Fire in Your Life

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Fire in your life

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Fire in your life "

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PUBLIC LIBRARY FORT WAYNE AND ALLEN COUNTY, NO. ALLEN COUNTY EXTENSION DEPT. I

ANTHONY 3333

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LOAN

UNTY PUBLIC LIBRARY

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Fire in

Your

Life

Books by Irving Adler

FIRE IN YOUR LIFE

TIME

IN

YOUR LIFE

THE SECRET OF LIGHT DISCOVER THE STARS (co-author)

IRVING ABLER

Fire in

Your

Illustrated by

Life

Ruth Adler

The John Day Company

New

York

Copyright

©

1955 by Irving and Ruth Adlei

All rights reserved. This book, or parts thereof, must not he repro-

duced in any form without permission. Published by The John Day Company, 62 West 45th Street, New York 36, N. Y., and on the same day in Canada by Longmans, Green 6- Company, Toronto.

Library of Congress Catalog Card Number: 55-9930

MANUFACTURED

IN

THE UNITED STATES OF AMERICA

VAN REES PRESS



NEW YORK

CO. SCHOOLS

.

M/y^i/i

i

I €711

I.

II.

III.

C478664 Man

Finds Fire

What

Is

9 19

Fire?

Learning To

Make

Fire

38

IV.

Fire,

Comfort, and Freedom

54

V.

Fire,

The Magician

66

VI.

Fire

and Power

91

VII.

Fire

and Destruction

101

Fuels and the Future

115

Index

128

VIII.

¥

Fire in

Your

Life

CHAPTER

I

Man Finds Fire Fire and

Old Bones

IN 1927

a tooth

was dug out

of the

Hmestone

in a

cave at Choukoutien, 37 miles southwest of Peking, China. This was no ordinary tooth.

now

called Peking

Spurred on by

It

was the tooth

Man, who

of an ape-man,

lived 500,000 years ago.

this find, scientists

continued to dig and

They found many and bones, including some fairly complete skulls. From these remains they figured out what Peking Man must have looked like. He had a slanting brow, bony ridges over his eyes, and practically no chin. His brain was much larger search in the cave for the next ten years.

more

teeth

than that of an ape, but not as large as the brain of modern

man. With the help of

this brain,

Peking

Man

or his ances-

had already made a great discovery that no other animal but man has ever made. He had learned how to use fire. This fact was proved by the heaps of charred animal bones found with his remains and his crude stone tools in the cave. So we know that man's knowledge of the use of fire is at least a tors

half -million years old.

Fire Is a Tool

An ape will sometimes pick up a stone and use it to crack open a nut. When he does so, he is using the stone as a tool. 9

Over

a million years ago, the ancestors of

who had

man were

ape-like

trick. They occasionally by picking up sticks and stones to use as tools. Then, later, some of them found that they could have a better tool by chipping one stone with another. Those who made this discovery were taking the first step in man's rise from the animal world. They were making the change from merely finding tools to making them. Ever since then man has distinguished himself as the only animal that makes his own tools to add to his

creatures

added

learned this

to their natural strength

strength.

man has learned man probably used fires that he found long before he learned how to make any himself. There were many places where early man could have found fire, because fire often came down from the sky Fire

is

one of the important

how to make.

or

tools that

But, as in the case of stone tools,

up from the ground.

Fire from the Sky

A

thunderstorm

gusts of

wind warn

is

a very dramatic thing. First, strong

of the approaching storm.

Then

a great

dark cloud follows the wind and turns day into night. The rain pours

down

in torrents. Streaks of lightning flash across

the sky, and the thunder roars like a thousand lions. Some-

times the lightning strikes a tree, and the tree catches If

other trees are close by, the wind can carry the

tree to tree,

and turn the

fire

fire.

from

forest into a blazing furnace. In the

United States alone, there are several hundred thousand each year, and a large number of them are caused by lightning. A million years ago, lightning must have started many fires, too, and may have given man his first forest fires

chance to discover 10

fire

and

its

uses.

when a tree catches fire,

the animals nearby run for their

To be caught by the fire means an agonizing death. Even the most ferocious animals are afraid of fire, and run away from it. Early man may have noticed this, and so found a use for the scraps of burning wood he could pick up when Hves.

the forest

fire

died down.

If

he kept a

fire

going through the

and slept beside it, the wild beasts, afraid of the fire, would leave him undisturbed. After a forest fire, early man must have found animals that had been trapped by the fire and burned to death. Eating one of these animals may have given him his first taste of roasted meat. This taught him another use of fire: to soften and improve the flavor of his meat.

night,

All primitive peoples tell legends to explain

how 11

their

ancestors got

fire.

In

many

of these legends, the

first fire

was brought from the sky by a stroke of lightning. A typical story is the one told by the natives of Queensland, in Australia. They say that their ancestors once returned from hunting kangaroos, and threw their catch on the grass. Just then a thunderstorm came, and lightning set the grass on fire. Some of the kangaroos were partly roasted by the fire. After the people ate the roasted meat, and liked it, they sent an old woman to get some of the fire which was still blazing in the distance. She found a burning stick, and brought it back to her people. After that, she was made caretaker of the fire, tending it day and night to be sure that it didn't go out. Several years later, during the rainy season, the out.

As a punishment 12

fire.

did go

go out, her She wandered

for allowing the fire to

people sent her out to search for more

fire

through the bush, hunting for

fire,

but had no luck at

all.

she was tired,

After several days of fruitless hunting,

of rage, she broke

two

twigs from a tree and rubbed them together furiously.

The

hungry, and very angry. In a

fit

She then returned to her people but the secret of making fire.

sticks burst into flame.

bringing not only

fire,

The Thunder Bird

To primitive man, who thought that everything that moved was alive, fire caused by lightning must have seemed like a living thing. The lightning swooped down out of the sky like a bird, with a deafening roar. tree,

it

flapped

its

When it perched

red and yellow wings, and began to

on a eat.

It had an enormous appetite. It ate tree after tree, and reduced them to thinned and blackened skeletons. This view of fire is preserved in many legends about a Thunder Bird, told in different parts of the world. Stories about a Thunder Bird are found among the Algonquins and other Indians of North America, the Karens of Siam, and the Bechuanas and

Basutos of South Africa.

The Lighthouse The

of the Mediterranean

Italian island of Stromboli

Sea, forty miles north of Sicily.

is

in the

The whole

shaped volcano rising out of the sea

Mediterranean

island

is

a cone-

3000 feet. Inside the volcano there is a reservoir of red-hot melted rock called lava. Every few minutes there are mild explosions that blow some of this lava into the air. The showers of rock pile up on the sides of the cone, building it up higher and higher. The explosions are caused by steam and other gases that are driven out of the lava by the heat. First they form to a height of

13

bubbles in the lava. Then,

when

the pressure in the bubbles

high enough, they break through the surface, blowing steam and rock high into the air. Steam is pouring out of Stromboli all day long. As it rises into the air, it cools and forms a cloud. At night the underside of this cloud reflects the red glow of the hot lava beneath it, so it can be seen

is

for miles around.

That

is

why

Stromboli

is

known

as the

"Lighthouse of the Mediterranean."

The Hot Wind

of

Mont Pelee

an island in the West Indies. At the north end of the island is the volcano of Mont Pelee, and at the base of the volcano is the site of the city of St. Pierre. In Martinique

is

1902 a great blast of hot gas and dust blew out of the volcano. At a speed of more than 60 miles an hour it swept across the city of

14

St. Pierre,

blowing over houses, tearing up

and setting the city on fire. Within a few minutes, all except one of the 30,000 people of St. Pierre were killed. The only survivor was a prisoner in an underground cell in trees,

jail.

Starting a Fire with

We

Water

often use water to put out a

hot enough,

it

can

start a fire too.

was water

fire.

Most

But,

when water

is

of the hot gas that

form of water vapor or steam. The hot steam made the wooden houses and trees hot enough to burn. Some volcanoes have small openings, or fissures, in their sides from which steam rises in a steady stream. If you thrust a stick into one of these openings, the stick will

set fire to St. Pierre

in the

blacken and smoke from the heat of the steam. Then

you

pull the stick out into the air,

Fire in the

it

when

will burst into flame.

Ground

Volcanoes have been active for millions of years. In some of

them there

are tongues of flame,

ing as they escape from the lava. often have set

when

fire to trees

Many way

fire

and

its

down

volcanoes brought

out of the ground, and gave primitive

chance to discover

of gases burn-

volcanoes must

red-hot lava rolled

into the surrounding woods. In this fire

made up

man

another

uses.

In some parts of the world, where people live near volcanoes, the volcanoes, rather than lightning,

may have

brought them their first fire. The people think so, anyhow, because their legends describe volcanoes as the places where fire was found. The Babine Indians of British Columbia, in Canada, live in a region that had active volcanoes in the past. In a story they tell, there was an old chief who had fire, but would not share it with anybody else. A muskrat stole it from him to bring it to the people. To escape from

he burrowed through the ground. Later, a column of smoke and tongues of flame rising from the mountain showed that the muskrat had gotten fire for man. Obviously the Babine Indians thought that a volcano (the mountain that gives out smoke and flame) had something to do with the discovery of the chiefs hut with the

fire,

fire.

A who

volcano also figures in the legend told by the people

on Samoa, an island in the Pacific Ocean. They tell of a man named Talanga who was a friend of the earthquake god, Mafuie. Mafuie lived under the ground where there was fire burning. Talanga used to visit him underlive

16

ground

to help him.

One day

Talanga's son

Ti-iti-i

followed

his father into the ground and asked Mafuie for some fire. Mafuie gave it to him, and Ti-iti-i built a fire to bake taro roots on hot stones. Then Mafuie came and blew up the oven, scattered the stones, and put out the fire. Ti-iti-i, angry at Mafuie for what he did, twisted his right arm off. He would have twisted his left arm off, too, but Mafuie begged for mercy. Ti-iti-i agreed to spare his left arm in

return for being told the secret of there

is

making

fire.

Now, when

an earthquake, Samoans say they are lucky Mafuie

has only one arm. Think of the

had two arms! The word volcano

damage he could do

if

he

comes from an ancient myth. We get it from the name of the Roman god of fire, Vulcanus, who was supposed to live in the volcano of Mt. Etna in itself

Sicily.

Fire from the

Wind

Roman author who lived two thousand years book called The Nature of Things. In this book he mentioned three ways in which fire occurs in nature and may have been discovered by man. He listed fires made by lightning, fires made by volcanoes, and fires made by the wind when it rubs one twig of a tree against another. The people of Rome must have seen fires made by lightning or volcanoes. But it is not likely that the wind in Italy ever rubbed twigs hard enough to make them catch fire. Still, Lucretius may have been right. It is said that in bamboo jungles, fires are often started when the wind rubs one bamboo stalk against another. So some people may have gotten their first fire in the jungle as a gift from the wind. Lucretius, a

ago, wrote a

17

Tending the Fire While you may

find fire "growing"

there every day. So, before

find

it

fire,

they had to guard the

fire

men

on a

tree,

learned

you don't

how

to

make

they had as their most pre-

To be sure that they would always have when they needed it, they never let the fire go out. As in

cious possession. fire

the story told by the natives of Queensland, they put people

charge of the fire, to feed it and protect it, and keep it burning forever. Sacred fires that must never die out became important parts of some early religions. Fire temples in

were

built,

Even long

and

priestesses

were there

to serve the fire god.

after the people

knew how

to

make

fire,

the tra-

Rome, two was kept by the six

ditions of the sacred fire continued. In ancient

thousand years ago, the sacred

fire

young women especially chosen for this honor. They were not permitted to marry during their Vestal Virgins,

goddess of the hearth. not to marry, they were punished

thirty years of service to Vesta, the If

they broke their

by being buried

18

vow

alive.

CHAPTER

What Is Thrown Out

of

II

Fire? Heaven

IN the rehgion of the ancient Greeks, Hephaestus was the god of fire and the protector of all metal workers. His father was Zeus and his mother was Hera. When he was born, his mother thought he was so ugly she threw him into the sea. Later he returned to heaven, and sided with his mother in one of her fights with Zeus. Zeus became angry and threw him out of heaven a second time. Hephaestus set up forges under Mt. Etna and in all other volcanoes of the world. At these forges he made and hammered metals. He also

made

the thunderbolts that Zeus sometimes hurled out

of the sky.

gods that we find among ancient peoples all over the world. In man's first attempts to understand nature, he thought of every natural force as a god. And so, together with sun gods and river This myth

is

one of many about

gods and earth gods,

we

fire

Egypt there was Agni, and in ancient Mexico there was Huehueteotl, the god with a black face and a red was

find fire gods too. In

Bast, in India there

body.

we

some of the knowledge about fire that the ancient Greeks had already acquired through experience. They knew the connection between In the story of Hephaestus

see

19

and lightning, and between fire and volcanoes. They were using fire in many ways, at home and in workshops, and considered the making of metals its most important

lire

use.

Fire Without

Gods

As men continued to use fire, they learned more and more about it. More knowledge meant less mystery. So they stopped thinking of fire as a god, and accepted it as just a 20

natural force. Science

was born when some Greek

philoso-

2500 years ago tried to explain how natural forces combined to make the world. There are thousands of different things in the world. But all of them, they said, are made of four elements. The elements were earth, phers

who

lived about

air, and fire. modern chemistry we don't recognize any of these four as elements. Water is a compound made of two elements, hydrogen and oxygen. Earth and air are mixtures of many compounds and elements. We recognize about one

water,

In

hundred elements today. And ment at all.

The theory

fire is

not considered an ele-

of the ancient Greeks

was very crude. But

one part of that theory remains true to the present day. Earth is a solid, water is a liquid, and air is a gas. Solid, liquid, and gas are the three states of matter. Fire, thought of as heat, is a form of motion or energy. And today we think of

sense

all

things as

made up

modern science

still

of matter

and energy. In

this

uses the four "elements" of the

ancient Greek philosophers.

One

Greek philosophers, Heraclitus, thought that and air, were made of fire alone. This idea, too, is found in modern science, because today we know that all matter is made up of concentrated lumps of energy. In fact, we have learned how to release some of this energy in the atomic bomb. all

of the

things, including earth, water,

Work and

Facts

People held on to the idea of the four "elements" for hundreds of years. Meanwhile they were busy working, doing all

the practical things of daily

livestock.

life.

They took minerals out

They

raised crops and

of the ground.

They 21

pre-

made clothing, put up buildings. With the help they made pottery, metals, glass, and many other

pared food, of fire

things. In doing this practical work, they learned that the

four "elements" were not simple things at that there

were many kinds of

all.

"earths,"

They found

a

variety

of

They also discovered many facts about fire. Some things burned more easily than others. Some things didn't burn at all. Fires had many colors, and some fires were hotter than others. All these facts made up the growing science of chemistry. But the more facts they had, the more they needed a theory to show how the facts are related to each other. Now, instead of using "waters," and different kinds of "air."

the four "elements" to explain the world, they looked for

simpler things to explain the "elements."

A

Theory To Fit the Facts

To have

a better understanding of

fire,

they wanted a

What happens And why do some things burn, while others do not? A chemist who lived in the seventeenth century thought he saw a clue in what happens to wood in a theory that could answer two questions:

when

a thing burns?

When

you burn a piece of wood, it gets smaller and smaller, until only a small amount of ash is left. This seemed to show that the wood was losing something as it burned. So he decided that there must be a fiery substance in wood that escapes from the wood through the flames of the fire.

fire.

He

called the fiery substance "phlogiston."

The phlogiston theory was accepted by chemists of the seventeenth

explain

many

things about

fire.

When

the

phlogiston and ash. escapes,

22

and eighteenth

and only the ash

is

centuries. It

Wood, they said, wood burns, the

left.

for most seemed to is

made

of

phlogiston

Coal, according to this

was almost pure phlogiston. That's why so little ash was left when you burned it. A stone, they said, has no phlogiston in it, and that's why it doesn't burn at all. theory,

Facts That Don't Fit the Theory

Soon First,

began to appear that didn't fit the theory. was known that a fire will not burn without air.

facts

it

Secondly, a candle burning in a closed jar will soon go out.

The phlogiston theory had no facts. Thirdly, some things, like

real explanation for these

gained weight by burning. But according to the phlogiston theory they should lose weight when they give up their phlogiston. Then an importin,

was made by the English chemist Priestley. By heating a compound of mercury he made a gas that we now know as oxygen. In this gas fires burn faster and more brightly than in ordinary air. The French chemist Lavoisier carried these experiments further. Lavoisier burned some tin in a closed flask. He weighed the tin, and found that it had gained weight as a result of burning. Then he weighed the air in the flask, and found that the air had lost weight. In fact, what the tin had gained was equal to what the air had lost. This proved that, in burning, the tin was taking something out of the air. Other experiments helped to show tant discovery

that

all

finally

things that burn take oxygen out of the

destroyed the phlogiston theory.

air.

This fact

The Nature

of Fire

Now we can give an explanation of burning that fits all the facts. A fire is a chemical process in which other chemicombine with oxygen, forming compounds called oxA fire will burn very rapidly in pure oxygen. It will burn more slowly in ordinary air because only one-fifth of cals

ides.

the air

oxygen.

is

Among

the things that can burn, two of the most impor-

tant are hydrogen air gas that is

burns in

air,

and carbon. Hydrogen

a lighter-than-

is

sometimes used in dirigibles. When hydrogen it combines with oxygen to form water in the

form of steam. Carbon is the black substance in coal. When carbon is burned in the presence of plenty of oxygen, the gas carbon dioxide is formed. Wood contains both carbon and hydrogen. So, when wood is burned, both water and carbon dioxide are formed. The reason why wood loses weight when it burns is that the carbon dioxide and water that are formed escape in the smoke. If they were caught and weighed with the ashes, the total weight would be more than the weight of the wood itself. This gain in weight is the weight of the oxygen that was taken out of the air by the burning.

When a candle burns in a closed jar,

it

uses

up the oxygen

smoke Including carbon dioxide

water

&

I

carbon atom-f- 2 oxygen

atoms

=

I

molecule of carbon dioxide +

while there

is

not enough oxygen

keep the candle burning. That

is

why

in the jar. After a

Fire and

A

energy

left to

the flame goes out.

Heat

gives out heat. The modern theory of the atom where the heat comes from. Let us take as an example the burning of carbon, in which each atom of carbon combines with 2 atoms of oxygen. A carbon atom is made up of a nucleus surrounded by 6 electrons. An oxygen atom is made up of a nucleus surrounded by 8 electrons. Each atom contains a certain amount of energy that depends on how the electrons are arranged around the nucleus. When the carbon and oxygen atoms combine, they share their electrons, and the electrons are rearranged around the three nuclei. The new arrangement has less energy than the old arrangement, when the atoms were separate. The energy the atoms lose when they combine is the fire

explains

heat that

is

given out.

Measuring Heat

some ways heat behaves like a liquid. You can store a liquid in a jar. And the more liquid you pour in, the higher the level it will reach in the jar. Heat can be stored, too, but it doesn't need any special container or jar. It can be stored in any body ( solid, liquid, or gas And the more heat you In

)

.

put into the body, the higher the heat level it will reach. The level of heat in a body is called its temperature, and it is

measured by a thermometer. 25

To measure temperature we make use of the fact that most bodies expand, or grow larger, as they get warmer. In the most common wall thermometer, some alcohol is sealed into a small glass reservoir, connected to a thin tube from which the air has been removed. When the alcohol is warmed up, it expands, and flows into the tube. The height to which it climbs in the tube shows the temperature. In English-speaking countries temperature is commonly measured on the Fahrenheit scale, where 32 degrees is the temperature at which water freezes, and 212 degrees is the temperature at which water boils. In other countries, and in scientific work in all countries, the Centigrade scale is

Centigrade

Fahr enheft

100'

water boils

37'

body temperature

normal human

water freezes

212'

98 6^

32'

used. Zero degrees Centigrade

is

the

same

Fahrenheit, and 100 degrees Centigrade

is

32 degrees the same as 212 as

degrees Fahrenheit.

A narrow jar

and a wide

jar

may

hold water reaching up

have more water may have the same heat level, or temperature, without containing the same amount of heat. So the amount of heat is not the same as the level of heat and has a different measure. The unit for measuring the amount of heat is called the calorie. The large calorie is the amount of heat needed to raise the temperature of 1 kilogram of water (about 2.2 pounds) one degree Centigrade. The large calorie is made up of one thousand small calories. English-speaking countries also measure heat in B.T.U.'s (British Thermal Units). One B.T.U. is the amount of heat needed to raise the temperature of one pound of water one degree Fahrenheit. It is about one-fourth of a large calorie. Burning a pound of coal produces about 14,000 B.T.U,'s. to the

same

level,

but the wide

jar will

than the narrow one. In the same way, two bodies

Heating the Heater

About 7000 years ago, men discovered the secret of farmyou bury some wheat seeds in the ground, and tend them properly, wheat plants will grow from them and give you more seeds than you buried. To get the earth to give you a lot of wheat seeds you must first give some seeds to ing. If

the earth. Fire has the

same kind

of secret.

To make wood burn

so

you a lot of heat, you must first give some heat wood. You have to warm the wood until it reaches its ignition temperature, or kindling point. This is the temperature at which it will start to burn in air. To make dry pine it

will give

to the

27

wood burn you have

800 degrees Fahrenheit. A temperature of 660 degrees Fahrenheit will make charcoal burn. About 1100 degrees Fahrenheit will make hydrogen burn. But a temperature of only 120 degrees Fahrenheit is needed to make yellow phosphorus burn. When you strike a match, a chemical process in the head of the

match heats

it

to heat

to

its

it

to

kindling point, so the

wooden wood

matchstick begins to burn at that end. The burning

warm the wood that is close to the flame. When this part of the wood reaches the ignition temperature, it, too, begins to burn. In this way the flame travgives out

els

enough heat

to

along the length of the matchstick.

Flame

in a

Cage

You can keep

Humphry Davy, 28

by putting it in a by the English scientist Sir

a flame from spreading

cage. This fact, discovered

saved

many

lives.

The English

coal min-

day were using oil lamps to give them light while they worked underground. Sometimes the flames of these lamps set fire to the coal dust and gas in the surrounding air, causing terrible explosions. Davy found that these explosions could be prevented by putting wire gauze around the flame. The wire gauze spread out the heat of the flame, so that no part of the gas and coal dust in the air would get hot enough to burn. This was the main idea of the safety lamp in which the flame was enclosed in a wire-gauze cage. ers of his

Inside the

The

Flame

active part of a fire

is its

flame. It

is

in the flame that

the actual burning takes place. But, strange as

not

all

of the flame

is

it

may

seem,

burning! In a candle flame, for ex-

ample, only the outer part

is

hot and burning, while the

Miner's Safety

Lamp

inside of the flame

is

cool.

To prove

this,

hold a toothpick

across a candle flame for about a second,

draw

it

quickly.

The two

and then with-

sections of the toothpick that

rested in the outer edges of the flame will be charred.

wood between

The

these points, which rested in the center of

the flame, will be unburnt. This shows that the center

is

cooler than the outer part of the flame.

To understand why

the center of a candle flame

is

cool,

examine the inside of the flame to see what is really happening there. When you light a candle, the heat of the match melts some of the paraffin that the candle is made of. The melted paraffin flows like water, and climbs up the wick. Here, as it receives more heat, it evaporates and becomes a gas, so the wick is surrounded by this gas. But the gas is surrounded by the air, which contains oxygen. Where the gas and the oxygen meet, they combine and give out heat. So it is only the outside of the flame that is burning, while the inside of the flame is made up of unburnt gas. The let's

30

burning part of the flame passes enough heat back through the cooler gas to evaporate more paraffin to replace the gas that burns up.

You can prove that there is unburnt gas in the center of a candle flame by drawing the gas out of the flame and burning it. Hold a bent piece of glass tubing over a candle flame, so that the lower

end

is

in the center of the flame just

over the wick. Unburnt gas will escape from the flame

through the glass tube. Hold a lighted candle to the upper end of the tube, and the escaping gas will begin to burn. The yellow light of a candle flame comes from glowing particles of

carbon

in the gas.

metal spoon in the flame. will

To

When

see the carbon, hold a

you remove the spoon

it

be covered with a black smudge of soot. This soot is of carbon particles that came out of the flame onto

made up

the cool spoon, the

way dewdrops come

the cool ground at night.

out of the air onto

Burning Oxygen

When we

on a gas stove we say the gas is burning. It would be just as accurate to say that the oxygen in the air is burning, because the gas and the oxygen are equal partners in making the flame. In fact, we can make them change places, and still get a flame. If a closed container is filled with hydrogen gas, and a jet of oxygen is turned on in it, you can light the oxygen with a spark. The oxygen will burn in the atmosphere of hydrogen that surrounds it, just as hydrogen burns in an atmosphere of oxylight a fire

gen.

Fire Without

You

Oxygen

don't need oxygen to

gases can sometimes take

remove

all

its

make

because other place. For example, you can a

fire,

the air from a closed container, and then

container with the poison gas chlorine.

Then you

fill

will

the still

be able to burn hydrogen in the container, because, when hydrogen combines with chlorine, the chemical action gives out heat and light. Hydrogen burns in chlorine with a whitish-green flame.

You can

by any chemical process that gives out heat and light. While fires without oxygen are possible, they are not usual, because most burning takes place in the air, through action with the oxygen that is in it. get

Fire Without

fire

Flame

Sometimes a

Then

the heat

32

fuel is

combines with oxygen very slowly.

carried

away by

the air as fast as

it

is

formed, so the heat In such cases

is

not noticed, and no hght

we have

a

v^ithout flame.

fire

is

given out.

When

iron

is

exposed to the air, it combines slowly with the oxygen in the air to form rust. Without any glow, and with no notice-

burning up just as surely as if it had burst into flame. To keep iron from rusting, you have to separate it from the oxygen in the air by covering it with a

able heat, the iron

is

film of oil or paint.

The drying

of paint

without flame. The

from the

air to

another example of slow burning

is

oil in

the paint combines with oxygen

form a hard

skin.

tective shield for the surface that

This skin serves as a pro-

was painted.

Fires That Light Themselves If oily

among

freely

heat that gen.

rags are

is

heaped

the rags.

Then

formed when the

The heat

and warmer.

the air cannot carry oils

is

they reach the kindling point, they

called

spontaneous

houses have been burned by

when

the

and the rags get warmer

burst into flames. This process, in which

themselves,

away

slowly combine with oxy-

collects in the rags,

When

cannot move

in a big pile, air

fires

that

fires

start

Many

combustion.

began

by

in this

way,

careless people left heaps of oily rags in their base-

ments.

There barn.

is

Wet

danger of fire, too, when wet hay is stored in a hay begins to rot. The rotting of hay is a process

of slow burning, like the rusting of iron.

Heat is given off and is trapped in the bales of hay. When the hay gets hot enough, it bursts into flame. Because of this danger, farmers know that their hay must be cut and stored in dry weather. That is why they say, "Make hay while the sun shines." 33

Explosions a gas that will burn

If

is

kept in a container and

leased into the air through a pipe,

mouth

Only the gas

of the pipe.

will burn,

because

it is

it

can be

at the

only there that

set

on

mouth

it is

is

re-

fire at

the

of the pipe

in contact

with

oxygen. The gas in the container must travel to the mouth of the pipe to find oxygen to

combine with, and get

its

chance to burn, too. So the flame stays at the mouth of the But if air is mixed with the gas in the container, then each part of the gas can find oxygen to combine with right

pipe.

where

it

is.

Then

a

fire

started at the

mouth

of the pipe

doesn't stay there, but spreads rapidly into the container.

burns almost at the same time. The hot gases that are suddenly formed try to spread out, and break

All the gas in

it

out of the container with a loud noise. This in

is

what happens

an explosion. Explosive mixtures can be formed from dust and

well as from gas and

air.

When

coal dust (which

is

air as

almost

pure carbon ) is mixed with air, each piece of coal dust can find oxygen to combine with in the air right next to it, so it can burn almost as easily as gas. That's why the coal dust in the air of coal mines sometimes explodes. We don't usually think of flour as a fuel, because we prepare it to eat and not to burn. But flour does burn, and flour dust mixed with air can form an explosive mixture, too. Many serious explosions have taken place in flour mills when too much flour dust has been allowed to collect in the air.

When you you need

is

have an explosive mixture of dust and

air, all

a spark to set off the explosion. But sometimes,

you don't even need the spark. Slow burning takes place on the surface of each dust particle. If the in a closed space,

34

can build up to the ignition point, and then an explosion takes place. IcLthis way an vto.scHooii ^u by itselr. explosion sometimes starts u heat 1

is

not carried away,



*.

The Explosion

in

it

I-

•*.

CJ4.78(j64

Your Kitchen

an explosion that takes place every day in your kitchen. It is the flame of your gas burner. But don't be alarmed, because this explosion is under control. If you look at the burner of your gas stove, you will see that there is an opening through which air is drawn into the pipe. So the gas is mixed with air before it is released from the burner. The flame tries to travel back into the pipe, the way it would in any explosion. But the flow of gas out of the pipe carries the flame out just as fast. So it stays at the top of the burner after all.

There

is

Things That Won't Burn

Some

things don't burn easily because they have a very

high kindling temperature. But there are other things, like

water and sand, that won't burn at

all. This is because they hydrogen burns, it combines with oxygen to form water. After it is burned it is unable to combine with any more oxygen, so it cannot burn again.

are already burned.

When

a metal.

When

Silicon

is

burns

silicon

dioxide, the chemical that sand

is

made

air

it

forms silicon

So sand,

of.

like

intake

gas intake

A Gas Burner

water,

is

a product of burning that cannot burn any more.

Carbon

that

only partly burned forms carbon monox-

is

deadly poisonous gas. Because the carbon in carbon monoxide has not lost all its power to burn, carbon monide, a

oxide can burn too. But carbon that has burned completely

forms carbon dioxide, and carbon dioxide will not burn at all.

Putting Out a Fire

To keep

a

burn, heat to

fire

going you have to feed

warm

it

fuel that will

up to its kindling point, and combine with. You can put out a fire

the fuel

oxygen for the fuel to by removing any one of these three things, the

fuel, the

heat, or the oxygen.

You can

fire by depriving it of fuel. Dig a wide that the flames can't jump across the ditch. This keeps the fire from getting at more grass. When the grass already on fire has burned out completely,

stop a grass

ditch around

the

fire will

it,

so

die out.

When you blow out a lighted match, you put out the fire by removing its heat. The stream of air you blow at it carries away the heat of the flame. This cools the match below its ignition temperature, and the flame goes out. You use the same idea when you put out a campfire by pouring water over it. The water draws a lot of heat out of the fire to make steam. The wood in the fire becomes cooler. When it is cooled below the ignition temperature, the wood stops burning.

The ings*

fire

extinguisher you find hanging in public build-

works by cutting off the oxygen supply of a fire. The is filled with sodium bicarbonate dissolved in

big cylinder water.

36

A

bottle held in place inside, near the top of the

When

cylinder,

contains sulphuric acid.

guisher

turned upside down, the stopper

is

the

fire

falls

out of the

extin-

and the sulphuric acid mixes with the sodium bicaris formed, and is forced out of the hose by its own pressure. Since carbon dioxide is heavier than air, it settles over the fire, and pushes the air away. When the fire is deprived of its oxygen supply in this way, bottle,

bonate. Carbon dioxide

it

dies out.

The

Fire Within

Us

Long before men found fire and learned how to use it, they had some "fire" and didn't even know it. They had life,

fire

and

life itself is

a

fire

that burns without flame. This

burns within you, in every part of your body.

part of the food

you eat

is

fuel for this

fire.

The

A

large

air

you

breathe in gives you the oxygen you need to burn this fuel.

The

air

that

is

body

you breathe out

made when the fuel made by this fire of

is

away the carbon dioxide burned. The warmth of your

carries is

hfe.

37

CHAPTER

III

Learning To Make Fire Tragedy

Old Stone Age

in the

THE

scene

is

a clearing in the forest.

The time

is

one hundred thousand years ago. The men are returning from the hunt, and they come with shouts of joy. They have killed a wild boar. Soon it will be roasting over the fire, and they will have a grand feast. Their mouths water as they think of the taste of juicy, tender meat.

They

step into the clearing,

are the children, are the

There

who

dead

silence in

Where meet them? Where

in confusion.

always rush out to

women, who always

is

and stop

them with happy smiles? the camp. The women and children greet

are there, near the tents, but their eyes are cast

down on

the ground. Something terrible must have happened. Soon

There is no fire! The old woman who tends and has let it burn out. The joy of the hunters is turned into gloom, because they do not know how to make a fire. Now they must eat their meat raw again, until they find another burning tree. This tragic scene must have happened many times in the past, until man discovered the secret of making fire. the truth

the

fire

38

is

was

out.

careless,

Heat Needed

You need heat

to

make

a

fire.

People learned

thousands of years ago by watching the

They saw how

A

begins to burn. So they a

fire. If

their

own

fire

knew they could use

went

out, they

might

using a burning stick from a neighbor's

did

that they

a fire spreads from one stick to anburning stick gives out heat, and makes another resting on it hot. When this stick is hot enough, it, too,

tended. other. stick

fires

this fact

this,

they weren't really "making"

start

fire.

fire.

a

fire to start it

again by

But when they

They were only

it from one place to another. The real problem of making fire arose when all the fires were out. To solve this problem they had to learn a way of making heat without

spreading

the help of

Heat

fire.

for the Fire-Makers

When you cut a piece of wood with a saw, the saw gets hot. When you drill a hole in wood, the bit gets hot. These ways in which you can get heat without the help of fire. The heat is made by the rubbing, or friction, of the saw or bit against the wood. Primitive man took the first step towards learning how to make fire when he made this discovare

ery thousands of years ago.

In the Old Stone Age,

They got and gathering fruits and

crops and raise cattle. fishing

men had

not yet learned to grow

food by hunting and roots from the wild plants their

But they were already making many tools to help them. They chipped or ground pieces of flint to make knives, axes, and arrowheads. They cut and scraped wood, and they carved bone. When they made and used their tools they were often rubbing one thing against that surrounded them.

39

another. Sometimes the heat caused by the rubbing

have been enough to

start a fire.

When

this

may

happened, they

discovered by accident the secret of making

fire.

which this may have happened is shown in a story told by the Basongo Meno tribe in the Congo valley in Africa. One of their ancestors, they say, was making a fishing trap. He was building it out of ribs of wood cut from the raflBa-palm tree. To be able to tie the ribs together, he

One way

in

drilled holes in them, using a pointed stick as a drill.

Once,

he twirled the drill by rolling it between his palms, the he was drilling burst into flame. This, they say, is how the fire drill was invented. The Basongo Meno now as

rib that

grow the

raflBa-palm tree for fire sticks

and

for material for

weaving.

Nursing the Fire In this story, and in the Queensland story told in Chapter

was rubbed hard burst into flame. Actually it by friction. The first bit of fire that you get with a fire drill is a small and delicate thing, and it must be handled gently and skillfully to be built up into a blazing fire. I,

a stick that

isn't

that easy to get a flame

In the simplest

fire drill,

a pointed stick

idly in a notch in another stick that rests

wood

is

twirled rap-

on the ground. As

worn away by the drilling, a small pile of wood dust is formed in the notch. The wood dust is charred by the heat of the rubbing, and then begins to burn with a faint red glow. The tiny fire smoldering in the heap of dust has a feeble hold on life. To keep it burning brightly, you must feed it air. You can do this by blowing over it, or fanning it gently. If you blow too hard, you will cool it off and put the fire out. Now you must use the heat of this glowing coal of the

40

is

wood

dust to start building up your

fire.

But a tiny heap of

burning dust gives out only a small amount of heat.

It is

enough to raise only a tiny bit of fuel to the kindling point. So you use tinder, like dry grass and leaves or thin shavings of wood. Once you have a small flame burning, you add more fuel, a little at a time, gradually using larger and larger pieces, until you have a good-sized roaring fire.

"^^

-

Improving the Fire Drill

We don't know when or where the fire drill was invented. It

may have been

many times by We know that the

rediscovered

different parts of the world.

ancient Egypt used the

people in people of

But it was also found on the other side of the world, in the hands of the North American Indians. It was used in the East by the Hindus, in the North by the Eskimos, and in the South by natives of fire drill.

Australia.

As people used the fire drill, they began to change it to make it work better. At first they made the drill turn by rolling it between their palms. Then they found they could make it turn faster by twisting a cord around it and pulling the cord. When they did it this way two people were needed, one to hold the drill, and the other to hold both ends of the cord. They made it a one-man job again when they attached the ends of the cord to a bow. To increase the friction as the drill turned, they would press down on it

with a hollowed-out stone.

More Wooden Fire-Makers In addition to the

fire drill,

several other

wooden

fire-

makers were invented in different parts of the world. Each of them uses rubbing to make heat, but does it in a different

ii?^P^^-v

way. The people who hve in the Polynesian Islands of the Pacific Ocean put a flat piece of hibiscus wood on the ground. Then, gripping a rounded stick in both hands, they

back and forth on the flat piece of wood. The stick digs a groove in the flat piece, and wood dust collects at the end of the groove. When it becomes hot enough from the rubbing, the dust begins to burn. Because the stick cuts a groove in the wood the way a plow cuts a furrow in the

rub

it

ground, this fire-maker

is

called the

fire

plow.

In India, Burma, and other places where the people developed a in half.

One

half

part up. Tinder

is

is

fire

saw.

A

stick of

bamboo bamboo

grows, is split

placed on the ground, with the rounded

placed in the hollow underneath

it.

From

and then used like a saw for scraping across the bamboo stick on the ground. The sawing gradually cuts a groove in the stick, and the hot sawdust falls on the tinder that is under it. The Dyaks of Borneo have a different kind of fire saw. Instead of sawing with a stiff sharp piece of wood, they use the other half a thin sharp strip

a flexible cord

made

is

cut,

of the fibers of the rattan palm.

43

The

cord

passed under the

is

and then

is

that rests

fire stick

on the ground,

pulled rapidly back and forth. As the cord cuts

into the fire stick, the hot

sawdust

piles

up under

it,

and

sets fire to the tinder.

The

Fire Piston

When

you pump

air into

your bicycle

tires,

your

pump

made warmer when it is compressed into a small space. The people of Burma, Java, the Philippines, and other places in the Far East make use gets hot. This

is

because

air is

of this fact in the fire piston. This fire-maker consists of a

made of wood or horn, and a rod that fits into One end of the rod is cup shaped. Some tinder is

hollow tube the tube.

placed in the cupped end of the rod, and the rod

Then

in the

mouth

when

the air in the tube was compressed.

is

placed

plunged into the tube. If the plunger is withdrawn quickly, the tinder is found to be burning. It was set on fire by the heat that was made of the tube.

it is

Fire from Stone

Fire-making became easier when men learned how to draw fire from stone. This discovery, like the invention of the

was probably made by accident during the Stone Age. In those days, when men had not yet learned how to make metal tools, their knives, hammers, axes, needles, and fishhooks were made out of stone. The stone usually used was flint, because flint is very hard and can be given a sharp cutting edge. The tools were shaped by striking one fire drill,

stone against another in order to chip off pieces.

The Stone Age men must have

tried to use

kinds of stone, to see which ones

made

many different

the best tools.

stone that surely would have attracted attention

44

is

A

iron

pyrites, a

compound

of iron

and sulphur that has a bright

Age man picked up one of these gleaming stones, it would have been natural for him to strike it with a piece of flint. But if he did, he would produce a spark, and if he caught the spark in some tinder, it would start a fire. Once this discovery was made, flint and

yellow shine.

If

a Stone

began to take the place of the fire drill as the chief means of making fire in Europe. Flint and pyrites fire sets have been found in the graves of Europe's first farmers, the men of the New Stone Age. They were also used by their descendants in ancient Greece and Rome. The name pyrites comes from the Greek word meaning fire-stone. pyrites

Flint

and

After

Steel

men began working metals, they found when struck by flint, also

for pyrites. Steel,

a substitute gives off a

spark. But, in the early days of the Iron Age, only small

amounts of steel were made, and they were needed for making swords and knives. So pyrites continued in use for a long time. A few hundred years ago, when steel became more common, it began to take the place of pyrites. "Flint and steel" sets were manufactured in England and sold all over the world. The flint and steel, and some charred linen that served as tinder, were always kept in a ''tinder box," ready to be used. The white settlers who came to America from Europe brought this method of fire-making with them. They passed it on to the Indians, who put aside their fire drills

when

Flint

and

The

they learned this faster

Steel,

New

way

of starting a

fire.

Style

and steel conquered the fire drill, only to be replaced later by the match. But the flint and steel has flint

45

made

comeback in the form of the cigarette hghter. It has changed somewhat, but still makes fire by striking a spark. The tinder is now a fluid instead of a piece of charred hnen. The fluid is stored inside the hghter, and chmbs up a wick. The flint has been replaced too. Instead of the hard, gray stone of the early spark-makers, the modern cigarette a

an alloy, a mixture of metals, that is 15 per cent and about 80 per cent "rare earth" metals.

lighter uses

iron

The Match Today, when we want to start a fire, we usually strike a match. There is no spark that must be caught and nursed in tinder. Instead, there is an immediate burst of flame. We still use friction to make the heat that starts the fire, but one short rub is enough. The small amount of heat is enough to start the flame without fanning or blowing, because the matches use a chemical with a low ignition point, and each

match has a built-in supply of oxygen. The great-grandfather of the modern match was the sulphur spunk. This was made of a thin stick of pine wood dipped in sulphur. First the flint and steel were struck, and a spark was caught in the tinder. When the sulphur spunk was touched to the glowing tinder, it took fire immediately. It became possible to do without flint and steel and tinder when phosphorus was discovered about the year 1669. is never found alone found in some minerals, and is also found in bones. To get phosphorus you have to separate it from the other chemicals with which it is combined. Natural phosphorus is a yellow, waxy solid. It has such a low ignition point, that the heat of your hand can set it on fire. You can even make it burn by simply leaving it in the air for a few

Phosphorus

in nature. It

46

is

is

a chemical element that

The slow burning without flame that takes place on the surface provides enough heat to make it burst into flame. If you want to keep phosphorus from burning, you have to store it under water. In 1833 the first real matches were made using phosphorus. The head of the match was made of several chemicals, including phosphorus and potassium chlorate. Potassium chlorate has a lot of oxygen hidden in it, but gives up the oxygen rather easily. When the match head was rubbed, the heat of the rubbing made the phosphorus burn. The burning phosphorus gave out more heat that made the matchstick hot. The extra oxygen supply in the head helped the wood of the matchstick catch fire quickly. These matches that could be struck anywhere, and gave you a fire at once, were very expensive at first. A box with just a few matches cost $5. But, with improved ways of making them, the matches became cheaper, and rapidly spread all over

minutes.

the world.

But there was one serious difficulty that came with the matches. Yellow phosphorus is poisonous. People who breathe phosphorus fumes develop a disease of the bones which makes their jaws and teeth decay. Workers in match factories were becoming sick by the hundreds. Fortunately, in 1845, a way was found of eliminating this danger. Another form of phosphorus was discovered that is not poisonous. This new phosphorus, which has a red color, doesn't burn as easily as yellow phosphorus, but can still be used to make matches. In 1872, Finland passed a law forbidding the use of yellow phosphorus in matches. Other countries took the same action in the years that followed. The United States was the last big couhtry to act, through a law passed by Congress in 1912.

47

Now we have

two types

of

matches

kind can be struck anywhere. In

in

common

this kind, the

use.

One

phosphorus

and potassium chlorate, mixed with some other chemicals, are in the head of the match. The other type is the safety match. In this kind, the phosphorus is separated from the potassium chlorate. The potassium chlorate is in the head of the match, and the phosphorus is on the match box. The safety match will light by rubbing only if the head is rubbed against the phosphorus on the box. Fire from the Sun

According

to

one of the myths of the ancient Greeks,

came from the sun. The giant Prometheus, pitying man's weak and defenseless condition, stole some fire from the sun and gave it to him. To punish Prometheus for this theft, Zeus had him chained to the top of a high mountain, where an eagle came every day to eat part of his man's

first fire

liver.

The Greeks themselves found

a

way

to repeat the "crime"

any risk to their livers at all. They from the sun with the help of a lens

of Prometheus, without

could "steal" some

fire

A

made

of rock crystal.

bends

the light that passes

lens held out in bright sunlight

together into a small spot.

comes The spot becomes hot enough to through

it

so that

it

all

on fire. Lenses, now made of glass, give us a way making fire without friction. You can play the part of Prometheus yourself by using an ordinary magnifying glass to burn a piece of paper with concentrated sunlight. Over two thousand years ago the scientist Archimedes is

set tinder

of

make the first death Romans attacked his native city of

said to have used a magnifying glass to

ray in history.

When

the

Syracuse, he used a giant lens to set their fleet on

48

fire.

— o —

Fire Gets a

A

Home

must be cared for to be kept alive. It has to be fed both fuel and air. It also has to be protected against wind and rain. So man began to build shelters for his fire. In fact, it is likely that man first moved indoors to live in caves and tepees in order to protect his fire rather than himself. But living in the same house with a fire has its unpleasant side.

A

fire

cave with a

fire in it

soon

fills

with smoke.

A

tepee has a

smoke out, but the same hole lets the and snow in. So man took the house over for himself and began to develop a separate home for his fire. The fireplace then grew up to be a stove. The first fires were probably built outdoors on the ground. To prevent the fire from spreading to the grass, people learned to surround it with stones, the way you do when you build a campfire. Then they found that the fire burned more brightly if they built it on top of some stones

hole on top to let the rain

49

instead of on the ground.

permitted

air to

The spaces between

flow in under the

fire,

keeping

the stones it

suppHed

with oxygen. This was the beginning of the grate, a platform with holes in it on which a fire is built. The flow of air into the fire

is

called the draft.

As a fire burns, the smoke is carried up by the warm air rising from the fire. When the fire moved indoors, an opening had to be made in the roof of the house to allow the smoke to escape. Then, finally, a passage had to be built to lead the smoke to the opening. In this way the chimney was born.

At first the indoor fireplace was open on all sides, just as in an outdoor campfire. Later, when it was built with a stone chimney, it was put up against a wall, so it was closed in on three sides. Finally, it was closed in on the fourth side as well. The hearth became a fire-box, and the fireplace became a st6ve, with a grate to let the air in, and a chimney to let the smoke out. When the fireplace was still open, the kettles in which food was cooked were hung over the fire. Now the pots and pans could sit right on top of the fire-box.

50

The Oven Climbs Out

of the

many

Ground

and shapes were growing up all over the world, a separate baking chamber was taking form in its own way. At first people baked roots and other foods by simply putting them into the hot ashes under the fire. But the food was sometimes burned, and the flavor of ashes did not improve the taste. Then they found a way of using the heat under the fire without being bothered by the ashes. A pit was dug in the ground and lined with While stoves

of

sizes

animal hides or broad leaves. Meanwhile big stones were heated in a fire. Then the hot stones were placed in the pit with the food. The pit was covered, and a top of

it.

the food

When

the

removed

fire

fire

was

built

on

died out, the pit was opened and

fully baked.

The baking

pit

was the 51

first

sy

oven.

With the help

_,d

p

ty

and stand on

of building materials like clay

oven next climbed out of the ground, to Later, when the stove had already taken shape, the oven moved indoors and was attached to the stove. This was how the range was born. The complete range has a fire-box where wood or coal is burned. Air goes up, and ashes drop down, through the grate. Smoke escapes through the chimney. Cooking is done on the top of the range, and baking is done in the closed oven chamber. More recently, this range has been replaced by the gas stove which has its fuel brought to it in pipes. The gas stove has several burners on top for cooking, and one big one down below in the baking chamber. brick, the

own

its

legs.

The Stove Without a

Fire

After developing the stove as a

home

man

for his fire,

then proceeded to keep the stove and throw out the

We now the heat

have stoves is

in

which there

is

no

fire at all,

fire.

since

supplied by electricity.

Actually the electric stove has not really thrown out the fire.

In most cases

52

it

has only

moved

it.

The

fire

now

burns

in the electric electricity.

The

power

where its heat is turned into comes to your home in wires, and

station,

electricity

the electric stove turns

it

into heat again. Fire

us faithfully in the electric stove, but

it

still

comes

serves

to us in

disguise.

53

CHAPTER

Fire, Comfort,

learned

FIRE how to

has brought use

it,

IV

and Freedom many

gifts to

man. Since he

over half a million years ago,

fire

has

most valuable tool. It has helped him make other tools that have increased his power over nature. Fire has helped man make great changes in nature, but it has also changed man himself. Because of man's use of fire, life is easier now than it was 500,000 years ago. It is also quite different. With fire man has burned his way from savagery

been

his

to civilization.

Keeping

Man

is

Warm a

within him

warm-blooded animal. The fire of life burning making heat all the time, and keeps his body

is

about 99 degrees Fahrenheit. When the air that surrounds him is cooler than that, his body loses heat to the air. If he loses heat too fast, his body will be chilled and he will be uncomfortable. He may get sick, and, if the air is cold enough, he may even freeze to death. Many warm-blooded animals have natural blankets that help protect them against the cold. Some have feathers and others have fur to trap their body heat and keep it from flowing away too fast. But man has neither feathers nor at a temperature of

fur.

A 54

naked man

is

comfortable only where the

air is

warm. In the early days of the human race, man had to warm climate. His need for warmth was like an invisible chain that kept him from wandering into colder regions of the earth. The masses of cold air that surrounded the north and south poles were like two solid walls that imprisoned him between them. But merely staying where he was did not protect man from the cold. During the Ice Ages big sheets of ice grew live in a

55

up and spread out from the poles. The walls of cold air moved in on the places where man lived. Many animals that could not stand the cold either moved in closer to the

man

equator, or died out. But

stood his ground.

He

broke

him to a warm climate. He and lived, because he had developed fire and clothing to help him. With clothing he made up for the fur and feathers he didn't have. With fire he got warm air in a cold climate by heating the air himself. Fire and clothing freed him to move into any climate, and so man spread to all regions of the earth. the invisible chain that tied

penetrated the walls of cold

air,

Saving the Heat

two ways. It sends out invisible warm up any body they strike. It also

Fire gives us heat in rays of heat that

warms up open

the air that

fire built

is

outdoors

near

it.

we have

To warm

catch the heat rays on our bodies.

from the over the its

ourselves at an

to stay close to the fire to

We

get

little

benefit

warmed, because the warm and flows away, while cool air flows in to take In this way most of the heat of an outdoor fire is air that is

air rises

fire

place.

wasted.

To save more of the fire's heat for ourselves we trap the warm air and make it hard for it to flow away. This is done by the walls and

roofs of the houses

indoors, only the small

fire is built

warmed

Some

we

live in.

amount

When

a

of air in the

of the heat escapes through the

house up. chimney, but enough remains inside to keep us warm. is

Spreading the Heat

The heat two ways. 56

carried

It

by the

air

moves away from the fire in air, and it also moves with

moves through the

Heat moves through the air when each part of the heat from warmer air that is closer to the fire and passes it on to cooler air that is further away from the fire. This movement is called conduction, and is very slow. Heat moves with the air when the warm air rises and flows away from the fire while cool air sinks and flows in toward the fire to take its place. This movement, in which the air as the

air.

air takes

well as the heat

is

moving,

is

called convection. It spreads

the heat more quickly than does conduction.

When

was a one-room cabin, an open fireplace or a simple stove was enough to keep it warm. But now, when houses have more than one room, heating a house is more complicated. Ways must be found to carry the heat from the room where the fire is kept to the other rooms of the house. There are several methods used to do this today. In one method, the heat is carried from room to room by the air. Openings, called registers, are placed in the a house

walls or ceilings to allow the air to pass through.

methods use steam or water

The other

to carry the heat. In the hot

heated by the stove or furnace. then pushed through pipes to radiators in

water system, water

is

The hot water is each room, where the heat passes from the the

air.

In a steam system, the water

is

made

radiators to

hot enough

The bubbles of steam that rise out of the boiling water then flow through the pipes to the radiators. to boil.

The use

of pipes

makes

The

it

possible to

remove the

fire

and

can be banished to the basement, while pipes carry its heat to the upper floors of the house. Or it can be taken out of the house altogether. One central heating station can supply heat, through pipes, for a large still

get the heat.

number

fire

of buildings.

57

Heating the Open Air People take great pains to avoid losing the heat of their furnaces to the open

air.

To

stop air leaks through cracks,

they plug them up with caulking materials and weather stripping.

To reduce

the flow of heat through windows,

To hold back the heat that and walls they line them with rock wool or fiber glass. Yet, some people purposely put stoves out in the open to heat the open air. This is done in the orange groves of Florida and California. Over sixty years ago Florida produced more oranges than any other state in the United States. Its orange trees they put up storm windows. flows through the roof

58

flourished in the

warm

Florida cHmate, and orange growing

was one of its major industries. Then, in December 1894 and February 1895, below-freezing weather swept into Florida and killed the orange trees. At one stroke a major industry was wiped out. It took many years to replace the orange groves of Florida. Meanwhile California took advantage of the situation and expanded its own orange groves. Now, although Florida oranges are back again, California

The

is

lesson of 1895 has not

growers.

They

frost again. in the lanes falls

the leading orange-growing state.

So

don't

now

want

their

been

lost

on the orange

orange trees destroyed by

they have heaters, called smudge pots,

between the

too low, they light

trees.

fires in

Whenever the temperature the smudge pots and heat

the open air to save their trees.

Turning Night into

Man

Day

has been taming nature through the

skillful

work

guided by his eyes, and controlled by his brain. But his eyes can help him only when there is light. At first the only light he had was the lighl that came from

of his hands,

the sky, the strong light of the sun,

and the feeble

light of

moon and stars. He did not control this light. It came and went without any regard to his wishes. And so he had to regulate his life by the coming and going of the light, by the rising and setting of the sun and moon. His need for light, like his need for warmth, served as an invisible chain. It bound him to places that could be reached by the light of the sky, and allowed him to be active only when this light was bright. This chain, too, was broken when man discovered fire, because with fire he could have light when and where he pleased. With fire he could bring light to the

the

59

He

darkest corner of the deepest cave.

up

in buildings,

could shut himself

he could burrow deep into the earth, he

could plunge into the black depths of the ocean, and

have

light to see with.

With

fire

still

he could turn night into

day.

At first man relied on the light of his campfire. But when he picked up a burning stick to carry the light with him, he invented the torch, ancestor of the candle and the lamp. Pine Splints and Nut Meats

The wood

of the pine tree contains resin, a fatty,

gummy

substance that burns brightly. So, on both sides of the Atlantic Ocean, in ancient

Greece, pine

Mexico

as well as in ancient

wood was chosen when

torches were being

made. In countries where pine doesn't grow, other resinous woods took its place. Later, people used the resin without the wood. In the East Indies, torches were made by wrapping resin in palm leaves. In Rome they were made out of resin-covered ropes.

60

The

torch that

we

often see in pictures

as the

symbol of

light

and knowledge was made by putting

a bundle of these resin-soaked ropes into a tube.

A

by burning some nut meats that are rich in oil. The Indians of Panama and the Polynesians of the South Pacific made torches by mounting nut meats on a thin pointed stick. bright light can also be obtained

Candles and Burning Birds

When

plant fat was replaced by animal fat the torch

became the candle. The animals that helped man make candles were as different as the cow and the bee; as big as the whale, and as small as scale insects living on the twigs of trees.

5peRMACe7>

^/

In northern Europe, for hundreds of years, candles were

made

of beef tallow. At

first

they were

made by dipping

the wick repeatedly in melted tallow. In later years the

was simply poured

wick hanging in the middle of each mold. In southern Europe, where the climate is warmer, tallow was too soft to be made into candles. There people found they could make candles out of the wax from which bees built their honeycombs. In China, where not much cattle was raised, there was no tallow to be used. There people made their candles from a wax produced by a scale insect they raised on the branches fat

into molds, with a

of trees.

In

the

eighteenth

and nineteenth

centuries,

candles

were made of spermaceti, a fat obtained from the sperm whale. Now most candles are made of paraffin, a waxy solid removed from petroleum oil that is taken out of the ground. Some animals were so full of fat that the animal itself made an excellent candle. The fishermen who lived on the

make candles out They would simply put a wick into the throat of a dead petrel, and they had a candle that would burn many hours. Some American Indians used to do the same thing Shetland Islands near Scotland used to

of a bird.

with a

fish

they caught on the shores of the Pacific Ocean.

The fish's body was so oily, all it needed was mouth to make it a bright-burning candle!

From Lamp

a wick in

its

to Electric Light

While solid fat is used to make candles, liquid fat is burned in lamps. The simplest lamp, like the ones used in ancient Rome, was merely a bowl of oil with a wick floating in it. Through a series of improvements, made during hundreds of years, it led to the modern lamp in which the wick, held in place in a metal tube, can be raised and lowered, and a glass chimney protects the flame while it gives

it

a better draft of

air.

For a long time fish, whale, and olive oil were the chief fuels for lamps. These oils were expensive, so during this 63

period candles \vere the

first

petroleum

still

oil

widely used. But the drilling of

well in Pennsylvania in 1858 led to

The growth

great changes.

the

of

petroleum industry

Then

the lamp began lamp itself was diswhich burned gas brought

produced large amounts of cheap

oil.

to displace the candle. Later the oil

placed in

cities

by the gas

into the houses in pipes.

light,

Then

the gas light gave

way

to

the electric light bulb of today. So, after thousands of years of

making

without the it

from the

fires to

As

fire.

give us light,

fire in disguise.

The

fire

power station makes heat that The electricity is turned back pushes

its

we now

get light

in the case of the electric stove,

way through

is

we

get

that burns at the electric

turned into

into heat

and

electricity.

light as

it

the wire in the electric light bulb.

Fire and Flavor

Soon after man discovered fire, if not from the very first, he began to use fire for the preparation of food. At first he used it for roasting, then for baking on hot stones or in pits. After the invention of pottery, he developed cooking in water, and frying in fat. Through thousands of years of experience he has learned hundreds of ways of preparing food.

Think of the many different ways of cooking eggs. You can have them soft boiled or hard boiled, poached, scrambled, or fried. You can have Spanish omelette or egg Foo Yung. You can have the egg yolk baked into a bread crust, or the egg white baked into a meringue pie. There are many other ways of cooking eggs that I could mention, and many more, Tm sure, that I never even heard of. Every country has

its

own

style of cooking, offering us a variety

of foods in a variety of flavors.

64

Fire and the

Food Supply

But fire has done more than add flavor to our food. It has helped to increase the supply of food. You wouldn't eat a raw potato, but you do eat it cooked or baked. Many plants that are tough and indigestible when raw, become tender, tasty, and nourishing when cooked. By increasing the number of things man can use as food, fire has freed him to spread out more over the face of the earth. Fire also helps to preserve food.

Cooked food

will not

uncooked food. Some foods, including meat and fish, can be preserved for long periods of time by being dried and smoked over a fire. The American Indians, spoil as rapidly as

after a successful buffalo hunt,

store of dried

meat

used

for the winter.

fire to

prepare their

Today we use

fire for

and vegetables, and prepared foods of every kind. Having food that will last a long time made man free to go on long journeys. Preserved food made it possible for him to venture into the desert and across the sea, taking a food supply with him. Fire has been used to flush out game and drive it toward the waiting hunters. Fire has smoked bees out of their hives so that men could get at their honey. Fire has burned down trees and brush to clear the land for planting. These are only some of the ways in which fire has helped give man more as well as better-tasting food. Before he had fire, man had to stay close to the places where he found things he could eat. His need for food, like his need for warmth and light, was like an invisible chain that tied him down. Fire broke this chain, too. Warmed bv fire's heat, his path illuminated by fire's light, his household equipped with more and longer lasting food, man was set free to go out and conquer the world. canning large quantities of meats,

fruits,

65

CHAPTER

Fire^

V

The Magician "PRESTO,

change-o/' the magician says, and he

changes an ace of spades into a ten of diamonds, or a pinknosed rabbit into a pretty girl. We applaud his performance, but we know he hasn't changed anything. He has really moved one thing to take the place of the other, and has managed to do it without letting us see what he has done. His act is not magic. It is only a trick done with speed and skill. But there are real feats of magic in which things are changed. They are performed every day by ordinary men and women using the magic of chemistry. They change soft earth into hard rock. They turn sand into clear, transparent glass. They transform earths and stones into shiny metals. They perform these magic feats with the help of fire.

The Invention

of Pottery

Thousan