[Illustration: A Blast Furnace.
Molten iron is brought from the blast furnaces to the open-hearth
furnaces, and dumped into a receptacle called a mixer, the capacity of
which ranges from 400 tons to 1000 tons, depending upon the number of
furnaces to be served.]
[Illustration: One-thousand-ton Mixer.]
Pictures in this story by courtesy of Bethlehem Steel Co.
[Illustration: INSIDE OF OPEN HEARTH FURNACE
Charging Side of an Open-hearth Furnace.
An open-hearth furnace consists of a long, shallow hearth, suitably
enclosed in fire-brick, and bound together with steel binding. The
furnace is heated by burning gas and air, which have previously been
preheated, so that a temperature is obtained in the furnace ranging
from 2900 to 3050 degrees Fahrenheit.]
[Illustration: Pouring Side of an Open-Hearth Furnace.
The open-hearth process consists of the purification of iron by
oxidizing out the impurities and burning out the carbon of the iron
until a tough and ductile steel is produced, which can be made of any
desired composition by the addition of the necessary quantities of
alloys just previous to tapping and pouring. The impurities in the iron
are oxidized by the slag lying on top of the metal, and the burning
out of the carbon, which is a very slow operation, is hastened by the
addition of iron ore, the oxygen of which combines with the carbon of
the iron and passes off is a gas going up the stack.
When an open-hearth furnace is ready for a charge, a variable amount
of scrap, say 30 per cent of the total weight of material used for
the heat, is charged into the furnace. With this scrap is charged
sufficient lime or limestone to make the slag, as well as some iron ore
to assist in reducing the carbon of the iron. In about two or three
hours the required amount of molten iron is brought from the mixer in
ladles, and poured into the furnace on top of the scrap, lime and ore.]
[Illustration: MOLTEN STEEL BEING POURED LIKE WATER
Molten Steel Being Poured Into Ladle.
When the scrap has all been melted, a test is taken to determine the
amount of carbon remaining in the bath. Iron ore is added from time
to time until the carbon in the bath has been reduced to the desired
point, and the metal is sufficiently hot to pour. At this point
“recarburizers” (consisting of Ferro-Manganese, Ferro-Silicon, and
pig-iron, or coal) are added to get the required composition. The tap
hole at the back of the furnace is opened, and the steel is allowed to
run out into a ladle, the slag coming last and forming a blanket over
the steel in the ladle.]
[Illustration: Crane Carrying Ingot and Soaking Pit Furnaces.
The ladle is picked up by an electric crane and carried over cast-iron
moulds, which are set on cars, the steel being poured into the moulds,
resulting in steel ingots. A sufficient amount of time is allowed for
the steel to become chilled or set, when the cars are pushed under an
electric stripper, where the moulds are removed from the ingots. After
the ingots leave the stripper they are taken to the scales and weighed,
and after weighing are put into the soaking pits. The pits get their
name from the part they play in the heating of the steel for rolling.
When the steel ingot is stripped the outside of the ingot is cool
enough to hold the inside, which is still in a liquid state, and the
steel is put into the soaking pits to allow the inside to settle into a
solid mass, after which the ingot is reheated for rolling. The length
of time in the soaking pits depends upon the size of the ingot, as the
larger the ingot, the greater length of time is required to set.
When the steel is ready for rolling it is taken from the pits by
overhead electric cranes, and placed into a dump buggy at the end of a
roller line, which leads to the blooming mill. The dump buggy derives
its name from the fact that when the ingot is placed into same in
an upright position, the buggy, in order to place the ingot into a
horizontal position on the roller line, dumps over, in the same way as
if one were to rock too far forward in a rocking-chair, the dump buggy
operating on the same principle.]
[Illustration: GETTING READY TO MAKE A RAIL
Blooming Mill and Engine.
The ingot travels down the movable-roller line to the blooming-mill
rolls, which roll it down from a piece 19 inches by 23 inches to what
is known as an 8 inch by 8 inch bloom, which is the size usually used
in the manufacture of rails. The blooming mill derives its name from
the fact that after an ingot is rolled in same it is no longer called
an ingot, but a bloom.
After leaving the blooming mill the bloom travels along another roller
line to the shears, where it is cut into two or three pieces, the
number of pieces depending on the size of the rail which is to be
rolled. The blooms are then lifted over the roller line at the shears
by a transfer crane, and placed on a traveling roller line which
connects with the rear of the reheating furnace. This furnace is about
35 feet long, and is so constructed that when the bloom is pushed in
at the rear of the furnace, another bloom drops from the front or
discharge end of the furnace.]
[Illustration: THE INGOT BECOMES A RAIL
The Ingot Becomes a Rail.
The bloom dropping out, being sufficiently hot to roll into rails,
travels along another roller line to the roughing or first set of
rolls. Here the bloom is given five passes in the rolls, and is then
transferred to the strand or second set of rolls, where it receives
five additional passes; after this operation it is transferred to
the finishing or third set of rolls, in which it is given one pass.
The bloom has now been converted into a rail, and the rail travels
on another roller line to the hot saw, where it is cut into 33-foot
lengths, this being the standard length in this country for all rails.
The rails when hot are cut by the hot saw to lengths of about 33 feet
6¹⁄₂ inches, the allowance of inches being made for shrinkage in
cooling. It is difficult to believe that steel shrinks to this extent,
but this is a fact, and while the rails are cooling on the hotbeds
they have the appearance of being animated, as they move first one way
and then the other. After the rails are on the hotbed a sufficient
length of time to cool, they are taken from the hotbed and placed
on a traveling roller line, which takes them to an endless chain
conveyor. The statement that rails are put on hotbeds for cooling seems
paradoxical, but the hotbeds are so called because the rails are placed
on them while hot, and are left there until they have cooled.
The endless-chain conveyor places the rails on another bed, from
which they are picked up by an electric crane and distributed to the
straightening presses, where all burrs (which have been caused by the
hot-sawing operation) are removed before the rails are straightened.
After straightening they are transferred to drill presses, where they
have holes drilled into them for the accommodation of the splice bar,
after which they are placed on the loading docks.]
[Illustration: After being carefully examined by the railroad
company’s inspectors they are picked up from the loading docks by
electric magnets attached to a crane, and are placed in cars ready for
shipment.]
Who Made the First Felt Hat?
The felt hat is as old as Homer. The Greeks made them in skull-caps,
conical, truncated, narrow- or broad-brimmed. The Phrygian bonnet was
an elevated cap without a brim, the apex turned over in front. It is
known as the “cap of liberty.” An ancient figure of Liberty in the
times of Antonius Livius, A.D. 115, holds the cap in the right hand.
The Persians wore soft caps; plumed hats were the headdress of the
Syrian corps of Xerxes; the broad-brim was worn by the Macedonian
kings. Castor means a beaver. The Armenian captive wore a plug hat.
The merchants of the fourteenth century wore a Flanders beaver.
Charles VII, in 1469, wore a felt hat lined with red, and plumed.
The English men and women in 1510 wore close woolen or knitted caps;
two centuries ago hats were worn in the house. Pepys, in his diary,
wrote: “September, 1664, got a severe cold because I took off my hat at
dinner”; and again, in January, 1665, he got another cold by sitting
too long with his head bare, to allow his wife’s maid to comb his hair
and wash his ears; and Lord Clarendon, in his essay, speaking of the
decay of respect due the aged, says “that in his younger days he never
kept his hat on before those older than himself, except at dinner.”
In the thirteenth century Pope Innocent IV allowed the cardinals the
use of the scarlet cloth hat. The hats now in use are the cloth hat,
leather hat, paper hat, silk hat, opera hat, spring-brim hat, and straw
hat.
What Is the Hottest Spot on Earth?
The hottest regions on earth is said to be along the Persian Gulf,
where little or no rain falls. At Bahrein the arid shore has no fresh
water, yet a comparatively numerous population contrive to live there,
thanks to the copious springs which break forth from the bottom of the
sea. The fresh water is got by diving. The diver, sitting in his boat,
winds a great goat-skin bag around his left arm, the hand grasping
its mouth; then he takes in his right hand a heavy stone, to which is
attached a strong line, and thus equipped he plunges in, and quickly
reaches the bottom. Instantly opening the bag over the strong jet of
fresh water, he springs up the ascending current, at the same time
closing the bag, and is helped aboard. The stone is then hauled up, and
the diver, after taking breath, plunges in again. The source of the
copious submarine springs is thought to be in the green hills of Osman,
some 500 or 600 miles distant.
Where Do We Get Ivory?
Ivory is a hard substance, not unlike bone, of which the teeth of
most mammals chiefly consist, the dentine or tooth-substance which in
transverse sections shows lines of different color running in circular
arcs. It is used extensively for industrial purposes and is derived
from the elephant, walrus, hippopotamus, narwhal, and some other
animals. The ivory of the tusks of the African elephant is held in the
highest estimation by manufacturers; the tusks vary in size, ranging
from a few ounces in weight to 170 pounds. Holtzapffel states that
he saw fossil tusks on the banks of rivers of Northern Siberia which
weighed 186 pounds each. Ivory is simply tooth-substance of exceptional
hardness, toughness, and elasticity, due to the firmness and regularity
of the dentinal tubules which radiate from the axial pulp-cavity to the
periphery of the tooth.
How Did Trial by Jury Originate?
~WHY JURIES HAVE TWELVE MEN~
A jury consists of a certain number of men selected according to law
and sworn to inquire into and determine facts concerning a cause or
an accusation submitted to them, and to declare the truth according
to the evidence. The custom of trying accused persons before a jury,
as practised in this country and England, is the natural outgrowth of
rudimentary forms of trial in vogue among our Anglo-Saxon ancestors.
The present system of trial by jury is the result of a gradual growth
under the English Common Law. There is no special reason why twelve is
the usual number chosen for a complete jury except the necessity for
limiting the number. In a grand jury the number according to law must
not be less than twelve nor more than twenty-three, and twelve votes
are necessary to find an indictment. The ancient Romans also had a form
of trial before a presiding judge and a body of judices. The right of
trial by jury is guaranteed by the United States Constitution in all
criminal cases, and in civil cases where the amount in dispute exceeds
$20. A petit or trial jury consists of twelve men, selected by lot
from among the citizens residing within the jurisdiction of the court.
Their duty is to determine questions of fact in accordance with the
weight of testimony presented and report their finding to the presiding
judge. An impartial jury is assured by drawing by lot and then giving
the accused, in a criminal case, the right to dismiss a certain number
without reason and certain others for good cause. Each of the jurymen
must meet certain legal requirements as to capacity in general and
fitness for the particular case upon which he is to sit, and must take
an oath to decide without prejudice and according to the testimony.
A coroner’s jury or jury of inquest is usually composed of from six
to fifteen persons, summoned to inquire into the cause of sudden or
unexplained deaths.
Can Animals Foretell the Weather?
Certain movements on the part of the animal creation before a change of
weather appear to indicate a reasoning faculty. Such seems to be the
case with the common garden spider, which, on the approach of rainy or
windy weather, will be found to shorten and strengthen the guys of his
web, lengthening the same when the storm is over. There is a popular
superstition that it is unlucky for an angler to meet a single magpie,
but two of the birds together are a good omen. The reason is that the
birds foretell the coming of cold or stormy weather, and at such times,
instead of searching for food for their young in pairs, one will always
remain on the nest. Sea-gulls predict storms by assembling on the land,
as they know that the rain will bring earthworms and larvæ to the
surface. This, however, is merely a search for food, and is due to the
same instinct which teaches the swallow to fly high in fine weather,
and skim along the ground when foul is coming. They simply follow
the flies and gnats, which remain in the warm strata of the air. The
different tribes of wading birds always migrate before rain, likewise
to hunt for food. Many birds foretell rain by warning cries and uneasy
actions, and swine will carry hay and straw to hiding-places, oxen will
lick themselves the wrong way of the hair, sheep will bleat and skip
about, hogs turned out in the woods will come grunting and squealing,
colts will rub their backs against the ground, crows will gather in
crowds, crickets will sing more loudly, flies come into the house,
frogs croak and change color to a dingier hue, dogs eat grass, and
rooks soar like hawks. It is probable that many of these actions are
due to actual uneasiness, similar to that which all who are troubled
with corns or rheumatism experience before a storm, and are caused
both by the variation in barometric pressure and the changes in the
electrical condition of the atmosphere.
Nearest Approach Ever Made to Perpetual Motion in Mechanics.
An inventor has patented a double electric battery which seems to
come exceedingly near to perpetual motion. Instead of using the zinc
battery, he professes to have hit upon a solution which makes a battery
seven times as powerful as the zinc battery, with absolutely no waste
of material. The power of the battery grows gradually less in a few
hours of use, but returns to its original unit when allowed to rest a
few hours. He has two batteries so arranged that the power is shifted
from one to the other every three hours. A little machine has been
running for some years in the patent office at New York. Certain parts
of the mechanism are constructed of different expansive capacities, and
the machine is worked by the expansion and contraction of these under
the usual variations of temperature. In the Bodleian Library at Oxford
there is an apparatus which has chimed two little bells continuously
for forty years, by the energy of an apparently inexhaustible
“dry-pile” of very low electrical energy. A church clock in Brussels is
wound up by atmospheric expansion induced by the heat of the sun. As
long as the sun shines this clock will go till its works wear out. Mr.
D. L. Goff, a wealthy American, has in his hall an old-fashioned clock,
which, so long as the house is occupied, never runs down. Whenever the
front door is opened or closed, the winding arrangements of the clock,
which are connected with the door by a rod with gearing attachments,
are given a turn, so that the persons leaving and entering the house
keep the clock constantly wound up.
Do Plants Breathe?
Plants, like animals, breathe the air; plants breathe through their
leaves and stems just as animals do by means of their respiratory
organs. When a young plant is analyzed it is found to consist chiefly
of water, which is all removed from the soil; there is about 75 per
cent or more of this fluid present, and the rest is solid material.
Of this latter by far the most abundant constituent is carbon, almost
every atom of which is removed from the atmosphere by the vital
action of minute bodies contained in the green leaves. The carbon is
taken into the plant as carbonic acid gas. Plants also absorb oxygen,
hydrogen, and nitrogen from the atmosphere in different quantities
through their leaves, and also by means of their roots. These new
products stored are in turn used in building up the different organs
of the plant. Plants give off used-up moisture through their leaves,
just as animals perspire through the pores of their skins. Calculations
have been made as to the amount of water thus perspired by plants. The
sunflower, only 3¹⁄₂ ft. high, with 5,616 square inches of surface
exposed to the air, gives off as much moisture as a man.
What Depth of Snow Is Equivalent to an Inch of Rain?
Newly fallen snow having a depth of about 11¹⁄₃ inches is equivalent to
one inch of rain. A cubic foot of newly fallen snow weighs 5¹⁄₂ pounds
and a cubic foot of fresh or rain water weighs 62¹⁄₂ pounds or 1,000
ounces. An inch of rain means a gallon of water spread over every two
square feet, or about a hundred tons to every acre. The density of
snow naturally varies a good deal according to the speed with which
it falls. Temperature, also, has much to do with its bulk. In cold,
crisp weather, when the thermometer registers several degrees of frost,
snow comes down light and dry; but in moist, cold weather, when the
temperature is only just below thirty-two degrees, the snow falls in
large, partially thawed flakes, and occupies much less space where it
falls than that which reaches the earth during the prevalence of a
greater degree of cold.
How Are the Stars Counted?
Stars are counted by means of the telescope and photography. The
Astronomer-Royal for Ireland, Sir Robert S. Ball, in one of his
lectures mentioned a photograph which had been obtained by Mr. Isaac
Roberts representing a small part of the constellation of the Swan.
The picture is about as large as the page of a copy-book, and it
is so crowded with stars that it would puzzle most people to count
them; but they have been counted by a patient person, and the number
is about 16,000. Many of these stars are too faint ever to be seen
in the greatest of telescopes yet erected. Attempts are now being
made to obtain a number of similar photographs which shall cover
the whole extent of the heavens. The task is indeed an immense one.
Assuming the plates used to be the same size as that above mentioned,
it would require at least 10,000 of them to represent the entire
sky. The counting of stars by the telescope was first reduced to a
system by the Herschels, who introduced “star-gauges,” which were
simply a calculation by averages. A telescope of 18 in. aperture, 20
ft. focus, and a magnifying power of 180, giving a field of view 15
in. in diameter, was used for the purpose. The process consisted in
directing this instrument to a part of the sky and counting the stars
in the field. This, repeated hundreds of times, gave a fair idea of the
average number of stars in a circle of 15 in. diameter in all parts of
the sky. From this as a basis it is possible to reckon the number of
stars in any known area.
How Is the Volume of Sound Measured?
Sound arises from vibrations giving a wave-like motion to the
surrounding atmosphere, the wave gradually enlarging as it leaves the
source of disturbance, while at the same time the motion of the air
particles becomes less and less. The simplest method of determining the
number of vibrations of a sound is by means of Savart’s apparatus. This
consists of two wheels--a toothed or cog-wheel and a driving-wheel.
They are so adjusted that the cog-wheel is made to revolve with great
rapidity, its teeth hitting upon a card fixed near it. The number of
revolutions is indicated by a counter attached to the axis of the
cog-wheel. Suppose that sound is traveling in the air at the rate
of 1,000 ft. per second, and that Savart’s wheel is giving a sound
produced by 200 taps on the card per second, it follows that in 1,000
ft. there will be 200 waves or vibrations, and if there be 200 waves in
1,000 ft. each wave or vibration must be 5 ft. in length. The velocity
of sound through air varies with the temperature of the latter, but is
usually reckoned at 1,130 ft. per second.
At What Rate Does Thought Travel?
Thought travels 111 feet per second, or about a mile and a quarter per
minute. Elaborate experiments have been made by Professors Heimholtz,
Hersch, and Donders, to ascertain the facts on this question, the
result of which was that they found the process of thought varied in
rapidity in different individuals, children and old persons thinking
more slowly than people of middle age, and ignorant people more slowly
than the educated. It takes about two-fifths of a second to call
to mind the country in which a well-known town is situated, or the
language in which a familiar author wrote. We can think of the name
of the next month in half the time we need to think of the name of
the last month. It takes on the average one-third of a second to add
numbers containing one digit and half a second to multiply them. Those
used to reckoning can add two to three in less time than others; those
familiar with literature can remember more quickly than others that
Shakespeare wrote “Hamlet.” It takes longer to mention a month when a
season has been given than to say to what season a month belongs. The
time taken up in choosing a motion, the “will time,” can be measured as
well as the time taken up in perceiving. If it is not known which of
two colored lights is to be presented, and you offer to lift your right
hand if it be red and your left if it be blue, about one-thirteenth of
a second is necessary to initiate the correct motion.
What Is the Largest Tree In the World?
In San Francisco, encircled by a circus tent of ample dimensions, is a
section of the largest tree in the world--exceeding the diameter of the
famous tree of Calaveras by five feet. This monster of the vegetable
kingdom was discovered in 1874, on Tule River, Tulare County, about
seventy-five miles from Visalia. At some remote period its top had
been broken off by the elements, or some unknown forces, yet when it
was discovered it had an elevation of 240 feet. The trunk of the tree
was 111 feet in circumference, with a diameter of 35 feet 4 inches.
The section on exhibition is hollowed out, leaving about a foot of
bark and several inches of the wood. The interior is 100 feet in
circumference and 30 feet in diameter, and it has a seating capacity
of about 200. It was cut off from the tree about twelve feet above the
base, and required the labor of four men for nine days to chop it down.
In the center of the tree, and extending through its whole length,
was a rotten core about two feet in diameter, partially filled with a
soggy, decayed vegetation that had fallen into it from the top. In the
center of this cavity was found the trunk of a little tree of the same
species, having perfect bark on it, and showing regular growth. It was
of uniform diameter, an inch and a half all the way; and when the tree
fell and split open, this curious stem was traced for nearly 100 feet.
The rings in this monarch of the forest show its age to have been 4,840
years.
Where Did the Term Yankees Originate?
This is a word said to be a corruption of Yengees, the Indian
pronunciation of English, or of the French “Anglais,” when referring
to the English Colonists. It was first applied to the New Englanders
by the British soldiers as a term of reproach, later by the English to
Americans generally, and still later to the people of the North by the
Southerners.
How Far Does the Air Extend?
It is, perhaps, generally known that enveloping the earth is a layer
of air fifty or more miles in thickness. Just how thick this layer is
we do not know, but we do know that it extends many miles from the
earth. You may assure yourselves of this in a very simple manner by
watching the shooting stars that may be seen on any clear night. These
are nothing but masses of rocks that give off light only when they
have been made red-hot by friction with the air in their rapid flight.
The fact that we often see these stars while they are still many miles
from the earth proves to us that the air through which they are passing
extends to that height.
What Makes Us Feel Hungry?
Hunger is a peculiar craving which we are accustomed to say comes
from the stomach. It is the business of the stomach to change such
food as we take into it in such a way that the rest of the organs of
the body which we have for the purpose can make blood out of it. When
you feel the sensation of hunger, it means that the blood-producing
system is calling on the stomach to furnish more blood-making material.
The stomach prepares the food for blood production by mixing with it
certain juices which the stomach is able to supply. As soon as the
stomach is then called upon to supply more blood-making material, it
goes to work on what is in the stomach and begins mixing things. If,
however, there is nothing in the stomach, the craving which we call
hunger is produced. It is, therefore, then not altogether the stomach
which makes us hungry, but the parts of our body which actually turn
the food into blood after the stomach has prepared it.
To prove this it is only necessary to say that the sensation of hunger
will stop if food which is easily absorbed and, therefore, does not
need the preparation which the stomach generally gives, is introduced
into the system through other parts of the body, as, for instance, by
injecting it into the large intestine, which is a part of the body, the
food passes through after it leaves the stomach ordinarily.
What Makes Us Thirsty?
Thirst is a sensation of dryness and heat which is generally
communicated to us through the tongue and throat. The sensation of
thirst can be artificially produced by passing a current of air
over the membranes which cover the tongue and throat, but thirst is
naturally due to a shortage of water in the body. The human body
requires a great deal of water to keep it in condition, and when the
supply becomes low a warning is given to us by making the membranes of
the tongue and throat dry.
In connection with thirst, however, as in the case of hunger, where
the warning is given by the stomach, thirst will be appeased by the
introduction of water, either into the blood, the stomach or the large
intestine, without having touched either the tongue or throat, which
proves that it is not our tongue or throat that is thirsty, but the
body itself.
What Is Pain and Why Does It Hurt?
Pain is the result of an injury to some part of our bodies, or a
disturbed condition--a change from the normal condition. Pain is caused
by nerves in the body. The network of nerves coming in big nerves from
the back bone or spinal chord branches out in all directions, and near
the surface of the skin they spread out like the tiny twigs of a tree,
covering every point of the body. Some parts of our bodies are more
sensitive than others. That is because the nerves are then nearer the
surface or else there are more nerves in that part. The heel is perhaps
the least sensitive part of the body, as the nerves do not lie so near
the surface there.
Pain is not a thing which you can make a picture of or describe in
words. Pain is a sensation of the brain caused by a disturbance of
conditions in some part of the body. If you cut your finger, you cut
certain veins or arteries and also the tiny nerves in the finger.
The nerves immediately let the brain know that they are injured, and
the brain sets to work to have the damage repaired. But there is a
congestion right where the cut is. The veins being cut, the blood which
would ordinarily flow through them back to the heart, pours out into
the cut and the inside of your finger is thus exposed to the oxygen of
the air, and the action of the air on the exposed part helps to make
the pain. It is not your finger, however, that hurts. It is the shock
that your brain gets when you cut your finger that hurts.
A pain in your stomach is a pain caused by something else than a cut.
If the stomach could always digest everything or any amount of stuff
you put in it, you would not have a stomach pain. But sometimes you
put things into your stomach through your mouth, of course, that the
stomach cannot handle. Or, it may be a combination of a number of
things that cause this unusual condition in your stomach. The stomach
makes a special effort to get rid of this troublesome substance and
generally succeeds eventually, but while the fight is going on, it
pains or hurts you.
Pain is the result of a disturbance of the nerves. It is just the
opposite of gladness. We sometimes are so glad we feel good all over.
Pain is just the opposite. You can prove that pain is not a real thing
but only a sensation. Perhaps you have had toothache. You go to the
dentist and he kills the nerve or takes it out. After that you cannot
have the toothache in that tooth again, because there is no nerve there
to telegraph to the brain, even though the cause of the hurt still
exists. You cannot feel pain unless the brain knows about the injury.
What Is the Horizon?
Of course you know what the horizon is. It is easiest to see the
horizon at sea when out of sight of land. There, when you look in
any direction from the ship to the place where the sea and the sky
meet you see a line which, if you follow with your eye as you turn
completely around, makes a perfect circle. It looks as though it marked
the boundary of the earth. On land it is not easy to see as much of
the horizon at one time, because of buildings and trees and hills in
the woods and elsewhere, but if the land were perfectly smooth like
the sea and there were no trees or buildings or hills in the way, you
could see just as perfect a circle on land as on sea. This proves that
the horizon is a movable circle. On land it is where the earth and sky
appear to meet, and on water it is where sky and water appear to meet.
How Far Away Is the Horizon?
The actual distance of the horizon away from us depends altogether upon
the height above the sea level from which we are looking as far as we
can. The horizon is always as far away as we can see. At the seashore,
where we are practically on a level with the water, we cannot see so
far as when we are up on a bluff or hill overlooking the sea. The
higher we go up straight from a given point the greater the distance
we can see up to a certain point and the farther away the horizon will
appear. The height of the person looking, of course, figures in this,
because when you are at sea level it is only your feet really that are
at sea level (if you are standing up straight) and the distance of the
horizon is measured from the eye of the person looking. A boy or girl
of ten would be, say, a little over four feet high, and the eyes of
such a person would be about four feet above the level of the sea. At
that height the horizon would be about two and a half miles away. If
the eyes are six feet above sea level the distance of the horizon will
be about three miles, so that practically every one sees a different
horizon, that is, one that appears at a different distance. A hundred
feet above the level of the sea the horizon will be more than thirteen
miles away, while at 1000 feet altitude it would be 42 miles away, and
if you could go a mile into the air the horizon would appear 96 miles
from where you are. The higher you go the farther away the circle which
apparently marks the joining of the earth and sky appears.
Why Can We See Farther When We Are Up High?
Remember that the earth is round and you will probably be able to
answer the question yourself. This one, like most questions boys and
girls ask, only requires a little thought. The earth, of course, as we
have learned long ago, is a globe. When you look out on the land or the
sea from a high place you can see more of the earth’s round surface
before the curve of the earth’s surface takes things beyond the range
of vision. If you are on a bluff 100 feet high at the seashore and
looking toward a point where a ship is coming toward shore, you will be
able to see the ship much sooner than if you were at the sea level. In
exact words, you actually see more of the earth’s surface the higher
up you are, because, as you go up your position in relation to the
curvature of the earth’s surface changes.
What Makes Lobsters Turn Red?
When a lobster is taken out of the lobster trap with which the
fisherman traps him, he is green, but when he comes to the table as a
choice morsel of food his shell is red. We know that he has been boiled
and we know that he goes into the boiling water green and comes out
red. This change in the color of the shell of the lobster is the result
of the effect of boiling water on the coloring material in the shell.
When the lobster is put in the boiling water the process of boiling
produces a chemical change in the color material in the lobster’s
shell. There is no particular reason why the lobster should turn red,
excepting that that is the effect boiling water has on the coloring
matter in the shell.
Why Do We Have to Die?
Death must come to all things that have life. All matter in the world
is either living (animate) or dead (inanimate). Inanimate things do not
change. They remain always the same. We can change the form and size of
inanimate things, and particles of them even help to make up the bodies
of the living things, but what they are made of always remains what it
was.
Death is one of the things that must occur if we are to continue to
have more life. The whole plan of living things includes the ability to
reproduce themselves. Every kind of life has the power to produce life
like itself and this process of reproduction is continuous. If there
were no death, then the world would soon be crowded with living things
to the point where there would be neither room nor food.
[Illustration: WHERE WINDOW GLASS COMES FROM]
Pictures herewith by courtesy of Pittsburgh Plate Glass Co.