HEAT AND COLD.
WHAT MAKES US WARM?
"[Illustration: M]Y thick, warm clothes make me warm," says some child.
No! Your thick, warm clothes keep you warm. They do not make you warm.
Take a brisk run, and your blood will flow faster and you will be warm
very quickly.
On a cold day, the teamster claps his hands and swings his arms to make
his blood flow quickly and warm him.
Every child knows that he is warm inside; for if his fingers are cold,
he puts them into his mouth to warm them.
If you should put a little thermometer into your mouth, or under your
tongue, the mercury (m[~e]r'ku r[)y]) would rise as high as it does out
of doors on a hot, summer day.
This would be the same in summer or winter, in a warm country or a cold
one, if you were well and the work of your body was going on steadily.
WHERE DOES THIS HEAT COME FROM?
Some of the work which is all the time going on inside your body, makes
this heat.
The blood is thus warmed, and then it carries the heat to every part of
the body. The faster the blood flows, the more heat it brings, and the
warmer we feel.
In children, the heart pumps from eighty to ninety times a minute.
This is faster than it works in old people, and this is one reason why
children are generally much warmer than old people.
But we are losing heat all the time.
You may breathe in cold air; but that which you breathe out is warm. A
great deal of heat from your warm body is all the time passing off
through your skin, into the cooler air about you. For this reason, a
room full of people is much warmer than the same room when empty.
CLOTHING.
We put on clothes to keep in the heat which we already have, and to
prevent the cold air from reaching our skins and carrying off too much
heat in that way.
Most of you children are too young to choose what clothes you will wear.
Others decide for you. You know, however, that woolen under-garments
keep you warm in winter, and that thick boots and stockings should be
worn in cold weather. Thin dresses or boots may look pretty; but they
are not safe for winter wear, even at a party.
A healthy, happy child, dressed in clothes which are suitable for the
season, is pleasanter to look at than one whose dress, though rich and
handsome, is not warm enough for health or comfort.
When you feel cold, take exercise, if possible. This will make the hot
blood flow all through your body and warm it. If you can not, you should
put on more clothes, go to a warm room, in some way get warm and keep
warm, or the cold will make you sick.
TAKING COLD.
If your skin is chilled, the tiny mouths of the perspiration tubes are
sometimes closed and can not throw out the waste matter. Then, if one
part fails to do its work, other parts must suffer. Perhaps the inside
skin becomes inflamed, or the throat and lungs, and you have a cold, or
a cough.
ALCOHOL AND COLD.
People used to think that nothing would warm one so well on a cold day,
as a glass of whiskey, or other alcoholic drink.
It is true that, if a person drinks a little alcohol, he will feel a
burning in the throat, and presently a glowing heat on the skin.
The alcohol has made the hot blood rush into the tiny tubes near the
skin, and he thinks it has warmed him.
But if all this heat comes to the skin, the cold air has a chance to
carry away more than usual. In a very little time, the drinker will be
colder than before. Perhaps he will not know it; for the cheating
alcohol will have deadened his nerves so that they send no message to
the brain. Then he may not have sense enough to put on more clothing and
may freeze. He may even, if it is very cold, freeze to death.
People, who have not been drinking alcohol are sometimes frozen; but
they would have frozen much quicker if they had drunk it.
Horse-car drivers and omnibus drivers have a hard time on a cold winter
day. They are often cheated into thinking that alcohol will keep them
warm; but doctors have learned that it is the water-drinkers who hold
out best against the cold. Alcohol can not really keep a person warm.
All children are interested in stories about Arctic explorers, whose
ships get frozen into great ice-fields, who travel on sledges drawn by
dogs, and sometimes live in Esquimau huts, and drink oil, and eat walrus
meat.
These men tell us that alcohol will not keep them warm, and you know
why.
The hunters and trappers in the snowy regions of the Rocky Mountains say
the same thing. Alcohol not only can not keep them warm; but it lessens
their power to resist cold.
[Illustration: _Scene in the Arctic regions._]
Many of you have heard about the Greely party who were brought home from
the Arctic seas, after they had been starving and freezing for many
months.
There were twenty-six men in all. Of these, nineteen died. Seven were
found alive by their rescuers; one of these died soon afterward. The
first man who died, was the only one of the party who had ever been a
drunkard.
Of the nineteen who died, all but one used tobacco. Of the six now
living,--four never used tobacco at all; and the other two, very seldom.
The tobacco was no real help to them in time of trouble. It had probably
weakened their stomachs, so that they could not make the best use of
such poor food as they had.
REVIEW QUESTIONS.
1. Why do you wear thick clothes in cold weather?
2. How can you prove that you are warm inside?
3. What makes this heat?
4. What carries this heat through your body?
5. How rapidly does your heart beat?
6. How are you losing heat all the time?
7. How can you warm yourself without going to the
fire?
8. Will alcohol make you warmer, or colder?
9. How does it cheat you into thinking that you
will be warmer for drinking it?
10. What do the people who travel in very cold
countries, tell us about the use of alcohol?
11. How did tobacco affect the men who went to the
Arctic seas with Lieutenant Greely?