Part 4

Several ways: smoke is one source, and the breath of animals another.

What has the breath to do with it?

Every time you respire, or breathe out, some carbonic acid comes out with air, and is carried into the atmosphere.

Why, father, you do not mean to say that my breath helps to make cabbages grow.

The carbon passing from your body may become a part of a cabbage, or gum tree, or a delicate tulip.

* * * * *

The next time Willie and his father were out together, the conversation again fell upon trees. The wonder of the boy had been strongly excited by the last lesson, and he had now lots of questions to ask. He knew enough to know that there must be a great deal more to learn. He had been told that trees fed the same as animals, and he felt sure that inside there must be some entrances for the food to reach parts needing supply. Then he sought to understand how the growing process was managed, and especially how seeds were formed, and how the plant sprang from them. Thus, question after question poured out from the boy’s lips, without even a pause for a reply.

“Stop, stop, my man,” said his father; “I am not like the Hindoo god with half-a-dozen pairs of ears, and half-a-dozen tongues. We will go now a little deeper into the subject; but we must take one thing at a time. What do you think of that gum tree yonder?

That is a noble fellow. What a barrel he has got for splitting paling out of! And hasn’t he got a fine top knot? Why, that must be almost as big as that Tasmanian tree you read about.

Oh, no; that one was 350 feet high, and was 104 feet round; while this is not above 100 feet high, and 30 round.

Well, then, that must be a monster surely. How curious to think it was once a tiny little thing that I could pull up with my finger! I say, father, how many cartloads of carbon this one must have got hold of! I fancy it has got gas enough to fill many a balloon. But how did it grow?

To answer that question, will give us some trouble, and take some time. First, tell me all the parts of the tree.

What I cannot see is the root; then comes the stem, then the branches, and then the leaves.

You forget the flower.

Flower! whoever heard tell of a gum flower? How funny the word sounds!

If there be no flower, how are you to get the seed?

I never thought of that. But flowers are always such pretty light things, that one would be sure to see them a long way off on a gum tree.

But if instead of having fine red leaves, my lad, the flower had none, and the other part was much the same colour as the leaves, do you think you would notice it so readily?

No, father. Won’t I give a good look out for it after this; for I am sure none of our boys at school ever talk of gum flowers, though we often go to gather wattle blossoms.

To go on with our tree--we will take the root, and there is a Stringy Bark blown over in the last storm.

And a strong root it has, too. How the wind must have puffed to overcome the weight of all the gravel and clay resting on that lot of roots, especially as they held the gravel like so many fingers. So these are the suckers of moisture and food out of the soil.

Yes, but you do not see the real suckers. They are very small, and were broken off and left behind. Those are called spongioles, because they suck up like a sponge. They are situated at the ends of the small fibres of roots, and have their mouths always open.

Yet I don’t see why the moisture rises. If I put my mouth into the rain cask, the water will not rush up into it.

Your mouth is too big. Supposing you put a lump of salt near a little water, so as to be touched, what will be the result?

The salt will gradually absorb the water, until there be none left.

After dipping the corner of a towel in the basin, and hanging it up by the opposite corner, does not the dampness run down when drying?

No, the moisture ascends and wets the dry part of the towel.

So you see, then, that the water in small particles can arise in the pores, or narrow openings of substances. This is because the sides attract it, and the process is called capillary, or hairlike, attraction. On this principle the moisture rises into the rootlets through the spongioles.