New National Fourth Reader Part 31

One of these is water. Sometimes you can see this for yourself. On a cold, frosty day, you know we can see the clouds of steam coming out of our mouths. This steam is only very fine particles of water.

In warm weather we do not see the steam, but the water is there all the same; if you will breathe on a looking-gla.s.s at any time, you will make it dim and damp directly with the water that is contained in your breath.

We also breathe out animal matter, little particles of our own bodies just ready to decay. We can not see them, but they soon give the air a close, disagreeable smell. Good air has no smell at all.

And now I have something to say to you about the use of noses.

I dare say you can not see much use in the sense of smell. Seeing, hearing, touching, are very needful to us, we all know; but as to smelling, that does not seem to have any particular value.

It is pleasant to smell a sweet rose or violet; and, I believe, smelling really forms a good part of what we call tasting.

Of all our senses, smell is the one that soonest gets out of practice.

If people would always accustom themselves to use their noses, they never would consent to live in the horrid air they do.

If you go from the fresh air into a close room, you will notice the smell at once. Then, if you remain there, you will soon get accustomed to the smell and not notice it; but it will still be there, and will be doing you a great deal of harm.

In good air there are, mainly, two sorts of gas.

The first is a very lively sort of gas, called oxygen; it is very fond of joining itself with other things, and burning them, and things burn very fast indeed in oxygen.

The second is a very slow, dull gas, called nitrogen; and nothing will burn in it at all. Pure oxygen would be too active for us to live in, so it is mixed with nitrogen.

When we breathe, the air goes down into our lungs, which are something like sponges, inside our chests.

These sponges have in them an immense quant.i.ty of little blood-vessels, and great numbers of little air-vessels; so that the blood almost touches the air; there is only a very, very thin skin between them.

Through that skin, the blood sends away the waste and useless things it has collected from all parts of the body, and takes in the fresh oxygen which the body wants.

You have often heard man's life compared to a candle. I will show you some ways in which they are much alike.

When a candle or lamp burns, if we keep it from getting any new air, it soon uses all the lively gas, or oxygen, and then it goes out. This is easily shown by placing a gla.s.s jar over a lighted candle.

If the candle gets only a little fresh air, it burns dim and weak. If we get only a little fresh air, we are sickly and weak.

The candle makes another kind of gas. It is called carbonic acid gas, which, is unhealthy and not fit for breathing. The heat of our bodies also makes this gas, and we throw it off in our breath.

Oxygen and carbon, in a separate condition, make up a good part of our flesh, blood, and bones; but when they are joined together, and make carbonic acid gas, they are of no further use to us.

You might go to a store and buy sand and sugar; but if they became mixed together as you brought them home, you would not be able to use either one of them, unless some clever fairy could pick them apart for you.

You see now one great way of spoiling the air. How are we to get rid of this bad air, and obtain fresh air, without being too cold?

In summer time this is quite simple, but in winter it is more difficult; because it is a very bad thing to be cold, and a thin, cold draught of air is especially bad.

The bad air loaded with carbonic acid gas, when we first breathe it out, is warm. Warm gases are much lighter than cold ones, therefore the bad air at first goes up to the ceiling.

If there is an opening near the top of the room, the bad air goes out; but if there is no opening, it by and by grows cold and heavy, and comes down again. Then we have to breathe it.

If you open the window at the top, it will let out the bad air, and you will not feel a draught. It is not often so very cold that you cannot bear the window open, even a little way from the top, and that is the best way of airing a room.

This is just as necessary by night as by day. People who shut in the bad air, and shut out the good air, all night long, can never expect to awake refreshed, feeling better for their sleep.

What becomes of the carbonic acid gas which the body throws off through our breath? Can any thing pick the carbon and oxygen in it apart, and make them fit for us to use again?

Yes. Every plant, every green leaf, every blade of gra.s.s, does that for us. When the sun s.h.i.+nes on them, they pick the carbon out and send back the oxygen for us to breathe. They keep the carbon and make that fit for us and animals to eat.

The gra.s.s makes the carbon fit for sheep and cows, and then we eat their flesh or drink their milk; and the corn makes the carbon fit to eat; so do potatoes, and all the other vegetables and fruits which we eat. Is not this a wonderful arrangement?

But perhaps you think, considering what an amazing number of people there are in the world, besides all the animals--for all creatures that breathe, spoil the air just as we do--there can hardly be trees and plants enough to set all the air right again.

Round about cities and large towns there are certainly more people than there are trees, but in many other parts of the world there are a great many more trees than there are people.

I have heard of forests in South America so thick and so large, that the monkeys might run along the tops of the trees for a hundred miles. So you see there are plenty of trees in the world to do the work.

But then, how does all the bad air leave the towns and cities where men live, and get to the forests and meadows?

The air is constantly moving about; rising and falling, sweeping this way or that way, and traveling from place to place.

Not only the little particles out of our breath, but any thing that gives the air any smell, does it some harm. Even nice smells, like those of roses, are unhealthy, if shut up in a room for some time.

Dirty walls, ceilings, and floors give the air a musty, close, smell; so do dirty clothes, muddy boots, cooking, and was.h.i.+ng. Some of these ought not to be in the house at all; others remind us to open our windows wide.

All the things I have been saying to you about pure air, apply still more to sick people than to healthy ones.

Directions for Reading.--Read the following sentences carefully, and avoid running the words together.

The good__air can not get__in at__all.

We are__apt to take__it for granted.

It__is sure to make them__ill.

Point out three other places in the lesson where similar errors are likely to occur.

Language Lesson.--Add _ment_ to each of the following words, and then give the meaning of the words so formed.

_arrange move settle encourage_