part he walks on. A horse walks on the end of his one toe. The nail of
the toe we call the "hoof." The true heel is the hock, a sharp joint
like an elbow nearly half way up the leg. Along each side of the cannon,
the long bone of this foot, lies a splint of bone, which is the remnant
of a toe, that is gradually being obliterated from the skeleton. These
two splints in the modern horse's foot tell the last chapter of an
interesting story. The earliest American horse, the existence of which
is proved by fossil bones, tells the first chapter. The story has been
read backward by geologists. It is told by a series of skeletons, found
in successive strata of rock.
The "Bad Lands" of the arid Western States are rich in fossil remains of
horses. Below the surface soil lie the rocks of the Quaternary Period,
which included the drift laid down by the receding glaciers and the
floods that followed the melting of the ice-sheet. Under the Quaternary
lie the Tertiary rocks. These comprise three series, called the Eocene,
Miocene, and Pliocene, the Eocene being the oldest. In the middle region
of North America, ponds and marshy tracts were filled in during the
Tertiary Period, by sediment from rivers; and in these beds of clay and
other rock debris the remains of fresh-water and land animals are
preserved. Raised out of water, and exposed to erosive action of wind
and water, these deposits are easily worn away, for they have not the
solidity of older rocks. They are the crumbly Bad Lands of the West, cut
through by rivers, and strangely sculptured by wind and rain. Here the
fossil horses have been found.
_Eohippus_, the dawn horse, is the name given a skeleton found in 1880
in the lower Eocene strata in Wyoming. This specimen lay buried in a
rock formation ages older than that in which the oldest known skeleton
of this family had been found. Its discovery made a great sensation
among scientists. This little animal, the skeleton of which is no larger
than that of a fox, had four perfect toes, and a fifth splint on the
forefoot, and three toes on the hind foot. The teeth are herbivorous.
_Orohippus_, with a larger skeleton, was found in the middle Eocene
strata of Wyoming. Its feet are like those of its predecessor, except
that the splint is gone. The teeth as well as the feet are more like
those of the modern horse.
_Mesohippus_, the three-toed horse, found in the Miocene, shows the
fourth toe reduced to splints, and the skeleton as big as that of a
sheep. In this the horse family becomes fairly established.
_Hypohippus_, the three-toed forest horse, found in the middle Miocene
strata of Colorado, is a related species, but not a direct ancestor of
the modern horse.
_Neohipparion_, the three-toed desert horse, from the upper Miocene
strata, shows the three toes still present. But the Pliocene rocks
contain fossils showing gradual reduction of the two side toes,
modification of the teeth, and increase in size of the skeleton.
_Protohippus_ and _Pliohippus_, the one-toed species from the Pliocene
strata, illustrate these changes. They were about the size of small
ponies.
_Equus_, the modern horse, was represented in the Pliocene strata by a
species, now extinct, called _Equus Scotti_. This we may regard as the
true wild horse of America, for it was as large as the domesticated
horse, and much like it, though more like a zebra in some respects. No
one can tell why these animals, once abundant in this country, became
extinct at the end of the Tertiary Period. But this is undoubtedly true.
The types described form a series showing how the ancestors of the
modern horse, grazing on the marshy borders of ancient ponds, lived and
died, generation after generation, through a period covering thousands,
possibly millions, of years. Along the sides of the crumbling buttes
these ancient burying-grounds are being uncovered. Within a dozen years
several expeditions, fitted out by the American Museum of Natural
History, have searched the out-cropping strata in Dakota and Wyoming for
bones of mammals known to have lived at the time the strata were forming
in the muddy shallows along the margins of lake and marsh. Duplicate
skeletons of the primitive horse types above have been found, and vast
numbers of their scattered bones. Each summer geological excursions will
add to the wealth of fossils of this family collected in museums.
The Tertiary rocks in Europe yield the same kind of secrets. The region
of Paris overlies the estuary of an ancient river. When the strata are
laid bare by the digging of foundations for buildings, bones are found
in abundance. Cuvier was a famous French geologist who made extensive
studies of the remains of the prehistoric animals found in this old
burial-place called by scientists the Paris basin. He believed that the
dead bodies floated down-stream and accumulated in the mud of the
delta, where the tide checked the river's current.
Skeletons of the Hipparion, a graceful, three-toed horse, were found in
numbers in the strata of the Miocene time. This animal lived in Europe
while the Pliohippus and the Protohippus were flourishing in America.
A great number of species of tapir-like animals left their bones in the
Paris basin, among them a three-hoofed animal which may have been the
connecting link between the horse and the tapir families. Cuvier found
the connecting link between tapirs and cud-chewing mammals.
THE AGE OF MAN
The hairy, woolly mammoth was one of the giant mammals that withstood
the cold of the great ice flood, when the less hardy kinds were cut off
by the changing climate of the northern half of Europe and America. In
caves where the wild animals took refuge from their enemies, skeletons
of men have been found with those of the beasts. With these chance
skeletons have been found rude, chipped stone spear-heads, hammers, and
other tools. With these the savage ancestors of our race defended
themselves, and preyed on such animals as they could use for food. They
hunted the clumsy mammoth successfully, and shared the caverns in the
rocks with animals like the hyena, the sabre-toothed tiger, and the cave
bear, which made these places their homes. In California a human skull
was found in the bed of an ancient river, which was buried by a lava
flow from craters long ago extinct. With this buried skull a few
well-shaped but rough stone tools were found. This man must have lived
when the great ice flood was at its height.
In southern France, caves have been opened that contained bones and
implements of men who evidently lived by fishing and hunting. Bone
fish-hooks showed skill in carving with the sharp edges of flint
flakes. A spirited drawing of a mammoth, made on a flat, stone surface,
is a proof that savage instincts were less prominent in these cave men
than in those who fought the great reindeer and the mammoth farther
north.
In later times men of higher intelligence formed tribes, tamed the wild
horse, the ox, and the sheep, and made friends with the dog. Great heaps
of shells along the shores show where the tribes assembled at certain
times to feast on oysters and clams. Bones of animals used as food, and
tools, are found in these heaps, called "kitchen-middens." These are
especially numerous in Northern Europe. The stone implements used by
these tribes were smoothly polished. A higher intelligence expressed
itself also by the making of utensils out of clay. This pottery has been
found in shell heaps. So the rude cave man, who was scarcely less a wild
beast than the animals which competed with him for a living and a
shelter from storms and cold, was succeeded by a higher man who brought
the brutes into subjection by force of will and not by physical
strength.
The lake-dwellers, men of the Bronze Age, built houses on piles in the
lakes of Central Europe. About sixty years ago the water was low, and
these relics of a vanished race were first discovered. The lake bottoms
were scraped for further evidences of their life. Tools of polished
stone and of bronze were taken up in considerable numbers. Stored
grains and dried fruits of several kinds were found. Ornamental
trinkets, weapons of hunters and warriors, and agricultural tools tell
how the people lived. Their houses were probably built over the water as
a means of safety from attack of beasts or hostile men.
In our country the mound-builders have left the story of their manners
of life in the spacious, many-roomed tribal houses, built underground,
and left with a great variety of relics to the explorers of modern
times. These people worked the copper mines, and hammered and polished
lumps of pure metal into implements for many uses. With these are tools
of polished stone. Stores of corn were found in many mounds scattered in
the Mississippi Valley.
The cliff-dwellers of the mesas of Arizona and New Mexico had habits
like those of the mound-builders, and the Aztecs, a vanished race in the
Southwest, at whose wealth and high civilization the invading Spaniards
under Cortez marvelled. The plastered stone houses of the cliff-dwelling
Indians had many stories and rooms, each built to house a tribe, not
merely a family.
The Pueblo, the Moqui, and the Zuni Indians build similar dwellings
to-day, isolated on the tops of almost inaccessible mesas.
Millions of years have passed since life appeared on the earth.
Gradually higher forms have followed lower ones in the sea and on the
land. But not all of the lower forms have gone. All grades of plants
and animals still flourish, but the dominant class in each age is more
highly organized than the class that ruled the preceding age.
To discover the earth's treasure, and to turn it to use; to tame wild
animals and wild plants, and make them serve him; to create ever more
beautiful and more useful forms in domestication; to find out the
earth's life story, by reading the pages of the great stone book--these
are undertakings that waited for man's coming.
* * * * *
PART II
THE SKY
* * * * *
EVERY FAMILY A "STAR CLUB"
The best family hobby we have ever had is the stars. We have a star club
with no dues to pay, no officers to boss us, and only three rules:
1. We shall have nothing but "fun" in this club--no hard work. Therefore
no mathematics for us!
2. We can't afford a telescope. Therefore we must be satisfied with what
bright eyes can see.
3. No second-hand wonders for us! We want to see the things ourselves,
instead of depending on books.
You can't imagine what pleasure we have had in one short year! The baby,
of course, was too young to learn anything, and besides he was in bed
long before the stars came out. But Ruth, our seven-year-old, knows ten
of the fifteen brightest stars; and she can pick out twelve of the most
beautiful groups or constellations. We grown-ups know all of the
brightest stars, and all forty-eight of the most famous constellations.
And the whole time we have given to it would not exceed ten minutes a
day!
And the best part is the _way_ we know the stars. The sky is no longer
bewildering to us. The stars are not cold, strange, mysterious. They are
friends. We know their faces just as easily as you know your playmates.
For instance, we know Sirius, because he is the brightest. We know
Castor and Pollux, because they are twins. We know Regulus, because he
is in the handle of the Sickle. And some we know by their colours. They
are just as different as President Taft, "Ty" Cobb, Horace Fletcher and
Maude Adams. And quite as interesting!
What's more, none of us can ever get lost again. No matter what strange
woods or city we go to, we never get "turned around." Or if we do, we
quickly find the right way by means of the sun or the stars.
Then, too, our star club gives us all a little exercise when we need it
most. Winter is the time when we all work hardest and have the fewest
outdoor games. Winter is also the best time for young children to enjoy
the stars, because it gets dark earlier in winter--by five o'clock, or
long before children go to bed. It is pleasant to go out doors for half
an hour before supper and learn one new star or constellation.
Again, it is always entertaining because every night you find the old
friends in new places. No two nights are just the same. The changes of
the moon make a great difference. Some nights you enjoy the moonlight;
other nights you wish there were no moon, because it keeps you from
spying out some new star. We have a little magazine that tells us all
the news of the stars and the planets and the comets _before_ the things
happen! We pay a dollar a year for it. It is called the _Monthly
Evening Sky Map_.
When we first became enthusiastic about stars, the father of our family
said: "Well, I think our Star Club will last about two years. I judge it
will cost us about two dollars and we shall get about twenty dollars
worth of fun out of it." But in all three respects father was mistaken.
Part of the two dollars father spoke of went for a book called "The
Friendly Stars," and seventy-five cents we spent for the most
entertaining thing our family ever bought--a planisphere. This is a
device which enables us to tell just where any star is, at any time, day
or night, the whole year. It has a disc which revolves. All we have to
do is to move it until the month and the day come right opposite the
very hour we are looking at it, and then we can tell in a moment which
stars can be seen at that time. Then we go down the street where there
is a good electric light at the corner and we hold our planisphere up,
almost straight overhead. The light shines through, so that we can read
it, and it is just as if we had a map of the heavens. We can pick out
all the interesting constellations and name them just as easily as we
could find the Great Lakes or Rocky Mountains in our geography.
We became so eager not to miss any good thing that father got another
book. Every birthday in our family brought a new star book, until now we
have about a dozen--all of them interesting and not one of them having
mathematics that children cannot understand. So I think we have spent on
stars fifteen dollars more than we needed to spend (but I'm glad we did
it), and I think we have had about two hundred dollars worth of fun!
Yes, when I think what young people spend on ball games, fishing,
tennis, skating, and all the other things that children love, I am sure
our family has had about two hundred dollars worth of fun out of stars.
And there is more to come!
You would laugh to know why I enjoy stars so much. I have always studied
birds and flowers and trees and rocks and shells so much that I was
afraid to get interested in stars. I thought it wouldn't rest me. But
it's a totally different kind of science from any I ever studied! There
are no families, genera, and species among the stars, thank Heaven!
That's one reason they refresh me. Another is that no one can press them
and put them in a herbarium, or shoot them and put them in a museum. And
another thing about them that brings balm to my spirit is that no human
being can destroy their beauty. No one can "sub-divide" Capella and fill
it with tenements. No one can use Vega for a bill-board. Ah, well! we
must not be disturbed if every member of our family has a different
point of view toward the stars; we can all enjoy and love them in our
own ways.
How would you like to start a Star Club like ours? You ought to be able
to persuade your family to form one, because it need not cost a cent.
Perhaps this book will interest them all, but the better way is for you
to read about one constellation and then go out with some of the family
and find it. This book does not tell about wonderful things you can
never see; it tells about the wonderful things all of us can see.
I wish you success with your Star Club. Perhaps your uncles and aunts
will start clubs, too. We have three Star Clubs in our family--one in
New York, one in Michigan, and one in Colorado. Last winter the
"Colorado Star Gazers" sent this challenge to the "New Jersey
Night-Owls:" "_We bet you can't see Venus by daylight!_"
That seemed possible, because during that week the "evening star" was by
far the brightest object in the sky. But father and daughter searched
the sky before sunset in vain, and finally we had to ask the "Moonstruck
Michiganders" how to see Venus while the sun was shining. Back came
these directions on a postal-card: "Wait until it is dark and any one
can see Venus. Then find some tree, or other object, which is in line
with Venus and over which you can just see her. Put a stake where you
stand. Next day go there half an hour before sunset, and stand a little
to the west. You will see Venus as big as life. The next afternoon you
can find her by four o'clock. And if you keep on you will see her day
before yesterday!"
That was a great "stunt." We did it; and there are dozens like it you
can do. And that reminds me that father was mistaken about our interest
lasting only two years. We know that it will not die till we do. For,
even if we never get a telescope, there will always be new things to
see. Our club has still to catch Algol, the "demon's eye," which goes
out and gleams forth every three days, because it is obscured by some
dark planet we can never see. And we have never yet seen Mira the
wonderful, which for some mysterious reason dies down to ninth magnitude
and then blazes up to second magnitude every eleventh month.
Ah, yes, the wonders and the beauties of astronomy ever deepen and
widen. Better make friends with the stars now. For when you are old
there are no friends like old friends.
THE DIPPERS AND THE POLE STAR
I never heard of any boy or girl who didn't know the Big Dipper. But
there is one very pleasant thing about the Dipper which children never
seem to know. With the aid of these seven magnificent stars you can find
all the other interesting stars and constellations. So true is this that
a book has been written called "The Stars through a Dipper."
To illustrate, do you know the _Pointers_? I mean the two stars on the
front side of the Dipper. They point almost directly toward the Pole
star, or North star, the correct name of which is Polaris. Most children
can see the Pole star at once because it is the only bright star in that
part of the heavens.
But if you can't be sure you see the right one, a funny thing happens.
Your friend will try to show you by pointing, but even if you look
straight along his arm you can't always be sure. And then, if he tries
to tell you how far one star is from another, he will try to show you by
holding his arms apart. But that fails also. And so, we all soon learn
the easiest and surest way to point out stars and measure distances.
The easiest way to tell any one how to find a star is to get three
stars in a straight line, or else at right angles.
The surest way to tell any one how far one star is from another is by
"degrees." You know what degrees are, because every circle is divided
into 360 of them. And if you will think a moment, you will understand
why we can see only half the sky at any one time, or 180 degrees,
because the other half of the sky is on the other side of the earth.
Therefore, if you draw a straight line from one horizon, clear up to the
top of the sky and down to the opposite horizon, it is 180 degrees long.
And, of course, it is only half that distance, or 90 degrees, from
horizon to zenith. (Horizon is the point where earth and sky seem to
meet, and zenith is the point straight over your head.)
Now ninety degrees is a mighty big distance in the sky. The Pole star is
nothing like ninety degrees from the Dipper. It is only twenty-five
degrees, or about five times the distance between the Pointers. And now
comes the only thing I will ask you to remember. Look well at the two
Pointers, because the distance between them, five degrees, is the most
convenient "foot rule" for the sky that you will ever find. Most of the
stars you will want to talk about are from two to five times that
distance from some other star that you and your friends are sure of.
Perhaps this is a little hard to understand. If so, read it over several
times, or get some one to explain it to you, for when you grasp it, it
will unlock almost as many pleasures as a key to the store you like the
best.
Now, let's try our new-found ruler. Let us see if it will help us find
the eighth star in the Dipper. That's a famous test of sharp eyes. I
don't want to spoil your pleasure by telling you too soon where it is.
Perhaps you would rather see how sharp your eyes are before reading any
further. But if you can't find the eighth star, I will tell you where to
look.
Look at the second star in the Dipper, counting from the end of the
handle. That is a famous star called Mizar. Now look all around Mizar,
and then, if you can't see a little one near it, try to measure off one
degree. To do this, look at the Pointers and try to measure off about a
fifth of the distance between them. Then look about one degree (or less)
from Mizar, and I am sure you will see the little beauty--its name is
Alcor, which means "the cavalier" or companion. The two are sometimes
called "_the horse and rider_"; another name for Alcor is Saidak, which
means "the test." I shall be very much disappointed if you cannot see
Saidak, because it is not considered a hard test nowadays for sharp
eyes.
Aren't these interesting names? Mizar, Alcor, Saidak. They sound so
Arabian, and remind one of the "Arabian Nights." At first, some of them
will seem hard, but you will come to love these old names. I dare say
many of these star names are 4,000 years old. Shepherds and sailors
were the first astronomers. The sailors had to steer by the stars, and
the shepherds could lie on the ground and enjoy them without having to
twist their necks. They saw and named Alcor, thousands of years before
telescopes were invented, and long before there were any books to help
them. They saw the demon star, too, which I have never seen. It needs
patience to see those things; sharp eyes are nothing to be proud of,
because they are given to us. But patience is something to be eager
about, because it costs us a lot of trouble to get it.
Let's try for it. We've had a test of sight. Now let's have a test of
patience. It takes more patience than sharpness of sight to trace the
outline of the Little Dipper. It has seven stars, too, and the Pole star
is in the end of the handle. Do you see two rather bright stars about
twenty-five degrees from the Pole? I hope so, for they are the only
brightish stars anywhere near Polaris. Well, those two stars are in the
outer rim of the Little Dipper. Now, I think you can trace it all; but
to make sure you see the real thing, I will tell you the last secret.
The handle of the Big Dipper is bent _back_; the handle of the Little
Dipper is bent _in_.
Now, if you have done all this faithfully, you have worked hard enough,
and I will reward you with a story. Once upon a time there was a
princess named Callisto, and the great god Jupiter fell in love with
her. Naturally, Jupiter's wife, Juno, wasn't pleased, so she changed the
princess into a bear. But before this happened, Callisto became the
mother of a little boy named Arcas, who grew up to be a mighty hunter.
One day he saw a bear and he was going to kill it, not knowing that the
bear was really his own mother. Luckily Jupiter interfered and saved
their lives. He changed Arcas into a bear and put both bears into the
sky. Callisto is the Big Bear, and Arcas is the Little Bear. But Juno
was angry at that, and so she went to the wife of the Ocean and said,
"Please, never let these bears come to your home." So the wife of the
Ocean said, "I will never let them sink beneath the waves." And that is
why the Big and the Little Dipper never set. They always whirl around
the Pole star. And that is why you can always see them, though some
nights you would have to sit up very late.
Is that a true story? No. But, I can tell you a true one that is even
more wonderful. Once upon a time, before the bear story was invented and
before people had tin dippers, they used to think of the Little Dipper
as a little dog. And so they gave a funny name to the Pole star. They
called it Cynosura, which means "the dog's tail." We sometimes say of a
great man, "he was the cynosure of all eyes," meaning that everybody
looked at him. But the original cynosure was and is the Pole star,
because all the stars in the sky seem to revolve around it. The two
Dippers chase round it once every twenty-four hours, as you can convince
yourself some night when you stay up late. So that's all for to-night.