlarge the apparent size of both the sun and
Jupiter, the differences in their appearances become
more marked still. There is no colour on the face of

202 STORIES BY THE SUN'S FAMILY

the sun ; there is but light and varying degrees of shade.
We can trace out the direction and place of the sun's
equator by diligent watching, for the spots and the
faculae seem to move in parallels of latitude as the sun
turns round. The spots and faculae themselves seem
often to lengthen out along these parallels, but the
length of the longest stream is short compared with the
circle of the sun on which it lies. Spots and faculae
seem to break out again and again along points in the
same parallel. If the sun-spots and the sun's faculae
remained permanently there and did not break out and
disappear again completely, we should expect to find
them, from what we know of them, to lie in dark and
light bands parallel to the sun's equator.

If the spots and faculae were not evanescent, but
permanent, or very long-lived, features on the sun, and
were greatly increased in size and number, we should
expect them to lie in bands parallel to his equator and
to look very much like the appearance that Jupiter
actually presents, but with the difference that we could
not have expected that these bright and dark spots
should show more than light and shade, and that some
of them should become tinted with various colours.

In Plates XXXIX. and XL. there are two paint-
ings of Jupiter by the Rev. T. E. R. Phillips ; the first
made on February 2, 1908, the other eight days later.
In both of these pictures it is perfectly easy to pick

THE PLANET JUPITER 203

out the position of Jupiter's equator : it is across the
thickest part of the disc and parallel to all the light and
dark bars.

But there are several other things to note about
these pictures of Jupiter. There are many different
colours on them, but the background seems to be a dull
yellow which deepens and smears all round the border
of the disc. In or under this yellow all the other
markings seem to lie ; it is the colour of Jupiter's atmo-
sphere, and we see that it is an atmosphere, for it
deepens near the horizons, where it seems to us to lie
thicker on the rounded body of the planet. But on
the sun we remember that we could see his bright mark-
ings, the faculae only, when near his rim, for only there
was the bright body of the sun dimmed enough for us to
distinguish the brightness of the faculae. We could not
see the sun's faculae in the centre. But here, on Jupiter,
it is in the centre that we see best all the markings,
whether dark or light ; towards his rim they fade into
the yellow. This shows us two things about Jupiter :
first, that the body of the planet is not very bright, and
is nowhere as bright as the white spots ; and second,
that all the markings, lig^t as well as dark, lie low down
in the atmosphere of Jupiter, and can therefore be most
clearly seen where Jupiter's atmosphere seems to us
to be shallowest, namely, at his centre.

The next feature to be remarked is that round either

204 STORIES BY THE SUN'S FAMILY

the north or the south pole of Jupiter, there is nothing
to be seen but greyness or yellowness, forming a broad
cap. So in the sun we found that the spots ceased when
they were about forty degrees north or south of the
equator ; the faculae were to be found a little farther to
the north or south, and the prominences yet farther.
But it would seem that the regions near the poles, on
both the sun and Jupiter, are undisturbed, inactive, and
dull.

There is nothing on the sun that we can recognize
as corresponding to the blue or crimson stripes in the
northern hemisphere of Jupiter ; nothing even that we can
compare with his even straight dark and light bands.
And if we compare the shapes and appearance of the
other white and dark markings with faculae and sun-spots,
we find very striking differences. The faculae seem
like mackerel clouds, or they sometimes mass together
like cumuli ; the spots are irregular, ragged, and torn,
with points of deeper blackness in the darkness of their
centres, and thatches of brightness projecting over them.
The white spots on Jupiter are smooth and round like
drops of milk, or eggs. The dark markings are also
smooth edged, with never a suspicion of shading towards
central pits, or of overhanging thatch. And both
light and dark are often tinted to a rosy or a purple
glow.

The picture of February lo is not the same as the

I'LATp; XXXLX.

JUPITER, 1908 February 2" 9" 40"' G.M.T.,
by Ihe Rev. T. E. R. Pliillips.

205

THE PLANET JUPITER 207

picture of February 2. We can recognize the yellowness
of the northern cap, and the greyness of the southern,
in both. We can see where one has a blue and a
crimson stripe, that the other has too ; we can find the
same style of marking at the same parallel of latitude
in both. But we cannot recognize the same marking
unchanged in the same surroundings on the two paint-
ings. Are we looking at different hemispheres of
Jupiter, or has his surface changed ? Both.

It takes about twenty-seven days for a marking on
the sun's eastern edge to come a second time to the
same position. The sun appears to us to turn round
in about twenty-seven days, that is, in about twenty-five
days in reality. We are in no uncertainty as to how
long it takes the earth to turn round ; it rotates in
twenty-four hours, never faster or slower, and everything
upon it rotates in the same piece, in the same time,
land and sea, hill and valley, at the equator or at the
tropics or at the poles. But as regards the sun we
cannot give the time of its rotation with any such pre-
cision, and this because faculae and spots seem to rotate
at different speeds. Not only are spots moving at
different rates from faculae, but all differ according to
their latitude ; and they differ in their own latitude for
some reason that we do not understand. According to
the spots we choose, the sun may appear to turn round
in any period between twenty-three and thirty-one days.

2o8 STORIES BY THE SUN'S FAMILY

Jupiter turns round also on his axis, but his turning
is shorter than the sun's, much shorter even than the
earth's, though he is so much larger. But his method
of turning is like that of the sun, rather than of the
earth. We can only say that he turns round in about
9 hours 55 minutes. White spots give a different
time of revolution from dark spots; the distance of
a spot from Jupiter's equator also seems to affect its
rate of moving ; and the same spot — white, dark, or
coloured — may move with different speeds at different
times.

There are always spots and belts on Jupiter ; he is
never free from them, as the sun may be for perhaps
years at a time. The spots of Jupiter are longer lived,
too, than those on the sun ; but they do change, it may
be in colour, or size, or shape, or brightness ; they may
even disappear altogether for a time, and leave, as it
were, the impress of where they have been.

The most remarkable of all the spots on Jupiter is
shown on the first painting by Mr. Phillips, in the
southern hemisphere of the planet. It is called the
' Great Red Spot,' and is the large grey oblong, lying
in a white cup, which seems to have hollowed a broad
dark band, lying to its north, as an Q.g^ might indent a
cushion. Another dark, smooth band arches over it to
the south. This great red spot owes its name, not to the
colour that it now has, but to that which it has had once

I'LATI-: XI.,

JUPITER, 190S Feb. 10" 13" 35'" G.M.T.,
by the Rev. T. E. R. Phillips.

2og

THE PLANET JUPITER 211

in the past. It has had a long history, if not a continuous
one. The ingenious Mr. Hooke observed it in the days
of Charles II. It appeared and vanished eight times
between the years 1665 and 1708, and then it remained
invisible until 1713. It became very conspicuous in
1878, and had then a brilliant colour. Since that date
it has always been visible in large telescopes, though
sometimes in small ones it has seemed as if it were
itself gone, and had left only its impress in the south
equatorial belt. Its impress remains clear whether itself
be visible or not, and it drifts through the dark belt,
or it may be the belt drifts past it ; or both move at
different and at changing rates.

Now, whatever the spot or the belt may be, they
are not rigidly attached to the planet's crust. We do
not see Jupiter's crust at all ; we cannot even tell if he
has a solid crust like our own earth. All the belts and
spots that we see on him must hang suspended in his
atmosphere. They are clouds in fact, clouds moving
under the influence of his winds and air currents. Our
clouds and fogs are made up of water-vapour, and of
dust. We think that the clouds that form the sun's
bright surface are made of carbon. Whether the clouds
of Jupiter are made of water- vapour or of carbon, or of
some other substance, we have as yet no means of
finding out.

CHAPTER XII

THE STORY TOLD BY THE PLANET
SATURN

T T is always the unexpected that happens in astronomy.
^ If there is one thing of which we can feel sure, it is
that when we come to study some new object, or some
object in a new way, it will present to us some feature
so unexpected, so bizarre, that, until we had witnessed
its actuality there, we should have declared that such a
feature was not only unnatural, but impossible. We have
noticed that the sun's corona is one such feature ; it is
utterly unlike what we might expect in the sun's sur-
roundings. We know of it, so to speak, by accident — ^by
the accident that the moon sometimes hides, and only
just hides, the sun; otherwise, though it exists, we
could not know of its existence. We have pointed out
that it is the vehicle to convey a disturbing power from
the sun to the earth. It has been proved many a time
and oft, proved without a flaw in the reasoning, that
the sun, or its spots, could not, by any means, by any
possibility, cause the magnetic storms on the earth.

212

THE PLANET SATURN 213

But the fact remains that he does. We can never
know ; we can always learn.

But the commonplace planet Saturn is the planet
that 'surprises by himself.' Turn back to the Story
told by the Planets. The other four had special stories
to tell for themselves. Mercury was the twinkler,
glancing out for a moment, now to the east, now to
the west, of the sun. Venus was the brightest jewel
in all the heavens ; the bright and morning star, the
chief brilliant in the crown of the evening. Mars was
the ruddy star, the blood-red star of war that alternately
threatened and retreated with the years. Jupiter was the
steady, bright-shining * Hebrew,' who crossed over the
meridian and paced out the heavens from end to end.
But Saturn had nothing special to say for himself. He
was only the yellowish star, duller than the rest, slow
moving in his westward course, slower moving in his
eastward; so slow and sluggish that the astrologers
gave him as his metal, lead : heavy, dull, inert — of little
use and less ornament.

He preserved this character through all the centuries
until Galileo turned his newly invented telescope upon
him, in the year 1610. What he saw is best given in
his own words — ■

' I have observed with great admiration that Saturn
is not a single star, but three together, which, as it were,
touch each other. They have no relative motion, and

214 STORIES BY THE SUN'S FAMILY

are constituted in this form, the middle being much
larger than the lateral ones. If we examine them with
a glass of inferior power, the three stars do riot appear
very distinctly. Saturn has an oblong appearance
somewhat like an olive, but by employing a glass which
multiplies the superficies more than one thousand times,
the three globes will be seen very distinctly and almost
touching, with only a small dark space between them.
I have already discovered a court for Jupiter, and now
there are two attendants for this old man, who aid his
steps and never leave his side.'

This observation was not generally accepted by the
other scientists of Galileo's day, because they argued
that they knew, and that, therefore, there could be no
more room to learn. And Galileo himself received a
great shock in perceiving that, during the next couple of
years, the lateral bodies were diminishing, though they
appeared to be immovable, both with respect to each
other and to the central body. Toward the close of
1612 they vanished altogether, and his opponents were
triumphant, whilst Galileo mourned —

' Are, perhaps, the two smaller stars consumed like
spots on the sun ? Have they suddenly vanished and
fled ? or has Saturn devoured his own children ? or was
the appearance indeed fraud and illusion, with which
the glasses have for so long mocked me and many
others who have observed with me ? . . . The shortness

THE PLANET SATURN 215

of time, the unexampled occurrence, the weakness of
my intellect, the terror of being mistaken, have greatly
confounded me.'

But Galileo was not mistaken, and by the middle of
161 3 he was able to announce that the lateral stars were
reappearing. They enlarged more and more until, in
16 16, he writes —

• Its two companions are no longer two small and
perfectly round globes, as they have hitherto appeared
to be, but are now bodies much larger, and of a form no
longer round, but, as shown in the annexed figure, with
the two middle parts obscured, that is to say, two very
dark triangular-like spaces in the middle of the figure
and contiguous to the middle of Saturn's globe, which
later is seen, as always, perfectly round.'

It was not until forty years later that Huygens saw
and described these strange lateral bodies as really parts
of a ring which girdles the equator of Saturn.

We have finer and more powerful telescopes than
Galileo made for himself; we are not so apt as he to be
confounded by the terror of being mistaken ; we ought
not to be, like his opponents, inclined to know more than
we learn. We may therefore study this beautiful drawing
of the planet Saturn for the sake of that which it can
teach us, (See Plate XL I.)

First, then, Saturn itself is a globe. We do not see
in this picture the entire hemisphere that is turned

2i6 STORIES BY THE SUN'S FAMILY

towards us, for the northern pole is hidden by his ring.
We cannot see the curve of the planet through the
bright ring; therefore that part of the ring is thick
enough, or opaque enough, to prevent us seeing through
it. The southern part of Saturn throws a shadow on
the far side of the bright ring ; therefore the planet is
opaque to the sun's rays, and does not shine of himself,
or not to any appreciable degree. The globe Saturn
has dark belts and bright bands, dark spots and light
spots, unmarked uniform polar caps ; liker the sun than
the earth, liker Jupiter than the sun. He is coloured,
too, like Jupiter ; unlike the sun, his poles are sometimes
blue or olive-green ; his spots show brown and purple
and ruddy tints ; his equatorial band is often of a
delicate pinkish tinge. He turns, too, on his axis in
about lo hours 14 minutes, but various regions move at
varying rates. He is so much more distant from us than
Jupiter, and so much smaller than the giant semi-sun,
that his belts and spots seem to us to have their irregular
edges smoothed off and rounded. In all this he is but a
lesser and more distant Jupiter.

But he has that which Jupiter has not. Girdling
his bright equatorial band, his thickest diameter, there
is poised a series of concentric flat rings ; not attached
to him, not touching him anywhere, but all hanging
even and level with his equator, and the nearest edge
fully nine or ten thousand miles from his surface.

THE PLANET SATURN 217

The innermost ring is dusky, transparent, crape-like ;
we can see the curve and body of Saturn distinctly
through it : it lies before his brighter surface like a veil.
This ring, then, is not solid or opaque.

The crape ring has a sharp line of demarcation from
the next ring, though there seems to be no space
between the two. And the next ring is bright and
very broad ; but it is brighter at its outer border than
at its inner ; it is a little dusky at its inner edge,
especially where we seem to see it spread out most at
the two ends of the oblong — for, though the ring itself
is truly circular, we are looking at it in perspective and
see it as if elongated. Here* it seems thin, almost
as if we could see through it ; here, too, it is not
solid, at least, nor is the substance of which it is com-
posed very closely woven together. Here and there,
too, especially on the right-hand wing, there seems
to be a darker line drawn, as if a cleavage was
beginning which might separate the broad band into
narrow rings.

Where this band is at its brightest, it ends, and a
broad line of cleavage separates it from a duller band.
Or it may be from a double band, for on the right-hand
wing of this there is to be traced for a space a distinct
tear, but one which does not seem to be continued all
round into the left-hand wing. This wing is not uniform
either, but appears gored, as are the seams of a dress ;

2i8 STORIES BY THE SUN'S FAMILY

it looks puckered and snipped as if to form a straight
strip of material into a circular band.

Saturn's ring girds Saturn's equator, and his pole
points, as ours does, at an angle to his path round the
sun. As he pursues his journey, and we pursue ours, we
see his equator and rings tilted at various angles ; we
look upon his northern pole and the northern face of the
rings, or upon his southern pole and their southern
face, or equator and rings are presented level to our
eyes. This last is when we cannot see the rings at all,
because, though the band in which they lie is nearly
40,000 miles broad, it is so thin that we cannot
see it edgewise. It cannot be thicker than a hundred
miles or so. It was at a time that the rings were so
turned to us that Galileo njade his horrifying observation
that Saturn had become a solitary and single globe.

The rings do not shine of themselves ; like Saturn,
they receive their light from the sun. Sometimes, then,
the sun is shining on their southern face whilst we are
looking on their northern, or vice versa, and we again
cannot see the rings, except where, at the cleavages near
the elongations, we can, through them, see part of their
sunlit face.

We can see through parts of the rings, so they
are not solid or liquid, since it would be impossible
to do so were they but a mile or so thick. But
they must have something material in them, since they

THE PLANET SATURN 219

intercept the sunlight and cast a shadow on the globe
where they come between him and the sun, just as a
wreath of smoke or a cloud of dust will cast a shadow.
Saturn's girdle is, in truth, a dust girdle; it is a ring,
not solid, or liquid, or vaporous, but made up of solid
particles which are 'free,' or move independently of
each other, each in its own orbit, like a true satellitoid
of Saturn. How big these bands of free satellitoids
are we do not know ; they may be rocks of many
tons mass ; they may be no more than pebbles in size ;
they may be true dust, such as the wind whirls down
our streets ; they may be no larger than those particles
which form the substance of the corona's great petals,
particles smaller than we can conceive. Saturn's rings
may, indeed, be his corona — a corona which does not
depart from the parent semi-sun in ever more widely
extending spirals as does the sun's, but a corona whose
particles are compelled to circle endlessly round the body
that gave them forth. But this, too, we do not know.

Besides these rings of satellitoids, Saturn has true
satellites, and we know of ten of them. Here we come
upon another of the unexpected happenings ; nay, more,
on an happening that was ' impossible.'

The sun, Mercury, Venus, the earth, the moon, Mars,
Jupiter, and Saturn, all turn upon their axes, and their
turning is alf in the same sense; some do not turn
from right to left, and others from left to right. Mercury,

220 STORIES BY THE SUN'S FAMILY

Venus, the earth, Mars, Jupiter, Saturn, all revolve
round the sun, and they all move in the same direction,
and it is the same sense in which all the bodies rotate.
Laplace, the great mathematician, was greatly struck by
this unanimity in the motion of the sun and his planets.
It could not be simply a chance, he argued, that all these
bodies, great and small, should all move in the one
direction. His argument was greatly strengthened by
the fact that all the moons of which he knew, the moons
revolving round the earth, or Jupiter, or Saturn, all
moved in the same direction round their planets, as
these moved round the sun. The overwhelming proba-
bility was that all the planets and satellites in the solar
system must move in this one direction. It seemed an
inconceivable thing, almost an impossible thing, that any
satellite or planet should pursue its course in a direction
the opposite of its companions.

Nevertheless, this inconceivable thing has occurred ;
this thing that was considered wellnigh impossible has
come to pass. Saturn, the planet of the unexpected,
furnished the example.

It was but a few years ago that Professor W. H.
Pickering discovered a small object on a photograph of
Saturn, which he believed was a satellite, but which he
could not find again for some years. Then, when at
last such an object was again picked up and kept in
view, its motions were so peculiar, and so puzzling, that

THE PLANET SATURN 221

' confounded ' by ' the terror of being mistaken/ he
hesitated for long to announce that this little satellite, so
distant from Saturn, so helpless and so small, was yet a
rebel to the universal law that the great sun and the
great Saturn obeyed ; that little Phoebe, as the new
satellite has been called, had struck out a new career for
herself, and was revolving round Saturn in a direction
contrary to all his other moons. It is better to learn
than to know.

And yet a second example has chanced. For,
within the last few months, Mr. Melotte at Greenwich
Observatory has discovered a new satellite to Jupiter,
an eighth in the 'court for Jupiter,' that Galileo
discovered. This satellite of Jupiter, as yet unnamed,
lies very far away from him, and like Saturn's Phoebe,
pursues a course round him contrary to all his other
moons.

There is one more instance that Saturn offers that
learning is oftentimes the enemy of knowledge. The
astrologers of times past, and of to-day, gave to Saturn
as his metal, lead : the dull, inert, heavy. But we can
weigh the earth, and the sun, and the planets, and of
them all we find that Saturn's globe is made up of the
lightest materials. He is seven hundred times the bulk
of the earth, yet he only contains in all that huge bulk
but ninety times the earth's mass. If Saturn could be
thrown into our ocean, he would not sink but float, for

222 STORIES BY THE SUN'S FAMILY

his density is but three-quarters that of water, lighter
than the substance of the sun, lighter than the substance
of Jupiter, as light as wood. There seems an irony in
this, which, were it possible, should teach astrologers
that it is better to learn than to invent sham knowledge.

TLATE XLI.

PLATE XLII.

(2)

Photographs from a Balloon,

(i) The Parade, Douglas, Isle of Man. Good photographic conditions. Air
moisture-laden ; little sunlight. i p.m. on November afternoon. (2) Over the
Ri\'er Medwaj', Kent. Bad photographic conditions. Air dry and hazy. Bright
sunlight ; summer afternoon.

224

CHAPTER XIII
THE STORY OF VENUS AND MARS

Oh wad some power the giftie gie us
To see ourselves as ithers see us !

BURNS might have added that this one gift is not
enough ; we should need a second to enable us to
recognize ourselves when thus seen.

Is there any other of the sun's planets like the earth ?
What do we look like from outside ? Should we know
ourselves to be what we are if we could look upon the
earth from some other planet ?

We can answer the first question partly if we put it
in another way. We can say what members of the solar
system are not earth-like. We can say at once that the
sun, Jupiter, Saturn, Uranus, and Neptune are not as
the earth is. Ours is a solid earth ; these are not ; they
are globes of vapour, or at most fluid, current riddled,
and without even a backwater of encrusted scum.

But of Mercury and the moons of other planets we
know too little to guess at any likeness to ourselves.

225

226 STORIES BY THE SUN'S FAMILY

There remain but three bodies amongst which we may
seek our kin — our own moon, Venus, and Mars.

We look out over our earth and find on it bare
mountains and deep valleys, craters and canons, wide
clefts and vast plains. On the moon we see all these
things unmistakably. Good ! The moon, then, is bone
of our bone. But on the earth we also see flowing
rivers and great tidal seas ; snow, cloud, and mists,
verdure and forest, follow upon these. On the moon
there is nothing of all this ; the moon is not flesh of our
flesh. On the earth the hard rigid skeleton is covered
above by living flesh ; that is to say, by fertile soil and
trees and verdure, of which the moon has nothing.

Suppose we then ascend above the earth, and, stage
by stage, as we ascend, examine the prospect that lies
beneath us. We ascend by daylight into a clear sky, so
that the higher we go, nothing but an increasing thick-
ness of unclouded atmosphere intervenes between us
and the earth's surface.

What is the atmosphere ? It is filled with exceed-
ingly small particles, capable of reflecting or scattering
light. Now, under the rays of the sun, these tiny par-
ticles have their sunward faces lit up, their earthward
faces in shadow. At any height above the earth we
can see skyward clearly, for we are looking at the
sheltered faces of the little atmospheric particles, but
when we are looking earthward the sunlit faces dazzle

STORY OF VENUS AND MARS 227

us and confuse the outlines of the objects on the
earth. The higher we go the greater is the number of
sunlit particles between us and the earth, and the more
pronounced the haziness of her appearance, no matter
how clear the atmosphere may be. With such an
atmosphere as ours we can well believe that were we
to look at the earth from but the distance of a hundred
miles or so, which is yet well within the outermost
confines of our air, we should see nothing below us
but a dazzlingly white and uniform disc of light, with
never a marking or shade to indicate which was land or
water, ice or forest, and that although no cloud floated
beneath us.

The amount of dust in the air varies astonishingly
from time to time, and the difference of the appearance of
the earth as seen from a balloon when the atmosphere is
charged with dust particles and when it has been cleaned
of them by heavy rain, is well illustrated by the two
photographs in Plate XLII. We are indebted for
these photographs, taken from a balloon, to the kindness
of Miss Gertrude Bacon, daughter of the well-known
aeronaut, the late Rev, J. M. Bacon. The upper photo-
graph shows the Parade at Douglas, Isle of Man, on a
November day when the air was laden with moisture.
The lower photograph shows the Medway, in Kent, on
a very bright day, but when the atmosphere was full
of haze and dust.

228 STORIES BY THE SUN'S FAMILY

Which of the two planets, Venus or Mars, that we
have left for comparison with the earth, shows such an
appearance ? Without doubt, Venus. We never see
her surface ; she presents but a dazzling disc, with never
a marking that we can be certain is not the result of
eyes tired with too much brightness. Whether her
atmosphere is clear or cloudy, or what lies behind that
dazzling light, we do not know. (See Plate XLV.)
Mars shows us markings in plenty, some well defined,
some ill defined. We can trace upon his face permanent
configurations of all shapes and sizes, of all tints and
shades. Certainly in his atmosphere, in his clouds and
vapours, the planet Mars differs importantly from the
planet earth.

Can we then say that, of all the planets, Venus is
nearest in kin to the earth ? If we could look upon
them from a common distance, we might see no
difference in their uniform brightness. But we know
what is beneath the earth's atmosphere ; we do not
know what is beneath that of Venus. The lesson that
the planet Saturn has taught us, we must not forget
here : We cannot know what we are not able to karn.
So far we have not learned, even yet, how long it takes
Venus to turn upon her axis. This is because there is
no marking on her that we can recognize again. We
can only tell the time more or less that it takes the sun,
Jupiter, or Saturn to turn round, not because there are

STORY OF VENUS AND MARS 229

no markings that we cannot recognize again, but because
the time given by one marlcing differs more or less
from the time given by another, and the pace, at which
any given marking moves, varies from time to time.
But Mars is in a different case from all these. He has
markings that can be recognized, no matter by whom or
where they are observed. These markings all move
together, all in a piece, as the planet turns ; each and
all turn round in the same time, and as the turning has
been watched for more than two hundred years, we can
say with certainty and precision that Mars rotates on his
axis in 24 hours 37 minutes 22*67 seconds, and that this
time is certainly not more than the one-fiftieth of a
second out from the true length of his ' day.'

So a ' day ' of Mars is only a few minutes longer
than a day on the earth. Let us examine the beautiful
painting (Plate XLIII.) that M. Eugene Antoniadi has
made of one of the sides that he presents to us every
twenty-four or more hours.

The whole is round and yellowish, but the deeper
yellow is near the centre of the disc where the least
thickness of his atmosphere comes between us and his
actual surface. Towards his rim, his horizons to us,
the yellow pales into white, so, like the sun and the
earth. Mars has an atmosphere, and we see more of
Mars himself at the centre of the disc, and more of his
atmosphere at his horizons. On the sun, the centre is

230 STORIES BY THE SUN'S FAMILY

brighter than the horizons, because it, is the sun himself
that is shining, not merely reflecting the light from
elsewhere, and his atmosphere tends to dim his light.
Mars is brightest^ near the rim, for he shines only by
light reflected from the sun, his atmosphere being a
better reflector than his surface, and in this he is like
the earth.

In the north of Mars we see a small round dazzlingly
white patch, as if marking out his north pole. So
brilliantly white it is we can only liken it to snow, and
we have such a snow-white patch round the north pole
of the earth, so that we readily connect this polar cap of
Mars with our polar ice and snow. We see the whole
of the Martian polar cap, because when this picture was
painted, it was the north pole of Mars that was turned
to us, his south cap was not then visible. Mars, like
the earth, has his summer and winter, and another point
of similarity between the polar caps of the earth and of
Mars is that in the summer of the Martian northern
hemisphere, his north polar cap diminishes, just as ours
does under like conditions. We think it probable, then,
that the polar caps of Mars are made up of ice and
snow ; but we do not actually know, and we do not yet
see how to find it out for certain.

But if the caps are made up of ice and snow, then
we naturally think that the dark ring, which spreads as
the cap diminishes, surrounding the north polar cap, is

PLATE XT. TIT.

NORTH
MARS, Ijy E. M. Antoniadi.

STORY OF VENUS AND MARS 233

melting ice — is water. And if this darkness round the
cap is water, so perhaps are the other dark markings
that we see. Perhaps, then, the dark areas on Mars are
seas and lakes, and the light are continents and islands.
Where the two border on each other we may see inlets
and bays, promontories and capes. According to this
assumption, the markings on Mars have been named.
The large dark triangle, not unlike the northern conti-
nent of America in shape, is called the 'Hour-glass
Sea ' or ' Syrtis Major.' ' Dawes Forked Bay,' like the
opened beak of a bird, lies in the south and nearly as
far to the right as the Kaiser Sea is to the left ; a great
continent lies between these, and to their north, its
northern portion being called 'Arabia,' along whose
border a long inlet, the ' Protonilus,' lies; and at the
end of this inlet is ' Lake Ismenius ' ; whilst ' Lake
Arethusa ' comes between ' Lake Ismenius ' and the
north polar cap. The continent ' Libya ' lies to the
extreme left-hand of the ' Syrtis Major,' and ' Thymia-
mata ' and ' Edom ' are on either side of ' Dawes
Forked Bay.'

The four drawings given in Plate XLI V. are by the
late Mr. N. E. Green, F.R.A.S., drawing-master to
Queen Victoria, and the truest astronomical artist of his
day. They are taken from a superb series of twelve,
published in Vol. XLIV. of the ' Memoirs of the Royal
Astronomical Society.' The entire series presents a

234 STORIES BY THE SUN'S FAMILY

complete rotation of the planet, so that all its varying
aspects can be easily followed. The four selected from
that series give a view of about three-fourths of the
planet's rotation.

The first of the above drawings shows the end of a
long, dark, straight marking, which used at one time to
be called by astronomers the ' Maraldi Sea ' ; it is now
known by two names — the ' Mare Sirenum ' and the
' Mare Cimmerium.' It is the latter half oi this marking
which forms the chief feature of the drawing. The dark
marking sloping from above the centre towards the
right is the ' Mare Tyrrhenum.' In the next drawing
the ' Mare Cimmerium ' has passed out of view, and the
' Mare Tyrrhenum ' has moved over to the left of the
picture ; whilst ' The Hour-Glass Sea * or ' Syrtis Major '
has come into view on the right. The * Syrtis Major ' is
seen fully presented in the third design, and the little
double triangle of ' Dawes Forked Bay ' has just come
into view on the extreme right. The last picture shows
a still further rotation of the planet on its axis.

It all looks very like another earth, an earth whose
continents and seas are differently distributed, with more
land than water, instead of more water than land, as
with us.

We can see the 'continents' and 'seas' on Mars
quite easily, though they are slightly hazy and ill-
defined. We see them just as distinctly as we should

STORY OF VENUS AND MARS 235

see the seas and continents of the earth if we looked
down on it, on a perfectly clear sunshiny day, from a
height of a dozen miles or so. And this is where the
difficulty comes in. For we are looking at the surface
of Mars not only through the whole thickness of our
atmosphere, but also through the whole thickness of his.
Ours is trouble enough to us, though we are observing at
night with no sun to light it up and dazzle us, even if
we choose the best and clearest climates we can for the
observation — it may be the desert of Arizona with
Professor Lowell^ or the clear equatorial skies of Ceylon
with Major Molesworth, where neither cloud nor haze
nor unsteady air may greatly trouble us. But the sun
is shining full on Mars, else we could not see him at
all. Changing our station on the earth, and securing
the best climate it affords, will not affect one whit the
conditions on Mars itself; we can avoid our cloud or
haze to some extent, but we cannot get away from his
bad weather conditions ; from haze or cloud on him ;
from the lighting up of his air particles even when his
atmosphere is at its clearest ; from the reflection of their
dazzling light which should prevent us seeing clearly,
or seeing at all, down to his surface.

But we do see down to his surface, and we see it
not so very indistinctly. So the atmosphere of Mars
must be very different from that of the earth ; it must
be very much less dense, and very much more

236 STORIES BY THE SUN'S FAMILY

transparent, even when scattering and reflecting the
sun's rays.

Now there are two ways in which we can speak of
the atmosphere of Mars as being less than ours ; it
may be shallower, or it may be less dense, less closely
packed. And here we are able to speak with certain
knowledge. We know that as we climb a mountain
on the earth, or go up in a balloon, the air becomes
rarer and rarer as we ascend. If, on the other hand,
we go down into a deep mine, it becomes denser and
denser the farther we descend, and the reason of this
is obvious. At any level the air is compressed by the
total weight of all the air above it. On the earth,
therefore, we find that when we have climbed three
and a half miles, that is to sa,y, a little higher than the
top of Mont Blanc, we have passed through half the
atmosphere as to weight ; the pressure upon us is only
one-half what it was at the sea-level. Another three
and a half miles would take us through half the
remainder, and the pressure would be reduced to one-
quarter ; and so on, every additional three and a half
miles upward would reduce the pressure by one-half.
The mercury in a barometer which stood at thirty inches
at the sea-level, would stand fifteen inches high at three
and a half miles, seven and a half inches high at seven
miles, three and three-quarters at ten and a half miles,
and so on.

PLATE XLIV.

1S77 Sept. 18'' 11'' 45"'
r.niiLjimde, 232''

1877 "Sept. 15'' 11'' 10'"
Longitude, 2c;o^

1S77 Sept. 10'' u'' 20'" iS77,Sept. 8'' 12'' 30'"

Longitude, 297" I,i5ngi(ude, 332"

MARS, by the late N. E. liieeii.
238

STORY OF VENUS AND MARS 239

Now, on the planet Venus, which is very nearly as
large, and very nearly as heavy a planet as the earth,
this rate of decline of the mercury would be very
nearly the same. It would take an ascent of four
miles to reduce the atmospheric pressure by one-half.
There would be no very great difference, therefore,
in the distribution of an atmosphere on Venus and
on the earth.

But the case is very different when we come to
Mars. He is a much lighter planet and a much smaller
planet than the earth, and the ' pull ' which its attraction
exercises at his surface is much less than it is with the
earth. His atmosphere, therefore, is piled much more
loosely above his surface ; the weight of a given amount
of air is much less on Mars than it is here. We should
have to ascend nine miles above Mars to pass through
half his atmosphere by weight ; eighteen miles to pass
through three-quarters ; and twenty-seven miles to pass
through seven-eighths. At twenty-seven or twenty-eight
miles above Mars we have, therefore, passed through
only seven-eighths of his atmosphere ; at the same height
above the earth we have passed through about |5| of
ours. If, therefore, the air at the surface With us was
thirty-two times as dense as that at the surface of Mars, at
twenty -seven or twenty-eight miles the density would be
about the same in both cases. If the total atmosphere of
Mars bears the same proportion to the total weight of

240 STORIES BY THE SUN'S FAMILY

the planet as it does with us, then the aneroid barometer
would give the pressure at the surface as about one-
eighth the pressure here. In other words, the atmospheric
density would be about equal to that which we should
get could we mount in a balloon ten miles above the
surface of the earth, a height at which nothing that
we know of could live. On Venus there would be no
very perceptible difference from the condition of things
here.

Our atmosphere is necessary for our life and vegeta-
tion ; the atmosphere of Mars is both deeper and much
less closely packed than our own, and we have no reason
to suppose that it is sufficiently dense even close to the
surface to support any form of life with which we are
acquainted here.

It must differ from our atmosphere in another feature.
The attraction of Mars being so much less powerful than
of the earth, the winds of Mars must be far gentler
than ours. A stone dropped on the earth will fall, in
obedience to the earth's pull, sixteen feet in a second ;
on Venus it would fall fourteen feet ; on Mars six feet.
So if, from some cause or another, the air in one region
of the earth should become heavier than in the region
round about, the heavier air tends to move to regions
where the pressure is less, and a wind is set up. A
similar wind on Venus would be not quite so violent;
on Mars it would be quite feeble. On Jupiter, on the

STORY OF VENUS AND MARS 241

other hand, where the stone would fall forty-one feet
in a second, the same difference of atmospheric pressure
would set up a terrible hurricane.

We can now realize to some extent the atmospheric
conditions of Mars ; it is very rare, rarer than we have
any experience of here on earth ; it is slow moving and
stagnant, which again is not favourable for life; and
there is little difference between the density of different
layers. This last means that clouds do not form readily,
nor rain.

From our point of view, the atmosphere of Mars,
though thin, is deep. We see the markings on his
surface, his ' seas ' and ' continents,' but we see them
somewhat hazily and indistinctly; the extraordinary
thing is not that we see them so, but that they are
visible at all. Mars has an atmosphere — we can see it
thickening towards his horizons — ^and it would be im-
possible for us to see any object on his surface except
indistinctly, hazily, and ill-defined.

But there are some objects on him that have been
seen with much distinctness, without any haziness or
want of definition. There is no doubt about them ;
any one can see them who has good eyes, a good
telescope, and clear enough atmosphere. The same
objects are so recognized again and again ; they have
been seen for many years; they are long and straight
and narrow — lines in fact. The better the telescope, the

242 STORIES BY THE SUN'S FAMILY

clearer our air, the narrower and more distinctly they
are seen. The man who first drew attention to them,
SchiaparelH, the greatest living Continental astronomer,
called them, in his native Italian tongue, ' canali,' which
has been literally rendered ' canals,' though ' channels *
would have been the better word. For they have been
seen not only as dark lines intersecting the continents,
but as darker lines running through the dark seas, and
sometimes as bright lines bridging the lakes.

We have said it is impossible ; and yet these
strange markings on Mars have been seen — some have
actually been photographed by Professor Lowell's
assistant, Mr. Lampland, But are these markings on
Mars actually as we see them, or do we only see them
like that ? In other words, does the explanation of the
impossibility which has occurred lie in our being unable
to see rightly ?

We know that we cannot always see rightly. If we
look at a big spot on the sun with the naked eye, it
appears like a round black nail driven to its head into a
golden plate. But that round dark nail is not the real
shape of the spot as we see it magnified in the telescope.
The jagged surrounding thatch, the bright bridges, the
great number of smaller outlying spots, are not suggested
by the sharp black dot which is all we see with the
naked eye.

If there were another spot upon the sun large

STORY OF VENUS AND MARS 243

enough to be seen by the naked eye, it would also seem
to us like a black round dot ; and if it were so near to
the first spot that the space (though in reality it might
be very great) was not large enough for the naked eye
to see it, these two spots would seem to us merged into
one elongated one. If, beyond the second, a third spot
lay, and then a fourth, and many more in a straggling
and uneven row across the sun, we should not see these
as separate dots, but all merged into one even line, as
sharp and defined in its edges as the black dots have
already been. This string of spots across the sun would
look to us like a sharp black line, without indentations
or gaps. Yet if we did not look at it with the naked
eye, but magnified it in the telescope, we should not
see it thus, but as an irregular and detached series of
spots, themselves irregular and broken. The apparent
sharpness would have been due, not to the actual
sharpness and definiteness of the object, but to the
inability of our eyes to detect the small gaps and
irregularities.

So we have no right to conclude that the straight,
sharp, even ' canals ' we see on the surface of Mars are
really as artificial as they seem to us. Markings there
are certainly, small, irregular, unevenly distributed ; and
since Mars is a very small and very distant object, our
small telescopes cannot make these separately visible at
all, our greater telescopes can only show them as merged

244 STORIES BY THE SUN'S FAMILY

into even sharp lines, as do our eyes with sun-spots
lying near together. But our greatest telescopes begin
to show some of these lines as losing their sharpness,
as varying their regularity with nodules, curves, and
gaps ; they are beginning to get at the actual mark-
ings which, by their seeming junction, give rise to
the hard, straight lines that have been called the
' canals.'

We are not sure that we should not see 'canals,'
somewhat like the Martian ones, if we ascended high
above the earth. The Gulf of California and the Red
Sea would look like perfect ' canals ' ; the Aleutian
Islands, or the Japanese, might well seem to be bright
bridges in the Yellow Sea, when looked at from a
height of fifty or a hundred thousand miles; or the
North American lakes unite into a narrowish, dark
streak under the same conditions — that is if we could
see these features on the earth at all.

We must therefore leave the question as to what
planet is nearest in kin to us without a final answer.
We know that in many important particulars Mars
differs from the earth. We know very little about
Venus, but what we do know of her size and atmosphere
and weight is all in favour of her being a true sister
planet to the earth. There remains the yet unsolved
problem as to the time in which she rotates on her axis.
If her day is about the same length as ours, she may

STORY OF VENUS AND MARS 245

well be the abode of life and of intelligence ; if her day
is the same length as her year, so that she always turns
one and the same face to the sun, then one half her
surface must be burned to a cinder, the other half
chained in eternal ice.

CHAPTER XIV

THE STORY TOLD BY THE MOON

' I 'HE sun is shining on a house. It is a house
-'■ furnished and inhabited, and muslin curtains hang
before the windows. The house is light within, for the
muslin curtains do not keep out the sun ; but from out-
side no one can see through them to the people or
furnishing within. Such a house is the Earth, lighted
up by the sun, but screened from the impertinent
scrutiny of those outside by her curtains of the air.
Such a house may Venus be, but she, too, is screened
from our prying by her veil, and we have no oppor-
tunity of looking behind it. {See Plate XLV.)

The sun is shining on a house. There are no
curtains veiling its windows, so we can see through
them into it, and we find no furnishing there. The
house is not inhabited, though it may have been once,
or may perhaps be again. Such a house is Mars. Men
such as we are can scarcely live there now, though in
the past or in the future the planet may provide a fitting
home for them.

246

PLATE XLV.

M;- \

Mai 9

Mm 21

Drawings of Venus in 1871, made at the Bothlcanip Observatory.

247

PLATE XL\'I.

Photograph of the Moon, taken by M. Puiseux, April 5, 1900. Moon's Age, 6 days

(Tlie Moon is shiown as seen in an in\erting telescope.)

248

THE STORY TOLD BY THE MOON 249

The sun is shining on a house. He can shine in
where he will, for it is but the shell of a house. Any-
one can look in from outside and see that it is not
in fit state to be furnished for the habitation of man.
Such a house is the Moon ; a house where life can find
no place to dwell in. Because the moon is a dead
world, a mere world-shell, there is offered no bar to our
prying where we will. Where the sun holds the candle
to guide us, there we may look. The moon neither
assists nor resists.

There are two bodies in the heaven which appear
to us to be of the same size. These two bodies are the
only ones that we can find exercising any real influence
on the earth. They are the sun and the moon. The
sun has already told his story ; how he turns round and
bears with him the spots, faculae, and prominences which,
from time to time, break out on him, and how this
turning has consequences upon our earth. The sun's
disc can be easily seen by the naked eye, and usually
is unblemished. But sometimes one or more round
black spots mar his fair surface, and then we see that
from day to day they seem to move across his face ; in
truth, the ' sun is turning and the spots turn with
him.

The moon's disc can as easily be seen by the naked
eye, but it is never unblemished ; great grey stains
curve in a chain along her upper part, and the brightness

250 STORIES BY THE SUN'S FAMILY

of the rest of her is not uniform : some parts are
almost dull, and at other points she glitters as if she
were set with diamonds. There are always the same
grey stains, the same gleaming points of light when the
moon is full. (See Plates VII., XLVL, and XLVII.)

And when the moon is not full ? When the moon
is still young and the silver bow of the evening has
widened enough for us to see any markings on it, in
the upper half we trace a dark oval stain like a sun-spot,
that has just come over the eastern edge. But as the
sunlight creeps over the moon, the stain does not move
as does the sun spot — it always keeps its oval shape ; it
never comes to the centre of the moon's disc, presenting
the full round ; it never shifts its place, though the sun-
light passes over it and leaves it ag^in in darkness.
And so with the other bright points of light or dark
stains ; they are in the sunshine or they are in darkness,
but they do not alter or move. The moon has been
taken by poets and philosophers in all ages as the
emblem of fickleness and change. But she is no true
emblem ; the dead cannot be fickle ; it is the sunlight
on her, not she, that changes. She does not suffer
change in herself; she does not alter her face, for she
does not seem to us to turn upon her axis. The moon
is but a

batter'd caravanserai
Whose doorways are alternate night and day.

THE STORY TOLD BY THE MOON 251

The moon is an interesting body to the naked eye
because we can, even unassisted, study some of her
features. But she gains beyond measure in beauty and
interest when seen in the telescope, unlike many other
astronomical objects, such as the planets Venus and
Mercury for instance. Her bright parts shine like the
purest silver, her parts in shadow are in blackest con-
trast, her grey stains are not dull greyness, but give
evidences of innumerable shades and inexhaustible
details. The moon is herself so black, so dependent on
the sun's light to make her visible, that as the sun
begins to rise on any part of her, little points of bright-
ness, like constellations, spring up where they seem quite
detached from her, for they are the protruding tips of
her mountains that themselves catch the first rays, but
shelter their sloping sides and valleys from the sunlight.
The rays creep down towards the hollows, and the con-
stellated points of light increase and run together,
forming here a round ringed wall, there a straight ridge,
or again, a solitary central peak within a crater. The
call for the month-long day has come :

Awake ! for Morning in the Bowl of Night
Has flung the Stone that puts the stars to flight :
And Lo ! the Hunter of the East has caught
The Sultan's Turret in a noose of Light,
Dreaming when Dawn's Left Hand was in the Sky.

Like many another fair lady, the moon's photographs

252 STORIES BY THE SUN'S FAMILY

cannot be made to do her full justice. Other heavenly
bodies there are that we fail to see completely, or
perhaps at all, with the eye, either aided or not by a
telescope. Such bodies are comets and nebulae, and to
study ^these fully we must photograph them. But parts
of the moon are so bright, and parts so dull, that a
photograph, timed not to over expose the first, will fail
to show the second ; and exposed sufficiently to photo-
graph the fainter parts, will show the brighter lost in a
confused glare. So we must photograph her under
many conditions of sunlight, and with varying times
of exposure.

The photograph given in Plate VII. was taken when
the moon was nearly at the full. It is usual with repre-
sentations of the heavenly bodies to place the south pole
at the top, the east being at the right hand, but in this
instance the moon is shown as seen in the sky.

In the first place, it will be noted that the edges of
the moon which are in full sunlight are perfectly sharp.
Neither are the moon's features near her borders any
less clearly defined, any more misty, than at her centre.
There is /no atmosphere on the moon ; none, at least,
that we can detect by even the most delicate method.
Therefore, there is no cloud, no rain, no vapour even.
And if there is no vapour-laden atmosphere on the
moon, neither are there oceans or rivers, snow or dew.
The earlier observers of the moon through the newly

PLATE XLVn.

Photograph of the Moon, taken by M. Puiseux, September 12, 1903. Moon's age, 19 da\'s.
(The Moon is shown as seen in an inverting telescope.)

253

PLATE; XLVIII.

NORTH

The 'Sea of Clouds,' showing the settling down of the Lunar Surface.
(From the Photographic Atlas of the Moon of the Paris Observatory, by MM. Lorcuy and Puiseux.)

254

THE STORY TOLD BY THE MOON 255

discovered telescope did not realize this. When they
saw craters and mountains similar to those on the earth
they jumped to the conclusion that the low, level, grey
markings were the lunar seas, and named them thus,
and so we call them to this day. Milton, in his Paradise
Lost, makes Galileo discover

Rivers or mountains on her spotty globe.

But Galileo himself denies this, and on February 28,
1 616, he wrote: 'I do not believe that the body of the
moon is composed of earth and water ; and, wanting these
two elements, we must necessarily conclude that it wants
all the other things which, without these elements, cannot
exist or subsist,'

There is no doubt that some time or other the great
grey lunar ' seas ' were filled with a flowing tide, but that
tide was probably of molten lava, and not water, as our
oceans are. Most of the lunar seas form a chain curving
through the northern hemisphere, not along the moon's
equator. So marked is the divergence of this 'sea-
band' from the moon's equator, that some have urged
that the moon's axis of rotation has shifted since the
' seas ' were formed. Somewhere Mark Twain says that
' there is not a parallel of latitude but thinks it should
have been the equator if it had had its rights,' and on
the moon it certainly looks as if one of these rebellious
circles had brought about a successful treason. The belt

256 STORIES BY THE SUN'S FAMILY

of seas are named thus, from left to right : the Seas of
Fruitfulness, of Peace, of Serenity, of Showers, and
of Storms. The Sea of Nectar lies to the south of
the Sea of Fruitfulness, and the Sea of Crises, the
oblong sea like a sun-spot, lies to its north. And the
Sea of Clouds lies to the south and east again of
the Sea of Storms.

Plate XLVIII., which shows part of the Sea of
Clouds and the little neighbouring Sea of Dews, exhibits
very clearly the evidence of the ' settling down ' of the
moon's surface at some period. The centre of the
photograph shows a number of long, curved, concentric
cracks, concave to the east, and cutting through both
plain and highland. A great but partly ruined walled-
plain lies on one of these cracks, just above the middle
of the picture, and looks as if it had partly sunk or
partly dissolved under the rising of the tide of molten
lava. Nearer the east of the picture a number of
curving ridges are seen practically concentric with these
cracks, and are due, no doubt, to the same disturbance
at a later stage of its action.

The chief mountain ranges on the moon are gathered
together and separate the Sea of Serenity from the Sea
of Showers. The Apennines form the most southerly
ridge. A broad pass cuts through their northern end,
and the Caucasus range trends to the west, whilst the
Alps trend to the east, forming the northern boundary

PLATE XLIX.

NORTH

The Chief Mountain Ranges of the Moon.
(From the Photographic Atlas of the Moon of the Paris Observatory, by MM. Loewy and Piiiseux.)

257

PLATE I..

25S

THE STORY TOLD BY THE MOON 259

of the Showery Sea. The Carpathians form its southern.
{See Plate XLIX.)

The full moon looks rather like a badly peeled silver
orange, the seas being the portions where the skin has
been torn off. The resemblance is increased by a
brilliant round crater in the southern hemisphere named
Tycho, which marks the place where the orange stalk had
joined, and from this place a great number of bright rays
radiate, as if to show the divisions of the fruit. These
lunar ' rays ' are only seen when the moon is near her
full, and we do not know to what they are due. They
extend into the hemisphere of the moon that we never
see, as well as in some cases right across the hemisphere
which is always turned to us. One such ray can be seen
surmounting every obstacle and radiating from Tycho
through the Sea of Serenity, and continuing almost to
the northern edge. There are other systems of rays
besides those from Tycho. Another system radiates
from the great ring-plain Copernicus, which lies between
the Seas of Showers, of Storms, and of Clouds. {See
Plate L.)

But the most remarkable features of the moon are its
craters and walled plains of all sizes, and in all states of
preservation or decay. Craters and craterlets are seen
everywhere : on the beds of the great solid * seas,'
aligning the 'rays,' on the slopes and summits of the
mountain ranges, in the valleys, on the crater walls of

260 STORIES BY THE SUN'S FAMILY

other volcanic peaks ; in the depths of their hollows ;
obliterating other craters. The very 'seas' seem but
the giant remnants of some earlier and still more
stupendous volcanic outburst ; while the mountain
ranges appear as half-broken-down crater walls to the
' seas,'

It is in the south, however, near the moon's pole,
that the craters are seen in greatest numbers. The
whole surface in this region is pock-marked, riddled
with pits and holes.

These pits have usually ring-like walls about them,
which slope very steeply to a central cavity, and more
gently towards the surrounding country. They vary
greatly in size ; the largest are more than a hundred
miles in diameter, while the smallest discernible are less
than a half-mile across. The number increases as the
size diminishes; there are many thousands of them,
so small that they are revealed only when sought for
with the most powerful telescopes and with the best
seeing.

In all these pits, except those of the smallest size, and
possibly in these also, there is within the ring wall, and
at a considerable, though variable, depth below its
summit, a nearly flat floor, which often has a central pit
of small size or, in its place, a steep rude cone. On the
floors of the larger craters, numerous small pits, or
craterlets, are found. The lunar pits certainly suggest

THE STORY TOLD BY THE MOON 261

that these features are volcanoes, and probably they are
in some way nearly analogous to the volcanic vents on
the earth. At some time in the moon's history these
allowed her pent-up energies to burst forth, and are
evidence of the violence of her activity at such a
time.

But whatever may have been the violence of the
moon's activity in the past, it is all spent now. No new
pits are now formed, no old ones are being defaced. We
mark no sure change on any part of the moon, and the
few instances of a slight suspected change are due to the
crumbling of a crater wall, perhaps from sheer force of
gravity, perhaps to the impact of a meteorite which has
upset its unstable equilibrium. One of the best known
instances of suspected change is the little crater Linne,
seen as a white spot in the great plain, the ' Sea of
Serenity,' on the west side of Plate XLIX.

The moon is the heavenly body which we know most
intimately ; we have mapped its surface more fully than
we have explored many parts of our own globe. Yet
all our scrutiny fails to yield us any evidence of forms of
life upon her such as we know here; or even of the
power to live. So far as we know there is no home for
life in the solar system, other than on our own world.
Saturn and Jupiter are not yet sufficiently condensed.
The moon is condensed and solid, but she has no
atmosphere. Mars is solid and with an atmosphere,

262 STORIES BY THE SUN'S FAMILY

but that atmosphere is insufficient for the sustenance of
life in the forms in which we know it, and the planet
does not receive sufficient light and heat from the
sun. Venus alone is a possible sister world, and we
deem her possible, simply because we know so little
about her.

CHAPTER XV
THE STORY TOLD BY COMETS

'"T'HERE is a strong family likeness between all the
■'■ members of the solar system that we have just
described. They are all globes revolving round the
sun in orbits that are very nearly circles, and all in the
same direction ; all the orbits lie in a thin slice of space ;
to all of them the sun rises in the east, and sets in the
west. They have their individual characteristics, it is
true — thus our moon is without any atmosphere that we
can perceive, and Saturn is distinguished from all other
planets by his wonderful ring — but their resemblances
are more pronounced than their differences.

The sun is, without doubt, also of the same family.
He, too, is a globe, revolving on his axis in the same
direction as his dependants, and some of the character-
istics of his surface have analogies upon several of
them ; on Jupiter, for instance, and on Saturn.

Though the sun belongs to the same family as the
planets, he differs from them in two very important
particulars. The first is in his stupendous bulk and

263

264 STORIES BY THE SUN'S FAMILY

mass ; in both he is greater than all his family put
together by many hundred times. The second is in
his possession of a corona, in the long, rod-like rays,
the fingers he stretches out as if to touch his family.
We know of nothing upon the earth to correspond;
we know of nothing like it, even on the giant planet
Jupiter. What are the conditions for a corona ? Does
the sun possess it because of his great size, or because
he is a highly heated body ?

If we look elsewhere for a corona, we do not find one
on the ponderous planet Jupiter, the largest, heaviest, and
probably the most highly heated of all the planets, but
we find what resembles it very closely in those members
of the solar system that seem of least weight and feeblest
influence. These members are called comets, and are
of all degrees of brilliancy, from the most faintly shining
mist which is only photographed in a powerful telescope
by long exposure, to objects so bright that they can
even be distinguished in the glare of the noonday sun.
There are, on an average, some twenty or thirty bright
comets to be seen in a century, that is to say, comets
that are conspicuous to the naked eye. During the last
quarter of a century, however, we seem to have fallen
into a blank space, for only one bright comet has been
seen since 1882, and this one was not visible to dwellers
in northern latitudes.

Comets, whether they are faint telescopic ones, or

THE STORY TOLD BY COMETS 265

bright and visible to the naked eye, have three features,
not indeed separate and distinct, but merging into each
other. The nucleus and coma together form the head ;
the nucleus in a naked-eye comet appearing like a star,
shining through a patch of mist or fog, which is the
coma. Stretching away from the comet is the tail, or
perhaps the tails. These narrow in near the head, and
not only diverge from each other as they recede, but
themselves grow wider and more diffuse, so that they
are always more or less fan shaped. {See Plate LI.)

The most brilliant of all the comets in the memory
of living men was that of 1858, known by the name of
its discoverer, Donati. It was first seen on June 2, but
was then only visible through a telescope, and as a
faint, white mist, without tail or nucleus. In the middle
of August a little tail began to be seen, and the comet
became visible to the naked eye early in September.
From this time it increased enormously in its pro-
portions and splendour, and for a whole month it
could be seen night after night. After October 10 it
began to fade away, and as it was then also travelling
towards the south, it was lost to observers in the
northern hemisphere. To watchers in the south it
remained visible in the telescope until the March of
1859. When at its brightest, the nucleus was equal in
lustre to Arcturus, which indeed appeared involved
in its tail on October 5, and the tail itself stretched out

266 STORIES BY THE SUN'S FAMILY

like a scimitar whose curving blade was over fifty
millions of miles in length. (See Plate LIT.)

But this great blade was not the only tail. On
September i6 an observer at the Strasburg Observatory
saw a faint outer envelope, like the thinnest of veils,
flung over and away from the comet's head, and on the
next evening a narrow straight ray, a secondary tail,
that seemed like a strand that had sprung to the straight
from the curved edge of the blade. This secondary tail
was visible for nearly three weeks, and during part of
the time a third tail was to be seen, straight like the
second, and lying between it and the curved blade-like
tail. This great blade was not evenly bright, but its
outer edges were more illuminated than its centre, as if
the nucleus cast a curving shadow. The tail seemed
formed by the envelopes thrown off one after another
from the nucleus towards the sun, and then cast back-
wards right and left to form the great branches of the
blade-like tail.

The coma, or the envelopes, seem drawn out of the
nucleus towards the sun, but the matter which thus
seems to be drawn out is soon swept away, as fast as it
is formed, in a contrary direction. Mr. R. A. Proctor
likened it to the steam from the funnel of an engine,
a funnel directed forwards, not upwards, and rushing
against a hurricane ; for the tail, which seems made up
of the matter drawn to him by the sun from the nucleus.

PLATE LI.

Daniel's Comet, 1907, d.
(From a photo^ra^h taken at the Royal Observatory, Greenwich, August 10, 1907.)

267

'LATE LII.

DoNATi's Comet, October 5, 1858, seen near Arcturus.
{From Cuil/emin's 'Lis Cometis.')

268

THE STORY TOLD BY COMETS 269

is continually swept away from the sun. Thus, in the
comet observed by Sir Isaac Newton in 1680-81, as it
approached the sun, its tail, which was some ninety
millions of miles in length, pointed back almost along
the orbit. But when, a few days later, the comet had
made its nearest approach to the sun, and was receding
from him, its tail, still of huge length, was pointing
forward, almost straight before the comet in the direction
in which it was moving, and in the opposite direction to
that which it had a few days previously. Now, we
cannot imagine that a comet's tail can be brandished like
a stick, so that we must believe that these were two
different tails, and that the matter of which they were
composed comes from the comet's head, just as the
matter of which the coronal rays are made comes from
the sun. Both sun and comet give of their substance
continually to form their tails. The sun's bulk is so
stupendous that he can afford to throw off his long
coronal rays ; the loss would make no appreciable differ-
ence to him even if the ray contained a quantity of matter.
But the head of a comet is but a small thing : it cannot
continue for a length of time to supply a tail that may
stretch into hundreds of millions of miles, if there is
much in the tail; each time that a comet approaches
near to the sun, it develops a coma and a tail, and
thereby expends itself; the tail must therefore be
almost inconceivably attenuated, or else each time

270 STORIES BY THE SUN'S FAMILY

it returned the comet would become smaller, until it
had become too faint and small to be seen at all.

For comets resemble the other members of the solar
system in this one respect : they all obey the law of
gravity. As all the planets move in orbits of which the
sun occupies a focus, so do all comets, but the paths
they follow may greatly differ from the orbits of the
planets or from each other. For sometimes we see a
comet that travels in a path of moderate extent ; some-
times one whose nearest point to the sun lies within
the corona, but whose farthest is many thousands of
millions of miles away from him, and whose 'year* of
travelling round it must be measured in millenniums.
So, too, comets do not confine their paths within the thin
slice of space wherein the orbits of the planets lie ; their
paths may be inclined to this at any angle that may be
named. Some may pursue a path in the same direction
that the planets move, others, many others, revolve
round the sun in a contrary direction.

Sir Isaac Newton was the first to show that a body
moving under the influence of the sun's attraction, must
follow one of three paths, either an ellipse, a parabola, or
an hyperbola. The ellipse is a closed curve, of which
the circle is a particular example ; but an hyperbola
or parabola is not closed, each of them extends without
end in two branches. In the case of the hyperbola
these branches continually diverge from each other, but

THE STORY TOLD BY COMETS 271

in a parabola they become ultimately two parallel
straight lines. {See Plate LIII., fig. i.)

Suppose that we have a beam of light coming
through the lens of a magic-lantern and falling on the
white sheet. If the lantern is fair and square to the
sheet, there is a circular disc of light upon it. But if
we twist the lantern a little askew, the circular disc of
light on the screen becomes oval-shaped; it is an
ellipse, and the more askew we twist the lantern the
more elongated the ellipse becomes, the long sides of the
oyal tend to open out, until, when the sheet is parallel to
the far side of the beam, or cone of light that we see
issuing from the lens, these two sides to the oval do not
close in again to each other, but become parallel
straight lines; the ellipse of light has become a
parabola. If we turn the lantern still farther askew to
the sheet, the sides of the parabola diverge instead of
being parallel, and the parabola of light has become an
hyperbola.

If, then, a comet were moving round the sun in an
ellipse, however long stretched out that ellipse might be,
the comet would return at last to the neighbourhood of
the sun. Its ' year ' might be a long one, but it would
have its limits. But if a comet were moving in a
parabola or an hyperbola, then, when once it had passed
away from the sun, it would never return, but would
retreat slowly, and yet more slowly, farther and farther

272 STORIES BY THE SUN'S FAMILY

from him. In most cases all that we can say of a comet
is that its path is probably a very long ellipse, almost a
parabola, so that the comet flies out to an immense
distance, not returning for hundreds, or, it may be,
thousands or tens of thousands of years. Yet even
when they lie in space many millions of miles beyond
the farthest planet, they still seem to have a part in that
motion through space that the whole solar system has.
All the comets of which we have knowledge form a
genuine part of the solar family ; and they are not, so
far as we can tell, visitors to us from other suns.

If, as these comets return to the sun from the region
where they have been moving far beyond the planets,
they should chance to pass near where a great planet is
circling, two things may happen : the comet may get
either a pull from the planet which will increase its
speed and send it out from the sun even farther than
before, or one that may diminish its speed, so that the
comet moves in a smaller orbit, where we can see it
swinging again and again past the sun. These last are
called periodic comets. Jupiter has been the most
powerful of the planets in forming a family of them, but
the greatest of all the periodic comets probably owes its
present orbit to a 'pull' by Neptune many hundreds
of years ago.

This is Halley's comet, which we expect to return to
a near approach to the sun in the year 1910. It is the

THE STORY TOLD BY COMETS 273

first comet whose return was predicted, for it was seen
during the time of the first Astronomer- Royal at Green-
wich Observatory and from his observations, H alley, the
second Astronomer- Royal, found its orbit, identified it
with a comet seen by Kepler in 1607, ^^^ foretold that
it would again return about 1758. It did actually
return in 1759, a little later than Halley had predicted,
for the pull of Jupiter and Saturn was sufficient to keep
it back a little. It was again seen in 1835, ^^'^ we hope
that it is still in existence to return again within the
next year or two. But we cannot predict with certainty
that a comet will return, especially a comet that goes
so far beyond the confines of the solar system as Halley's
does. There may be planets out there, of which we
know nothing, that may pull it into a new and unknown
orbit, or it may have split up as other comets have been
known to do ; or it may have expended all its substance
in its tail. For it would seem to have been diminishing
in brightness at each return to the sun, at each display
of its splendid tail. An early record of its appearance
was in the days of the conquest of England by William
the Norman, when it was a fear-inspiring sight.
William's Queen ^Matilda worked into her Bayeux
tapestry the appearance that it presented to them. So,
too, when it appeared in the thirteenth and fourteenth
centuries, it struck terror into all the nations. But it
was not to be compared to some other comets of the

274 STORIES BY THE SUN'S FAMILY

first half of the nineteenth century, when it appeared in
1835, and if it comes again in 1910, it may seem but as
a spendthrift noble at a Court: dull, lustreless, and
bereft of all its former shining train. (See Plate LI 1 1.,
fig. 2.)

BOOK IV

STORIES TOLD BY THE STARS
AND NEBULAE

CHAPTER XVr

THE STORY TOLD BY THE STAR IN
THE CENTAUR

Star Distances

"TNOES the sun go round the earth, or does the earth
'^ go round the sun ? Which is the right doctrine
to hold, the first or the second? When we ask the
question to-day, certainly nine hundred and ninety-nine
persons out of every thousand would affirm the second.
But if it had been asked three or four centuries ago, the
majority would have been as great in affirming the first.
So it is no proof that a given assertion is true, that
every one believes it.

Three hundred years ago the gates of the sky were
thrown wide. A young Italian professor of mathe-
matics, Galileo Galilei by name, heard a rumour that
a Dutch optician had made someglasses that appeared
to bring far things near. This rumour set Galileo
thinking, and he said : 'It appeared to me that it
depended upon the laws of perspective. I reflected on
the manner of constructing it, and was at length so

377

278 STORIES BY STARS AND NEBULAE

entirely successful that I made a spy-glass which far
surpasses the report of the Flanders one.' The principle
on which Galileo constructed his telescope was that
which we to-day use in an opera-glass. When he had
constructed one powerful enough to magnify an object
about twenty times, Galileo turned it on the heavens,
and, without leaving Italy, became the Columbus of a
new and greater world. He discovered four moons to
Jupiter ; he observed the mountains on the moon, and
measured the height of some of them ; he discovered
the phases of Venus ; he observed a curious triple
appearance of Saturn, which we have since learned to
be due to its rings ; he found innumerable new stars and
nebulae, and he also found spots on the sun. Like the
Ancient Mariner, he was

... the first that ever burst
Into that silent sea;

and where everything was new, everything was to be
discovered. Of all astronomers, surely he was the most
fortunate, the one most to be envied.

But there was another side to the shield. His dis-
coveries made the name of Galileo famous throughout
the length and breadth of Europe, and brought him
many friends. But they also brought him enemies, and
these were the more powerful. The scientific writers
held most in esteem in those days were the old Greek

THE STAR IN THE CENTAUR 279

philosophers, who taught that the universe was con-
structed as they conceived it ought to be, not as they
might have observed it to be ; and the ideas of these
philosophers were held by the world of Galileo's day,
but were weighed and found false by Galileo. He
became an old man, weighed down by family griefs and
afflicted with many diseases. He was a devout Catholic,
and he was accused of teaching that which led his pupils
to err from the Catholic faith. He was called upon to
abjure this teaching, and this he did on June 22, 1633, in
the following words —

' Because I have been enjoined, by this Holy Office,
altogether to abandon the false opinion which maintains
that the sun is the centre and immovable, and forbidden
to hold, defend, or teach, the said false doctrine in any
manner ; and because ... I held and believed that the
sun is the centre of the world and immovable, and that
the earth is not the centre and movable. . . . Therefore
with a sincere heart and unfeigned faith, I abjure,
curse, and detest the said errors and heresies, and,
generally, every other error and sect contrary to the
said Holy Church.'

Galileo had based his belief that the earth went
round the sun, and was therefore merely a planet like
other planets, on the resemblances between the earth
and the moon, and the more distant heavenly bodies.
Venus, he showed, had her phases like the moon, so that

28o STORIES BY STARS AND NEBULAE

both earth and planets got their light from the sun, and
were dark when turned away from him. He brought
forward the resemblance between Jupiter, with his family
of small bodies, and the sun, with his family of planets.
All these, however, were analogies only, and, however
convincing they might be, they were not proofs.

But Galileo also showed that it was more probable
that the earth went round the sun, instead of the other
way about, since the motions of the planets were thus
seen to be less complex. Further, if the stars were all
distinct and independent bodies, and not immovably
fixed in a crystal sphere, he urged that it was improbable
that the laws controlling their motion about a fixed
earth should result in revolutions timed uniformly for all,
and at the same time of enormous rapidity. The pre-
cession of the equinoxes, too, in virtue of which the
direction of the earth's axis in space moves slowly, com-
pleting a revolution in about 26,000 years, would make
the motions of the different stars inconceivably complex.
Above all, Galileo relied on the ebb and flow of the
tides as showing the motion of the earth both on her
axis and round the sun. These, however, we know are
really unconnected, and Galileo was relying here on a
false argument.

But there was a difficulty which was as fatal to the
doctrine of the earth going round the sun — unless the
stars were all immovably fixed in a crystal sphere — as

THE STAR IN THE CENTAUR 281

the precession of the equinoxes was fatal to the doctrine
that both sun and stars went round the earth. Galileo
recognized this difficulty, and to the end of his life
hoped against hope that evidence would be forthcoming
to clear it away. But all his efforts, and those of other
astronomers, were worse than unavailing ; the more
powerful their instruments, the more exact and care-
ful their observations, this fatal difficulty to the truth
of the doctrine that the earth went round the sun only
became the more pronounced. There are those who
consider that Galileo sinned against the light when
he abjured the doctrine 'that the sun is the centre
of the world and immovable, and that the earth is not
the centre and movable.' 'There are those,' as Sir
Oliver Lodge says, 'who lament that he did not hold
out, and accept the crown of martyrdom.' But instead of
sinning against the light when he abjured, Galileo knew
that he had failed to procure essential evidence for the
truth of the doctrine that the earth moves. Until he
could procure that evidence, he could not be sure of
the truth of that doctrine ; he ought not to be sure of
it. That evidence was not procured until wellnigh two
hundred years after Galileo's death.

The difficulty in the way of accepting the doctrine
that the earth moves round the sun may be explained
thus. If we are looking at the picture of a landscape,
with trees, streams, men, and animals in it, we cannot

282 STORIES BY STARS AND NEBULAE

get any of these objects to shift their positions with
regard to any of the other objects, no matter from what
point of view we regard the picture, no matter how
perfectly they are represented in perspective. We may
shut first the right eye and then the left, we may regard
the picture from above or from below, we may look at it
from any angle to the incident light; but the picture
simply shifts to us as a whole, with its trees, streams,
men, and animals. We cannot by any means superpose
one of the objects on another, or separate between two
that touch. This is because they are all on the canvas,
all at the same distance from us ; their perspective effect
is but make believe.

But it is different if we are looking at the real
landscape, no matter how still and fixed the objects
may remain. Then, the looking with the right eye or
the left, the shifting from one point of view to another,
will bring some of the objects more into line, will tend
to throw others apart. This is because they are at
different distances from us. Though the objects re-
main immovable, and it is ourselves who shift about,
all the objects will seem to move, and the nearer
objects will seem to move more than the more distant
ones.

Now, the distance of the sun from the earth is about
93,000,000 miles ; so that if the earth goes round the
sun, the sun and the stars really remaining fixed, the

THE STAR IN THE CENTAUR 283

earth is in June fully 186,000,000 miles away from
the spot where she is in December; and 186,000,000
miles is no small distance. Such a. shift of the earth
ought to make the stars, if they are at different distances
away, appear to shift among themselves. Now the stars
look as if they are at different distances ; the bright
stars certainly seem to stand out well in front of the
starry background of the Milky Way. As the earth
gives her half-yearly swing of 186,000,000 miles, these
bright jewels in the foreground should swing out towards
the opposite direction, across the fainter star-set back-
ground. They ought to swing as the earth swings;
they must swing as the earth swings.

But they did not, let Galileo test each and every
star with his most perfect telescopes. They did not
shift to and fro, no single one of them, as Galileo's great
astronomical successors tested them with telescopes
incomparably more powerful and more accurate than
his. The Astronomers- Royal of Greenwich, one after
another, searched for a swing to and fro in star after
star, for a swing corresponding to the earth's swing
round the sun, and no star gave it. The ingenious
Mr. Hooke, the incomparable Sir William Herschel,_
whose telescope seemed able to peer even to the very
outermost confines of 'the stars, all these searched for
the swing of even a single star, and failed to find it.
And now it was nigh two centuries since Galileo had

284 STORIES BY STARS AND NEBULAE

expressed his belief that the earth did move and not
the sun, and had abjured it.

Are the stars all, then, like the men and trees of the
picture we described, some painted in small so as to
look far off, some painted in large as if they were near,
but all at the same distance from us so that they cannot
seem to shift to each other as we shift our position ?
Are the stars really set like jewels on a crystal globe, as
men used to believe very long ago, so that they cannot
move from their setting ?

Not so. During the two hundred years since Galileo
died, evidence was continually accumulating that the
stars did move from their setting, each with its own
* proper motion.* Flamsteed, the first Astronomer- Royal,
and Bradley, the third, each made catalogues of stars,
giving their exact places in the sky; but the stars in
the two catalogues had not quite the same places ; the
stars had moved slightly, not all in the same way, not
all in the same direction, but indiscriminately, one a
good distance that way, another but a small distance
this way. It was not that either Flamsteed or Bradley
were careless and inexact in marking down the place
where they saw the stars, for in the catalogues that have
been since made the same movements are emphasized.
Each star has its own motion, its ' proper motion,' as it
is called; but it is a steady motion, straight on, year
after year, not the swing to and fro in a year, which

PLATE LIII.

-is

PLATE LIV.

Photograph of the Milky Way around Alpha Centauri, taken by Mr. Franklin- Adams.

286

THE STAR IN THE CENTAUR 287

the earth's revolution round the sun should make it
seem to have. And later still, when the spectroscope
has been used on the light of the stars, it has been
found that they have their ' proper motions ' towards
us, or from us, as well as their ' proper motions ' along
the face of the sky. And these proper motions in the
direction of a line joining the star to us are very great
and rapid motions, amounting, it may be, to scores of
miles in each second of time. So the stars truly move
from their places.

At last, a little more than two centuries after Galileo
had abjured his belief in the movability of the earth,
evidence was forthcoming that the earth did swing to
and fro, by the little corresponding swing that was
observed in the case of two stars. The evidence for
both was forthcoming almost at the same time, in the
winter of the year 1838-39, by two observers, for one
of the stars could only be seen by those in the southern
hemisphere, and the other by those in the northern.

The southern star is the brightest in the constella-
tion of the Centaur, the third brightest star in the whole
heavens. It has a large ' proper motion ' of about three
and a half seconds of arc annually; that is to say, in
about six. hundred years it would move from its place
among the stars by a distance equal to the apparent size
of the moon. A Royal Observatory had been lately com-
pleted at the Cape of Good Hope in order to supplement

288 STORIES BY STARS AND NEBULAE

for the southern hemisphere the observations made at the
Royal Observatory at Greenwich ; and it was by Hender-
son, Director of the Cape Observatory, that the obser-
vations were made which showed that Alpha Centauri
had a swing in a year of about a second of arc. Such
a swing would be about the width that a sixpence would
seem to have, if it were held up at Charing Cross for
an observer at Millbank to measure. But such a swing
would mean that the star Alpha Centauri is distant from
us about 206,265 times 93 millions of miles, a distance
that we cannot conceive of in our own mind. {See
Plate LIV.)

And yet Alpha Centauri is not even so near to us as

that, for Henderson's measures made the swing too large,

and later observers have reduced the shift to and fro to

only three-fourths of a second of arc, which means that

the star is 206,265 times | times 93 millions of miles away

from us. This shift of the star in a year is only just

about as much as the apparent shift in the sky that the

cross on the top of St. Paul's would appear to us to

have, if we looked at it first with the right eye, and

then with the left, from a distance about two miles

away, say from the roof of the Tate Gallery. The

shift is due to the swing of the earth in her huge orbit,

round the sun, of 186,000,000 miles in span; the star

appears to describe in fact a miniature copy in the sky

of the earth's orbit, but this copy, so minute, is the

THE STAR IN THE CENTAUR 289

exact representation in size and shape of the orbit
described by the earth, as it would be seen by an
inhabitant of Alpha Centauri, — if he could perceive
the earth at all.

Is it any wonder that Galileo failed to detect or
measure a shift so small ? Besides, no star in the
northern hemisphere has so great a one. For Alpha
Centauri is the nearest neighbour that we know of
amongst the stars, and Galileo never saw a star that
lies so far to the south. The number of miles that this
nearest star is distant is so great that the recital of their
number conveys no meaning to us. We prefer to
express his distance by the time that it takes the light
from him to reach us, and that time we do not measure
in seconds or in liours, but in years. It takes over four
years for the light from the nearest star to travel to us ;
if Alpha Centauri was extinguished to-day and became
darkness, then more than four years would elapse before
we should know it.

The star whose shift was measured at the same time
as Alpha Centauri is not so near ; it takes eight years
for its light to travel to us. This star is an insignificant
one in the Swan. It is only faintly visible to the naked
eye, for it is but of the sixth magnitude, and is not
dignified by a letter, a name, or a Greek letter, but only
by a number. It is No. 61 in the constellation of the
Swan. Its shift in the sky is about as much as the

290 STORIES BY STARS AND NEBULAE

shift of the cross of St. Paul's would appear to be when
viewed first with one eye and then with the other from
a distance of four miles.

No doubt, by this time, you do not wonder so much
that such a shift cannot be measured with extreme
exactness, as that such a shift can be even conceived
of, much less measured at all. How can a measure be
made of a displacement so small that the keenest eye
could not see it?

Practically, what is done is this. A star which is
either very bright, or has a large 'proper motion,' is
supposed to be much nearer in actuality than the
surrounding stars, which are fainter, or do not seem to
move so quickly across the sky. Throughout the year
a great number of measures are made of the distance of
this star from as many other stars as possible, and these
measures are repeated year after year. The measures
may be made either directly with a measuring machine
— a micrometer — at the telescope, or with the micro-
meter on photographs of the region in which the star
lies. The neighbouring stars are supposed to be so far
off that they do not shift at all, so that if the measures
seem to show that the bright or quickly moving star
has swung ever so little as regards the other stars,
this swing is supposed to be all its own, and due to its
nearness. {See Plate XVI., fig. 5.)

In all the myriads of stars, there are only about

THE STAR IN THE CENTAUR 291

thirty whose distances we have measured at all, and of
none of these can we be sure that we know the real
distance within several hundreds of thousands of millions
of miles. Alpha Centauri is our nearest neighbour as far
as we know, and is distant over four light years. The
next nearest is a little star too faint to be seen without a
telescope, and light takes seven years to come from this
star to us. Next comes No. 61 in the Swan, distant
eight light years ; and then Sirius, the brightest star in
the whole sky, but its light, that we now see, left it
more than eight and a half years ago. No other star
that we know of as yet, is nearer to us than a distance
that it takes ten years to cross ; from the Pole star the
light we see to-night left it forty-four years ago.

So, though we know now for a certainty that the
earth does move, and swings round the sun, we have
not been able to send our fathoming line very far into
space. We cannot measure out the depths of the stars,
for we can barely and uncertainly touch their nearest
fringe.

CHAPTER XVII

THE STORY TOLD BY THE STARS IN
THE PLOUGH

Star Drift

'T~'HERE are seven stars that every one knows, for
-■■ year in and year out they are always present in
our skies, shining in the north. The Romans called
them the Seven Plough Oxen, ever treading the
same unseen furrow in the sky. Dante, the poet, named
them the Lords of Cold, as hanging continually over the
frozen regions of the north ; we ourselves call them the
Plough, or Charles' Wain, that is, the waggon of the churl
or peasant. These seven stars are part of a larger
constellation, the Great Bear ; the Plough itself being
the hindquarters of the beast, and its Handle the tail
possessed by the heavenly bear, unlike his curtailed
brothers on the earth.

Each of the seven stars had a special name given to
it by the Arabs, and we, to-day, either use these names
or one of the first seven letters of the Greek alphabet.

The stars are named Dubhe, Merak, Phecda, and

292

THE STARS IN THE PLOUGH 293

Megrez in the ploughshare, the line from Merak to
Dubhe passing through the Pole star, so that these are
sometimes called the Pointers ; and Alioth, Mizar, and
Benatnasch in the plough handle. Megrez is the faintest
star of the seven, and Mizar has a fainter star very close
to it called Alcor. Mizar and Alcor can be seen as two
stars by those with average good sight.

Long ago, men thought that the heavens moved
round the earth and that they were built up of a series
of transparent crystal spheres. Seven inner spheres
carried the ' seven planets,' that is, the sun, the moon,
Mercury, Venus, Mars, Jupiter, and Saturn. An eighth
sphere carried all the stars, so that these were placed all
at the same distance from us, like lights in the roof of a
vast dome, and the shape of any group of stars, as we
saw it, was its true shape. But the star in the Centaur
told us that all the stars are not at the same distance
from us, not even all the stars that look to us of the
same brightness. We have measured the distances
roughly of only thirty or forty stars, and these lie at
very different distances. For all the rest their annual
shift, or ' parallax,' is too small to be measured, but we
cannot believe that, though immeasurably small, it is the
same for all. They, too, are at vastly different distances
from us and from each other. Are they all then discon-
nected ? Do any of the stars form groups ? Have
we been foolish in calling all these stars in the

294 STORIES BY STARS AND NEBULAE

Plough by one name, as if they were members of one
family ?

If the old idea were true that the stars were fixed in
a crystal sphere, then they could not alter their places
with regard to each other. But just as we have been
able within the last seventy years to measure 'annual
parallax,' that is, the yearly shift in the position of a
star, so, too, we have been able to measure 'proper
motion,' the motion across the sky peculiar to each star.
In most cases this is a very small amount indeed, but it
can be found more easily than parallax, because its effect
accumulates year after year. If, then, we are able to
observe a star over a period of fifty, a hundred, or a
hundred and fifty years, a very minute annual movement
will have brought the star over a distance that is quite
easy to see and to measure. It so happens that for
something like three thousand stars we have really
accurate observations, which go back nearly one hundred
and fifty years. These were the observations of the places
of stars, made by Bradley, the third Astronomer- Royal.
These observations we compare with those made quite
recently, and so get the ' proper motions ' of these stars.

Some years ago the late Mr. R. A. Proctor drew
out a chart of the sky, in which he indicated for some
sixteen hundred stars the rates and directions of their
' proper motions ' ; and it became evident from this chart
that there were companies amongst the stars, groups of

THE STARS IN THE PLOUGH 295

stars moving in fellowship together through space,
having the same direction, and moving at the same
rate. Of these companies, the most striking was found
in the constellation of the Plough.

It is not all the seven stars that move thus together ;
the foremost, Dubhe, and the hindermost, Benatnasch (at
the extremity of the handle), have a different direction.
But the other five show a striking similarity in their paths.

This, of itself, would make us think that the five
stars form a true brotherhood; but there is in their
spectra another indication of family likeness. The five
middle stars of the Plough are made of the same
materials, which are combined in the same way, but
they differ in this respect from the first and last. The
spectroscope gives still further evidence that these five
are a travelling company, for it shows that they are
coming in our direction, and all with the same rapid
speed, or very nearly the same, of about eighteen miles
a second.

So these five great suns form one company, making
a common pilgrimage through space, just as the sun and
his family of planets travel together. But only ninety-
three millions of miles separate the earth from the sun ;
not quite three thousand millions separate Neptune, the
furthest planet, from him. What can be the distance
that separates Merak from Mizar ? Of what nature can
be the bond between them ?

296 STORIES BY STARS AND NEBULAE

We can point one leg of a compass to Merak and
the other to Mizar, and measure on a protractor the
angle that they make as about 19°. So, too, we can
measure with the compass the diameter of the sun or
of the moon, and find that they each cover about half a
degree. But we cannot say how many miles go to the
degree, the minute, or the second, until we know the
distances of Merak and Mizar from us, just as, until
we learned that the sun is distant about ninety-three
millions of miles, and the moon about 238,400, we could
not tell that, in the one case, about half a degree meant
866,400 miles, and in the other 2,163 miles. How are
we to find the distances of Merak and Mizar so as to
know how many miles, or light years, go to the 19°
or more that separate them ? If they were as near
as Alpha, the bright star in the Centaur, which is
our nearest neighbour amongst the suns, then each
second would mean | multiplied by 206,265 multiplied
by ninety-three millions of miles ; and there are 3,600
seconds in each degree ; or, in all, 1,750,000 millions of
millions of miles between Merak and Mizar, But they
are at an untold distance further than Alpha in the
Centaur, therefore each second of arc means an untold
number of millions of miles more with them than it does
at the nearer star.

The yearly shift of any of these five stars is too
small for us to see or to measure, but it is possible

THE STARS IN THE PLOUGH 297

to gauge their distance from us — of course, only very
inaccurately — from the manner in which the five stars lie,
and the direction in which they are all travelling. In the
diagram of the Plough (Plate LV. fig. 2a) given here-
with, we see that four out of the five stars lie very
nearly on a straight line, and the directions in which the
proper motions of the five stars carry them lie very
nearly in this line, or else parallel to it. Mizar seems
to lead the procession of five, and Merak brings up the
rear, whilst Phecda marches a little on one side, like
a sergeant bringing out his policemen to their beats.
If it were a celestial globe on which we were looking,
and not a flat sheet of paper, the four stars would seem
to lie very closely to a circle that passes through the
centre of the globe, and the motions of all the five
stars would seem to lie very nearly, but not quite,
parallel to this circle. This means that we on the earth
and these four stars lie in one plane, in a thin slice of
space; that Phecda lies so as to make that thin slice
somewhat thicker ; and that all the stars are moving so
as not to leave it. They all move in one plane, just as
the earth and the other planets do in the ecliptic plane.

Now the proper motions of all these stars are very
nearly indeed in the same direction, but not quite. It
seems quite reasonable to suppose that all five are really
moving at the same actual pace and in the same actual
direction, but that the small differences in these paces

298 STORIES BY STARS AND NEBULAE

and directions that we see are due to the five stars
being at different distances from us. We see them
moving with a perspective effect; and if we compare
the motions together we find that the perspective point,
'the vanishing point,' as it is called in drawing, is
situated just about the place in the sky where the fore-
foot of the Seagoat nearly touches the hindquarters of
the man-horse, who is called the Archer. It is towards
this point that they are actually moving in space, and
we see this motion partly projected on the sky as
* proper motion,' partly as motion directly towards us as
measured in the spectroscope. The actual motion of
the star company through space is compounded of these
two motions, and, since we know the direction of the
whole, we can find a proportion between the two. But
the motion towards us is measured in miles per second,
and the ' proper motion ' is measured in seconds of arc.
We have, therefore, got what we wanted in this par-
ticular case, and find that, at Mizar, a second of arc
is equal to about 60 times 206,265 times 93 millions of
miles. Light takes about four years to reach us from
the star in the Centaur ; it takes, on this estimate, one
hundred and eighty years to travel from the Plough stars.
As observed above, if we point the two legs of a
compass, one towards Mizar, and the other towards
Merak, we find the angle between them is about 19°. If
these stars are at about the same distance — more or

THE STARS IN THE PLOUGH 299

less — from us, then the distance of Merak from Mizar
must be about one-third the distance of Mizar from us.
If Merak is more distant than Mizar, as is probable,
then the distance between them is greater than a third
of the distance to us. But this implies that it must take
sixty years at least for light to travel from the van to
the rearmost of this great company. To bridge the
distance even from Mizar to its near neighbour, Alioth,
light must take at least fourteen years.

We look upon our sun as being isolated in space, for
light which travels faster than we can conceive cannot
cover the distance between our nearest neighbour and
ourselves in less than four years. Yet we can count
several stars nearer to us than Alioth is to Mizar. Both
Altair and Sirius are, for instance ; but they are not of
our kin, they are not made of the same stuff and they
do not travel in our company. All the stars whose
yearly shift we have measured are closer to us than
Mizar is to Merak, for Polaris, the farthest from us; is
but distant forty-four light years, whilst these great twin
suns of the Plough are separated by sixty light years.
Were our earth a planet of Mizar's, then, even with our
most delicate instruments, we could not see or measure
the yearly shift of Merak.

These five stars are amongst the brightest in our
northern heavens, and yet they are enormously distant
from us. In just the same proportion, they must be

300 STORIES BY STARS AND NEBULAE

enormously great. Most of them are fully of the second
magnitude of brightness, yet if we circled round Mizar,
and looked from that distance upon our sun, we would
account him but of the eighth magnitude.

Mizar is itself a double star ; this has been told us
by the spectroscope, and also that the twin stars lie 140
millions of miles apart, though this vast space is so
dwarfed to us by distance that we can never distinguish
them separately. But this twin Mizar has also another
star, a faint one of the fourth magnitude, circling in ten
thousand years, at a seeming distance from it of fourteen
seconds; and yet a third, Alcor, far from it, but yet
moving with it, as bound in the same chains.

The picture presented to us of these five suns, so
vastly superior to our own in brightness and size, and, in
the case of Mizar, consisting itself of so complex a system
of suns, the whole five separated by infinitudes of space,
but subject to the same impulse and travelling on the
same journey — this picture gives us a hint of manners
and systems in the star depths far transcending our own.
We may liken our ruling sun and his little dependants
to some small, isolated, country village, remote from
telegraph or rail, where the movement of the great
world is hardly felt. Its great man is the local squire,
and the villagers hardly dream that a more important
personage exists. His word is their simple law, his de-
cision final ; round him, as its centre, their life revolves.

Epsilon

Alioth.

Delta
Megi-ez.

PLATE LV.

Zeta

Mizar

(with

Alcor).

Eta
Benat-
nasch.

Alpha
Dubhe.

Beta ■
Merak.

Gamma
Phecda.

Fig. I. — The Stars of the Plough.
(From a photograph by F. IV. Longbottom.)

Fig. 2. — Drift of the Stars of the Plough.

i(rt) Showing amount and direction of drift, {b) Appearance of the Plough 100,000 years ago. (c) Appearance
of the Plough at the present time, (a") Appearance of the Plough 100,000 years hence.

PLATIi L\'I.

The Great Nebula of Orion.
(Pliotografhcd at the Royal Observatory, Greemuieh.)

302

THE STARS IN THE PLOUGH 303

Yet, perchance, there filters down to them, from time
to time, some hint or rumour of a greater world without,
of greater, more important, persons than their squire.
They hear of the five great powers of Europe, of their
rulers, of the great statesmen who guide them. They
hear of arbitrations and conferences, of intricate diplomacy,
whose course they find it hard to follow. In something
like their perplexity we watch this vast star-system of
suns, so much greater than our own, of motions on a
scale for which the law of gravity seems hopelessly
inadequate. And we are like the villagers in another
respect. Their news from afar reaches them much after
date. The latest European crisis is known to them it
may be a week, it may be two, after the event. Our
news from the five great suns of the Plough is older still.
It has come to us on the wings of light, without hindrance
or delay, one hundred and eighty-five thousand miles in
every second of time, but it has been a hundred and
eighty years in the coming. We see these five suns,
not as they are, nor where they are, but as they were,
and where they were when the first Hanoverian George
was come to the throne of England.

As far as we know, our sun is a solitary one, bound
to no others by invisible bonds, nor travelling with any
others to the same goal. He has neighbours nearer to
him than any two of the great Plough stars are to each
other ; but these neighbours of his are not made of his

304 STORIES BY STARS AND NEBULAE

stuff, they are not flesh of his flesh, or they are travelling
in divergent ways. But the Plough stars are five great
suns — Mizar and his family we may count as one, even
as Jupiter and his moons count for one in the planets
of the sun — moved by the same impulse, and carved
out, we must believe, from the same great block of
world-stuff, though they lie so far apart. The five
great confederates lie in a wilderness, a void ; for though
there are many other stars, faint or bright, that seem to
lie near them, yet none of them partakes of their motion ;
they all lie nearer us, or else in the far depths of space
beyond. For we cannot conceive that any alien force
could dare to intrude within the spheres controlled by
the vast confederacy, -or, if intruding, could resist, for a
moment, their sway.

We see, then, that the great block of space occupied
and controlled by the five confederate suns is not a
crowded one; not nearly so crowded as the space in
which our sun moves. The stars are, then, not dis-
tributed evenly throughout the universe. Are there
regions more crowded than where the sun is ?

CHAPTER XVIII
THE STORY TOLD BY THE NEBULAE

A MONGST the stories told by the sun was the one
■^*- he told in concert with the moon, when the latter,
in a total eclipse, screens our atmosphere for a short
time from the sun's bright illumination, and shows us
that he is surrounded by a wonderful halo, the corona.
Again, in the solar system we have seen that there are
sundry strange, filmy bodies, erratic in movement and
weird in form, that we know as comets ; like the corona
in their peculiar filmy appearances. And far out in the
star depths we meet again, faint diffused objects, weird
in shape and shining with much the same sort of filmy
light that we have already recognized in corona and
comet.

These are the nebulae. Many thousands of these
are known, and a volume could easily be written simply
to describe the chief classes into which they may be
divided. But there is one nebula which stands out as
by far the most beautiful and mysterious of them all :
the great nebula in the constellation Orion.

305

3o6 STORIES BY STARS AND NEBULAE

The great nebula is easily found if we know the
constellation of Orion, the brightest in the entire sky.
Three bright stars mark the giant's girdle, and below
them shines

A single misty star
Which is the second in a line of stars
That seem a sword beneath a belt of three.

The misty star grows in a powerful telescope into
a vast filmy cloud of glowing emerald light. It is not
a regular diffused glow ; in one place it is, as it were,
curdled into greater brilliance, and close at hand faint
arches are flung out into space. Elsewhere, it is carded
and combed like wool or tangled hair. But, most
striking of all, some of its brightest portions have edges
sharp as in an engraving and border regions of intense
blackness. {See Plate LVI.)

The first mystery about the nebulae, in particular
about such a nebula as that in Orion, is that we can
see any form in it. None of the stars are so near,
or so large, as to offer any visible size even in the
most powerful telescope ; indeed, the greater and more
powerful the telescope, the sharper and smaller becomes
the point of light which is all we see of a star. We
can quite understand why this is, for if Sirius even, the
brightest of all the stars, were so huge as to fill the
entire space between the earth and the sun — 93,000,000
of miles — that is to say, if it were more than one

THE NEBULAE 307

hundred times the diameter of our sun, and more than
a million times its volume, it would still only be one-
third of a second of arc in diameter, or about the
apparent size of a halfpenny seen nine miles away.

But the great nebula in Orion, and nebulae in
general, are not mere points of light ; they are objects.
The central, most brilliant, part of the Orion nebula
appears very considerably larger than the full moon,
and its outer extensions are several degrees in
length.

One of two things then. Either the nebula is very
near us ; or it is enormously large. But it is not near
us ; it is no nearer us than the stars are. Hitherto, all
attempts to discover a 'parallax' for a nebula have
failed ; there is no difference, that we can see, in the
place of a nebula when observed from one end of the
earth's orbit, and when observed from the other,
1 86,000,000 of miles away. Of course a large, diffused,
filmy object like a nebula, often very irregular in shape>
is not at all an easy object to measure, and the argu-
ment for their great distance is, therefore, not quite so
direct as in the case of stars. But in not a few cases
stars are found which at least appear to be enmeshed
in a nebula, and such stars show no shift that we can
detect as the earth swings round in her orbit.

Suppose that this nebula in Orion is as near to us
as the five stars of the Plough — and we have no reason

3o8 STORIES BY STARS AND NEBULAE

to suppose that it is such a close neighbour to us —
suppose, in other words, that it takes light at least one
hundred and eighty years to cross the space between
us and the nebula, then the central and most brilliant
part of the nebula must be so enormous that it would
more than half fill the space between us and our neigh-
bouring star, Alpha Centauri. But the greater its dis-
tance the greater its real size must be, and we have
made a very modest estimate of its distance; it is
probably even farther away. In this case, both our
sun and his twin. Alpha Centauri, distant from him
more than four light years, might both be deeply en-
gulfed in the densest central meshes of such a nebula.
But the bright central portion is but a small part of
the whole, for the nebula sends its spirals and branches
far and wide. Were our sun in such a nebula, its
tentacles would reach out to and enfold not only Alpha
Centauri, but the star in the Swan, Sirius, and every
star whose shift we can measure as the earth swings
round in her orbit; even Polaris itself, from whom it
takes forty-four years at least for light to come.

Light is the swiftest messenger we know, but it
takes at least sixty years for it to speed between Merak
and Mizar, and it certainly cannot traverse the distance
between the most outlying parts of the great nebula in
Orion in much less time. But, as far as we can see,
Merak and Mizar and the other stars of the Plough

PLATE L\'II.

SOUTH

Neeulosities in the Constellation of Orion.

(F7-om photographs by Dr. Max Wolf.)

The two photographs overlap by nearly an inch in the N.-S. direction ; but the sonthern photograph is
displaced two-thirds of an inch towards the East as compared with the northern.

PLATE LVIll.

TjiE Great Neuui.a in Andromeda.
{P/iofogra/Iii'd at tJie Royal Obscrvaioiy^ C/ra/^o/t-//.)

THE NEBULAE 311

are isolated; no visible connexion stretches between
them, no filmy cloud or tentacle enfolds them. The
Plough stars travel to a common goal, under a common
law ; but we cannot see what binds them all together.
In the nebula we seem to see such a bond. The space
between the stars is filled up with star mist, mist that
seems infinitely rarer than even the shining veil that we
see in coronal ray or in comet's tail. Both these shine,
in part at least, by reflection fi-om the sun ; but the star
mist shines of itself. It must, therefore, be a luminous
gas, a gas that is less dense than any vacuum that we
can make. It passes our comprehension how such a rare
gas can assume and retain the definite forms such as
we see in Professor Max Wolf's beautiful photographs
of the Orion nebula. It looks as if the gas was in
violent motion under the influence of some powerful
force, but how or when or where the force is impressed
we cannot see. {See Plate LVII.)

The Orion nebula is the greatest in the heavens ; it
is an ' irregular ' nebula, but with outlying spiral branches.
But it has a rival, running it near in beauty and size.
This is the great nebula in Andromeda, one of the
' regular,' or spiral^ nebulae. This nebula can really be
seen by the naked eye, and the old Arabic astronomers
were familiar with the ' little cloud ' near the most
northern of the three stars in the girdle of Andromeda;
but this ' little cloud ' in the first telescope took on the

312 STORIES BY STARS AND NEBULAE

appearance of a ' candle shining at night through a semi-
transparent horn/ and in the more powerful telescopes of
the later centuries it showed as a steady luminous cloud,
gradually brightening from the circumference to the
centre, where it abruptly condensed to a small nucleus of
indistinct outline under high magnifying powers, but
containing no star. The telescope, too, extended its
borders to a great distance, and showed strange dark
rifts, or ' canals,' whose connexion with the nebula it was
very hard to understand.

For the eye at the telescope is not very capable of
seeing nebulae ; a nebula such as Andromeda's extends
over a large space in the sky, and the more powerful
the telescope, the more confined the space that can be
seen at a time ; it is like surveying a glacier through a
pinhole. It was not until the photographic plate was
substituted for the eye and eye-piece of a telescope that
we could learn what is the true form of the nebula, and
the meaning of the dark 'canals.' {See Plate LVIII.)

Then the nebula was seen to be of a form that
distinctly recalls the appearance of the ringed planet
Saturn. But Saturn, though the lightest of the planets,
is still a globe with defined edges. In the nebula the
central glowing nucleus is not globular, but is undefined
and merges into the rings. For rings are there, incon-
ceivably more huge, and not so regular, as the rings of
Saturn, but showing divisions — for the dark ' canals '

THE NEBULAE 313

are, in the photographs, seen to be but divisions — with
blotches and differences in brightness, such as that
between Saturn's crape ring and the others.

Saturn's rings are neither solid, liquid, nor gaseous,
but seem made up of a number of solid particles which
revolve independently and freely round the planet, like
so many little satellitoids. We do not know how big
these particles may be ; they may be mere fog or mist
particles, they may be of the size of dust, or of pebbles,
or even of great boulders. So, too, as far as we can
tell, the nucleus and the rings of the nebula in Andro-
meda are not gaseous, but are composed of solid
particles. But here the particles cannot be of the size
even of those in fog or smoke ; they must be smaller
than anything that we can conceive of, and they cannot
lie close together. For we cannot consider nebulae as
being merely painted in the sky, having length and
breadth, but no thickness. Through many of them we
must be looking through their greatest thickness, a
thickness as great as that of the length or breadth as
we see it in the sky. This thickness must amount to
millions of millions of miles, and yet we can see through
it. The matter in such a huge volume must be incon-
ceivably attenuated, inconceivably light ; else it would be
as opaque as a wall, and the attraction of its mass would
perturb the universe. The most empty vacuum that
we can make is crowded as compared with the emptiness

314 STORIES BY STARS AND NEBULAE

in any part of the nebula. Yet it shines by its own
light.

There are very many nebulae in the sky, some com-
posed of diffused particles, very sparsely scattered, but
self-luminous like the one in Andromeda, some com-
posed in whole or in part of glowing gas like the one in
Orion. Most of them assume the spiral form ; even the
' irregular ' nebula of Orion has been shown by Dr. Max
Wolf to have outlying, far-extending, spiral branches.
Whence comes such a spiral form ? Is it always there,
or can we ever watch it forming ?

It is only within the last decade that an event
happened which gives some sort of answer to these
questions. In the early part of the year 1901, a ' new
star' burst out in the constellation Perseus. In a few
days it sprang from invisibility to the first magnitude.
After February 24 it slowly faded, but with many
fluctuations in light, until, in August, it was but of the
sixth or seventh magnitude. By this time its spectrum
had become more like that of a gaseous nebula than
like that of a true star; but when Professor Barnard
examined it with the great telescope of the Yerkes
Observatory, the most powerful in the world, in early
September, he could detect no trace of nebulosity.
But on the night of September 20, Professor G. W.
Ritchey, also of the Yerkes Observatory, photographed
the 'new star' with a reflecting telescope of two feet

PLATE LIX.

Nebula about A'uva Persei, September 20, 1901.

^^\\ . ' ■

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" ii^^^M

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Me .

iP^^SBSB

Es'K"' '• '

'-'^'^'^^^Hv'mBH

reS^^e^SS^H^^I

^^SliS

Shb^EB^^B^S

I^kP^^sS

MlBfi^^^PH

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Fig. 2. — Nebula about Nova Persei, November 13, 1901.
[Photiigraphid by Professor G. W. Ritchey at the Yerkes Observatory.)

PLATE LX.

316

THE NEBULAE 317

aperture, giving an exposure of four hours, and on this
photograph were seen two wisps of nebulosity, extending
from the new star to the west, then curving toward the
north. The new star had given off a nebula of complex
form, whose interlacing branches seemed to be of a spiral
form. In the middle of November, at two American
observatories — at the Yerkes and at the Lick — photo-
graphs with long exposure were again taken ; and it
was seen that not only was the spiral nebula round the
star more pronounced and distinct, but that parts of it
had moved, as it were, along the spiral branches, extend-
ing, outwards, and at a rate that would have carried the
moving parts over about eleven minutes of arc in a year.
On September 20 the nebula almost fitted into a square
on the sky of about fifteen minutes (just under half the
apparent diameter of the moon); on November 13 it
fitted into a rectangle of about seventeen minutes by
sixteen. (See Plate LIX.)

Now, is it probable that the nebula was actually
spreading out in space in this rapid and peculiar way ?
Might it not be possible that the spiral nebula was
always there, though dark, and when the star in its
centre burst out, its light illuminated the dark nebula
travelling from the star out to the outlying branches?
On this assumption, it would take light a year to travel
across a distance which to us appears eleven minutes of
arc in size. If this is so, then the new star and nebula

3i8 STORIES BY STARS AND NEBULAE

in Perseus must be distant from us at least three hundred
light years ; that is to say, the outburst of the star and
the lighting up of the nebula actually took place about
the time that Galileo first turned his telescope upon the
heavens, and the news of this great stellar catastrophe,
though speeding to us on the wings of light, only reached
us in the year 1901. It also means that seven months
after the first outburst of the ' new star ' the nebula was
lighted up to a length and breadth of eight and a half
millions of millions of miles, or about a third of the
distance from the sun to Alpha Centauri.

Now, whether the outbursting new star shot forth
the spirals, or whether it simply lighted up the nebula,
it is quite certain that the two are in closest connexion.
The nebula is an appendage of the star ; the star is
involved in the nebula. In this case, at least, it is
evident that the phenomena are not distinct.

But there are other cases where the connexion of
stars with nebulae, where the evidence of stars being
bound together by nebulous bonds is even more
distinct. The most notable of all these is to be found
in the cluster of the Pleiades.

This little group was happily described by Tennyson
as —

. . . like a swarm of fireflies tangled in a silver braid.

For they seem so close together that the eye connects

THE NEBULAE 319

them up by chains of light. When seen through a
telescope the light chains are broken ; and the more
powerful the telescope, the more stars come into view ;
but each star stands out distinctly, unsheathed in nebulous
light.

But it is not the eye at the telescope that teaches
us most about the cluster of the Pleiades, but the
photographic plate. ■ For the eye sees all that it can see
at once ; prolonged gazing will strain the sight without
increasing knowledge. But the sensitive plate does not
tire, and, unlike the eye, it sums up the sensations it
receives during its whole length of exposure. A very
faint, dim light, if falling on the plate for a long time,
will be as effectual in its impression as a bright light in
a short time. Photographs of different exposures will
give information of different kinds.

If we look at the starry heavens we cannot fail to
notice — as in the words of the Apostle — that ' one star
differeth from another star in glory.' Men have there-
fore divided them into six classes, according to their
brightness — classes which are commonly spoken of now
as magnitudes. The ordinary 6th-magnitude star is one
which can be clearly seen by average sight on a good
night, and it gives us about one-hundredth the light of
an average 1st magnitude star. Sirius, the brightest of
all the fixed stars, would require some two and a half
million stars of the 14th magnitude to equal it in light.

320 STORIES BY STARS AND NEBULAE

Several years ago, some observatories began to make
a census of the stars which would embrace all those
from the brightest down to the 14th magnitude. The
work went on steadily until the observers entered on the
region of the Milky Way ; but here the numbers of the
stars presented to them were so great as to baffle all
ordinary means of observation ; and the census threat-
ened to come to a complete standstill for lack of power
to deal with the wealth of material.

Just at this time immense interest was caused in the
astronomical world by the appearance of the great comet
of 1882. It was watched and observed and sketched by
countless admirers, but more important still, it was
photographed, and some of its photographs (Plate
LX.), taken at the Royal Observatory, Cape of Good
Hope, showed not only the comet with marvellous
beauty of detail, but also thousands of stars ; and the
success of these photographs suggested to Sir David
Gill, then Director of the Cape Observatory, that in
photography, more or less prolonged, we possessed the
means for making a complete sky census, even to the
14th magnitude. This project was thought over in
all its bearings, and in 1887, a great conference of
astronomers at Paris resolved upon an international
scheme for photographing the entire heavens. The
form of telescope by which the scheme has been carried
out is represented in Plate LXI.

PLATli LXI.

The ' Astrographic Telescope' of the Royal Observatoiy, Greenwich, i.e. the Photographic
Telescope in use for the International Photographic Chart of the Heavens.

331

PLATli LXIl.

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1^ a

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322

THE NEBULAE 323

A telescopic camera turned on the Pleiades, then,
will succeed only in getting those stars visible to the
naked eye if the exposure is but for a few seconds ; but
as the seconds are prolonged to minutes, more and more
stars appear on the plate, just as more were seen with
the increase in power of the telescope. The accompany-
ing photograph (PlAte LXII.) had an exposure of forty
minutes, the standard time for those taken to form part of
the great International Chart of the Heavens. For this,
eighteen observatories, scattered over the face of the
earth, are federated to photograph the entire sky in two
series, one with but half a dozen minutes' exposure in
order to form a great catalogue of the brighter stars, the
other with an exposure of forty minutes, so that all stars
down to the fourteenth magnitude may be charted. On
this photograph there is a ' reseau,' or cross-scale, printed,
in order to give the positions of the stars with reference
to these cross-lines. But if the minutes of exposure be
prolonged to hours, then the form of the great stars is
lost in patches and clouds of filmy mist; patches and
clouds that are shredded and combed into wisps and
threads, as flax on a distaff. Not only is the star mist
that shrouds the great stars combed out into these
curious straight lines, but straight wisps of nebulosity
join star to star. {See Plate LXII I.)

On the short exposure photographs, the stars stand
out sharp, clear, distinct, and unveiled. On the long

324 STORIES BY STARS AND NEBULAE

exposure photographs in the places where should be the
stars, there are dense patches of nebulosity ; to each of
the greater stars its own nebulous veil. And with the
increase of exposure, the nebulous veil deepens and
extends, but centres still round the places of the stars,
until, as in the wonderful photograph (Plate LXIV.),
by Dr. Max Wolf, the entire group of the stars of the
Pleiades is masked by a vast nebula which stretches its
arms far beyond it into space. In a total eclipse of our
sun, when his brightness is screened, we see and can
photograph a nebulous veil surrounding him ; and the
longer the exposure, the more extended seems his nebula.
So in the Pleiades, with greater exposure we find these
stars shrouded in nebulae — in veils which we might
speak of as their coronae, but coronae on an immeasur-
ably greater scale than that which surrounds our sun.

PLATE LXIII.

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325

I'LATl'; LX1\'.

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326

CHAPTER XIX
THE STORY TOLD BY THE MILKY WAY

'T^HE earth is very differently populated in different
-■■ parts. There, in the Australian bush, a man
may need to ride for a day in order to visit his nearest
neighbour; here, in London, millions of persons are
crowded into a plot of ground fifteen miles square.

So, in the universe of stars. In the story by the
five great brothers of the Plough, it was told that they
held sway over a vast space, so long that it extended
over the eighteenth of the whole heavens' span ; a sway
so unchallenged that, for aught we could see, the five
confederates were there alone, their domain swept bare
of rivals. This quarter of the universe is certainly not
a crowded one.

But there are parts of the sky which certainly appear
to be crowded. There is that

Broad and ample road whose dust is gold
And pavement stars, as stars to thee appear,
Seen in the Galaxy, that Milky Way,
Which nightly as a circling zone thou seest
Powdered with stars.

327 R

328 STORIES BY STARS AND NEBULAE

and in this description, Milton has touched on the two
wonderful characteristics of the Milky Way. It is a
starry zone, a visible belt, spanning the vault of heaven,
just as the equator and ecliptic are imaginary belts. It
is strewn with powdered stars ; stars so small and faint
that the naked eye cannot perceive them singly, yet set
so closely together that they form a golden road by the
shining of their numbers, for the eye confuses their
innumerable points of light into a continuous star surface.
But the telescope shows them to be separate stars, and
the more powerful the telescope the more widely does it
separate them, the more of star-points does it bring into
view. The five stars of the Plough are moving together
to a common goal, under a common impulse ; but in the
vast spaces between them, the most powerful telescope,
the most prolonged exposure, brings out but few stars,
and has not hitherto given evidence of any nebulous
bonds linking them together. In the family of the
Pleiades, on the other hand, the photographic plate
shows that the great stars are bound together by
straight nebulous ribbons, and on these ribbons are
strung fainter stars, as beads might be threaded on a
string. But the Plough stars and the Pleiades each
form a single community ; does the Milky Way form
one also ? The Milky Way spans the heavens in a
complete and great circle ; the Plough stars stretch
over but the eighteenth of this, and the Pleiades

THE MILKY WAY 329

might almost be covered by the full moon. If the
Milky Way is a unity, does it take after the vast
emptinesses of the Plough, or the vast crowdedness
of the Pleiades ?

Since the Milky Way is a girdle to the sky, inclined
to both equator and ecliptic, some part of it can be seen
on any night of the year ; but in spring time it lies at
night close to the northern horizon, and is too low in
the sky to be well observed. Its sweep at midnight in
mid-July, in this country, is from the north-eastern
horizon, where the constellation Auriga is just rising,
through Perseus and Cassiopeia on to Cygnus in the
zenith ; descending again on the other side through
Aquila, Serpens, Sagittarius, and Scorpio to the horizon
in the south-west. It continues to cross the zenith at
midnight until mid-December, when it sweeps upward
from the south-eastern horizon in Argo between Orion
and Gemini to the zenith now marked by the constella-
tion Auriga ; from whence it passes downwards through
Perseus and Cassiopeia to the north-west horizon, where
the constellation Cygnus is setting. It makes its nearest
approach to the north pole of the heavens in the con-
stellation Cassiopeia, where it is broad and rather faint.
This part is always visible to dwellers in this country, at
all times of the year, and at any time of the night. It
makes its nearest approach to the south pole of the
heavens in the constellation of the Southern Cross,

330 STORIES BY STARS AND NEBULAE

where it is rather narrow, and exceedingly brilliant.
This part, being always below our horizon, is never
visible to us, but it is always to be seen by the dwellers
in the southern hemisphere, and it helps very greatly to
make their starry heavens more brilliant than ours. It
crosses the equator in the constellations of the Unicorn
and of the Eagle. In the first it is at its broadest and
faintest, indeed, the whole section of the Milky Way,
from the Unicorn to Cassiopeia, is wide and dim. But
in the Eagle it is divided into two great branches which
have sprung up in the Swan, both of them narrow and
very brilliant.

There are two ways by which we can read, at least
in part, the story told by the Milky Way. We can
study it and draw it as the naked eye sees it, or we
can photograph it, or parts of it, with different sorts of
telescopes and different lengths of exposure. By the
first way, we draw its form or outline, marking in the
hollows, and tracing out the spurs and branches ; giving
due value to the different grades of brightness. This is
the method pursued by many astronomers, but it is not
the one that we will now adopt ; so that we will only
quote here the opinion of Dr. Easton, one of the most
thorough of these students of the Milky Way. He
judges that the Milky Way is one system as a whole,
but a system with perhaps two or more long spirals,
certainly with many small spurs and branches. This

THE MILKY WAY 331

spiral girdle of the Millcy Way, lie says, completely
surrounds the solar system, but though we lie in its
plane, we do not lie at tl^e centre of the ring, but are
nearer to those parts that are broad and faint, and
further from those that are narrow and bright. He
argues this last on the supposition that the Milky Way
is just about as thick as it is broad, and does not extend
to an indefinitely great distance ; as it were, our sun is
situated inside a ring, not inside a hole in a board.
The nearer we are to one side of the ring the larger
does it there appear to be, but also the larger appear
the spaces between the stars, and the greyer is the
whole. The farther we are from one side of the ring
the narrower does it appear, the spaces between the
stars seem to close up, and the stars coming closer
together give a more brilliant effect. So a flock of
crows at a distance seems a small black cloud, but the
nearer they come the larger and greyer does the cloud
appear, until it seems no longer a cloud, but we see the
several birds.

But we are going to examine the Milky Way from
another point of view ; we will not consider its form and
constitution as a whole, but examine samples of it, as it
were ; studying only small portions of it, photographed in
this region or in that. First we will study a photo-
graph of the region of the Swan, where the Milky
Way divides into two great branches. The photograph

332 STORIES BY STARS AND NEBULAE

(Plate LXV.) was taken ^ in the second week of
August, in 1900, with an exposure of six and a half
hours. The scale of the photograph is very small, so
that it covers a very wide area — about one thousand
degrees in all. The moon on this photograph would
have a diameter of about the one-thirteenth of an inch,
and the whole breadth of the Milky Way in both its
branches is comprised well within the borders of the
plate. The brightest star near the centre of the photo-
graph is Alpha Cygni, the most brilliant in the constella-
tion of the Swan. No. 61 Cygni, our nearest neighbour
but two, is one of the small stars about one-fifth of the
way from Alpha to the south-east corner of the plate.

This photograph shows that the Milky Way in
Cygnus is not merely double, but is divided into five
fairly distinct regions, separated from each other by
lanes that look comparatively dark. The most westerly
of the branches is roughly crescent shaped, and the
whole of this region appears to be covered by a diffuse,
but not uniform, faint cloud, which gives the appearance
of nebulosity, but which is seen to be, if the plate be
examined under a microscope, not nebulosity, but faint,
fairly well defined stars. The next region, rather more
to the east, is smaller, but more striking, since not only
are the faint stars aggregated so as to suggest, a
nebulous bed, but brighter stars are also massed

1 By Annie S. D. Maunder.

PLATE LXV.

s
a

333

PLATE LXVI.

Region of Nebula, Rho Ophiuchi.
(Photograph by Profi-ssor E. E. Barnard.)

334
334

THE MILKY WAY 335

together, giving the appearance of numerous and super-
imposed layers of stars, whose brightness diminishes
with their distance from us. More to the east, again,
there is a huge region, not seeming to differ in its
composition, so far as this photograph can show, from
the first two, except in the greater frequency of its local
aggregations of both bright and faint stars, and its more
numerous channels where no stars appear, or only a few
sporadic ones.

But the next region to the east is the most interesting
of all. It is small, and Alpha Cygni lies on its western
border. To the unassisted eye, this region appears on
the negative from which this photographic print is
taken to consist of a dense nebulous patch, intersected
by extremely fine streaks. Under a magnifying-glass,
the nebulosity, to some extent, resolves itself into faint
and fainter streams and bands of stars, these being
again bound together by still fainter bands, which are
not always capable of being resolved into separate stars.
The streaks are some of the spaces where no star or
connecting-stuff is seen, between the streams and the
bands that are not capable of being resolved into stars.
Many of the stars and the bands form themselves
into connected spirals. There is one due east of
Alpha Cygni, half superposed on the most brilliant
of the regions of the Milky Way. An even more
curious feature on the original negative is a hole.

336 STORIES BY STARS AND NEBULAE

slightly elliptical, but about the diameter of the full
moon, situated about halfway between Alpha and the
north-east corner of the photograph. But on this
photograph, though the general form and structure of
the Milky Way in Cygnus is well shown, there is
probably no true nebulosity — except perhaps in the
bright region due east of Alpha — but only apparent
nebulosity due to the aggregation of small discrete stars
too faint to be separately perceived by the unaided eye.
From this photograph alone, then, we cannot judge
whether the Milky Way is really a connected structure,
or only appears to be so by the perspective crowding
of the stars. To judge of this we will examine six
beautiful photographs taken by Professor E. E. Barnard
with a telescope whose object-glass measured ten inches
instead of the one and a half inches of the little lens
with which the Cygnus photograph was taken. Pro-
fessor Barnard gave exposures to these photographs
of from four and a half to five and a half hours. The
Cygnus plate was taken just at the starting point of the
two great branches of the Milky Way. These continue
separately their course southward past the equator,
where they are most brilliant ; and three of Professor
Barnard's photographs are taken of the Milky Way's
western branch where it passes through the constella-
tion of the Serpent-holder, and three of its eastern
branch, where it lies in the constellation of the Archer,

PLATE LXVII.

SOUTH

Region of Theta Ophiuchi.

(Photograph by Professor E. E. Barnard.)

337

PLATE LWTII.

Photogkapii of the great rift near theta ophiuchi.
{Pholograph by Professor E. E. Barnard.)
338

THE MILKY WAY 339

The first of Prof. Barnard's photographs (Plate
LXVI.) is of the region where the foot of the Serpent-
holder is pressing down upon the head of the Scorpion.
To the west of the picture there are stars in plenty,
separate stars such as were seen in the Cygnus photo-
graph. In the centre of the picture there is also a great
mass of something that is not merely layer on layer of
stellar points crowded into one ; it seems in part to be
truly nebulous star mist, and in part to be made up of
powdered stars. But there is something in this picture
that is more remarkable than either crowded stars or
powdered star mist ; there are long and short, straight
and crookedly winding lanes and rifts that are empty,
almost entirely empty, of stars, great or small, or of star
fog, glowing or dim, speckled or curdled. These channels
run everywhere, cutting through the star crowds and the
nebula equally, and impressing blackness upon them.
The next two photographs {Plates LXVI I. and
LXVIII.) are of the region of the foot of the Serpent-
holder which is being stung by the tail of the Scorpion.
Here the stars sometimes appear simply crowded to-
gether, sometimes they look as if they are powdered into
a nebulous bedwork. But whichever their condition,
the narrow or broad rifts and channels plough through
them. In the north-west of Plate LXVI I. there is
a broad bow that seems half filled with grey star stuff,
with a few separate stars sprinkled upon it. A little

340 STORIES BY STARS AND NEBULAE

further to the east and south a giant note of interrogation
is scooped out of the nebulous froth ; this, too, is half
filled with nebula. Farther to the south, again, there is,
as it were, a black S imprinted on the stars, but with
the ink smeared off from its tail towards the east. All
along the whole south there is an irregular great grey
patch, but the grey bed of the channel is seamed and
scored by blacker rifts. On the whole there is more
nebula here than star dust, and the nebulosity looks
curdled like whey because of the rifts and channels.

In Plate LXVIII., which is near the same region as
the second, we have principally to do with star crowdings
and with rifts, rather than with nebulosity and rifts.
Consider the great straight band running from the
centre to the south-west corner, which is evidently a
dark channel, across which the stars have drifted just as
snowflakes cover again a path that has been swept.
Running from the centre due east there is a broader,
less regular, band, like a river with flat wet banks, let
us say, on which the falling snowflakes melt when fallen.

The next two photographs are parts of the con-
stellation of the Archer. In Plate LXIX. the stars
are certainly so crowded together that we cannot see
between them, yet where they seem to thin we see
that they lie imbedded in a grey, nebulous mist. The
whole might almost do for a photograph of a mackerel
sky. But in Plate LXX. the stars are certainly not

PLATIl lxix.

SOUTH

Great Star Cloud in Sagittarius.

(Pliotograph by Professor E. E. Barnard.]

341

PLATE LXX.

SOUTH

Small Star Cloud in Sagittarius.

(Photograph by Professor E. E. Barnard.)

342

THE MILKY WAY 343

so crowded in many places, we can see everywhere
between them into blackness. There are one or two
black channels here, or channels that are sprinkled over
quite thickly. Almost in the centre of the plate there is
a large, very black hole, with but a star or two upon it,
and this hole is evidently connected with the principal
dark channel, which seems to run from the hole towards
the south-west, behind the stars. But there are other
bands, bright ones, or bridges, shall we say, in which the
stars do not seem to be unduly crowded, but they seem
to be in, or upon, or behind a nebulous ribbon. The
most noteworthy of these runs from the great star-cloud
in the centre of the picture in a slightly south-easterly
direction.

The sixth picture is from the little triangular space
between the constellations of the Archer, the Eagle, and
the Serpent, which the astronomers of the late middle
ages devoted to form a new constellation, that of
Sobieski's shield. This contains a famous cluster of
stars, visible to the naked eye, and called * the flock
of wild ducks.* It lies a little to the north of the
centre of the picture. {See Plate LXXI.)

The stars are certainly crowded in this picture,
though not so crowded that they often run together to
form a continuous cloud-like surface. But here and
there weirdly shaped channels are seen, some absolutely
sharp and black, as if engraved and inked in, containing

344 STORIES BY STARS AND NEBULAE

no star or nebulous matter. Note the sharp figure, as of
a 7 (upside down) in the north-west quarter of the photo-
graph. Note the V (lying sideways) in the north-east
and very near the eastern edge. One arm of the V
stops abruptly, as if it dipped down deep below the
stars, or they had drifted over it, and then continues
as abruptly farther on. In the very centre of the plate is
a curious four-branched figure, only slightly obliterated
by stars, the junction of the four branches being marked
by a sharp, round hole, and the north-west branch
straggling broadly into another hole, out of which one
might have imagined that the ' flock of wild ducks ' had
flown.

Now, what is the meaning of these extraordinary
va.cant lanes in the Milky Way ? Not only are they
often devoid of stars, but they seem to be darker even
than the surrounding sky. Neither stars nor nebulae
appear in them. Are they really vacant spaces, or do
they contain some black substance that hides the stars
and nebulae from our view ?

How can we answer this question ? We do not yet
know ; but whether these lanes be empty or full, they
teach us one thing about the Milky Way, that it is one
structure; its different parts are not unconnected with
each other. For, suppose that the channels are really
vacant of stars and star mist, then some force has acted
on all the Milky Way in that region to sweep these

THE MILKY WAY 345

channels bare. The presence of the lanes shows that
the Milky Way has a definite form and structure of its
own ; that its parts form a body.

And suppose that the channels are due to some
black substance, to an opaque nebula which blots out
the bright stars and star mist, then consider the black
hole which we saw in the centre of the fifth of Professor
Barnard's pictures. It was large and quite black, so
that it is evident that if there is black stuff there, it is
between us and the Milky Way, for it blots out the Milky
Way. But from this hole, we saw that several channels
ran to the south-west, channels that were not black on
the whole but overlaid fairly thickly by a layer of stars,
stars that evidently form part and parcel with those that
are adjacent and fairly remote from the channels, and
the farther from the hole, the more thickly do the stars
lie upon the channel, blotting it out. We can even trace
the channels out into the comparatively vacant spaces
to the south-west, out beyond the great star-cloud which
occupies the centre of the picture.

Whether the hole and channels, then, be made up of
emptiness or of black absorbing stuff, it is evident that
it lies askew to this great star-cloud. The black round
patch is in the forefront of it, the channels work back
to its further end. The star-cloud, the ' hole,' and the
channels are mixed up together ; they form a composite
whole.

346 STORIES BY STARS AND NEBULAE

The story that the Plough stars told us was that they
were of one family ; bound upon a common pilgrimage,
vast and distant. The story that the nebulae of Orion,
of Andromeda, and of the Pleiades told us, was that
they each were one also, bound by ties of inconceivable
attenuateness, but bound securely; wonderful in form,
vast spiral structures, though how vast or how distant
we do not know. So, too, the story that the Milky Way
tells us is, that it is one, vaster than we can conceive,
more distant than we can conceive, but yet one, because
of the complicated structure uniting its parts.

• • • • •

Such are a few of the stories which ' the heavens are
telling.' Some of them were read by men thousands of
years ago ; some we are only just now beginning to spell
out. But they are all stories of that great building which
the hands of God have reared. First of all, men learnt
how the world on which they lived was set amongst the
shining lights of heaven, and how these seemed to move
around it. They learned in time the shape and size of
that world ; then of the size and distance of moon and
sun and planets. They learned of the different states
and conditions of the sun and the planets, and their
relations to each other as members of the same system.
Then, greatly daring, they have soared upwards to the
stars, and tried to stretch the line of thought out to the
uttermost depths of that unfathomable immensity. And

PLATE LXXl.

Region of Cluster, Messier ii.
(Photograph by Professor E. E. Barnard.)

347

PLATi; LXXII.

SOUTH

The Veil Nebula in Cygnus (New General Cata. No. 6960).

{From a photograph iahcii at the Yerkes Observatory^ by Professor G. JF. Ritehey.)

' Frontiers quickening under prophetic motions from God.'

348

THE MILKY WAY 349

there they have still found the tokens of structure ; all
that we see is part of one building. But of its im-
mensity what can we say ? The only thing that saves
us from being crushed by the immensity of the pro-
portions which are here revealed to us, is that the
human mind refuses to realize the significance of the
figures by which those distances are expressed. Were
it otherwise, the human spirit would be overwhelmed^
as in the old German rhapsody that De Quincey trans-
lated.

' God called up from dreams a man into the vestibule
of heaven, saying, " Come thou hither, and see the
glory of My house." And to the angels which stood
around His throne, He said, " Take him, strip from him
his robes of flesh ; cleanse his vision, and put a new
breath into his nostrils, only touch not with any change
his human heart, the heart that weeps and trembles."
It was done ; and with a mighty angel for his guide the
man stood ready for his infinite voyage; and from the
terraces of heaven, without sound or farewell, at once
they wheeled away into endless space. Sometimes
with the solemn flight of angel wings they passed
through zaharas of darkness, through wildernesses of
death, that divided the worlds of life ; sometimes they
swept over frontiers that were quickening under pro-
phetic motions from God. Then, from a distance which
is counted only in heaven, light dawned for a time

350 STORIES BY STARS AND NEBULAE

through a shapeless film ; by unutterable pace the light
swept to them, they by unutterable pace to the light.
In a moment the rushing of planets was upon them ;
in a moment the blazing of suns was around them.

• Then came eternities of twilight, that revealed but
were not revealed. On the right hand and on the- left
towered mighty constellations, that by self-repetitions
and answers from afar, that by counter-positions, built
up triumphal gates, whose architraves, whose archways,
horizontal, upright, rested, rose, at altitude, by spans
that seemed ghostly from infinitude. Without measure
were the architraves, past number were the archways,
beyond memory the gates. Within were stairs that
scaled the eternities around; above was below and
below was above, to the man stripped of gravitating
body ; depth was swallowed up in height unsurmount-
able, height was swallowed up in depth unfathomable.
Suddenly, as thus they rode from infinite to infinite,
suddenly, as thus they tilted over abysmal worlds, a
mighty cry arose that systems more mysterious, that
worlds more billowy, other heights and other depths,
were coming, were nearing, were at hand.

• Then the man sighed and stopped, shuddered and
wept. His overladen heart uttered itself in tears, and
he said, " Angel, I will go no farther ; for the spirit of
man acheth with this infinity. Insufferable is the glory
of God. Let me lie down in the grave, and hide me

THE MILKY WAY 351

from the persecution of the Infinite, for end I see there
is none." And from all the listening stars that shone
around issued a choral voice, " The man speaketh truly :
end there is none that ever yet we heard of!" "End
is there none ? " the angel solemnly demanded ; " is there
indeed no end ? And is this the sorrow that kills you ? "
But no voice answered, that he might answer himself.
Then the angel threw up his glorious hands to the
heaven of heavens, saying, " End is there none to the
universe of God. Lo ! also, there is no beginning." '

When I consider the heavens, the work of Thy fingers.

The moon and the stars, which Thou hast ordained ;

What is man, that Thou art mindful of him?

And the son of man, that Thou visitest him ?

For Thou hast made him a little lower than the angels,

And hast crowned him with glory and honour.

INDEX

ACRONYCHAL risings of Stars, 67

Alcor. See Plough stars.

Aldebaran, 81

Alioth. See Plough stars.

Alpha Centauri. See Centaur.

Alpha Cygni. See Swan.

Altair, 299

'Ancient Mariner,' 57, 278

Andromeda, great nebula in, 311,

312, 313, 314, 346
Antares (The Scorpion's Heart), 75,

76, 77, 88, 172
Antoniadi, £. M., 229
Aquila. See Eagle.
Archer, the, 76, 77, 78, 79, 87, 89, 90,

298, 329. 340, 343
Arcturus, 172
Argo (The Ship), 329
Ashtoreth Kamaim (Ashtoreth of

the Horns), 43
Astronomers-Royal, 283
Auriga (The Holder of the Reins),.

81, 329

Babylonians, 38, 43, 51, 73. 92
Bacon, Miss Gertrude, 227

„ Rev. J. M., 227
Balasi (Assyrian astronomer), 55
Barnard, E. E., 314, 336, 339, 345
Bayeux tapestry, 273
Benatnasch. See Plough stars.
Betelgeuse, 8i
Bradley, third Astronomer - Royal,

284, 294
Bull, 65, 81, 82, 90
Bums, Robert, 225

Calcium, 175

Cape Observatory, 124, 287, 288,

320
Carbon, 211
Cassiopeia (The Lady in the Chair),

6S, 74, 329, 330
Castor. See Twins.
Centaur, chief star in (Alpha Cen-
tauri), 172, 287, 288, 289, 291, 296,
298, 308,318
Chart of the Heavens, International,

320, 323
Chromosphere, 150, 153, 154
Circle, 270, 271
Comet, coma, 265

„ Donati's, 265, 266

„ Halley's, 272, 273

„ nucleus, 265

„ of 1 882.. 264, 320

„ orbits of, 270

„ taU, 26s, 311

„ „ movement of, 269
Comets, 263-274

., 252, 30s
Corona, the sun's, 150, 153, 154, 264,

305, 3"
„ changes of, 153, 158, 161,

162
Crab, 82, 88
Craters. See Moon.
Crescent. See Moon.
Croly, 42, 50
Cygnus. See Swan.

Dante, 292
Dayspring, the, 35

353

354

INDEX

Decrescent. See Moon.

De Quincey, 349

' Descent of Istar,' 43, 51, 92

Distance of moon, how determined,

123
Distance of sun, how determined,

124-128
Donati's Comet, 265, 266
Dubhe. See Plough stars.

Eagle, 329, 330, 343
Earth, 226

„ influence on sun-spots, 191

„ shape of, 36, 37

„ size of, 37, 41

„ support of, 38, 41
Easton, Dr. C, 330
Eclipse of Sun, 146, 149

„ „ 1896.. 149

„ „ 1900.. 146

„ „ colours during, 146,

149
Ecliptic, 36, 67
Ellipse, 270, 271
Equator, 36

Equinoxes, precession of, 280
Eratosthenes, 37
Eros, 127
Evening stars, 66, 67, 86, 87, 89

Faculae, 116, 144, 202
Famines, Indian, 180, 183
Fishes, the, 80, 86, 87, 90
Flamsteed, first Astronomer-Royal,

107, 284
'Flock of Wild Ducks.' See

Messier 1 1
Four Feathers, 71

Galileo, 107, 213, 214, 215, 255,

277, 279, 280, 281, 283, 318
Gemini. See Twins.
Genesis i. 14 . . 23
Gill, Sir David, 320
Goethe, 74

Great Dog. See Sirius.
Green, N. E., 233

Greenwich Observatory, 24, 107, 123,
221, 273, 288

Halley, second Astronomer- Royal,

273
Halley's comet, 272, 273
Hampton, Lord, 149
Heliacal risings of stars, 67
Henderson, 288
Herschel, Sir John, 128

„ Sir William, 283
Hesperus, 89, 90
Hilly Fields, 23, 24, 34
Holder of the Reins, 81, 329
Holmes, Oliver Wendell, 58
Hooke, Robert, 211, 283
Huygens, 215
Hydrogen, 175
Hyperbola, 270, 271

Indian famines, 180, 183
International Chart of the Heavens,

320, 323
Istar, S3

„ descent of, 43, 51, 92

JANSSEN, 117
Job xxvi. 7 . . 73
„ xxxviii. 12.. 35
Jupiter, 197-211

„ 90, 91, 92, 94, 96, 99, 213,

214, 216, 219, 225, 261,

263, 264, 273, 278, 280, 304

„ apparent path of, 81, 82, 85

86
„ attraction of, 240
' „ bands of, 201, 204
„ eighth satellite of, 221
„ great red spot of, 208
„ influence upon comets, 272
„ polar caps of, 204, 207
„ rotation period of, 208, 228
„ white spots upon, 203, 204

Kepler, 273
Kipling, Rudyard, 60

Lampland, 242

INDEX

355

Laplace, 220

Lesser Dog. See Procyon.

Lick Observatory, 317

Light, refraction of, i66

Line of sight, motion in, 176, 177

Linn€ (lunar crater), 261

Lion, the, 88

Lodge, Sir Oliver, 281

Lowell, Percival, 235, 242

Magnetic needle, 184, 185

„ „ movements of,

184, 185, 186
„ storms, 186, 187, 188,

189, 190
Mark Twain, 255

Mars, 90, 96, 99, 125, 213, 219, 226,
228, 270
„ apparent path of, 76, 7T, 78,

79, 80, 85, 86
„ atmosphere of, 229, 235, 236,

239, 261
„ attraction of, 240
„ ' canals ' of, 242, 243, 244
„ markings on, 233, 234
„ poles of, 230
„ rotation of, 229, 234
Mason, A. E. W., 71
Megrez. See Plough stars.
Melotte, P., 221
Merak. See Plough stars.
Mercury, 91, 93, 106, 108, 213, 219,
225
„ period of, 93
Merodach, 92
Messier 11 ('Flock of Wild

Ducks'), 343, 344
Milky Way, 827-351

„ „ 81, 320

„ „ dark holes m, 340, 343,
344, 345

„ „ dark rifts in, 339, 340,
343, 344, 345
Milton, 52, S3, 89, 25s, 327
Mizar, See Plough stars.
Molesworth, Major P. B., 235
Months, rule for length of, 54
Moon, 42-57, 246-262

Moon, 226, 363

„ bright rays on, 259

„ cause of phases, 46, 49, 50

„ crater Linn^, 261

„ craters on, 259, 260

„ crescent, 56

„ decrescent, 56

„ distance of, 123, 124

„ markings on, 249, 250, 251

„ mountain ranges on, 256, 259

„ no atmosphere on, 252

„ phases of, 42-46

„ photographs of, 252

„ ' seas ' on, 255, 256, 260

„ spots on, 46

„ suspected changes on, 261

„ unequal motion of, 56

„ walled plains on, 259
Morning stars, 66, 67, 86, 89
Motion in line of sight, 176, 177

Nebulae, The, 305-323
Newton, Sir Isaac, 269, 270

Orion, 81, 172

„ Nebula in, 306, 307, 308, 311,
314

Parabola, 270, 271

Parallax, stellar, 283, 284, 287, 288,

291, 294
Perseus, 81, 329

„ new star in, 314, 317, 318
Phillips, Rev. T. E. R., 202
Phoebe, 221
Phosphorus, 89, 90
Pickering, Prof. W. H., 220
Planets, 74-100

„ 85, 86, 96

„ elongatioiis of, 89, 93

„ oppositions of, 96

„ retrogressions of, 85, 96

„ ' seven,' 293

„ stationary points of, 85
Pleiades, 318, 319, 328, 346

„ nebulae in, 323, 324
Plough, 292-304

356

INDEX

Plough, 62, 68, 74, 307, 311, 327, 328,
346
„ stars: Alcor, 293, 300
„ „ Alioth, 293, 299
„ „ Benatnasch, 293, 295
„ „ Dubhe, 292, 295
„ „ Megrez, 293
„ „ Merak, 292, 295, 296,

297, 298, 299, 308
„ „ Mizar, 292, 295, 296,
297, 298, 299, 300,
304, 308
„ „ Phecda, 292, 297
Pole star, 68, 71, 72, 291, 299, 308

„ „ height of, 71, 73
Pollux. See Twins.
Precession of the equinoxes, 280
Prism, 165

Proctor, R. A., 266, 294
Procyon (Lesser Dog), 81
Prominences, 150, 153, 154, 175

„ changes of, 150, 157

Proper motion, 294
Psalm viii., 351
„ xix., 19, 20, 38

Rainfall, annual, 180

Ram, 90

Ritchey, Professor G. W., 314

Sagittarius. See Archer.
Saturn, 212-222

» 90. 96, 99, 225, 261, 263, 273,
278, 312

„ apparent path of, 80, 85, 86

„ period of, 95

„ rings of, 215, 216, 217, 218,
263

„ nature of rings, 219

„ rotation of, 228
Scales, 76

Schiaparelli, Professor G, V., 242
Scorpio. See Scorpion.
Scorpion, 88, 89, 329, 339
Scorpion's Heart. See Antares.
Seagoat, 79, 87, 94, 298
Sea-monster, 80
Serpens, 329, 343

Serpent-holder, 339

Shakespeare, 19, 33, 55

Sinbad the Sailor, 131

Sirius (The Great Dog), 81, 172,291,

299. 308, 319
Sobieski's shield, 343
Sodium, spectrum of, 172, 173, 174
Solar system, scale of, 99, 106, 129
Southern Cross, 71, 329
Spectroscope^ 168, 171
Spectrum, 167, 168, 171

„ explanation of, 174
„ lines in solar, 171
„ of sodium, 172, 173, 174
„ of sun, 168, 171, 172, 173
Stars, 58-73
„ acronychal risings of, 67
„ apparent movement of, 60-62
„ evening, 66, 67, 86, 87, 89
„ heliacal risings, 67
„ in Perseus, new, 314, 317, 318
„ morning, 66, 67, 86, 89
Stonehenge, 34
Sun, 19-41
„ 225,263,305
„ appearance of surface, 1 16, 1 17,

118
„ atmosphere of, 104
„ dayspring, 35
„ distance of, how determmed,

124-128
„ inclination of path of, 27, 28,

29.30
„ methods of observing, 106, 107
„ midday height, 29, 30
„ rising points, 27, 28, 29, 30
„ rotation of, 108, in, 207, 228
„ spectrum of, 168, 171, 172, 173
„ surface of, 116
Sun-spots, 131-143

103, 105, 178, 179, 188,
189, 202, 242, 243
„ appearance of, 112
„ bridges, 112
„ changes of, 115
„ cycle, 138
„ duration of, 115
„ influence of, 180, 183, 190

INDEX

357

Sun-spots, latitudes of, 136, 137
„ movements of, 132, 135
„ nucleus, 112
„ penumbra, 112
„ size of, 129, 178, 179
„ umbra, 112
„ zones, 137, 138, 141

Swan, 329, 330, 331, 339

„ Alpha, the bright star in, 332,

335
„ No. 61 in, 289, 308, 332

Taurus. See BulL
Tennyson, 65, 318
Twins (Castor and Pollux), 81, 82,
88, 90 •

Underworld, 38
Unicom, 330
Uranus, 225

Vega, 172

Venus, 90, 91, 92, 93, 96, 108, 213,
219, 226, 228, 244, 246, 262

„ atmosphere of, 239, 240

„ attraction of, 240

„ period of, 94

„ phases of, 278, 279

„ rotation of, 228, 244
Virgin, 76, 88, 90

Waterpourer, 79, 87, 90
Wolf, Professor Max, 311, 324

Yerkes Observatory, 314, 317

Zodiac, 67

„ constellations of, 67

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E. J. BEDFORD

340 pp. Small Medium 8vo. Cloth Gilt. Gilt Top.
Price 5^. net.

In this book the Author deals in an interesting, informing, and popular manner
with the commoner species of British insects, some of which are likely to come under
the notice of the reader. The style of treatment is intended to encourage the
intelligent life-study of insects by our younger folk, to discourage collecting, and to
stimulate the profitable employment of one's eyes and ears in town or country. It
has been his aim to point out many of the wonders of insect life, and to show how
even these minute creatures supply a fund of interest and amusement, and teach
wonderful object-lessons of patience, intelligence, design, and beauty. The illustra-
tions in this sumptuous volume are very numerous and remarkable. The eight
coloured plates, from the talented brush of Mr. E. J. Bedford, have been adjudged by
competent critics as most life-like and beautiful; whilst the fine series of micro-
photographs and others combine to make this work the best book ever issued dealing
exclusively with British Insect Life.

ROBERT CULLEY
25-35 City Road, and 26 Paternoster Row, London, E.C.

UNIFORM WITH THIS VOLUME

The Story of Hedgerow and Pond

R. B. LODGE

MEDALLIST, ROYAL PHOTOGRAPHIC SOCIETY; GOLD MEDAL, ST. LOUIS
EXHIBITION, 1904; BRONZE MEDAL, PARIS EXHIBITION, igOO

306 pp. Small Medium 8vo.

With Illustrations on nearly every page, and Eight Full-Page
Coloured Plates by G, E. LODGE.

Elegantly bound in Cloth Gilt, Gilt Edges, and Bevelled Boards.

Price SJ. net.

The Author takes a roadside hedge and pond, such as are within reach of almost
every one, and describes the birds, beasts, insects, and flowers found therein at the
various seasons of the year, laying bare some secrets of their lives, so as to stimulate
his readers to find out more for themselves.

* The Author has told his story well, in a plain, unvarnished, understandable, and
informing way, and we very highly commend this volume.' — Naturalists^ Quarterly
Review.

BY THE SAME AUTHOR

The Birds and Their Story

Small Medium 8vo. 156 Illustrations and Eight Coloured Plates.

Some of the Contents:

The Birds of Prey. The Insect Eaters. Seed and Vegetable Eaters,

The Wading Birds. Fresh-water Birds. Sea Birds.

The Flightless Birds.

' No better book than this of Mr. Lodge's could be put into the hands of a boy
or girl for stimulating and satisfying one of the most lasting and pleasurable of all
tastes, the taste for field natural history.' — County Gentleman.

ROBERT CULLEY
25-35 City Road, and 26 Paternoster Row, London, E.C.

UNIFORM WITH THIS VOLUME

The Flowers and Their Story

HILDERIC FRIEND

With 155 Illustrations of Flowers and Flower Studies from the
Author's Photographs, and Eight Coloured Plates.

316 pp. Small Medium 8vo. Cloth Gilt. Gilt Top.
Price $s. net.

For nearly a quarter of a century the Author's Mowers and Flower-
Lore has been a popular and standard work; and in the present
volume the results of long and patient study have been brought together.
Such chapters as those on Dame Nature's Tuck-shop, Honey-pots and
Honey-guides, Moss-troopers, Fairy Gold, Balloons and Floats, Flags
and Banners, or Acrobats and Steeple-jacks, can hardly fail to appeal
to the schoolboy ; while the girls will turn with pleasure to those on
Lords and Ladies, Among the Nobility, the Flowers of Mary, The
Emerald Chalice, A Visit to the Nursery, or In the Showroom.

Illustrations have been freely used, because it is felt that readers
will be able, by their aid, the more easily to recognize the plants when
they see them growing. The volume has been carefully planned with
a view to the fostering of the love of Nature among yoimg people.

ROBERT CULLEY
25-35 City Road, and 26 Paternoster Row, London, E.G.

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